LTER All Scientists Meeting 2022

Long-Term Ecological Research Network

This is the virtual poster session for the LTER All Scientists Meeting.

The virtual format allows us to greatly expand our coverage of LTER science, but also provides a standing website where visitors can revisit posters for up to one year from the ASM.

Virtual poster abstracts are submitted through a form on our website, which triggers an invitation to submit to this platform. If you submitted a poster but did not receive an invitation, please contact the Network Office.

To make the virtual platform more engaging, we're asking participants to upload a short video walking through their poster. For instructions, see our poster submission guidelines.

More info: https://na.eventscloud.com/website/41801/

Filter displayed posters (350 keywords)

Marine (6) Resilience (6) disturbance (6) marine (6) Disturbance (5) Seagrass (5) ecology (5) kelp (5) Remote Sensing (4) coastal (4) zooplankton (4) Antarctica (3) Climate Change (3) phytoplankton (3) resilience (3) sea level rise (3) Biophysical Modeling (2) Climate change (2) Coral Reefs (2) Data Nuggets (2) Foundation Species (2) K-12 (2) Phytoplankton (2) Population Connectivity (2) Zooplankton (2) beach (2) blue carbon (2) carbon flux (2) climate change (2) coastal ecosystem (2) community (2) coral reefs (2) drought (2) education (2) greenhouse gas (2) macroalgae (2) modeling (2) nitrogen (2) nutrients (2) polar marine (2) recovery (2) remote sensing (2) restoration (2) seagrass (2) subsidies (2) time-series (2) wrack (2) show more... 13CO2 (1) Acoustic telemetry (1) Air-sea interaction (1) Alaska (1) Algae (1) Algal turf (1) Ameriflux (1) Amplicon Sequencing (1) Artificial and Natural Habitats (1) Autonomous (1) Benthic microalgae (1) Biodiversity (1) Biogeochemistry (1) Blue Carbon (1) CCE-LTER (1) Carbon (1) Chlorophytes (1) Coastal (1) Community Composition (1) Community Ecology (1) Community ecology (1) Comprehensive Everglades Restoration Plan (1) Coral reefs (1) Cross-slope Transport (1) Cyberinfrastructure (1) DEB modeling (1) DNA (1) DOC (1) Data Classroom (1) Data Visualization (1) Diel Vertical Migration (1) Drone (1) Drought (1) Eastern oyster (1) Ecological Covariates (1) Ecology (1) Ecosystem Functioning (1) Ecosystem functioning (1) Everglades (1) Experimental Drought (1) FLATS (1) Forest Soils (1) Forestry (1) Freshwater (1) Gas Flux (1) Genomics (1) Giant Kelp (1) Giant kelp (1) Greenhouse gas (1) Groundwater (1) Heatwave (1) Heatwaves (1) High Frequency Radar (1) Hydrology (1) Information Management (1) Inorganic cycling (1) Konza Praire (1) Lakes (1) Landscape Ecology (1) Lawns (1) Loop Current (1) MCM (1) Machine Learning (1) Macroalgae (1) Marine Ecology (1) Marine Heatwaves (1) Marine Microbes (1) Mass Spectrometry (1) Material legacies (1) Metabolomics (1) Metacommunity (1) Methane (1) Microbial Communities (1) Microbial Ecology (1) Microhabitats (1) Modeling (1) NDWI (1) NGA (1) Nitrogen Fixation (1) Nutrient Transport (1) Nutrients (1) Ocean properties (1) Oceanography (1) Organic Matter (1) Peatlands (1) Physiology (1) Plume (1) Polar (1) Population Genetics (1) Porites (1) Primary Production (1) Primary Productivity (1) Regime shifts (1) Residential Landscape Sustainability (1) Resistance (1) Restoration (1) River (1) Rocklands (1) Salt marsh (1) Santa Barbara (1) Scleractinian (1) Sentinel (1) Sentinel-2 (1) Soil (1) Soil Hydrology (1) Soil Organic Carbon (1) Soil Sensors (1) Southern Ocean (1) Spartina alterniflora (1) Submesoscale Eddies (1) Surface currents (1) Synchrony (1) Temperature (1) Tidal Flooding (1) Tidal Wetalnds (1) Time Series (1) Trait diversity (1) UAV (1) Urban Greening (1) Vector (1) Vegetation Change (1) Warm Core Ring (1) West Florida Shelf (1) abiotic (1) agriculture (1) along-shore transport (1) alternate states (1) annual net primary productivity (1) antarctica (1) appendicularians (1) aquatic eddy covariance (1) autonomous vehicle (1) barrier island (1) beach consumer (1) benthic incubation chamber (1) bioacoustics (1) biocrust (1) biodiversity (1) bioenergy cropland (1) biogeochemical (1) biogeochemical cycling (1) biogeochemistry (1) broader impacts (1) camera traps (1) carbon accounting (1) carbon cycle (1) carbon cycling (1) carbon dioxide (1) carbon export (1) chemical analysis (1) climate (1) climate extremes (1) climate variability (1) coastal fishes (1) coastal forest (1) coastal resilience (1) community ecology (1) competition (1) connectivity (1) cooling (1) copepods (1) coral bleaching (1) coral recruitment (1) coral-associated fauna (1) data (1) data access (1) data literacy (1) demography (1) diet (1) dominant species (1) dryland (1) drylands (1) dune grass (1) dunes (1) ecosystem stability (1) ecotones (1) efficacy study (1) elemental stoichiometry (1) endangered species (1) endemic species (1) environmental shifts (1) euphausiids (1) fire history (1) fish (1) fishing (1) flow cytometry (1) food webs (1) foundation species (1) freshwater flow (1) gas diffusion (1) global synthesis (1) grasslands (1) habitat restoration (1) hurricane (1) hydrology (1) hydrophone (1) imaging (1) inbreeding (1) infrastructure (1) insects (1) interannual variability (1) intertidal (1) invasive (1) krill (1) land use change (1) landscape connectivity (1) location (1) long term trends (1) long-term data (1) long-term press (1) mammalian activity (1) marginal reef (1) marine biogeochemistry (1) marine heat waves (1) marine particles (1) marine reserves (1) methane (1) micro-structures (1) microbes (1) migratory drivers (1) milkweed (1) mixed layer (1) monarchs (1) movement ecology (1) multidecadal change (1) mutualism (1) net ecosystem exchange (1) non-hydrostatic (1) numerical model (1) nutrient excretion (1) nutrient limitation (1) ocean fronts (1) ocean glider (1) ocean warming (1) oceanography (1) outreach (1) pH (1) partial migration (1) patchiness (1) pelagic imaging (1) permafrost (1) perturbation (1) phase shifts (1) photoacclimation (1) photobiology (1) photophysiology (1) pigments (1) plankton (1) plant defense (1) plant ecology (1) plant production (1) plants (1) population (1) population dynamics (1) populations (1) predator-prey interaction (1) primary productivity (1) productivity (1) pyrosomes (1) rangland (1) recruitment (1) regime shifts (1) research experience for teachers (1) research study (1) resistance (1) respiration (1) riverine fishes (1) salinity (1) salp (1) salt marsh (1) sandy beach (1) science communication (1) sea ice (1) sea urchins (1) seagrass meadow metabolism (1) seagrass restoration (1) sediment accretion (1) sediment carbon (1) sensors (1) short-term pulse (1) shruland (1) skipped spawning (1) small-mammal (1) soil (1) soil fertility (1) soil microbiome (1) soil respiration (1) spatial ecology (1) stable isotopes (1) stirring (1) storms (1) student learning (1) sulfur hexafluoride (1) symbiosis (1) tallgrass prairie (1) temperature (1) trace metals (1) traits (1) trophic cascades (1) upwelling (1) vegetation (1) water level (1) wetland (1)

Show Posters: with Recorded Presentation

Tracks

Climate Change (13)

Disturbances (15)

Education/outreach (1)

Marine (41)

New methods/tech (3)

Nutrient Cycling (4)

Other Networks (1)

Population Studies (5)

REU (1)

Science Communication (3)

Socio-ecological research (1)

Soils (3)

Synthesis (1)

Terrestrial (4)

▼ Climate Change Back to top

Estimating Trace Gas Flux Dynamics in Boreal Wetlands

Eleanor Serocki, Evan Kane, Laura Bourgeau-Chavez, Michael Battaglia, Merritt Turetsky

Abstract

As the climate crisis accelerates, it is of ever increasing importance to understand the changing carbon dynamics of the peatlands that dominates the Arctic Boreal Zone. Moderate fens, such as that we are studying as part of the Alaska Peatland Experiment (APEX) at the BNZ LTER, dominate interior Alaska and are likely to increase in cover as hydrology continues to change. As such, we aim to leverage over 15 years of gas flux information from this site paired with publicly available satellite imagery to find a best practice for mapping gas flux for moderate fens. Both Sentinel-1 (active) and Sentinel-2 (passive) sensors are being explored in order to identify the indices most closely tied to water table depth. Though more recent information challenges traditional narratives tying water table depth directly to both carbon dioxide and methane flux, we believe that the mapping of water table depth can create a jumping off point for creating landscape level maps of estimated gas flux, providing both land managers and decision makers with valuable information on the stability of carbon in a vital landscape.

Presented by

Eleanor Serocki

Institution

Michigan Technological University

Other Affiliations

Michigan Tech Research Institute, University of Colorado Boulder

Keywords

Climate Change, Peatlands, Remote Sensing, Gas Flux

Watch Presentation

Diffusive gas transport in frozen soil: implications for surface GHG flux in permafrost landscapes

Jack McFarland, Chris Green, Fred Murphy, Kristen Manies, John Keech, Stephanie James, Mark Waldrop, Jamie Hollingsworth, Baptiste Dafflon and Vladimir Romanovsky

Abstract

Permafrost contains significant quantities of organic carbon (OC), which is vulnerable to atmospheric release upon thaw. Yet, permafrost does not need to thaw to yield high-profile greenhouse gases (GHGs), e.g. CO2 and CH4. Concentrations of GHGs in near surface permafrost (< 3m) can exceed those in the atmosphere by several orders of magnitude (up to 25-30% soil gas volume) based on direct measures of gas in frozen soil. Despite its frozen state, permafrost contains liquid water, the abundance of which is closely correlated with temperature among other factors. The presence of liquid water enhances microbial transformation of incorporated OC to GHGs. However, it is not clear whether biogenic production of GHGs contribute meaningfully to surface flux while permafrost is intact. To improve our understanding as to whether GHGs in permafrost are legacy reservoirs with no connection to atmospheric pools, or the result of de novo production with potential to contribute to surface flux we need better characterization of transport processes in near-surface permafrost. To improve our understanding of transport dynamics for GHG among permafrost of varying thermal regime, we installed a gas-tracer experiment in intact permafrost at two sites within the North Campus Area of the University of Alaska, Fairbanks (UAF). The first site, Smith Lake 1 (SL1), resides on a gradual south-facing slope where average annual permafrost temperature at 200 cm is a few tenths of a degree below 0°C. The second, Smith Lake 4 (SL4), is in a basin that drains to Smith Lake; average annual permafrost temperature at 200 cm for this site is -1.7°C. In May 2021, at each site, we installed a series of six passive gas sampling “capture” probes at alternating depths (140 and 200 cm) in a radial array (50 cm distant) around an injection probe installed at 170 cm. Probes consist of a subterranean reservoir (485 mL) open to gas exchange with surrounding permafrost at the terminus across a polydimethylsiloxane (PDMS) membrane. Each probe is isolated from the surface with a bentonite-polymer blend which creates a low-permeability seal resistant to shrinkage. We employed isotopically-enriched 13CO2 (x(13C) = 99%; bioreactive) and SF6 (non-reactive, but similar solubility to CH4) as our tracers. Following tracer application, we sampled capture probes, as well as surface flux collars (n = 3 installation-1) placed between injection and capture probes, every 3 weeks through October 2021, then every 4-5 weeks thereafter. Additionally, adjacent to each installation, we extracted soil gas from cores collected down to 240 cm depth and monitored active layer and permafrost liquid water content to 200 cm depth using nuclear magnetic resonance (NMR). Neither site demonstrated evidence of talik formation, meaning active layers froze to the permafrost table each winter. The colder, wetter site (SL4) yielded almost 10x more CO2 and CH4 from extracted cores than the drier, warmer site (3.74 x 105 versus 2.04 x 106 µmol · m-2 for SL1 and SL4, respectively); however, both installations exhibited methanotrophy at the permafrost-active layer boundary as indicated by significant enrichment of δ13CH4 and depletion of δ13CO2 signatures at those depths. This may explain the very low flux of CH4 observed at the surface. Among capture probes, CH4 is two orders of magnitude lower at SL1 versus SL4 despite that permafrost temperatures at SL1 are > 1.4°C warmer. However, CH4 concentrations at SL1 increased throughout the 2021 growing season before declining again overwinter, suggesting an uptick in methanogenesis in response to slightly warmer permafrost during summer months. Lastly, though the 13CO2 tracer has not been ‘captured’ at either installation, we detected SF6 among capture probes and monitoring collars within 4 weeks following injection at SL1 and within 14 weeks at SL4, indicating that gases can migrate effectively through permafrost. The speed with which SF6 was detected at SL1 indicates that air-filled porosity at the warmer site likely contributes to transport, since diffusion of gas within air is 10,000x faster than through water. Collectively these results suggest that near-surface permafrost is biologically active, and may be a contributor to surface flux. Monitoring for the 13CO2 tracer will continue until June 2023.

Presented by

Jack McFarland

Institution

US Geological Survey, Geology, Minerals, Energy and Geophysics Science Center

Other Affiliations

University of Alaska, Fairbanks

Keywords

Greenhouse gas, permafrost, gas diffusion, 13CO2, sulfur hexafluoride

Watch Presentation

Interanual and Seasonal C Flux in a Northern Chihuahuan Desert Shrubland

Marguerite Mauritz [1] Gesuri Ramirez [1] Anthony Darrouzet-Nardi [1] Gerald Flerchinger [2] Libia Gonzalez [3] David P. Huber [1,2] Aline Jaimes [4] Christine M Laney [5] Marcy E Litvak [6] Robin Luna [5] Xia Song [7] Craig E. Tweedie [1]

Abstract

Dryland ecosystems are an important driver of global inter-annual variation of terrestrial carbon storage and rainfall variation is considered the primary driver of dryland carbon dynamics. However, the relationships between net ecosystem exchange (NEE) and rainfall are complex and it remains unclear how seasonal timing, and inter-annual rainfall variation influence plant productivity and NEE. Here, we examine ten years of NEE measurements to understand variation in CO2 sink strength in a mixed Creosote-Mesquite shrubland at the Jornada LTER located in the northern Chihuahuan Desert in southern new Mexico shown in box 1. Also in box 1, we see that at this site monthly average are temperatures range from 5C to 35C-though I don’t show it, cold extremes that can drop as low as -10 and -20C so this is a pretty harsh environment. Monthly precipitation can be as much as 100mm – most of the rainfall occurs with the summer monsoon so we can think of the climate envelope as dry and cold or dry and warm, and also wet and warm. The future of this region is almost certainly hotter and although the trend in rainfall itself is unclear, warmer temperatures will increase the aridity of the region and we expect greater extremes in rainfall with more intense wet periods and more intense dry periods.

If we look at carbon dynamics, the middle panels, box 2 and 3 show the daily and seasonally aggregated net ecosystem exchange pattern. Negative numbers indicate net CO2 uptake and positive numbers indicate net CO2 release from the ecosystem. In both these graphs we notice two uptake periods, one during the spring and one during the summer. Interestingly, the spring uptake period is often larger and more consistent than the summer uptake period even though June-September is the main rainfall period. This bimodal C uptake period is typical of other drylands in the US southwest and hints at the importance of ecosystem water storage that drives the spring uptake period and is decoupled from summer rain.

If we look at box 4 with the Annual Cumulative precipitation and NEE patterns, we see the seasonal trends in a different format. Again, these show steady and consistent spring-time C uptake with little concurrent rainfall, and highly variable summer C uptake during the main rainfall period. If we look at just the endpoints of these graphs, we see that each year the system has net cumulative C uptake ranging from 75 to 200g C per year. This means that for ten years the ecosystem has acted as a net C sink. Rainfall totals ranged from 150 to 350mm per year and we see clusters of consecutive years with high, medium, and low rainfall. It's also interesting to note that the highest rain and highest C uptake or lowest rain and lowest C uptake years aren’t a 1:1 match which suggests there are lag-effects and non-linearities that warrant more exploration.

Presented by

Marguerite Mauritz <memauritz@utep.edu>

Institution

University of Texas at El Paso

Other Affiliations

[1] University of Texas at El Paso, El Paso, TX, United States [2] USDA-ARS Northwest Watershed Research Center [3] Freeport Minerals Corporation, Phoenix, United States [4] University of California Berkeley, School of Information, Berkeley, United States [5] Battelle, National Ecological Observatory Network (NEON), Boulder, CO, United States, [6] University of New Mexico, Biology, Albuquerque, NM, United States, [7] Co-Star Group, Washington DC, TX, United States

Keywords

carbon flux, dryland, shruland, primary productivity, respiration, net ecosystem exchange

Watch Presentation

Warming and drought effects on volatile emissions of Solidago canadensis

Kara Dobson, Phoebe Zarnetske

Abstract

Volatile organic compounds (VOCs) are secondary metabolites emitted by all plant species in unique, species-specific blends. A species’ VOC mixture is not static, however, and is known to change in response to stressful events. These induced VOCs, which relay information on imminent stressors to nearby plants, are crucial forms of communication for plant communities and aid in plant defense. Currently, there is a lack of knowledge on how abiotic climate change stressors affect chemical emissions for many plant species in natural plant communities. To address this knowledge gap, we collected VOC emissions from Canada goldenrod (Solidago canadensis) within five climate treatments of the Rainfall Exclusion eXperiment (REX) at the Kellogg Biological Station Long-Term Ecological Research (KBS LTER) site (Hickory Corners, MI, USA): warming, drought, warming + drought, irrigation, and no treatment (ambient). These treatments were applied to the plants in situ using open-top chambers to mimic climate warming and rainout shelters to manipulate water availability for the plants. While there was no effect of any climate treatment on VOC emissions prior to the start of drought treatments, after three weeks of drought and five months of warming, the composition of plant VOCs differed between the drought and non-drought treatments, and drought treatments also decreased overall abundances of VOCs. As plant VOCs play an important role in plant defense, community dynamics, and plant-insect interactions, experiments that investigate these stress-induced shifts in plant emissions are crucial in our efforts to predict and plan for climate change effects on plant communities.

Presented by

Kara Dobson

Institution

Michigan State University

Other Affiliations

W.K. Kellogg Biological Station

Keywords

Climate change, plant ecology, community ecology, plant defense

Dune Restoration Trajectories to Inform Coastal Resilience Approaches

Karina Johnston, Dr. Jenifer Dugan, David M. Hubbard

Abstract

Climate change is impacting coastal communities in many ways, including increasing threats looming, particularly for sandy shore ecosystems and the services they provide. Planning for adaptation to sea level rise, storm erosion, flooding and other coastal hazards poses challenges, particularly for coastal communities. Nature-based adaptation approaches, including dune restoration, can enhance resilience, restore and preserve soft sediment coastal ecosystems, and provide a range of ecosystem services. Our study tracks and evaluates the recovery of coastal dunes on a groomed urban beach in Los Angeles, California, over a five-year period to date and seeks to inform trajectories and expectations for similar restoration projects. Evaluating the restoration of dynamic ecosystems, like coastal dunes, requires long-term data.

Santa Monica Beach has been groomed intensively for >50 years, severely degrading the dune and beach ecosystem. Our project goal was to restore dunes on this heavily impacted beach and to enhance the resistance and resilience of this ecosystem to climate change. We initiated passive dune restoration at Santa Monica Beach in December 2016 by installing a perimeter sand fence to delineate it from the mechanically groomed (raked), adjacent beach areas, and adding native dune plant seeds across the 3-acre site. To track responses and recovery trajectories of metrics including sand accretion, dune formation, wildlife use, and vegetation establishment, we conducted physical and biological surveys quarterly over a five-year period in the restoration area and the adjacent control area (groomed beach).

Vegetation cover and topography in the restoration area have diverged from initial conditions (baseline) and the control site over time. Increases in topographic complexity and elevation are evident over time, with greater than a meter of sediment accumulation after five years associated with sand fencing. Groomed control areas remained flat and uniform, while the restoration area developed a foredune ridge and small dune hummocks, along with increases in berm height, and consistent sand retention across seasons and years.

Patches of dense vegetation were interspersed with bare sand, similar to natural California coastal strand habitats. Six native plant species were identified on surveys, including coast woolly heads, a rare plant (not seeded). Vegetation reached a maximum of approximately 25% cover adjacent to the fence lines. No vegetation was present in the control site.

Our pilot passive dune restoration project resulted in substantial sand accumulation and increasing vegetation cover over time. The removal of stressors (i.e., grooming), restoration of physical processes, and recovery of key dune forming vegetation species has allowed the site to accumulate sediment at a rate faster than sea level rise. Dune restorations like this project could be used to increase protection and resilience of the beach and its adjacent infrastructure. Long-term monitoring of dune restoration sites can provide valuable information on the dynamics, disturbance, and recovery of sandy shores and a foundation for understanding restoration and adaptation trajectories.

Presented by

Karina Johnston

Institution

University of California Santa Barbara, Marine Science Institute

Keywords

coastal resilience, dunes, habitat restoration, vegetation

Air-water gas exchange in temperate seagrass meadows

Kayleigh Granville, Peter Berg, Bongkeun Song

Abstract

Seagrass meadow carbon storage and sequestration can be partially offset by emissions of greenhouse gases such as carbon dioxide (CO2) and methane (CH4). Even though the importance of understanding air-water CO2 and CH4 fluxes is widely recognized, there is a lack of reliable data. Existing fluxes are often uncertain due to internal site variability, low sampling frequencies, and methodological limitations. More local CO2 and CH4 flux measurements are needed to constrain variability and identify diurnal and seasonal patterns. In this study, we derived mid-summer CO2 and CH4 fluxes over a temperate seagrass meadow (South Bay, Virginia Coast Reserve LTER). To achieve a fine temporal resolution, in situ data were collected every minute for 5 days. To address potential methodological limitations, we measured wind speed, a variable commonly used to estimate air-water gas fluxes, on site. We compared on-site wind speed to wind data collected at a regional NOAA station. The regional wind speed data consistently underestimated on-site wind speeds and gas fluxes. The time series of CO2 and CH4 fluxes derived from the on-site data reveals diurnal patterns and the effect of a storm event. The seagrass meadow was generally a sink of CO2, but became a source of CO2 for 5-10 hours per day around dawn and during the storm event. This pattern may be attributed to seagrass meadow photosynthesis and respiration. Surprisingly, the meadow was a consistent sink of dissolved CH4. The magnitudes of the CO2 flux and the CH4 flux both increased during the storm event, potentially due to storm surges increasing sediment resuspension. Overall, the high temporal resolution applied in this study demonstrates the internal variability at our site. Measurements will be taken again after the growing season to assess the effect of seagrass senescence on gas fluxes.

Presented by

Kayleigh Granville <keg8fb@virginia.edu>

Institution

University of Virginia, Department of Environmental Sciences

Other Affiliations

Virginia Coast Reserve Long-Term Ecological Research Site; Virginia Institute of Marine Science, William and Mary

Keywords

Seagrass, greenhouse gas, carbon dioxide, methane, blue carbon

How are increases in marine and fresh water changing coastal wetland DOC?

Kenneth J. Anderson, John S. Kominoski

Abstract

The Everglades is in the midst of the largest restoration project in the world to restore freshwater flows, while at the same time marine water influence is increasing as a result of sea-level rise. Our goal with this research is to better understand how changing hydrology throughout the Everglades drives carbon cycling across the two major drainages of the Everglades along freshwater to marine gradients. For this research we used cross-wavelet analyses to track the relationship between dissolved organic carbon (DOC) and water depth, along with the fluorescence of dissolved orgamic matter (fDOM) to understand that composition of that carbon. We used long-term DOC and fDOM data from two major drainages of the Everglades: the longer hydroperiod Shark River Slough and shorter hydroperiod Taylor Slough. We used time series from both freshwater and mangrove sites for each slough and found that increasing water depths and hydrologic connectivity among ecosystems mobilizes humic DOC from both marsh and mangrove sources.

Presented by

Kenneth Anderson <kande094@fiu.edu>

Institution

Florida International University

Keywords

DOC, hydrology

Watch Presentation

Climate change and climate variability revealed by the CCE zooplankton

Mark D. Ohman, Laura E. Lilly, Linsey M. Sala

Abstract

CCE-LTER collaborates actively with CalCOFI, the longest interdisciplinaryocean time series in the U.S. EEZ. Because of the inherent natural variability of Eastern Boundary Current Upwelling Ecosystems, it is essential to have multiple decades of measurements in order to detect the ‘emergence’ of long-term climate trends from natural ecosystem variability. CalCOFI sampling, with CCE data analyses, enables us to detect and analyze some key underlying changes and to distinguish between long-term secular changes and intrinsic climate variability, here illustrated by time series of the mesozooplankton.

Presented by

Mark D. Ohman

Institution

Scripps Institution of Oceanography/UC San Diego

Keywords

climate change, climate variability, populations, zooplankton, euphausiids, copepods, pyrosomes, appendicularians

Watch Presentation

Kate Wilkins, Melinda Smith, Martin, Holdrege, Peter Wilfahrt, Scott Collins, Alan Knapp, Osvaldo Sala, Jeffrey Dukes, Richard Phillips, Laura Yahdjian, Laureano Gherardi, Timothy Ohlert, Claus Beier, Lauchlan Fraser, Anke Jentsch, Michael Loik, Fernando Maestre, Sally Power, Qiang Yu, Andrew Felton, Seth Munson, Yiqi Luo, the Drought Network

Abstract

Droughts are increasing in frequency and severity, but a comprehensive understanding of how drought affects plant production across terrestrial ecosystems is lacking. We used the International Drought Experiment, a coordinated globally distributed experiment, to assess the effects of single-year extreme drought on the production of grasslands and shrublands. Grasslands subjected to extreme drought treatments saw a 34% reduction of aboveground production, while aboveground production in shrublands only decreased by 20%. We found wide variation in responses across all sites. The main factor that explained this variation was the severity of the drought treatment, dictated by ambient precipitation and the precipitation reduction treatment. This is an ongoing project supported by an LTER synthesis working group.

Presented by

Timothy Ohlert

Institution

Colorado State University, Department of Biology

Keywords

Drought, plant production, global synthesis

Watch Presentation

Effects of sea level rise on the root chemistry of Chamaecrista lineata var. Keyensis

Nicole Donate, Leslie Toll-Roque, Dr. Diego Salazar Amoretti, Dr. Oscar Valverde-Barrantes

Abstract

Globally, the effects of climate change are being felt. As the temperatures reach historic highs, associated risks are becoming more apparent. Due to this, coastal flooding is a more prominent issue now with increasing intensity and frequency of hurricanes coupled with sea-level rise. Many plant species are bound to be affected by the increased fluxes in salinity, since a high presence of salt can not only can prevent water absorption and nutrient uptake, but it can also negatively affect plants' essential functions of life: growth, reproduction, and defense. The effects of increased salinity have been studied in many agricultural crops, however the effect of increased salinity on the coastal ecosystems has yet to be studied well, since they are especially vulnerable to both hurricanes and sea level rise. The Florida Keys are an important example of such ecosystems, since they house the Pine Rocklands, an ecosystem that is left with only 2% of its original surface area and houses many endemic and endangered species of plants. In this study, the endemic and endangered plant Chamaecrista lineata var. keyensis (Fabaceae/Ceasalpinoidae) is used as the species of interest to investigate how different salinity levels could affected the growth and reproductive output of this endangered species.

We used 346 seed-germinated plants of C. lineata, collected from 28 different maternal lines. All plant were transplanted into identical 8” deep pots and using a standard potting mixture. To reproduce different salinity scenarios, we use an “ebb and flow” system. Pots were placed in 5 large “flooding trays” (hereafter referred to as treatments), each one was filled with salt water twice a week for 4 consecutive weeks. Each treatment varied in terms of the concentration of salt in the water. We used 5 treatments total: 0, 2, 4, 8, and 16 ppt of salt.

Presented by

Nicole Donate

Institution

Florida Interrnational University, Institute of the Environment

Other Affiliations

The Salazar Laboratory for Plant Chemical Ecology, The Valverde Lab for Tropical Root Ecosystem & Ecology

Keywords

ecology, sea level rise, chemical analysis, endemic species, endangered species, Rocklands

▼ Disturbances Back to top

Flooding in Landsat Across Tidal Systems (FLATS): Application for Sentinel-2

Caroline R. Narron, Deepak R. Mishra, Jessica L. O’Connell, David L. Cotton, Peter A. Hawman, & Lishen Mao

Abstract

The Flooding in Landsat Across Tidal Systems (FLATS) index was created to identify flooded pixels in Landsat 8 30-meter data and provide a simple, finer spatial resolution inundated pixel filtering method than previously developed methods. FLATS was developed using ground truth inundation data from a PhenoCam and Landsat 8 pixels within the Spartina alterniflora tidal marsh PhenoCam field of view at the GCE-LTER site on Sapelo Island, GA, USA. We established the need to apply FLATS when conducting vegetation time-series analysis in coastal marshes in order to reduce the per-pixel reflectance variations attributed to tidal flooding. This project continues on the work of FLATS by applying it to a higher spatial and temporal resolution satellite, Sentinel-2, as well as adding a second, more vegetatively diverse site to test the applicability of this vital flood detection tool.

Presented by

Caroline R Narron

Institution

University of Georgia, Department of Geography

Keywords

Tidal Flooding, Remote Sensing, Spartina alterniflora, Sentinel-2, FLATS

Material legacies can degrade resilience: Structure-retaining disturbances promote regime shifts on coral reefs

Kai L. Kopecky (1), Adrian C. Stier (1), Russell J. Schmitt (1,2), Sally J. Holbrook (1,2), and Holly V. Moeller (1)

Abstract

Standing dead structures of habitat-forming organisms (e.g., dead trees, coral skeletons, oyster shells) killed by a disturbance are material legacies that can affect ecosystem recovery processes. Many ecosystems are subject to different types of disturbance that either remove biogenic structure or leave it intact. Here, we use a mathematical model to quantify how the resilience of coral reef ecosystems may be differentially affected following structure-removing and structure-retaining disturbance events, focusing in particular on the potential for regime shifts from coral to macroalgae. We found that dead coral skeletons can substantially diminish coral resilience if they provide macroalgae refuge from herbivory, a key feedback associated with recovery of coral populations. Our model shows that the material legacy of dead skeletons broadens the range of herbivore biomass over which coral and macroalgae states are bi-stable. Hence, material legacies can alter resilience by modifying the underlying relationship between a system driver (herbivory) and a state variable (coral cover).

Presented by

Kai Kopecky <kaikopecky@ucsb.edu>

Institution

University of California, Santa Barbara

Other Affiliations

(1) Department of Ecology, Evolution and Marine Biology; (2) Coastal Research Center

Keywords

Disturbance, Resilience, Regime shifts, Material legacies, Coral reefs, Macroalgae, Modeling

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Spatial variation of micro-structures on the reef scape influence settlement preference and post settlement success of larval and juvenile coral

J. David Muñoz Maravilla, Dr. Peter Edmunds

Abstract

Scleractinian corals are important reef builders that are exposed to major disturbances such as ocean acidification, high ocean temperatures, outbreaks in diseases, and storms. The long-term implications of the effects of these disturbances on scleractinians are modulated by their ability for population recovery by recruitment as well as post-settlement growth and survival. This project addresses the role of coral recruitment in maintaining reef resilience and habitat function by accessing how the spatial variation of micro-structures on the reef scape influence settlement preference and post settlement success of larval and juvenile coral. This research was conducted in the backreef along the northern shore of Moorea, French Polynesia. Through field surveys and experiments, this research highlights that the abundance of coral recruits is disproportional to the availability of microhabitats found on the reef scape, normalized to their planar area. This pattern was shown to be apparent on two types of common substratum: pavement and bommies. In addition, this research showed that settlement preference and survival of coral larvae varied among microhabitats located within larger-scale pits and grooves on the benthos. The results of this project underlines how substratum heterogeneity effects the distribution and abundance of coral recruits. The natural refuge offered by the different shaped micro-structures of the sea scape will continue to be integral in helping replenish and aid in the maintenance of coral populations.

Presented by

J. David Muñoz Maravilla <jose.munoz.375@my.csun.edu>

Institution

California State University, Northridge

Keywords

Microhabitats, Scleractinian, coral recruitment, micro-structures

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Cross-Island Connectivity on Virginia Barrier Islands

Alexander Sabo, Max Castorani, Michael Cornish, Julie Zinnert

Abstract

Barrier islands are comprised of distinct habitats including beach, dune, swale, and back-barrier marsh. These habitats are separated by slight differences in elevation, morphology, and vegetative community. Interactions between these variables are important for understanding island response to disturbance events. This work focuses on Hog and Metompkin Islands, part of the Virginia Coast Reserve LTER. Hog Island is considered disturbance resisting due to a long, linear foredune ridge. Metompkin Island is more frequently disturbed and is experiencing high rates of overwash and shoreface migration. Three cross-island transects were established on Hog and Metompkin Islands in 2020. At each plot along the transect, species composition, percent cover, biomass, and elevation have been sampled annually. Further, drone flights have been conducted to create digital elevation models (DEM) representing elevation on the islands. The combination of this imagery and biomass sampling, suggests that dune height impacts annual net primary productivity (ANPP) in the swale habitat. Hog Island has higher dune ridges that protect the swale from overwash, while the swale habitat on Metompkin Island is more frequently disturbed. As disturbance events occur, the dune shape and size will reinforce the disturbance responses in the swale community, therefore determining productivity.

Presented by

Alexander Sabo

Institution

Virginia Commonwealth University

Other Affiliations

Virginia Coast Reserve LTER

Keywords

landscape connectivity, annual net primary productivity, barrier island

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Stability of Antarctic Lake Enrichment Consortia Under Nutrient Stress: MCM LTER

Bradley Krzysiak, Dr. Rachael Morgan-Kiss

Abstract

Lakes within the McMurdo Dry Valleys represent some of the last perennially ice-covered lakes in the world. Through both geographical and physical isolation from the surrounding environments, the undisturbed nature of these lakes make them ideal for investigating the effects of environmental factors on organisms within the lakes. These lakes are entirely dominated by microbes and this, in combination with their pristine nature, provide an ideal system for monitoring the effects of climate change. We investigated the stability of these lake microbial consortia in response to nutrient deprivation using enrichment cultures designed to promote interactions between primary producers and those organisms that commonly interact with them. Enrichment cultures were used as a simplified representation of the natural communities, these cultures were subjected to both nitrogen and phosphorus deprivation and their stability was analyzed using resistance and resilience indices generated from sequencing data in combination with bacterial and algal growth measurements.

Presented by

Bradley Krzysiak

Institution

Miami University, Department of Microbiology

Keywords

Microbial Ecology, Resistance, Resilience, Disturbance, Climate Change

Disturbance and recovery of seagrass carbon stocks: a large in situ experiment

Carolyn J. Ewers Lewis and Karen McGlathery

Abstract

Seagrass ecosystems have suffered substantial global losses over the last century, but success stories of large-scale restorations and natural recovery offer signs of hope. Still, the impact of the accelerating stressors of climate change on the resilience and recovery of seagrasses and the ecosystem services they provide are poorly understood. In the Virginia Coast Reserve Long-Term Ecological Research site, a large-scale restored seagrass site was hit by a marine heatwave in 2015 that resulted in a massive die-off and loss of sediment carbon stocks. However, the meadow was not impacted uniformly, and it is believed that differences in water temperatures and residence times played a key role in the degree of impact of the heatwave and recovery thereafter. We set up the largest in situ seagrass disturbance experiment to date in two areas of the meadow that experience differing degrees of thermal stress to 1) measure the impact of seagrass loss, as would be experienced during a heatwave, on sediment carbon stocks, and 2) characterize the recovery trajectory of carbon stocks and sequestration rates in disturbed sites. Using a novel in situ sediment plate method, we tracked changes in surface elevation to quantify changes in sediment accumulation, carbon stocks, and sequestration rates, as well as organic matter and grain size. This study will help elucidate the role of thermal stress in seagrass carbon stock preservation during disturbance and recovery trajectories concurrent with seagrass recolonization.

Presented by

Carolyn J. Ewers Lewis

Institution

University of Virginia

Other Affiliations

Virginia Coast Reserve LTER

Keywords

seagrass, blue carbon, sediment carbon, sediment accretion, disturbance, recovery, marine heat waves

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MCMLTER: Ecophysiology of Sentinel Chlorophyte Taxa in Lake Bonney, Antarctica

Devon Popson, Dr. Rachael Morgan-Kiss

Abstract

The perennially ice-covered lakes of the McMurdo Dry Valleys host isolated communities completely comprised of microbial organisms. Chlorophytes act as essential drives of these stratified microbial communities through their role as primary producers. Additionally, these organisms are particularly sensitive to changes in light, salinity, nutrients and other environmental factors due to the stable environment they have evolved under. Through a combination of manipulation ecological studies and physiology studies, we aim to characterize these integral species as early predictors or sentinels of environmental disturbance. A comprehensive understanding of these sentinel organisms should allow for more rapid detection of environmental disturbance, which is increasingly needed as these communities face increasing impacts from climate change.

Presented by

Devon Popson

Institution

Miami University

Keywords

Ecology, Physiology, Disturbance, Sentinel, Chlorophytes

Fire History and Climate Drive Patterns of Post-Fire Recovery in Everglades Upland Ecosystems

M. Grace McLeod, Daniel Gann, Michale S. Ross, Sparkle L. Malone

Abstract

In fire adapted landscapes, regular disturbance by fire is critical for maintaining biological and structural diversity, supporting ecosystem function, and maintaining resilience. Fire regimes are the spatial, temporal, and magnitudinal patterns at which fires occur. In the Florida Everglades, fire regimes have created a mosaic of upland communities, ranging from fire dependent pinelands, to fire adverse hardwood hammocks, but changes in land management and climate change have altered plant communities and fire ecology. Using long-term fire history data, we evaluated past fire regimes across Everglades upland ecosystems to understand how variability in regimes could affect ecological responses to fire. Pinelands are more prone to fire compared to hammocks, and exhibited greater fire frequency and burned area. Next steps for this ongoing project include using NASA Landsat imagery to assess differences in spectral recovery across upland ecosystems under varying fire history scenarios, while controlling for fire severity. The objective of this work is to determine the degree and direction to which fire history and climate influence post-fire recovery.

Presented by

M. Grace McLeod

Institution

Florida International University

Other Affiliations

Florida Coastal Everglades LTER, Yale School of the Environment

Keywords

recovery, fire history, Everglades, remote sensing, disturbance

The long-term recovery of tallgrass prairie communities following the removal of two dominant species, Andropogon gerardii and Sorghastrum nutans

J. Alexander Siggers, Dr. Melinda Smith

Abstract

Studies investigating the influence of dominant species in ecological communities have garnered momentum in recent years. Considered to be locally abundant species with proportional influence on community and ecosystem processes, the formulation of the Mass Ratio Hypothesis brought further attention to this seemingly ubiquitous trend. Understanding how scaled processes, such as community formation, occur in the absence of dominant species is critical to determining the extent of their influence. We conducted a targeted removal (via glyphosate application) of the two dominant grass species, Andropogon gerardii and Sorghastrum nutans, in native tallgrass prairies communities. The species-level response was recorded in the form of absolute cover (1996, 1997, 2000) and presence/absence (2004, 2011, 2019) data, along with biomass by functional group. We conducted a suite of analyses including Permutational ANOVA, NMDS, and similarity percentage analyses to assess changes. We found that A. gerardii populations crashed and did not fully recover until 2019. However, S. nutans populations rapidly recovered exceeded the absolute cover of control plot populations by 1997. Functional group response was divergent over the course of recovery. Forbs, notably Ambrosia psilostachya and Salvia azurea, initially accounted for most of the absolute cover but were quickly replaced by other graminoids, including Schizachyrium scoparium and Sporobolus compositus. These species also compensated for biomass loss, leading to equivalent biomass in removal and control plots by 2011. This study provides evidence of compensatory response and highlights the role of key subdominant species following the loss of the dominant species in a tallgrass prairie ecosystem.

Presented by

J. Alexander Siggers

Institution

Colorado State University, Department of Biology

Other Affiliations

Graduate Degree Program in Ecology

Keywords

Community ecology, dominant species, tallgrass prairie

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The stability of soil respiration after land-use change and severe drought in biofuel croplands

Yahn-Jauh Su, Steve Hamilton, G. Phil Robertson & Jiquan Chen

Abstract

To mitigate the global climate change and achieve the 2050 goals of Paris Agreement, Natural-based solutions (NbS) were proposed widely as an important solution in many countries’ Nationally Determined Contributions (NDCs). However, many studies have claimed that the mitigation capability of NbS to climate change may be overestimated due to limitations such as the saturation of carbon storage in ecosystems. Robertson et al. (2022) revealed that the combination of the NbS and cellulosic bioenergy in a single geographic area can be a possible solution to fulfill the goals of the Paris Agreement. However, there are still debates, knowledge gaps and uncertainties. The responses of soil respiration to disturbances plays a crucial role in ecosystem carbon dynamics and is required for adjusting earth observation models, thus, impact our estimation on ecosystem carbon sequestration ability. Ecosystem stability has been a well-known concept of ecology to understand how an ecosystem respond to different types of perturbation. Many metrics have been developed to explore how much the community traits and the system functions move after a perturbance, whether it returns to the pre-perturbation condition and how fast it reach the pre-perturbation status or move to a new equilibrium. Soil respiration is an important ecosystem function, not only because it represents the metabolism of an ecosystem, but also crucially affects carbon flux between the ecosystem and the atmosphere. Soil stores two times of carbon than the atmosphere. Soil respiration is the second largest carbon flux between terrestrial ecosystem and air, and it is very sensitive to climate change. Soil respiration is, thus, an important component of ecosystem carbon fluxes which can determine the carbon source or sink of an ecosystem, and the amount of carbon emission or sequestration. The estimate of potential soil respiration during the growing seasons and its temperature sensitivity helps us understand the mechanisms that modify the responses of soil respiration to climate scenarios and disturbance and improve the accuracy of the Earth Observation models. Land use change (LUC) and severe drought events are two important disturbances that bioenergy cropping ecosystem may face. These anthropogenic and climate disturbances may mitigate the neutronization of greenhouse gas (GHG) emissions from bioenergy applications. The pre-LUC land use status and post-LUC crop types may be crucial on how soil respiration respond to these disturbances. We established land use conversion from two previous crops (i.e., conventional continued corn, a.k.a. AGR sites) and bromegrass (Conservation Reserve Program, a.k.a. CRP sites)) to three biofuel crops (i.e., continued corn (C), switchgrass (Sw) and restored prairie (Pr) sites), plus an undisturbed CRP (reference site (Ref)). The resistance (Rst), resilience (Rsl) and recovery (Rc) were calculated based on logged soil respiration at 20 degrees Celsius (LR20) and the temperature sensitivity of soil respiration (beta) underneath different land use history (LUH) and present crop type (CROP). We monitored the soil respiration during 2011 and 2014 which were from the second year to the 5th year after LUC (2010) and from one year before to three years after severe drought (2012). We found that the sites with different crop types (annual vs perennial crops) between LUH and CROP (i.e., CRP-C, AGR-Sw & AGR-Pr) tended to reach a new equilibrium status (low Rc & Rsl) while the same crop type between LUH and CROP (i.e., CRP-Sw, CRP-Pr) tended to return to pre-disturbance status (high Rc & Rsl). The results implied that CROP has a dominant effect on LR20. Perennial crops (Sw, Pr and bromegrass) have higher LR20 than annual crop (corn) no matter which LUH. For the effects of severe drought, perennial crops (Ref, CRP-Sw, CRP-Pr, AGR-Sw & AGR-Pr) always had high resistance (Rst) than annual crop (CRP-C & AGR-C), especially the aged reference site. We don’t find the obvious effect of LUC and drought underneath different LUH and CROP treatments. Additional research are required to exploit the mechanisms which affect the temperature sensitivity of soil respiration.

Presented by

Yahn-Jauh Su

Institution

W.K. Kellogg Biological Station, Michigan State University.

Other Affiliations

Great Lakes Bioenergy Research Center, Michigan State University. Department of Geography/CGCEO, Michigan State University. Department of Integrative Biology, Michigan State University. Department of Crop and Soil Sciences, Michigan State University

Keywords

soil respiration, carbon cycle, disturbance, land use change, drought, bioenergy cropland, agriculture

Storms and Sea Ice: An Investigative Analysis in the Palmer LTER Region

Mary E. Stack, Scott C. Doney

Abstract

The impacts of changing Antarctic sea ice range from local effects to the global scale including decreased albedo, altering ocean circulation, indirectly affecting sea level rise, and impacts to biogeochemistry and ecology of the ecosystem. Large storm events reduce sea-ice extent and expose ice shelves to the open water, making them more vulnerable. An improved understanding of the influence of storms on sea ice is imperative for sea level rise projections and planning for future conditions under a changing climate. This study investigates the temporal relationship of sea ice indices (advance, retreat, and duration), storm intensity, and storm count from 1979 to 2016 along the coast of the West Antarctic Peninsula. Linear regression is utilized to better understand how storm count and intensities could be impacting sea ice indices along three regions of the Palmer LTER sampling area. Each region is subdivided into coastal, shelf, and slope and relationships are investigated at this sub-group level. The study found no significant change in storm intensity from 1979 to 2016. Storm frequency showed a statistically significant increase over time for the austral Fall season only. Sea ice advance is shifting later in many areas, predominantly coastal zones. The regions and sub-regions experience different relationships with mean storm intensity and sea ice indices. Coastal zones experience a delayed advancement when the mean storm intensity is increased. Future work is needed in order to understand the geospatial components to these relationships.

Presented by

Mary Stack <nyd9rw@virginia.edu>

Institution

University of Virginia

Keywords

Antarctica, polar marine, disturbance, sea ice, storms

MCM LTER: Identity & distribution of sentinel taxa in Lake Fryxell, Antarctica

Rochelle Pereira & Dr. Rachael Morgan-Kiss

Abstract

The McMurdo Dry Valley, Antarctica houses a variety of lakes that consist of a food web that is entirely microbially dependent, with photosynthetic algae forming the base of the food web. The microorganisms that live in this environment are accustomed to a variety of harsh conditions including low temperatures, low light, and high salt concentrations. A small change in environmental conditions, such as a slight increase in temperature, could pose as a stressor on the microbial communities. The pristine nature of these lakes make them ideal models for observing the impact of climate change. Our research focuses on investigating the effect of environmental disturbances on microbial communities. We aim at identifying sentinel organisms that would be most affected by environmental disturbances in the lakes and observing their distribution within these lakes. The current study is focused on Antarctic Lake Fryxell. Our study found organisms belonging to certain phyla to be significantly affected by certain nutrients. Thus, we suspect these organisms could pose as sentinels in these communities.

Presented by

Rochelle Pereira

Institution

Miami University

Keywords

Air-sea interaction processes during Hurricane Sandy: Coupled WRF-FVCOM model simulations

Siqi Li and Changsheng Chen

Abstract

A fully-coupled atmospheric-ocean model was developed by coupling WRF (Weather Research and Forecasting Model) with FVCOM (the unstructured-grid, Finite-Volume Community Ocean Model) through the Earth System Model Framework (ESMF). The coupled WRF-FVCOM is configured with either hydrostatic or non-hydrostatic oceanic dynamics and can run with wave-current interactions. We applied this model to simulate the 2012 Hurricane Sandy in the western Atlantic Ocean. The experiments examined the impact of air-sea interactions on Sandy’s intensity/path and oceanic responses under hydrostatic and non-hydrostatic conditions. The results showed that the increased storm wind rapidly deepened the mixed layer depth when ocean processes were included. Intense vertical mixing brought cold water in the deep ocean towards the surface, producing a cold wake within the maximum wind zone underneath the storm. This process led to a sizeable latent heat loss from the ocean within the storm, and hence rapid air temperature and vapor mixing ratio drop above the sea surface. The storm intensified as the central sea-level pressure dropped. Improving air pressure simulation with ocean processes tended to reduce the storm size and strengthen its intensity, providing a better simulation of hurricane path and landfall. Turning on the non-hydrostatic process slightly improved the hurricane central sea-level pressure simulation and intensified the winds on the right side of the hurricane center. Hydrostatic and non-hydrostatic coupled WRF-FVCOMs captured Sandy-induced rapidly-varying flow over the shelf and the wind-induced surge level at the coast. The coupled models predicted a higher water elevation around the coastal areas where Sandy made landfall than the uncoupled model. The uncoupled and coupled models both showed more significant oceanic responses on the right side of the hurricane center, with a maximum during the Sandy crossing period when the clockwise-rotating frequency of Sandy wind was close to the local inertial frequency. The area with a maximum response varied with Sandy’s translation speed, more prominent in the deep region than over the slope, and more substantial under the non-hydrostatic condition. The simulated ocean responses agreed with the theoretical work of Price (1981). The nonhydrostatic experiments suggest that to resolve a fully storm-induced convection process, the oceanic model grid configuration should meet the O(1) criterion for the ratio of local water depth to the model horizontal resolution.

Presented by

Siqi Li

Institution

School for Marine Science and Technology, University of Massachusetts Dartmouth

Keywords

Air-sea interaction, hurricane, numerical model, non-hydrostatic

Seagrass Resilience Experiment

Spencer Tassone, Michael Pace

Abstract

A marine heatwave caused a 90% dieback in seagrass shoot density within a restored seagrass meadow in South Bay, VA in June 2015. This dieback was spatially heterogenous with the central section of the meadow having the greatest shoot loss while the northern edge, which is closest to an oceanic inlet, appeared undisturbed. We initiated an experiment in June 2020 that emulated the effects of the 2015 marine heatwave by removing the above-ground seagrass biomass in replicated treatment plots at the center and northern edge of South Bay. We measured seagrass resilience (i.e., recovery time), recovery shape, and recovery mechanism amongst the two locations. Linear recovery of the central sites occurred after 24 months whereas recovery was incomplete for the northern edge sites and projected to require 124 months. Differences in recovery times are likely due to storm-driven sediment erosion at the northern edge treatment sites. The recovery mechanism at both locations appeared to be mediated by lateral clonal growth from the treatment plot edges as well as seedling recruitment within the treatment plots.

Presented by

Spencer Tassone <sjt7jc@virginia.edu>

Institution

University of Virginia, Department of Environmental Sciences

Other Affiliations

Virginia Coast Reserve LTER

Keywords

Seagrass, Resilience, Disturbance, Heatwave

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Experimental Assessment of Functional Redundancy and Resilience of Benthic Algal Metacommunities

Thomas Shannon and Evelyn Gaiser

Abstract

A more holistic understanding of how ecosystems and landscapes will respond to pulse and press disturbances requires a deeper understanding of how the metacommunities across those landscapes change or remain resilient in the face of disturbance, on both a compositional (taxonomic) and functional (ecosystem contributions) level. This research project seeks to experimentally assess the compositional and functional resilience of a benthic algal metacommunity in a subtropical coastal wetland (the southern Everglades) in response to simulated seawater intrusions. Research is ongoing, but we intend for this experiment to help parse the ways in which ecological phenomena like dispersal, diversity, and functional redundancy may influence metacommunity resilience.

Presented by

Thomas Shannon <tshan018@fiu.edu>

Institution

Florida International University, Institute of Environment and Department of Biological Sciences

Keywords

Algae, Metacommunity, Resilience, Coastal,

▼ Education/outreach Back to top

Mowing Milkweed for Monarchs: Learning Outside the Classroom

Gabriel Knowles, Britney Christensen, Kara Haas, Elizabeth Schultheis, Doug Landis, Nate Haan

Abstract

Research Experience for Teachers participants, Gabe Knowles and Britney Christensen participated in research related to milkweed and monarchs for two summers, In summer 2001, they worked within the ReGrow Milkweed for Monarchs Citizen Science Study to research whether monarchs prefer to lay their eggs on younger milkweed plants. In summer 2021, a follow up questions was asked, does mowing milkweed patches reduce the number of predators of monarch eggs? visit the poster to see the data and learn about how Knowles and Christensen brought the experience to their 4th grade students in engaging ways!

Presented by

Gabriel Knowles <gabrielknowles@whitehallschools.net>

Institution

Michigan State University

Other Affiliations

Whitehall District Schools

Keywords

education, outreach, research experience for teachers, milkweed, monarchs, K-12, insects, plants

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▼ Marine Back to top

Autonomous Zooglider measurements of zooplankton prey-predator interactions

Mark D. Ohman, Sven Gastauer, Jeffrey S. Ellen

Abstract

Zooglider is an autonomous buoyancy driven ocean glider designed and built by the Instrument Development Group, Scripps Institution of Oceanography. Zooglider enables non-invasive measurements of mesozooplankton and marine snow, profiling from 400-0 m in the ocean, in missions lasting from 3-6 weeks and traversing a few hundred km. Each time Zooglider surfaces it telemeters a subset of the most recently measured data via Iridium, and has full 2-way communications. In addition to standard sensors, Zooglider includes: Zoocam: a custom shadowgraph imaging system for mesozooplankton and marine snow; Zonar: a custom dual-frequency (1000 kHz/200 kHz) echosounder permitting size classes of acoustic backscatterers to be resolved; Acousonde: a broadband hydrophone particularly well suited to recording whale, fish, and invertebrate vocalizations. We illustrate some of the ecological phenomena that have been resolved by Zooglider, including the importance of oceanic frontal regions as ‘hot spots’ of elevated zooplankton biomass and abrupt changes in community composition; the spatial overlap of prey and predators on fine vertical scales; body size- and season-dependent Diel Vertical Migration; and the diel periodicity in feeding calls by blue whales and in fish choruses, both potential sources of top down zooplanktivory in the CCE site.

Presented by

Mark Ohman

Institution

Scripps Institution of Oceanography/UC San Diego

Keywords

autonomous vehicle, ocean glider, imaging, bioacoustics, hydrophone, Machine Learning, ocean fronts, Diel Vertical Migration

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Submesoscale Eddies in the Southern California Bight Derived from a Decade of High Frequency Radar Observations

Ali Reza Payandeh, Libe Washburn, Brian Emery, Carter Ohlmann

Abstract

A decade (2012–2021) of hourly maps of surface currents on a 2-km-grid generated by a network of high-Frequency (HF) radars reveal new insights into the spatial and temporal patterns of submesoscale eddies in the Southern California Bight. Eddy occurrences were organized into approximately 19 “hot spots’’ of eddy activity, classified by both eddy location and rotational direction. Cyclonic eddies were most often found (1) off Dana point and (2) within a broad area at the center of the Santa Barbara Channel. In contrast, anticyclonic eddies were more widespread within the radar coverage area. Of 98616 eddies detected, 51 % were cyclonic and 49 % were anticyclonic suggesting that anticyclonic eddies were more abundant than previously reported. Most eddies moved less than 10 km from their starting points over their, 2–50 hr, lifespans. Eddies were seasonal in occurrence with more cyclonic eddies during summer and more anticyclonic eddies during fall. Variability examined by conditional averaging suggests different physical drivers for different hot spots. For example, within some eddy hot spots, conditional averaging suggests diurnal reoccurrence of eddies possibly due to tidal influence or diurnal wind effects. This speculation is supported by spectral analysis of eddy vorticities which exhibited strong diurnal peaks. Sentinel-3 satellite ocean color data combined with HF radar-derived surface currents in multiple eddy hot spots indicated that submesoscale eddies generate cross-shore transport pathways of phytoplankton in the Southern California Bight.

Presented by

Ali Reza Payandeh <alip@ucsb.edu>

Institution

University of California Santa Barabara, Marine Science Institute

Keywords

High Frequency Radar, Submesoscale Eddies, Nutrient Transport

Spatial ecology of phase shifts in a heterogenous coral reef system

Scott D. Miller, Andrew Rassweiler

Abstract

Presented by

Scott D. Miller

Institution

Florida State University

Keywords

coral reefs, spatial ecology, phase shifts, alternate states

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Differential ability to withstand benthic competition in massive Porites colonies between marginal and non-marginal habitats

Jack Corso, Dr. Peter Edmunds

Abstract

Coral populations in marginal habitats offer insight into the potential mechanisms driving patterns of resistance to future predicted conditions historically considered sub-optimal for coral growth (e.g., high turbidity, low light, and elevated temperatures). As coral cover declines and macroalgae become more abundant throughout the tropics, the intensity of coral-algal competition increases. Yet coral populations growing in marginal habitats persist, despite being exposed to environmental conditions that are similar to those predicted to occur throughout large areas of the topics within the coming decades. This study focuses on the competitive ability of coral versus algae in contrasting environmental conditions, and evaluates whether habitat influences the outcomes of coral-algal competition. Bay and fringing reef (marginal) environments were compared to the back reef (non-marginal) in Moorea, French Polynesia. Historical data shows the environmental conditions of these habitats differ in both sedimentation rate and light availability, but preliminary sampling suggests these differences can vary over time. Competitive interactions between massive Porites and algal turf were assessed over 21 days in both habitats. Massive Porites was the dominant coral in all habitats with turf algae being the most prominent benthic competitor. Independent of colony size, corals in the marginal habitat overgrew algal turf in direct contact with its perimeter at 0.44 cm2 wk-1, whereas colonies in the non-marginal habitats lost in competition with algal turf and were overgrown at -0.16 cm2 wk-1. These results suggest that habitat influences the attenuation of negative effects on coral growth affiliated with algal turf competitive pressures. These results suggest that habitat influences the attenuation of negative effects on coral growth affiliated with algal turf competitive pressures. Such patterns may contribute to the success of coral populations residing within marginal reefs exposed to sub-optimal conditions.

Presented by

Jack Corso

Institution

California State University, Northridge

Keywords

competition, marginal reef, Porites, Algal turf

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Predicting the effects of submarine groundwater discharge on coral reef biogeochemistry and ecosystem functioning

Silbiger, Nyssa*., Hagedorn, B., Zeff, M., Jorissen, H., Barnas, D., Kerlin, J., Maine, B., Justis, E., Sparagon, W., McClintock, R., Nelson, C., Donahue, M.

Abstract

Submarine groundwater discharge (SGD) is a worldwide phenomenon in coastal ecosystems. The unique physicochemical environment created by SGD, including high nutrients, low pH, and cool water, can alter key ecosystem functions. SGD fluxes are affected by physical parameters that are expected to change with climate change (e.g., sea level rise and precipitation), but changing SGD fluxes and its impact on coastal biogeochemical and ecological processes is often excluded from climate change predictions. With a focus on coral reefs, we use high resolution time-series data from two different SGD sites in Mo’orea, French Polynesia to 1) better understand the interacting effect of tides, waves, and precipitation on SGD flux and 2) determine how changing SGD alters reef ecosystem metabolism. We broadly show that waves have a significantly higher effect on SGD flux than tides in Mo’orea, a microtidal habitat. Further, we show a substantial pulse of low pH, low salinity, cool, and high nutrient water onto the reef after a major wave event that led to changes in net ecosystem production and calcification on the reef. As the unique biogeochemistry from SGD can affect ecological processes on coral reefs, our data can uncover how changing physical conditions may lead to altered coral reef ecosystem functioning via changes in SGD.

Presented by

Nyssa Silbiger

Institution

California State University, Northridge

Other Affiliations

University of Hawaii at Manoa, California State University, Long Beach, Hawaii Institute of Marine Biology

Keywords

Marine, Ecosystem Functioning, Coral Reefs, Biogeochemistry

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Natural Environmental Gradients Alter Ecosystem Functioning Through Changes in Community Composition

Danielle M. Barnas, Maya E. Zeff, Dr. Nyssa J. Silbiger

Abstract

Biodiversity-ecosystem functioning relationships can be impacted by local and global stressors and environmental shifts. These relationships are particularly important for highly diverse and highly productive ecosystems like coral reefs. One source of environmental influence affecting coral reef communities is submarine groundwater discharge (SGD), a land-sea exchange of water to a marine environment found globally around coral reef ecosystems. SGD is an important conduit for elevated nutrients, pollutants, and variably altered biogeochemistry (e.g., total alkalinity and pH). However SGD impact on community and ecological shifts has been seldom studied along coral reefs, and the particular effect on functional diversity has not been examined. Therefore, in this study we assessed the impact of SGD on species and functional diversity of a coastal coral reef community through benthic surveys. These surveys occurred along the SGD gradient to understand how community diversity shifts from high to low SGD influence. We anticipated a community shift in both species and functional diversity along the SGD gradient, and observed enhanced species richness in moderate SGD compared to high SGD or a near-ambient environment. SGD is a ubiquitous source of altered biogeochemistry and environmental conditions to global coastal ecosystems including highly productive coral reefs, and this study is the first to look at the connection between SGD on community functional diversity and ecosystem functioning of a tropical coral reef ecosystem.

Presented by

Danielle Barnas

Institution

California State University, Northridge, Department of Biology

Keywords

Trait diversity, Ecosystem functioning, Groundwater

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Modeling the effects of fish excretions on coral growth and bleaching

Raine Detmer, Ross Cunning, Ferdinand Pfab, Alexandra Brown, Adrian Stier, Roger Nisbet, Holly Moeller

Abstract

Coral reef ecosystems are increasingly threatened by coral bleaching events, which occur when stressors trigger the breakdown of the symbiosis between stony corals and endosymbiotic algae. Many species of fish shelter within coral colonies, and their nutrient-rich excretions may enhance coral growth. However, less is known about how these fish influence their host coral’s risk of bleaching. Here, we used data from the Mo’orea Coral Reef LTER to incorporate a population of coral-dwelling fish into a published dynamic energy budget model of the coral-algal symbiosis. We then used this model to explore how fish excretions affect corals during periods of low and elevated light stress.

We found that although fish-derived nitrogen can promote coral growth, in some cases it may also exacerbate coral bleaching. This switch from positive to negative effects of fish was due to a “Goldilocks” effect of nitrogen, where both too-low and too-high levels of nitrogen were harmful to the coral. Both the sign (positive or negative) and magnitude of fish effects were dependent on environmental conditions. Future empirical tests of this model’s predictions and assumptions should lead to a more mechanistic understanding of how coral-dwelling fishes influence the bleaching response of their host corals.

Presented by

Raine Detmer

Institution

University of California, Santa Barbara, Department of Ecology, Evolution, and Marine Biology

Other Affiliations

Daniel P. Haerther Center for Conservation and Research, John G. Shedd Aquarium Chicago, IL

Keywords

coral bleaching, nutrient excretion, coral-associated fauna, DEB modeling, symbiosis

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Tidal phase modulates sandy beach prey subsidies to a surf zone fish

Jessica R. Madden, Jenifer E. Dugan, David M. Hubbard, Kyle A. Emery

Abstract

Food webs of sandy beaches rely on cross-ecosystem subsidies of kelp and phytoplankton to fuel highly productive trophic intermediates, such as beach hoppers and sand crabs, that are prey for birds and fish. Surf zone fish support recreational, artisanal, and commercial fisheries, but their trophic relationships are not well understood. Although suspension-feeding sand crabs are known as an important prey resource for surf zone fish, the role of the abundant kelp wrack-associated and other invertebrates as prey for these fish is unknown. To explore this question, we compared the availability of kelp- and phytoplankton-dependent macroinvertebrate communities to the diet of barred surfperch, Amphistichus argenteus, an abundant surf zone fish on SBC sandy beaches and surf zones. Lunar tide phases predictably modify patterns of beach inundation and can resuspend the kelp wrack colonized by beach macroinvertebrates. These regular tidal shifts potentially alter the variety, timing, and magnitude of beach prey resources to barred surfperch. We expected a greater diversity and abundance of kelp-dependent beach invertebrates in surfperch diet during spring tides that sweep more of the intertidal beach than during neap tides. During spring tides, barred surfperch diet was more diverse, with more kelp-dependent taxa consumed, and a lower dominance of sand crabs. In addition, overall biodiversity of prey on the beach correlated with more diverse fish predator diets. These results suggest that when kelp- subsidized beach macroinvertebrate communities are affected by spring tide inundation or by wave events they are subject to predation by fish. Our evidence of this tidally modulated predator-prey interaction expands connectivity between kelp forest donor ecosystems and recipient beach food webs. Our findings provide new insights into how higher trophic levels may respond to long-term variability in kelp subsidies and beach condition in an understudied ecotone that is vulnerable to negative impacts of anthropogenic disturbance and climate change.

Presented by

Jessica Madden

Institution

Marine Science Institute, University of California Santa Barbara

Keywords

food webs, diet, predator-prey interaction, beach, connectivity, subsidies, kelp, coastal, ecology

Water level and surface salinity trends in the Everglades freshwater-saline ecotone

Amanda Richey, John Kominoski, Paulo Olivas, Sparkle Malone

Abstract

Dramatic loss of function and even ecosystem collapse can ensue as a result of increased frequency or intensity of stressors and disturbances. Globally, coastal vegetated ecosystems can be stressed and eventually transformed by rising sea level, with salt tolerant species replacing freshwater adapted ones within ecotones. The development of low productivity states can accompany coastal ecosystem transition. Within the Everglades, one low productivity zone has persisted within the ecotone between saltwater mangrove scrub and sawgrass-eleocharis sp. prairie since it was first documented in the 1950s.

Competing drivers of fresh and marine water contribute to ecotone development here, but the effects of different sources of water level (pulses or presses) on salinity remain poorly understood. The primary objective of this work was to identify marine and freshwater influences in the ecotone, by evaluating water level trends over time and surface salinity-water level relationships. Trends in long term water levels were quantified across the landscape using gap-filled time series data. Surface-salinity water level relationships were modeled at a 6 month time step to determine if salinity changes over time and assess weekly water level influence on salinity values. Water levels increased throughout the landscape. Model salinity values predicted higher salinities with higher water levels. Next steps for this research include assessing different time scales of water level on surface salinity and analyzing ecosystem response to abiotic drivers of water level and salinity through the eddy covariance method.

Presented by

Amanda Richey

Institution

Florida International University, Department of Biological Sciences

Other Affiliations

Florida International University, Department of Earth and Environment; Yale University School of the Environment

Keywords

sea level rise, water level, salinity, ecotones

A random forest model of salt marsh aboveground biomass at multiple LTER sites on the eastern coast of the US

Asa R. Julien and Deepak R. Mishra

Abstract

The goal of this study was to develop a machine learning model of salt marsh end-of-year aboveground biomass at three LTERs along the east coast of the US. Long-term biomass monitoring efforts at each site were used as ground truth data. A remote sensing-based random forest regression was developed, utilizing daily climate data, elevation data , and vegetation indices derived from Landsat imagery as predictors of end-of-year aboveground biomass. The output of the model was mapped over the study period (approximately 20 years), though only one year is shown in the poster.

Presented by

Asa Julien <asajulien@uga.edu>

Institution

University of Georgia, Department of Geography

Keywords

Salt marsh, remote sensing, productivity

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Long-term changes in upper ocean properties along the West Antarctic Peninsula (PAL-LTER)

Michael Cappola, Carlos Moffat, Megan Cimino, Scott Doney, Ari Friedlaender, Oscar Schofield, Deborah Steinberg, Sharon Stammerjohn, Ben Van Mooy

Abstract

• We use hydrographic data (temperature, salinity, pressure) collected by the Palmer (PAL) LTER to characterize changes in upper ocean properties along the West Antarctic Peninsula continental shelf between 1993-2018. • We found the thickness of the upper layer (defined as the water above the stratification maximum) has roughly halved in the study period. • During the same period, the upper layer stratification nearly tripled, although the time series shows significant variability. • A notable period of reversal of the above trends occurred in 2005-2015, as large winter sea-ice reversals were also observed. • Although the mixed layer has cooled and become fresher throughout the shelf, the shallowing of the mixed layer is only significant in the northern shelf, consistent with previous studies (Schofield et al. 2018).

Presented by

Carlos Moffat

Institution

University of Delaware

Other Affiliations

University of California-Santa Cruz, University of Virginia, Rutgers University, Virginia Institute of Marine Sciences, INSTAAR - University of Colorado, Boulder, Woods Hole Oceanographic Institution

Keywords

Ocean properties, long term trends, mixed layer, antarctica

The effects of selectively fishing key herbivores on coral resilience

Dana Cook, Holly Moeller, Sally Holbrook, Russ Schmitt

Abstract

Coral reefs are dynamic ecosystems that can shift between coral- and macroalgae-dominated states. Herbivorous fishes facilitate coral-dominated reefs, however different herbivores often specialize in the way they feed and/or in the types of algae they consume, influencing whether and how they contribute to coral resilience. Further, many of these key herbivores are important to small-scale reef fisheries. There is mounting evidence that overfishing can result in coral-to-macroalgae regime shifts, however the effects of selectively harvesting certain functional groups on coral resilience remains unclear. To explore this gap in knowledge, we use a dynamic model that simulates the differential harvest of two key herbivores (that differ in diet and life history) linked to the competitive dynamics between key benthic spaceholders (i.e., coral, turf, and macroalgae). Our main objective is to explore the effects of selectively fishing key herbivores on the dynamics of regime shifts, and in particular, the resilience of corals, to better inform the management of aquatic ecosystems where herbivores are directly targeted by humans. Our findings provide insight on how fisher behavior can act to strengthen or weaken coral resilience while simultaneously influencing fish yields, providing direct application for reef management.

Presented by

Dana Cook

Institution

University of California Santa Barbara

Other Affiliations

Moorea Coral Reef LTER Site

Keywords

Resilience, regime shifts, fishing, coral reefs

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Three decades and counting: Long-term changes in zooplankton community structure along the west Antarctic Peninsula

Deborah K. Steinberg, Maya I. Thomas, Andrew D. Corso, Patricia S. Thibodeau, John A. Conroy, & Joseph S. Cope

Abstract

Presented by

Deborah K. Steinberg

Institution

Virginia Institute of Marine Science

Keywords

zooplankton, climate, Antarctica, Southern Ocean, krill, salp

Emily Stidham

Emily Stidham, Russell Hopcroft

Abstract

Mucus-net feeders are under-appreciated in the literature with limited information regarding their abundance and biomass. In the Northern Gulf of Alaska (NGA) and Prince William Sound (PWS) this group is represented primarily by pelagic tunicates (larvaceans, doliolids, salps) and pelagic snails (pteropods). These mucus-net feeders are being studied in the NGA and PWS over a period of ten years (2012-2021) along the Seward Line as well as stations within PWS to update the preceding 11-year record for May and September. Summer (July) collections also exist from 2001-2004, and 2018 onward. The new abundance data will be compared to patterns of changes in the physical and biological environment, to confirm earlier observations that community composition was linked to water temperature changes, plus explore additional environmental drivers based on expanded measurements. As in the past, we see strong seasonal shifts in numbers and biomass for larvaceans as well as changes in species composition. Pteropods also show seasonal patterns particularly in their distribution and size abundances. We compare the species-level identification possible from a 53-μm net to the genus-level data and size spectra generated by 150-μm and 505-μm mesh nets that collect only larger individuals in lower abundances. Long-term species-level records of mucus-net feeder biomass and abundance in the NGA and PWS provide a better understanding of how the zooplankton community may shift in the face of a changing ocean.

Presented by

Emily Stidham <eastidham@alaska.edu>

Institution

University of Alaska Fairbanks

Keywords

Marine, Time Series, Zooplankton

Coastal sand dynamics structure the spatial synchrony of kelp forest communities

Ethan Kadiyala, Jonathan Walter, Max Castorani

Abstract

Spatial synchrony, correlated fluctuations of populations in different locations, is a central aspect of population dynamics that impacts population stability, persistence, and resilience. This project investigates the synchrony of reef substrate change and giant kelp population dynamics, and the relationship between them over space in sites across Southern California. Our statistical models revealed positive relationship between giant kelp abundance and rocky cover (P < 0.05). Likewise, understory algae, sessile invertebrate, and mobile invertebrate abundances displayed a positive relationship with rocky cover (P < 0.05). The magnitude of the effect varied across community guilds, likely do to varying morphologies across the community. Next, the stacked composition plots visualize the change in the relative abundance of species groups across increasing levels of rockiness. Grouping by morphology, it is evident that certain types of species comprise a greater share of community biomass when rock is scarce, while other groups are more dominant in rocky. Our spatial synchrony analysis found reef composition to be substantially less correlated over space than giant kelp. Specifically, at the regional scale, giant kelp populations exhibit a spatial decay over 0-15 kilometers, followed by a gradual decline at longer distances. This contrasts with rocky cover, which declines to no correlation over distances of 0-10 kilometers. Similarly, the local scale analysis reveals spatial correlation in giant kelp exhibits a spatial decay over 0-4 kilometers, while rocky cover remains low over the same distances. This indicates that reef composition contributes to desynchronizing local giant kelp population dynamics, operating over smaller scales compared to typical oceanographic processes.

Presented by

Ethan Kadiyala <ekadiyala@virginia.edu>

Institution

University of Virginia, Department of Environmental Sciences

Other Affiliations

Santa Barbara Coastal LTER

Keywords

Synchrony, Foundation Species, Marine, Giant Kelp, Community Ecology

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Using in situ imaging to describe zooplankton communities in the Northern Gulf of Alaska

Hannah E. Kepner, Russell R. Hopcroft, Tom B. Kelly

Abstract

Presented by

Hannah Kepner <hekepner@alaska.edu>

Institution

University of Alaska Fairbanks, College of Fisheries and Ocean Sciences

Other Affiliations

NGA LTER

Keywords

pelagic imaging, zooplankton

Biological Connectivity of Crassadoma gigantea in the Southern California Bight

Hayley Goss, Rachel Simons, Paige Miller, Susan Zaleski, Robert Miller, Donna Schroeder, Henry Page

Abstract

Population connectivity is an important process that affects ecosystem resilience and metapopulation stability. This ongoing study uses biophysical modeling and genetic analysis to investigate relationships between physical oceanographic processes and genetic structure of C. gigantea (rock scallops) in the Santa Barbara Channel (SBC) and greater Southern California Bight (SCB). C. gigantea is an ecologically and recreationally important species with a planktonic larval duration (PLD) of ~30 days, typical of many marine species. We are modeling connectivity and sampling scallops for genetic analysis at 34 sites (rocky reefs, offshore platforms, piers) across the SCB, including several SBC LTER subtidal rocky reefs. Preliminary modeling suggests that average potential connectivity between all sites varies seasonally and is greater in fall than in spring. These results also suggest asymmetric connectivity between sites and the potential for self-recruitment and localized retention. We have extracted and sequenced genomic DNA from 12 individuals at each site to create reduced representation libraries (n = ~400 individuals). Bioinformatics and statistical analysis of data is ongoing and will be used to compare modeled potential connectivity estimates to observed genetic connectivity between sites. Our research will provide insight into the larval dispersal and genetic structure of rock scallops in the SCB, which may be useful in policy and management, including MPA design/evaluation and the impact of anthropogenic structures on ecosystem dynamics.

Presented by

Hayley Goss <hgoss@ucsb.edu>

Institution

Marine Science Institute, University of California Santa Barbara

Other Affiliations

Bureau of Ocean Energy Management, Department of the Interior and Earth Research Institute, UCSB

Keywords

Population Connectivity, Biophysical Modeling, Population Genetics

Fate of the Copper River Plume

Isaac Reister, Seth Danielson

Abstract

The Norther Gulf of Alaska's relatively deep continental shelf adjacent to the Copper River prodelta decouples the river plume from the direct effects of seafloor-induced mixing, allowing the iron-rich Copper River outflow to spread across the NGA shelf. A portion of the spreading plume feeds the Alaska Coastal Current and contributes to along-shore advection. Another portion of the plume spreads offshore in a thin surface layer. The plume’s trajectory is sensitive to wind direction and under suitable wind conditions coastal waters can be swept into the shelf-break flow regime, at times even delivering coastal waters beyond the slope to the iron-poor HNLC basin.

Presented by

Isaac Reister

Institution

University of Alaska Fairbanks

Keywords

Freshwater, River, Plume, Alaska

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Impacts of a Marine Heatwave on Microbial Communities in the Gulf of Alaska

Jake Cohen, Suzanne Strom, Seth Danielson, Eric Collins, G. Hennon

Abstract

Climate change has led to a gradual increase of sea surface temperatures in the Northern Gulf of Alaska (NGA) interspersed with marine heatwaves (MHW) which impose rapid but short-lived warming. MHWs have the potential to alter marine microbial community structure, which may impact the production and transfer of carbon to higher trophic levels. The years 2019-2020 were characterized as a short-term MHW, with sea surface temperatures reaching 2.5 degrees above normal, while 2021 had near-average sea surface temperatures. Samples for DNA and flow cytometry were collected on NGA Long Term Ecological Research cruises in summers 2018-2021. Flow cytometry sample analysis revealed higher abundances of picoeukaryotes, Synechococcus, and Nanoeukaryotes in the summer of 2019 relative to 2020 and 2021 on the continental shelf. The diversity of eukaryotic microbes was lower in 2018-19 than in 2020-2021, with similar trends observed within the diversity of individual eukaryotic taxa. Conversely, the diversity of prokaryotic microbes was higher in 2019 than in 2020. Different environmental variables were found to correlate with both small cell abundance and microbial diversity. Picoeukaryotes abundance correlated with higher temperature while Synechococcus abundance also correlated with lower concentrations of nitrate and phosphate. Picoeukaryote abundance was anti-correlated with chlorophyll a concentrations. Shannon diversity of 18S reads correlated with lower salinity measurements while Shannon diversity of 16S reads did not significantly correlate with any biological or environmental variables. These correlations between small cells, microbial diversity, and environmental variables indicate the potential for shifts in microbial community structure during future marine heatwaves.

Presented by

Jake Cohen

Institution

University of Alaska Fairbanks

Other Affiliations

Northern Gulf of Alaska LTER

Keywords

Marine Microbes, Heatwaves, Amplicon Sequencing, Community Composition, Phytoplankton

Impacts of Marine Reserves on Sea Urchin Populations in the Santa Barbara Channel

Katrina Malakhoff, Robert Miller

Abstract

Presented by

Katrina Malakhoff

Institution

University of California Santa Barbara

Keywords

trophic cascades, marine reserves, sea urchins

Investigations of nutrient limitation of phytoplankton in coastal upwelling filaments

Kiefer Forsch, Kayleen Fulton, Lauren Manck, Katherine Barbeau

Abstract

The goal of this research is to characterize a coastal filament in terms of its iron content and ability to sustain primary production, by examining growth limitation at multiple scales relevant to this physically dynamic, biologically productive, and globally representative ecosystem.

Presented by

Kiefer Forsch

Institution

University of California, San Diego, Scripps Institution of Oceanography

Keywords

trace metals, nutrient limitation, elemental stoichiometry, phytoplankton

Effects of reef physical conditions on intertidal oysters at the Virginia Coast Reserve LTER

Kinsey N. Tedford and Max C.N. Castorani

Abstract

Oyster reef restoration has the potential to improve the recovery of depleted oyster populations while enhancing valuable ecosystem services, but has experienced mixed success. Oyster conservation may be improved by identifying physical conditions that constrain or facilitate the success of oyster restoration. Hence, we explored how wind fetch and elevation relate to recruitment and growth of intertidal Eastern oysters. We assessed recruitment and growth in 2021 at 16 restored reefs within the coastal bays of Virginia, USA. Oyster recruitment declines with fetch and strong recruitment is more common at mid-elevations. Recruit growth displays no relationship to fetch and greater variability on shallower reefs. There was also no evidence for density-dependent recruit growth. Findings from this work may help to optimize conservation efforts by informing the siting and design of intertidal oyster restoration.

Presented by

Kinsey Tedford <ktedford@virginia.edu>

Institution

Department of Environmental Sciences, University of Virginia

Other Affiliations

Virginia Coast Reserve LTER

Keywords

Eastern oyster, foundation species, intertidal, recruitment, restoration, population dynamics

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Broadening a Belowground Ecosystem Resiliency Model for Spartina alterniflora salt marshes

Kyle Runion, Jessica O'Connell, Deepak Mishra, Merryl Alber

Abstract

The Belowground Ecosystem Resiliency Model (BERM) is a recently developed tool to characterize salt marsh productivity from aboveground biophysical metrics through geospatial informatics modeling. Here, we aim to improve BERM and understand the change in overall performance of BERM as we increase the range of hydrodynamic and biogeochemical conditions of the calibration dataset. As we added multi-year, year-round measurements from more areas with different hydrogeomorphology, model performance improved in aboveground vegetation models and slightly worsened in the belowground biomass model. When compared to a model trained using original data (narrower range of conditions) and tested using new data (wider range of conditions), the newly created model (trained and tested on the wider range of conditions) was more accurate. The additional calibration data, which provides a wider range of biotic and abiotic conditions, has broadened the parameter space of the models and allows us to have more confidence in novel estimates.

Presented by

Kyle Runion <kyle.runion@utexas.edu>

Institution

University of Texas Marine Science Institute

Keywords

salt marsh, sea level rise, modeling, wetland, resilience

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Thermal vulnerability and resilience of seagrass

Kylor Kerns, Karen McGlathery, Peter Berg, Amelie Berger

Abstract

Seagrasses are widely regarded as carbon sinks that can sequester carbon and reduce greenhouse gas concentrations. At the same time, they are vulnerable to ocean warming and marine heat waves, which can lead to the loss of sediment carbon stores. Understanding how marine heatwaves vary spatially and temporally at a system-wide scale is important for determining the efficacy of carbon offset projects under current carbon market policies. We are addressing this in the Virginia Coast Reserve (VCR) coastal bay system, home to one of the world's most successful seagrass restoration projects. We are using sensors to continuously measure water column and sediment temperatures from May to September at 50 sites in the coastal lagoons (6 for sediment) to describe the spatial and temporal variance of temperature and to link it to warming and marine life heatwaves that may occur. Using two novel heating metrics: cumulative heat stress (as heating degree-hours) and thermal stress relief (as cooling degree-hours), I quantified in situ temperature data from four seagrass bays at the VCR. We found a north-to-south temperature gradient in the meadow with a strong northern inlet. In 2022, the north and middle sites had 81% and 73% more heating degree hours during a marine heatwave event than the previous summer in 2021. There was a decrease in seagrass density between the two years as well. We found temperature stratification and dampening in the sediment layers that may prolong or buffer heat stress (Berger et al. submitted). There is currently no risk assessment for heatwave vulnerabilities for seagrass carbon offset credits, yet this is arguably the greatest threat to carbon permanence. My research will make carbon accounting and restoration efforts more accurate for Virginia.

Presented by

Kylor Kerns

Institution

University of Virginia

Other Affiliations

Virginia Coast Reserve LTER

Keywords

Seagrass, Blue Carbon, Marine Heatwaves, Restoration, Resilience, Carbon, Temperature

Drivers of seagrass-associated invertebrate communities in coastal Virginia

Lauren Brideau, Max Castorani

Abstract

Seagrass meadows provide important ecosystem services, such as increasing biodiversity. Many environmental processes structure seagrass density making it variable over different spatial scales. The goal of this study is to analyze how seagrass complexity impacts the abundance of infaunal and epifaunal taxa. We use long-term data on seagrass and fauna counts collected at 50 sites in restored seagrass meadows at the Virginia Coast Reserve LTER. Fauna were sampled using infauna benthic cores and epifauna throw traps, with 3 replicates per site. As seagrass density increased, amphipod, gastropod, and shrimp abundance also increased while crab, bivalve and worm abundance decreased. Understanding the response of fauna to seagrass characteristics is important as restoration can support services and functions provided by seagrass-associated biodiversity.

Presented by

Lauren Brideau <ysd4wx@virginia.edu>

Institution

University of Virginia, Department of Environmental Science

Other Affiliations

Virginia Coast Reserve LTER

Keywords

Marine, Seagrass, Biodiversity

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Benthic microalgal contributions to eelgrass meadow blue carbon sequestration

Luke Groff, Karen McGlathery, and Peter Berg

Abstract

Seagrass meadows have been established as important contributors to the trinity of blue carbon ecosystems, alongside salt marshes and mangroves. As the global market recognizes the importance of these ecosystems, carbon offset crediting and blue carbon initiatives become a larger focus for world governments. As such, it is becoming more urgently necessary to decode the complex carbon cycling processes within seagrass meadows and blue carbon ecosystems in general. South Bay, Virginia has been a hub of studies geared towards better understanding the role of restored seagrass ecosystems in carbon and nitrogen cycling. Since the restorations inception in 1999, the meadow has reached maturity and flourished, now behaving indiscernibly from a natural seagrass meadow. Studies in South Bay have shown that over half of the carbon stored in the sediments are attributable to benthic microalgae (BMA). Despite this, the contributions of BMA to seagrass meadow metabolism are relatively understudied and BMA-stored carbon is excluded from blue carbon offset crediting in the US. This study seeks to understand the proportional contribution of BMA to eelgrass meadow metabolism, and better understand interactions between BMA and eelgrass. To do so, I utilized a novel benthic incubation chamber design to directly assess meadow metabolism and compared this to measurements of whole system metabolism captured using aquatic eddy covariance. I also sought to compare benthic chlorophyll concentrations to shoot densities within the meadow. I found initial evidence that BMA contributes up to half of the oxygen produced within the meadow, and that seagrass density did not appear to be a main driver for benthic chlorophyll concentrations. Further studies will be necessary to continue to develop our understanding of BMA in seagrass meadows.

Presented by

Luke Groff

Institution

University of Virginia, Department of Environmental Sciences

Other Affiliations

Virginia Coast Reserve LTER

Keywords

Benthic microalgae, carbon accounting, aquatic eddy covariance, benthic incubation chamber, seagrass meadow metabolism, seagrass restoration

Beyond Datazoo: Interactive access to CCE-LTER data

Marina Frants and Mark D. Ohman

Abstract

The majority of CCE-LTER datasets are available for download on the site’s central data repository, Datazoo: https://oceaninformatics.ucsd.edu/datazoo, in addition to being archived at the Environmental Data Initiative (EDI) repository and accessible via the Biological and Chemical Oceanography Data Management Office (BCO-DMO) website. However, some data are stored in non-tabular formats (such as netcdf, binary, or .mat files), while others are spread across multiple database tables and require complex queries for access. For such cases, CCE-LTER Information Management has provided several interactive web sites for plotting and downloading the data.

Presented by

Marina Frants

Institution

Scripps Institution of Oceanography, University of California San Diego

Keywords

CCE-LTER, Information Management, data access

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High Biomass Indicates Importance of Small Phytoplankton Cells

Megan O’Hara, Dr. Suzanne Strom

Abstract

The Northern Gulf of Alaska is a highly productive ecosystem in summer and fall, despite low chlorophyll levels. Nanoeukaryotes and cryptophytes are crucial components of the NGA. There is a strong link between the biological needs of small-celled phytoplankton groups and their environment, particularly nutrient availability. While short- and long-term variability impact the biomass of phytoplankton, this research suggests that small cells have the capacity for high trophic transfer efficiency to fuel the NGA ecosystem.

Presented by

Megan O'Hara

Institution

Shannon Point Marine Center, Western Washington University

Keywords

phytoplankton, flow cytometry, marine

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Consequences of state change on community productivity: The effects of seagrass restoration on bivalve food supply, productivity, and survival

Michael R. Cornish, Katharine C. Schlachter, Max C.N. Castorani

Abstract

The effects of foundation species on energy flows suggest their loss can dramatically alter secondary productivity and associated game and fisheries. Hence, understanding such controls on secondary production is a central goal in natural resource management and an urgent challenge given global declines of foundation species. To understand the influence of a restored foundational seagrass species Zostera marina on system productivity in coastal Virginia, we sought to determine whether these ecosystems serve as sources or sinks for water-column primary production associated with filter-feeder secondary production, and whether the habitat subsequently influences hard clam productivity and survival. We compared water-column chlorophyl-a concentrations across the landscape at different depths, utilized shell-sectioning methods to determine long-term growth rates of clams that persisted through a seagrass state change, deployed an in-situclam growth experiment, and deployed a predation experiment. We found that chlorophyl-a concentrations were high near the seafloor in early fall within seagrass meadows, a relationship not found at unvegetated sites or higher in the water column. Sectioned clam shells showed a signal from seagrass presence, with growth rates largely higher when the plant was present. Contemporary clam growth was variable across the seascape, with the lowest productivity occurring at sites furthest from the seagrass meadow. Finally, adult clam predation was lower in dense seagrass, while juveniles experienced similar pressure across the seascape. Our results show that the restored seagrass habitat appears to provide several benefits to hard clams, with observed increases in food availability and short and long-term productivity, and reduced predation for adult individuals. However, we also observed high predation on juveniles, indicating recruitment may be limited by clam predators facilitated by seagrass.

Presented by

Michael Cornish <mrc8bn@virginia.edu>

Institution

University of Virginia

Other Affiliations

Virginia Coastal Reserve LTER

Keywords

Marine Ecology, Seagrass, Foundation Species

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Genetic data reveals population connectivity of a non-native bryozoan in the Santa Barbara Channel

Paige Miller, Henry Page, Makenna Colucci, Rachel Simons, Susan Zaleski, Robert Miller

Abstract

Watersipora subatra, a non-indigenous byrozoan, has colonized artificial and natural habitats in the Pacific Outer Continental Shelf region (OCS: Santa Barbara Channel/Santa Maria Basin and San Pedro Basin). Watersipora has a short, non-feeding larval stage with an estimated planktonic larval duration (PLD) of less than 24 hours. Population connectivity through the dispersal of larvae is an important process that controls species distributions, genetic diversity, and metacommunity dynamics. Currently the effects of offshore infrastructure on genetic connectivity have mainly been examined using biophysical modeling of larval dispersal through particle tracking simulations. Our research uses molecular genetic tools to test predictions of larval connectivity derived from modeling. We are using DNA extracted from colonies of Watersipora found on offshore oil and gas platforms, other artificial habitats, and natural reefs in the Pacific OCS to evaluate genetic connectivity between populations occupying these different habitats. In addition, the visible skeletal structures of Watersipora colonies used for DNA analysis will be evaluated using Scanning Electron Microscopy (SEM) to relate phenotypic variation to genotypic variation.

Presented by

Paige M Miller <paigemiller@ucsb.edu>

Institution

Marine Science Institute, University of California, Santa Barbara

Other Affiliations

Bureau of Ocean Energy Management, Department of the Interior and Earth Research Institute, UCSB

Keywords

Population Connectivity, Biophysical Modeling, Artificial and Natural Habitats

Cyberinfrastructure to Monitor Soil Organic Matter in Salt Marshes of the Georgia Coast

Rajneesh Sharma, Jianwei Hao, Deepak Mishra, In Kee Kim, S. Sonny Kim, Lakshmish Ramaswamy, and Lori Sutter

Abstract

Salt Marshes serve a variety of ecosystem services such as upland runoff nutrients absorption, sediment filtration, and atmospheric carbon sequestration. However, since the Industrial Revolution, the contiguous US has lost 53% of its wetlands. Wetlands store almost 20—25% of the global SOC stock with just 4—6% of the global land area. Loss of this carbon can lead to major increases in CO2 in the air. This makes monitoring, modeling, and mapping SOC dynamics in salt marshes a critical research area. However, conventional field sample-based mapping of SOM in wetlands is cost and labor-intensive. In this project, we demonstrate a field-deployable and remotely communicable cyberinfrastructure for SOC monitoring in tidal wetlands, with the ultimate goal of scaling up field-based remote sensing SOM models to satellites

Presented by

Rajneesh Sharma

Institution

University of Georgia, Department of Geography

Other Affiliations

School of Computing, University of Georgia, Athens, Georgia; College of Engineering, University of Georgia, Athens, Georgia; Biology & Marine Biology, University of North Carolina Wilmington

Keywords

Tidal Wetalnds, Soil Organic Carbon, Cyberinfrastructure, Soil Sensors

Surface flow and primary productivity in the Santa Barbara Channel

Richard J. Brokaw, David A. Siegel, Libe Washburn

Abstract

Primary productivity in the Santa Barbara Channel (SBC) is dominated by phytoplankton blooms, which are forced by the upwelling of deep, nutrient-rich water to the surface. The magnitude and spatial extent of these blooms are highly variable and are often complicated by surface flow processes. We analyze the atmospheric factors which cause variable surface current patterns in the SBC, and how these patterns drive spatial and temporal variability in sea surface temperature and chlorophyll. Simulated surface drifter trajectories using High-frequency radar surface current measurements provide an estimate of surface water retention within the channel. Seasonal analysis suggests that the combination of upwelling-favorable wind stress and a poleward alongshore pressure gradient force creates a retentive environment, which helps determine the spatial pattern of phytoplankton blooms. We additionally implement empirical orthogonal function (EOF) analysis to elucidate the dominant modes of surface current variability. We find evidence that suggests significant changes in along-channel flow may lead to the advection of surrounding waters into the SBC and the alteration of surface temperature and chlorophyll observed within the channel. Stepwise linear regression indicates that the horizontal advection of surrounding water masses is more important than retention in determining phytoplankton bloom magnitude, and we are presently working on defining and quantifying this along-channel flow mechanism.

Presented by

Richard J Brokaw <rbrokaw@ucsb.edu>

Institution

University of California, Santa Barbara

Keywords

Surface currents, Primary Productivity, Phytoplankton

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Effects of climate change and water management on West Florida Shelf’s dynamics

Robert Burgman and Laurent Cherubin

Abstract

In the present study we evaluated, in a high resolution simulation (1.5 km), the separate and combined effects of freshwater discharge management and climate warming by 1 °C on the Loop Current (LC) intrusions on the West Florida Shelf (WFS) and its dynamics in the subtropical western Atlantic. Based on a one-year simulation in which a LC and its eddy intruded on the WFS, either the increase of freshwater discharge or the climate warming led to a change in the stratification properties of the WFS significant enough to affect the type of LC intrusions. Increased freshwater discharge contributed to the intensification of shelf water mixing that favors surface intrusion of LC waters. On the contrary, 1 °C warming led to increased shelf waters stratification that favors bottom intrusions. Either type of intrusion leads to a different oceanographic regime on the shelf to which the ecosystem might respond differently. Our study suggests, however, that increased freshwater discharge could mitigate the effect of climate warming on the WFS by reducing shelf waters stratification. The WFS response to cold air outbreaks that are common in the fall and winter months was also analyzed. It showed that under a warmer climate, the increased stratification due to the freshwater discharge at the end of the boreal summer wet season is cancelled by the warmer climate and reduces the available potential energy on the shelf, limiting coastal upwelling, instabilities, and shelf convection.

Presented by

Robert Burgman

Institution

Florida International University

Other Affiliations

Institute of Environment

Keywords

West Florida Shelf, Loop Current, Climate Change, Comprehensive Everglades Restoration Plan

Fine-scale findings at fronts and filaments: tracking plankton patches in the California Current Ecosystem

Shailja Gangrade, Inès Mangolte, Marina Lévy, Mark Ohman, Peter Franks

Abstract

Oceanic mesoscale (10-100 km) stirring features, such as fronts and filaments, are common sites of enhanced plankton biomass in the California Current Ecosystem, a region in which wind-driven upwelling of nutrient-rich waters stimulates plankton growth. While many studies have described how in situ biogeochemical reactions, such as growth and grazing, contribute to biological enhancement at these flow features, the physical movement of plankton patches is less discussed. Because waters flow at 50-80 km/d along these features, waters are resident within them for only a few days, leaving little time for local reactions to regulate the average biological signal. Therefore, we ask: what biological and physical mechanisms drive the development of plankton patchiness in these flow features, and what are the water mass origins and “histories” of these plankton-rich waters? Source-water trajectories using satellite-derived velocities and in situ hydrographic and biological sampling reveal that unique water mass pathways (“histories”) determine planktonic community structure: upwelling pulses generate plankton patches at the coast, and distinct patches from inshore and offshore origins converge at fronts and filaments. We also find that water mass histories influence the spatial and taxonomic structure of the plankton community on scales of 10-50 km over a days-weeks. Such fine-scale gradients allow us to reinterpret physical-biological dynamics at fronts and filaments. Because these dynamics also regulate the flux of organic carbon horizontally and vertically, this study provides spatial and temporal scales that can help parametrize carbon flux modeling in this ecosystem.

Presented by

Shailja Gangrade

Institution

University of California San Diego, Scripps Institution of Oceanography

Keywords

plankton, patchiness, nutrients, stirring, upwelling

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Connectivity and habitat use along an environmental gradient analyzed with metabarcoding and traits

Stephanie A. Matthews, Erica Goetze, Mark D. Ohman

Abstract

Changes in the physical environment, including increased stratification, can decrease nutrient availability and depress rates of primary productivity. The cross-shore gradient within the California Current Ecosystem ranges from active upwelling to more stratified mesotrophic environments, and can be used in a space-for-time substitution framework to test the potential effects of future warm, stratified oceans on mesozooplankton distributions. We hypothesized that mesozooplankton vertical distributions covary with cross-shore environmental gradients, with vertical shifts varying among traits. Here, we test these hypotheses using Zooscan imaging and DNA metabarcoding of depth stratified MOCNESS samples collected between the surface and 450m. We find that vertical distributions of mesozooplankton do shift in the cross-shore direction and that light penetration, a proxy for predation risk, is the strongest predictor of magnitude of vertical shifts. These shifts in vertical distribution are most uniform among carnivorous taxa, while herbivorous taxa tend to co-occur with the chlorophyll maximum even in clear offshore waters. We also observed greater cross-shore community similarity in the mesopelagic depths than in the surface ocean, indicating that deep-dwelling zooplankton communities may be structured by different pressures than surface communities. Our results indicate that increased stratification of future oceans may drive mesozooplankton communities deeper in the water column.

Presented by

Stephanie A. Matthews

Institution

Integrative Oceanography Division and California Current Ecosystem LTER site, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, 92093-0218, USA

Other Affiliations

Department of Oceanography, University of Hawaii at Manoa, Honolulu, HI, 96822, USA

Keywords

Zooplankton, DNA, traits, environmental shifts, ocean warming

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Efficient carbon export in the Northern Gulf of Alaska during the 2019 Pacific Marine Heatwave

Stephanie O’Daly, Gwenn Hennon, Thomas Kelly, Suzanne Strom, Andrew McDonnell

Abstract

Sinking marine particles transport carbon to the deep ocean from the ocean’s surface, in a process termed the biological carbon pump. This process is important in modulating atmospheric carbon dioxide concentration and supplying food to the benthos. Few in situ measurements exist of the biological carbon pump in the Gulf of Alaska and therefore modeling studies predicting carbon fluxes in this region are poorly constrained. In this study, we aim to (1) characterize the magnitude and efficiency of the biological carbon pump and (2) identify drivers of carbon flux in the northern Gulf of Alaska. We deployed drifting sediment traps to collect bulk carbon flux measurements and intact sinking particles in polyacrylamide gels simultaneously. We found high carbon flux magnitude, with low attenuation over depth, and high export efficiency during the 2019 Pacific marine heat wave in the northern Gulf of Alaska. We quantitatively attributed carbon flux between 9 particle types, including various fecal pellet types, dense detritus, and aggregates using polyacrylamide gels. The contribution of aggregates to total flux (47 – 96%) suggests that aggregation processes, not zooplankton repackaging, played a dominant role in carbon export during the summer of 2019 in the northern Gulf of Alaska. These results run counter to the prevailing expectation that marine heat waves will decrease the magnitude and efficiency of the biological carbon pump. These results and further studies may improve climate models and benthic fisheries management in the North Pacific.

Presented by

Stephanie O'Daly

Institution

University of Alaska Fairbanks

Keywords

Oceanography, carbon cycling, carbon flux, marine particles

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Maya I. Thomas & Deborah K. Steinberg

Abstract

Climate-induced changes in zooplankton abundance and species composition can dramatically affect the pelagic food web and biogeochemical cycling. As part of the Palmer Antarctica Long-Term Ecological Research program, we examined long-term (1993 to the present) and spatial trends in fecal pellet carbon production by zooplankton along the Western Antarctic Peninsula (WAP), one of the most rapidly warming regions on Earth. While large, solitary (asexual stage) salps produced fecal pellets with the highest individual carbon content, adult Antarctic krill (Euphausia superba), due to their higher abundance, contributed the most to fecal pellet production (FPP) at the community level. E. superba FPP follows a 5-year cyclic pattern in peak FPP which is tied to their abundance and life cycle. Salp FPP peaks occur in years of massive salp blooms, which do not occur in the same years as krill FPP peaks. Due to their habitat preferences, adult E. superba dominated FPP in the coastal and far south subregions of the WAP, while salps (aggregate, sexual stage) dominated the south and slope subregions. FPP in krill and salps is thus a function of animal size, abundance, and environmental conditions. Long-term, or interannual, alteration in ecosystem structure from one dominated by krill to one by salps could directly affect export of fecal pellet carbon.

Presented by

Maya I. Thomas <mithomas@vims.edu>

Institution

Virginia Institute of Marine Science, William & Mary

Keywords

zooplankton, Antarctica, biogeochemical cycling, carbon export

▼ New methods/tech Back to top

Soundscape recordings & machine learning reveal Arctic ecological dynamics

Natalie T. Boelman, Lamont-Doherty Earth Observatory, Michael Mandel, Enis Coban (City University of New York Brooklyn);Todd Brinkman, Megan Perra, Scott Leorna, Heather Greaves (Univ. of Alaska Fairbanks); Glen Liston, Adele Reinking (Colorado State Univ.); Eleanor Davol (Barnard College)

Abstract

Across North America, Arctic and boreal regions have been warming at a rate two to three times higher than the global average. At the same time, human development continues to encroach and intensify, primarily due to demand for natural resources, such as oil and gas.

The vast and remote nature of Arctic-boreal regions typify their landscapes, environment, wildlife, and people, but their size and isolation also make it difficult to study how their ecosystems are changing.

To overcome these challenges, autonomous recording networks can be used to characterize “soundscapes” – a collection of sounds that emanate from landscapes. Soundscapes contain quantitative information about wildlife occupancy, behavior, and phenology, as well as environmental conditions, insect activity, and anthropogenic activity. Soundscape ecology, where quantitative relationships between landscapes and the composition of their sounds are defined and evaluated, is a relatively new methodology that is growing steadily. Unlike traditional observing methods that are expensive, labor-intensive, and logistically challenging, sound-recording networks provide a cost-effective means to both monitor and understand the response of wildlife to environmental and anthropogenic changes across vast areas.

However, the efficient extraction of useful ecological information from the large volumes of soundscape data that are collected has proven difficult. New, automated techniques are necessary to analyze observed, landscape-level acoustic datasets that have previously been considered too large and complicated for use in wildlife research. The information these datasets provide will provide better understanding of how wildlife is influenced by changing environmental and anthropogenic change. The study presented here is part of a larger, five-year, NSF Navigating the New Arctic (NNA) funded project with the overall goal of understanding the influence of both environmental dynamics and increasing anthropogenic activity on the behavior and phenology of migratory songbird, waterfowl, insect and caribou (Rangifer tarandus, not included in this poster) communities in Arctic-boreal Alaska and northwestern Canada.

Presented by

Natalie Boelman

Institution

Lamont-Doherty Earth Observatory, Columbia University

Keywords

Remote sensing of seasonal open water moats in an ice-covered Antarctic lake

Michael Stone, Mark Salvatore, Peter Doran

Abstract

The perennially ice-covered lakes of the McMurdo Dry Valleys, Antarctica provide a year-round reservoir of liquid water in a normally frozen landscape. During the austral spring and summer, solar radiation penetrates the lake ice covers, causing the sediment beneath the shallow lake margins to heat up and melt the overlying ice. Melting progresses upward toward the lake surface, creating a liquid "moat" around the perimeter of the lake. An "open" moat is an area where this moat water breeches the surface. Open moats provide an avenue for gas and nutrient exchange between the lake waters and the atmosphere. The area of an open moat determines the rate of these processes and affects the amount of light and turbidity that near-shore benthic communities are exposed to. Despite its ecological importance, current methods for tracking open moat area rely on slow, subjective manual analysis of satellite imagery, producing a low-resolution record with little quality control. Here we present a new, remote sensing-based method for measuring open moat area in multi-band satellite imagery that is both faster and more objective than manual analysis. Initial results show agreement between both methods and provide a higher resolution record of intra-seasonal variability in open moat area. Future work will extend the open moat area record at this lake and expand it to other Dry Valley lakes.

Presented by

Michael Stone

Institution

Louisiana State University, Department of Geology & Geophysics

Other Affiliations

Northern Arizona University, Department of Astronomy and Planetary Science

Keywords

Remote Sensing, NDWI, Lakes, Polar, MCM

Neural Networks in Saltmarsh Mapping

Yiyang Xu, William Cole Franks, Sergio Fagherazzi

Abstract

Presented by

Yiyang Xu

Institution

Boston University, Department of Earth and Environment; MIT, Department of Mathematics

Keywords

▼ Nutrient Cycling Back to top

Contribution of WCRs/WCEs to the cross-slope transport on DIN

Lu Wang, Changsheng Chen, Joseph Salisbury

Abstract

Warm core rings (WCRs) and warm core eddies (WCEs) are common in a western boundary current system like the Gulf Stream. The biogeochemical processes for example the nutrient cycle in the US northeast coastal region would be considerably affected by the associated shelf-slope exchanges. The Northeast Biogeochemistry and Ecosystem Model (NeBEM) was developed to study the contribution of WCRs and WCEs to cross-slope nutrients transport. There were 5-6 WCRs during January to April in the year 2017 and 2018. The duration influenced by WCRs and WCEs from in that period were about 53 d, 49 d, 19 d and 38 d in Scotia Shelf (SS), Northeast Chanel (NEC), Gorges Bank (GB) and Mid Atlantic Bight (MAB), respectively. From January to April, the flux was increased 44%, 29% and 39% with the influence of WCRs and WCEs than without. The flux direction through GB could be revised when the WCRs and WCEs happened.

Presented by

Lu Wang <lwang1@umassd.edu>

Institution

University of Massachusetts Dartmouth, School of Marine Science and Technology

Keywords

Warm Core Ring, Cross-slope Transport

New Insights into the Nitrogen Dynamics of Santa Barbara Coastal-LTER Kelp Forests

Natalie Dornan, Kristen Michaud, Bob Miller, Alyson Santoro

Abstract

Kelp forest ecosystems along the western coast of North America are largely supported through fertilization of coastal waters with upwelled nitrate (NO3-). In the Santa Barbara Channel, upwelling is seasonal and ceases from summer into late fall. Research from the Santa Barbara Coastal-LTER (SBC-LTER) found the giant kelp Macrocystis pyrifera can survive during warm periods when [NO3-] is insufficient to maintain growth (<1 μM). Kelp’s survival when [NO3-] is limiting suggests: 1. Accessing recycled nitrogen to alleviate the deficit, and/or 2. A higher affinity for [NO3-] than previously known. This research seeks to better understand how M. pyrifera uses various ambient nitrogen compounds, and how it can survive in exceedingly low [NO3-]. Preliminarily, we focused on increasing measurements of recycled nitrogen within and outside of kelp forests and processing kelp tissue for δ15N. We collected high-resolution recycled nitrogen data from 2021-2022 (n=276) at two sites within kelp forests (Arroyo Quemado and Mohawk) and one offshore (Mohawk Offshore), finding significantly different recycled nitrogen within kelp forests across seasons. Additionally, we processed five years of archived monthly kelp tissue data (2015-2020) from QM for stable isotope analysis. These results show a seasonality of δ15N and %N influenced by spring upwelling that can be predicted by ambient [NO3-], but does not fully explain all of the variance (R2 = 0.09, p = 0.03 and R2 = 0.2, p = 0.001 respectively). Our findings provide new insights into nitrogen dynamics of ambient conditions and kelp tissue chemistry in Santa Barbara kelp forests. Continued research into spatiotemporal trends of kelp-nitrogen dynamics allows us to better understand and predict their production and resilience in future climate scenarios.

Presented by

Natalie Dornan <nataliedornan@ucsb.edu>

Institution

University of California, Santa Barbara (UCSB)

Other Affiliations

UCSB's Marine Science Institute, NOAA's Office of National Marine Sanctuaries

Keywords

Nutrients, nitrogen, marine, biogeochemistry, kelp, coastal ecosystem, stable isotopes, time-series

Characterization of a marine Ecosystem through Autonomous Bio-optics

Thomas Kelly, Hisatomo Waga, Suzanne Strom

Abstract

Primary production is a key, top-level ecosystem process that influences energy availability and biogeochemical rates. Through a unique combination of bio-optical instruments, and paired with traditional measurements, we strive to map spatial and temporal patterns in primary production and phytoplankton community composition across a dynamic marine ecosystem. Such a study may be transformative with respect to ecosystem modeling and driver identification and informative as a relative baseline against which to monitor continuing regional change.

Presented by

Thomas Kelly

Institution

University of Alaska Fairbanks

Keywords

NGA,Primary Production, Autonomous,marine,biogeochemical

Spatial and Temporal Distribution of Particulate Iron in the Northern Gulf of Alaska

Emily Ortega, Ana Aguilar-Islas

Abstract

Particulate material constitutes an important source of potentially bioavailable labile particulate iron to the surface waters of the Northern Gulf of Alaska with seasonal variability. This particulate material enters the system throughout the year with peak inputs of driven by glacially fed rivers in summer and fall. This fraction contributes to the overall pool of bioavailable iron through exchange with the dissolved phase especially at inshore stations near point sources such as the Copper River where total particulate iron can be found at concentrations >2μM during the summer months. These inputs help fuel primary production in the NGA.

Presented by

Emily Ortega <elortega@alaska.edu>

Institution

University of Alaska Fairbanks, College of Fisheries and Ocean Sciences

Other Affiliations

NGA LTER

Keywords

Inorganic cycling, nutrients, marine biogeochemistry, coastal ecosystem

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▼ Other Networks Back to top

Methane emission potential across subtropical, temperate, and arctic ecosystems

Sparkle. L. Malone, Youmi Oh, Roisin Commane, Alexandra R. Contosta and Ruth Varner

Abstract

Limiting methane concentrations in the atmosphere is a key strategy to avoid runaway warming due to climate change. To do this, we need to better constrain the global methane budget, especially the least certain part of the budget that involves biogenic sources and sinks.The Continental Methane Observatory (CMO) will be a mid-scale infrastructure project designed to capture the magnitude and variability of biogenic methane fluxes in the US. Design elements include physical infrastructure, cyber infrastructure, and supporting capabilities for the construction of both.

Presented by

Sparkle L. Malone

Institution

Yale University

Other Affiliations

Florida Coastal Everglades LTER, AmeriFlux, NEON

Keywords

Methane, infrastructure, Ameriflux

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▼ Population Studies Back to top

Mosquito population dynamics within Miami-Dade County households: the use of community-based mosquito surveillance programs to facilitate infestation, genetic, and sense of community research

Helen Wagner*, Gabriel Perez, Jessica Quinones, Michael Ramon, Kristian Lopez, Dr. Andre da Costa da Silva, Dr. Anthony Bellantuono & Dr. Matthew DeGennaro

Abstract

Populations of non-native Aedes aegypti, the main vector for dengue virus transmission and other infectious diseases, are expanding throughout Florida due to the state’s tropical and subtropical climate. In Florida, the exposure of insecticides is not evenly distributed through every county, potentially generating genetic diversity in target populations of Ae. aegypti. The primary aim of this project is to characterize the Ae. Aegypti whole genomes in order to determine the level of genetic variation in Florida. Currently, low levels of genetic variability have been observed throughout South Florida. Using the AaegL5 version of the reference genome, Ae. aegypti whole genomes could serve as a potent tool to reveal different levels of gene flow and variability. After studying the interactions between the spatial patterns and the ecological covariates, I will evaluate interactions between infestation and landscape features and the effectiveness of the Florida Aedes Genome Group (FLAGG) community mosquito surveillance program. This study will provide the foundational science required for the development of vector control management programs that use knowledge on mosquito expansion and infestation in urbanized subtropical landscapes to understand vector capacity.

Presented by

Helen Wagner <hwagn008@fiu.edu>

Institution

Florida International University

Other Affiliations

FCE LTER

Keywords

Genomics, Vector, Landscape Ecology, Ecological Covariates

Camera-Trap Assessment of Small Mammal Occupancy in a Coastal Virginia Forest

John H. Porter and Raymond D. Dueser

Abstract

We monitored small mammal species composition, occupancy and activity along a gradient of elevations relative to tidal flooding as part of an experimental study examining the effects of sea level rise on forest composition at a coastal site in Virginia. We developed a small, light-weight camera-trapping system for surveys of small mammals. The “Mousecam” (a low-cost variant of a “Hunt trap”, McCleery et al. 2014. Wild. Soc. Bull. 38:887-891) uses a $50 wide-angle trail camera enclosed in two, nested, inverted, 5-gallon buckets which are accessible by small animals through holes cut in the sides. Here we report the results of the first field-scale application of the Mousecam in the collection of small mammal data.

Presented by

John H. Porter

Institution

University of Virginia

Other Affiliations

Virginia Coast Reserve LTER

Keywords

small-mammal, camera traps, mammalian activity, location, coastal forest

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Primed and Cued: Linking Interannual and Seasonal Variations in Freshwater Flows to the Spawning Migrations of Common Snook in the Florida Coastal Everglades

J.A. Massie, R.O. Santos, R.J. Rezek, W.R. James, N.M. Viadero, R.E. Boucek, D.A. Blewett, A.A. Trotter, P.W. Stevens, and J.S. Rehage

Abstract

Spawning migrations are widespread among fishes, often occurring in response to changing conditions prompting movement into habitats favorable to reproduction (migratory cues). However, some individuals may choose not to migrate, and conditions preceding the spawning season (migratory primers) may influence this decision. Few studies have provided empirical descriptions of these prior conditions, partly due to a lack of long-term data allowing for robust multi-year comparisons. To investigate how primers and cues interact to influence migration, we use eight years of acoustic telemetry data (2012-2019) from Common Snook (Centropomus undecimalis) in the Florida Coastal Everglades. A contingent of Snook migrate between rivers and coastal spawning sites, varying annually in both the proportion of the population that migrates and the timing of migration. We hypothesize that 1) interannual differences in hydrologic conditions preceding the spawning season contribute to the number of individuals migrating each year, and 2) specific environmental cues trigger the timing of migrations during the spawning season. We modeled both the annual and seasonal migratory response in relation to flow characteristics (river stage, daily rate of change), other abiotic conditions (temperature, salinity), fish size, and phenological cues (photoperiod, lunar cycle). Our results indicate that the timing/extent of minimum river stage prior to migration and fish size act as primers for Snook migration, and that high stages and daily rates of change serve as primary cues triggering spawning migrations. Mechanistic descriptions of conditions that promote migration and reproduction can help inform management decisions aimed at conserving ecologically and economically important species.

Presented by

Jordan Massie

Institution

Florida International University, Institute of Environment, Department of Earth and Environment

Keywords

Acoustic telemetry, coastal fishes, freshwater flow, migratory drivers, movement ecology, long-term data, partial migration, riverine fishes, skipped spawning

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Towards a Demographic Model of Giant Kelp: Using Data to Constrain Parameters

Nathalie Eegholm, Thomas Bell, David Siegel

Abstract

Giant kelp, Macrocystis pyrifera, is an important foundation species found in temperate coastal regions worldwide. Giant kelp forests are highly dynamic systems, with variable seasonal and annual fluctuations that make predicting biomass challenging. To improve our understanding of the spatiotemporal dynamics of these ecosystem engineers, we have leveraged knowledge of the life history of giant kelp and a suite of long-term datasets collected and curated by the Santa Barbara Coastal Long Term Ecological Research (SBC LTER) to construct an agent-based demographic model of giant kelp at key sites in the Santa Barbara Channel. The model tracks individual giant kelp plants and their individual fronds and is forced with annual cycles of nutrients, light, and waves, which all work in combination to modify giant kelp growth, reproduction, and mortality. Our results have shown that our model is able to capture seasonal cycles of biomass and canopy fluctuations consistent with observed in situ data and remotely sensed data from drones and Landsat, but we will need to better constrain important giant kelp life history processes that drive the model to improve our model's performance. Here, we reiterate the utility of using long-term datasets collected by the SBC LTER in helping us gain a process-based understanding of giant kelp plant recruitment and frond elongation. We also consider future data needs for model improvement and application on a regional scale.

Presented by

Nathalie Eegholm <nheegholm@ucsb.edu>

Institution

University of California, Santa Barbara

Other Affiliations

Woods Hole Oceanographic Institute

Keywords

Giant kelp, modeling, population, demography, data, Santa Barbara, macroalgae, marine

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Seagrass restoration enhances coastal fish abundance and diversity

Sean Hardison, Karen McGlathery, Max Castorani

Abstract

Restoration is accelerating to reverse massive global declines of key habitats and recover lost ecosystem functions, particularly in coastal ecosystems. However, there is high uncertainty about the long-term capacity of restored ecosystems to provide habitat and increase biodiversity, and the degree to which ecosystem services are mediated by spatial and temporal environmental variability. We addressed these gaps by sampling fishes biannually for 5–7 years (2012–2018) at 16 sites inside and outside of a rapidly-expanding restored seagrass meadow in coastal Virginia, USA. Despite substantial among-year variation in fish abundance and species composition, seine catches in restored seagrass beds were consistently more numerous (6.4×) and speciose (2.6×) than adjacent unvegetated areas, particularly during summer (vs. fall). Structural equation modeling revealed that, by constraining seagrass distributions, longer ocean water residence times indirectly reduced fish catches and species richness, and that fish community structure was largely consistent between two meadows that varied with respect to depth and proximity to ocean inlets. Together, our results indicate that seagrass restoration yields large and consistent benefits for coastal fishes, but that restoration and its benefits are sensitive to the dynamic seascapes within which it is established. Consideration of landscape-scale environmental variability in the siting of habitat restoration will improve restoration outcomes and the subsequent provisioning of ecosystem services.

Presented by

Sean Hardison

Institution

University of Virginia, Department of Environmental Science

Keywords

fish, community, ecology, restoration, seagrass

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▼ REU Back to top

Consequences of the Invasive Macroalga Undaria pinnatifida for a beach wrack consumer Megalorchestia corniculata

Carina Donne, Alex Siggers, Leena Vilonen, Melinda Smith1, Pankaj Trivedi

Abstract

Presented by

Carina Donne

Institution

Colorado State University

Keywords

Experimental Drought, Konza Praire, Microbial Communities

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The effect of inbreeding on mutualisms

Isabela Borges, Luana Fenstemacher, Sarah Fitzpatrick

Abstract

Presented by

Isabela Lima Borges

Institution

Kellogg Biological Station, Michigan State University

Other Affiliations

College of Engineering, Oregon State University

Keywords

inbreeding, mutualism

ChANGE: The effect of nitrogen gradients on semi-arid versus mesic grassland communities

Mary C Linabury, Melinda D Smith

Abstract

Presented by

Mary C Linabury

Institution

Colorado State University, Department of Biology

Other Affiliations

Graduate Degree Program in Ecology

Keywords

ecology, grasslands, community, nitrogen

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Species Effects on Dune Building

Emily Riffe, Laura Moore, Julie Zinnert

Abstract

The goal of this project is to identify species specific differences in dune growth. Plots were set up with 3 species: Ammophila breviligulata, Uniola paniculata, and Spartina patens on Hog Island which is part of the Virginia Coast Reserve LTER. In just one year, sand accretion was significantly increased with Spartina plots having the highest accretion change (p<0.001). Lateral expansion of vegetation was significantly increased, with Ammophila having the furthest expansion (p<0.001). Percent cover had more variability, with Spartina losing cover, but Ammophila and Uniola had increased cover overall (p=0.02).

Presented by

Emily Riffe <riffee2@vcu.edu>

Institution

Virginia Commonwealth University

Other Affiliations

Virginia Coast Reserve LTER

Keywords

coastal, dune grass

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