Applicants will need to select from one of these research topics to include in Part I of their application. Fellow candidates who are invited to submit a Full Proposal will work with the project co-advisors to develop specific objectives and a research plan for how to accomplish those objectives in the two-year fellowship timeframe:
Resilience and Restoration of Seagrasses in West Falmouth Harbor (Co-Supervisors: Mirta Teichberg and Ketil Koop-Jakobsen, Ecosystems Center at Marine Biological Laboratory, Woods Hole, MA)
This project is part of the Long-Term Research in Environmental Biology (LTREB) initiative in West Falmouth Harbor, which focuses on understanding the impacts of nutrient enrichment and climate variability on coastal ecosystem dynamics, including seagrass health and resilience. Over the past decades, seagrass cover in West Falmouth Harbor has drastically declined, yet some populations persist in regions characterized by extreme sedimentary conditions, including high sulfide concentrations (as high as 2 mM). This project will investigate the drivers behind seagrass decline to try to understand the traits that enable survival under harsh conditions, and explore innovative strategies for seagrass restoration. Assessments of sediment chemistry, nutrient dynamics, water quality, and historical land use changes will be used to identify drivers of seagrass decline such as eutrophication, sediment anoxia, and sulfide toxicity. Advanced microelectrode and planar optode techniques could be used to provide high-resolution data on oxygen and sulfide gradients around roots, shedding light on the capacity of seagrasses to modify their immediate microenvironment through processes such as root oxygen leakage. A transplantation experiment relocating seagrasses from both high-stress and low-stress environments within West Falmouth Harbor to areas where seagrasses have been lost will be used to determine whether seagrasses adapted to harsh conditions possess traits that make them better suited for recolonizing degraded habitats.
How Changes in Climate and Land-use Influence Nutrient Delivery to Buzzards Bay (Co-Supervisors: Christopher Neill, Woodwell Climate Research Center, Woods Hole, MA and Casey Kennedy, UMass Cranberry Station, Wareham, MA)
Changes to climate will interact with land-use to shape future hydrology and chemistry in the coastal rivers and streams that flow to Buzzards Bay. This project will examine the interactions of these processes to address one or more of the following: changes to river flow regimes; processes and mechanisms that influence nutrient (particularly nitrogen) delivery from soils to streams and through river networks; and how changing management practices and expanding wetland restoration of the region’s major agricultural crop—cranberries—will affect watershed nutrient balances and ecosystem services. We would support projects that are field-based, modeling-based, or combinations of the two.
Investigating Signatures of Marsh Loss around Buzzards Bay (Co-supervisors: Zoe Hughes, Boston University, Boston, MA and Neil Ganju, U.S. Geological Survey, Woods Hole, MA)
This project will investigate signatures of marsh loss using both coarse and fine-scale imagery. There is a recently developed 40-year time series of the unvegetated to vegetated ratio (UVVR) of Buzzards Bay marshes. UVVR has been used to quantify salt marsh status and vulnerability to sea level rise and to predict salt marsh lifespans. The UVVR time series allows examination for the leading indicators of instability and vegetation loss. Stressors to marsh vegetation in Buzzards Bay include the impacts of sea level rise, high levels of nitrogen, and crab herbivory. Changes at UVVR across sites can be compared with other data (e.g., local relative sea level rise, upland land use, and sediment supply) to help determine drivers. Sites across Buzzards Bay can be analyzed for whether key drivers are consistent or differ across sites. Finer scale aerial imagery from plane flights and drones is available for 13 sites from recent years, which will allow a finer scale spatial analysis of marsh vegetation loss over a shorter period of time.
Carbon Sequestration in Salt Marshes: The Impact of Coastal Squeeze and Salt Marsh Migration (Co-Supervisors: Ketil Koop-Jakobsen and Javier Lloret, Ecosystems Center at Marine Biological Laboratory, Woods Hole, MA)
Building on extensive research from the Great Sippewissett Marsh, a well-documented site of marsh ecosystem dynamics under sea level rise, this project will compare carbon sequestration capabilities in marshes constrained by coastal squeeze versus those experiencing inland migration. The project integrates field-based studies of Great Sippewissett Marsh experiencing coastal squeeze and other sites such as Allens Pond and Ocean View Farm Reserve, where there are not barriers to inland migration and marsh migration initiatives are underway. Shifts in plant species composition and marsh zonation will be compared to document the changing marsh landscape under sea level rise. Carbon stocks will be quantified to determine the difference in relative carbon storage potential of marshes experiencing inland migration and those where coastal squeeze prevents inland migration. How sedimentation influences the resilience and carbon sequestration potential of salt marshes under different sea level rise scenarios will be examined. This project’s comparative analysis of the carbon sequestration benefits associated with mitigating coastal squeeze versus enabling marsh migration can help guide decision-makers on how different management strategies will influence the carbon sequestration potential of salt marshes.
Biomarker assessment of fish contamination in Buzzards Bay (Co-Supervisors: Jed Goldstone and John Stegeman, Woods Hole Oceanographic Institution, Woods Hole, MA)
New Bedford Harbor was historically contaminated with very high levels of polychlorinated biphenyls (PCBs), persistent organic pollutants used in electrical equipment and building materials. Forty years ago, studies of fish in areas of Buzzards Bay distant from New Bedford Harbor showed high levels of biomarker genes that could be induced by PCBs. Cytochrome P450 1A was effectively 100% induced in scup obtained from near the Weepecket Islands and Buoy 13 near the Woods Hole channel. Following the remediation of New Bedford Harbor, we propose to assess molecular biomarkers in scup and other fish from locations in Buzzards Bay to address whether effects that could be attributed to PCBs from New Bedford Harbor have diminished. These analyses could indicate whether there is ongoing exposure to either PCBs or other chemicals that act via the aryl hydrocarbon receptor.
Evaluating innovative technologies to reduce the impact of septic system contaminants (Co-Supervisor: Jed Goldstone, Woods Hole Oceanographic Institution, Woods Hole, MA; collaboration with Barnstable County and Helen Poynton, University of Massachusetts Boston)
Innovative/alternative (I/A) septic systems are designed to remove nitrogen from household sewage. However, I/A systems may have the additional co-benefit of removing contaminants of emerging concern (CECs) – unregulated chemicals often associated with complex non-point source effluents. We currently study the effects of septic effluent on gonadal development and sex reversal in blue and ribbed mussels, in collaboration with the Massachusetts Alternative Septic System Test Center (MASSTC). These studies will document the ability of I/A systems to remove effluent components that affect bivalve reproduction. Postdoctoral projects could be focused on gene expression, gonadal development, or chemical analyses.
Mechanisms of evolved chemical resistance and effects of site remediation on fish populations in the New Bedford Harbor Superfund site (Co-Supervisors: Mark Hahn and Sibel Karchner, Woods Hole Oceanographic Institution, Woods Hole, MA)
New Bedford Harbor was placed on the Superfund List in 1983 because of extreme contamination with polychlorinated biphenyls (PCB). The contamination drove the evolution of PCB resistance in a local population of Atlantic killifish. Site remediation has taken decades but is nearing completion. Potential postdoctoral projects could better understand the mechanisms and impacts of the pollution and its remediation at multiple levels of biological organization (molecular to ecosystem). At the molecular level, genomic studies have implicated the AIP gene and four AHR genes as candidate resistance genes. How these genes confer resistance is not well understood but can be investigated using genomic models (CRISPR-Cas9-mediated loss-of-function mutants of AIP and AHRs) that we have in killifish and zebrafish. At the population and ecosystem level, there are questions about whether the genetic changes that confer resistance to the killifish population will (1) be maladaptive (have fitness costs) after remediation, and (2) whether the resident population will have lost its PCB resistance (and hence its genetic markers of resistance). Other projects could study possible interactions between chemical (PCB) and environmental stressors (e.g., hypoxia). These projects represent a unique opportunity to understand mechanisms of population-level effects of pollutants and how they change after remediation, advancing our understanding of the long-term impact of chemicals on the Buzzards Bay ecosystem.
Organic pollutants in marine bivalves (Co-Supervisor: Jed Goldstone, Woods Hole Oceanographic Institution, Woods Hole, MA)
Blue mussels (Mytilus edulis), ribbed mussels (Geukensia demissa), and oysters (Crassostrea virginica) are foundation species in New England coastal waters. These foundation species establish and maintain the key habitats that provide essential ecosystem services along the North Atlantic coast. Blue mussels influence principally rocky intertidal surfaces, as “ecological engineers,” while ribbed mussels are key to the physical structure of saltmarshes by contributing both to the vertical resilience and resistance to shoreline erosion. Oysters, once hugely abundant, are important aquaculture species that filter tons of suspended organic matter per year from coastal waters. All of these sessile bivalves are “active samplers” of chemical contaminants, and gene transcriptional responses could provide both readouts of contaminant exposures and predictors of animal health. Bivalves have been used to track chemical trends (NOAA MusselWatch program), but transcriptomic analyses are a much cheaper analysis option. We would like to develop a better understanding of pollutant responses in these keystone organisms, and understand the contributions of pollutants to population changes. Postdoctoral projects could be focused on transcriptomics, enzyme analyses, and/or chemical analyses.
Seagrass Restoration Research in Buzzards Bay (Co-Supervisor: Matthew Long at Woods Hole Oceanographic Institution, Woods Hole, MA)
This project involves addressing coastal water quality issues in parallel with developing new platforms for eelgrass restoration in Buzzards Bay. These restoration techniques focus on advancing eutrophication reduction through the development of seagrass-sediment bioreactors to enhance denitrification while also enabling seagrass restoration in coastal bays and estuaries where seagrass was historically abundant. Seagrass-sediment bioreactors are designed to increase sediment surface area exposed to oxygenated water and to allow the height of seagrass growth to be manipulated to ensure sufficient light and oxygen for the seagrass to thrive. Topics to research include the effectiveness of the bioreactors and stimulating seagrass growth and denitrification.
How the Balance of Shorebird and Crab Populations Impact Marsh Loss around Buzzards Bay (Co-supervisors: Alice Besterman, Towson University, Baltimore, MD and Zoe Hughes, Boston University, Boston, MA)
Salt marsh ecosystems are impacted by a variety of stressors including sea level rise, nutrient pollution, and crab herbivory. The stressors can have potentially compounding effects. This project would explore the interactions between how sea level rise may be enhancing the habitat suitability of marsh edges for crab burrowing, the ability of changing shorebird populations to control salt marsh crab populations, and potential feedbacks between populations of different marsh crab species. The effects on marshes around Buzzards Bay are not uniform and differences between sites around the Bay would be investigated to understand drivers for the level of impact.
Marsh Hydrology Impacts on Marsh Resilience (Co-supervisors: Brian Yellen and Jon Woodruff, UMass Amherst, Amherst, MA)
To keep pace with sea level rise, salt marshes must accumulate sediments either through trapping sediments delivered with incoming tides or by deposition of biomass and growth of root material. The geometry of salt marsh creeks and whether they exist as a single channel or a network of smaller channels may affect the delivery of sediments to the salt marsh platform. This project would examine how sediment deposition is affected by marsh hydrology and geometry. Buzzards Bay is a relatively low sediment system, and this project would also provide insight into the role of marsh sediment trapping in marsh accumulation in Buzzards Bay.