Meagan J Eagle , PhD
My research lies at the interface of land and sea and is used to build new tools to address coastal hazards. This dynamic region is experiencing rapid change, with new pressures from rising temperatures and sea level adding to those already wrought by the impacts of coastal development.
Biography
I utilize a suite of geochemical tools, including naturally occurring radioisotopes in the Uranium-Thorium decay series, to understand both the magnitude and rate of change within coastal ecosystems. In particular, I am interested in how salt marshes have responded to a century of accelerating sea level rise, with a focus on their ability to store carbon and dynamically build elevation. I combine historical ecosystem information, gleaned from analysis of salt marsh peat, with modern environmental drivers to constrain future ecosystem responses.
I studied geology at Stanford University (BS/MS) and received a PhD in Chemical Oceanography from the Massachusetts Institute of Technology and Woods Hole Oceanographic Institution Joint Program. There I studied groundwater discharge and associated chemical fluxes. Between going to school, I did a Fulbright Fellowship in Mauritius and worked at Woods Hole Oceanographic Institution. I came to the Woods Hole Coastal and Marine Science Center of the US Geological Survey in 2013 and have worked on coastal wetland and groundwater projects across the US.
Science and Products
Environmental Geochemistry
Coastal Environmental Geochemistry research at the Woods Hole Coastal and Marine Science Center spans multiple ecosystems and topics, including coastal wetlands, aquifers, and estuaries, with the goal of providing data and guidance to federal, state, local, and private land owners and managers on these vital ecosystems.
Continuous Monitoring Data From Herring River Wetlands, Cape Cod, Massachusetts, 2015 to January 2020
The Herring River estuary (Wellfleet, Cape Cod, Massachusetts) has been tidally restricted for over a century by a dike constructed near the mouth of the river. The U.S. Geological Survey collected continuous monitoring data (including water level, soil temperature, air temperature, and meteorological parameters). These datasets can help evaluate key ecosystem drivers.
Continuous Monitoring Data From Natural and Restored Salt Marshes on Cape Cod, Massachusetts, 2016-17
Continuous monitoring data reported are a portion of data from a larger study investigating changes in soil properties, carbon accumulation, and greenhouse gas fluxes in four recently restored salt marsh sites and nearby natural salt marshes. For several decades, local towns, conservation groups, and government organizations have worked to identify, replace, repair, and enlarge cu
Collection, Analysis, and Age-Dating of Sediment Cores from Salt Marshes on the South Shore of Cape Cod, Massachusetts, From 2013 Through 2014
The accretion history of fringing microtidal salt marshes located on the south shore of Cape Cod, Massachusetts, was reconstructed from sediment cores collected in low and high marsh vegetation zones. The location of these marshes within protected embayments and the absence of large rivers on Cape Cod result in minimal sediment supply and a dominance of organic matter contribution to sediment...
Modeling the spatial dynamics of marsh ponds in New England salt marshes
Ponds are common features on salt marshes, yet it is unclear how they affect large-scale marsh evolution. We developed a spatially explicit model that combines cellular automata for pond formation, expansion, and drainage, and partial differential equations for elevation dynamics. We use the mesotidal Barnstable marsh (MA, USA) as a case study,...
Mariotti, G.; Spivak, A.; Luk, S.Y.; Ceccherini, G.; Tyrrell, M.; Gonneea, Meagan An important biogeochemical link between organic and inorganic carbon cycling: Effects of organic alkalinity on carbonate chemistry in coastal waters influenced by intertidal salt marshes
Organic acid charge groups in dissolved organic carbon (DOC) contribute to total alkalinity (TA), i.e. organic alkalinity (OrgAlk). Its effect is often ignored or treated as a calculation uncertainty in many aquatic CO2 studies. This study evaluated the variability, sources, and characteristics of OrgAlk in estuarine waters exchanged tidally with...
Song, Shuzhen; Wang, Zhaohui Aleck; Gonneea, Meagan; Kroeger, Kevin D.; Chu, Sophie N.; Li, Daoji; Liang, Haorui Getting to the core of the matter
The topic of carbon sequestration in coastal salt marshes can serve as the basis of an investigation story line with plenty of authentic relevance and drama! Consider establishing the context with students as an introduction to this lesson. Many resources for teaching about carbon uptake and sequestration in coastal wetlands can be found at the...
Gonneea, Meagan Water salinity and inundation control soil carbon decomposition during salt marsh restoration: An incubation experiment
Coastal wetlands are a significant carbon (C) sink since they store carbon in anoxic soils. This ecosystem service is impacted by hydrologic alteration and management of these coastal habitats. Efforts to restore tidal flow to former salt marshes have increased in recent decades and are generally associated with alteration of water inundation...
Wang, Faming; Kroeger, Kevin D.; Gonneea, Meagan; Pohlman, John; Tang, Jianwu Salt marsh ecosystem restructuring enhances elevation resilience and carbon storage during accelerating relative sea-level rise
Salt marshes respond to sea-level rise through a series of complex and dynamic bio-physical feedbacks. In this study, we found that sea-level rise triggered salt marsh habitat restructuring, with the associated vegetation changes enhancing salt marsh elevation resilience. A continuous record of marsh elevation...
Gonneea, Meagan; Maio, Christopher V.; Kroeger, Kevin D.; Hawkes, Andrea D.; Mora, Jordan; Sullivan, Richard; Madsen, Stephanie; Buzard, Richard M.; Cahill, Niamh; Donnelly, Jeffrey P. Uncertainty in United States coastal wetland greenhouse gas inventorying
Coastal wetlands store carbon dioxide (CO2) and emit CO2 and methane (CH4) making them an important part of greenhouse gas (GHG) inventorying. In the contiguous United States (CONUS), a coastal wetland inventory was recently calculated by combining maps of wetland type and change with soil, biomass, and CH4 flux data from a literature...
James Holmquist; Windham-Myers, Lisamarie; Blanca Bernal; Byrd, Kristin B.; Steve Crooks; Gonneea, Meagan; Nathan Herold; Sara Knox; Kroeger, Kevin D.; John McCombs; J. Patrick Megonigal; Lu Meng; James Morris; Ariana Sutton-Grier; Tiffany Troxler; Donald Weller Blue carbon as a tool to support coastal management and restoration: Bringing wetlands to market case study
A collaborative research approach involving substantial end user and stakeholder engagement was applied to great effect to guide broad, integrated investigation of the science, policy, and management of blue carbon and carbon markets as drivers for coastal wetland management and restoration.Expanding awareness about blue carbon concepts among...
Windham-Myers, Lisamarie; Crooks, Stephen; Troxler, Tiffany G.; Surgeon-Rogers, Tonna-Marie; Kroeger, Kevin D.; Gonneea, Meagan; Abdul-Aziz, Omar I.; Tang, Jianwu; Moseman-Valtierra, Serena Deciphering the dynamics of inorganic carbon export from intertidal salt marshes using high-frequency measurements
The lateral export of carbon from coastal marshes via tidal exchange is a key component of the marsh carbon budget and coastal carbon cycles. However, the magnitude of this export has been difficult to accurately quantify due to complex tidal dynamics and seasonal cycling of carbon. In this study, we use in situ...
Chu, Sophie N.; Wang, Zhaohui Aleck; Gonneea, Meagan; Kroeger, Kevin D.; Ganju, Neil Kamal Environmental controls, emergent scaling, and predictions of greenhouse gas (GHG) fluxes in coastal salt marshes
Coastal salt marshes play an important role in mitigating global warming by removing atmospheric carbon at a high rate. We investigated the environmental controls and emergent scaling of major greenhouse gas (GHG) fluxes such as carbon dioxide (CO2) and methane (CH4) in coastal salt marshes by conducting data analytics and empirical modeling. The...
Abdul-Aziz, Omar I.; Ishitaq, Khandker S.; Tang, Jianwu; Moseman-Valtierra, Serena; Kroeger, Kevin D.; Gonneea, Meagan; Mora, Jordan; Morkeski, Kate Relationship between water and aragonite barium concentrations in aquaria reared juvenile corals
Coral barium to calcium (Ba/Ca) ratios have been used to reconstruct records of upwelling, river and groundwater discharge, and sediment and dust input to the coastal ocean. However, this proxy has not yet been explicitly tested to determine if Ba inclusion in the coral skeleton is directly proportional to seawater Ba concentration and to further...
Gonneea, Meagan; Cohen, Anne L.; DeCarlo, Thomas M.; Charette, Matthew A. Twentieth century warming of the tropical Atlantic captured by Sr-U paleothermometry
Coral skeletons are valuable archives of past ocean conditions. However, interpretation of coral paleotemperature records is confounded by uncertainties associated with single-element ratio thermometers, including Sr/Ca. A new approach, Sr-U, uses U/Ca to constrain the influence of Rayleigh fractionation on Sr/Ca. Here we build on the initial...
Alpert, Alice E.; Cohen, Anne L.; Oppo, Delia W.; DeCarlo, Thomas M.; Gaetani, Glenn A.; Hernandez-Delgado, Edwin A.; Winter, Amos; Gonneea, Meagan Intertidal salt marshes as an important source of inorganic carbon to the coastal ocean
Dynamic tidal export of dissolved inorganic carbon (DIC) to the coastal ocean from highly productive intertidal marshes and its effects on seawater carbonate chemistry are thoroughly evaluated. The study uses a comprehensive approach by combining tidal water sampling of CO2parameters across seasons, continuous in situ measurements of...
Wang, Zhaohui Aleck; Kroeger, Kevin D.; Ganju, Neil K.; Gonneea, Meagan; Chu, Sophie N.
Raising Awareness in the Classroom about Natural Hazards Facing U.S. Coastal Communities
USGS scientists present newly developed education outreach materials at the Smithsonian Science Education Academy for Teachers (SSEATs) held at the USGS National Headquarters in Reston, Virginia.