Kevin D Kroeger, PhD
Kevin Kroeger has studied coastal ecosystems since 1990, with focus on a range of topics including fluxes and biogeochemistry of nitrogen in groundwater discharge to estuaries and wetlands, estuarine water quality, and carbon and greenhouse gas cycling and fluxes in coastal wetlands.
Kroeger is lead of the Biogeochemical Processes group at Woods Hole Coastal and Marine Science Center, and lead of a new project titled: Biogeochemical Drivers of Wetland Persistence and Feedbacks on Coastal Hazards The objectives of this Project are to provide guidance to federal (National Park Service, Fish & Wildlife Service, Army Corp of Engineers), state, local and private land owners and managers regarding stability and persistence of coastal wetlands under a range of hydrological management conditions and changing environmental conditions. Tidal wetlands provide critical services to society, including protection of infrastructure from coastal hazards, and habitat provision for economically important species. A large fraction of U.S. tidal wetlands, however, has been lost or degraded during recent centuries due to human actions, largely related to development and utilization of coastal lands. Feedbacks and interactions among natural and anthropogenic drivers have altered the stability and persistence of coastal wetlands. Decisions regarding hydrological management can alter the balance of organic matter production, retention and preservation, and thus management actions can either promote wetland persistence and resilience, or cause catastrophic loss of elevation, putting coastal infrastructure at increased risk of flooding or storm damage. This project impacts wetland management decisions. The contiguous U.S. has close to 2 million hectares of estuarine and marine wetlands. Nearly all of that area is under some level of management, with the federal government being the largest single manager. Land managers at FWS and NPS, and flood managers at ACOE, must make decisions regarding whether to spend substantial funds to maintain, repair and enhance water control structures under increasing rates of sea level change, or alternatively whether to reduce or remove hydrological management, to restore managed wetlands to more natural hydrology and enhance the capability of wetlands to build elevation over time, and to migrate landward. Society needs guidance and predictions regarding the result of those decisions for continued elevation gain, migration, and ongoing persistence of the wetlands.
Science and Products
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.
Submarine groundwater discharge (SGD) is an ubiquitous coastal process that is driven by a composite of climatologic, hydrogeologic, and oceanographic processes. For example, terrestrial hydraulic gradients that reflect both short and long term climatic conditions almost always transport both surface and ground water toward the coast. In coastal waters, physical oceanographic processes such as...
Advancing understanding of ecosystem responses to climate change with warming experiments: what we have learned and what is unknown?
Advancing our mechanistic understanding of ecosystem responses to climate change is critical to improve ecological theories, develop predictive models to simulate ecosystem processes, and inform sound policies to manage ecosystems and human activities. Manipulation of temperature in the field, or the “ecosystem warming experiment,” has proved to be a powerful tool to understand ecosystem...
Collection, analysis, and age-dating of sediment cores from salt marshes on the south shore of Cape Cod, Massachusetts, from 2013 through 2014
Elevation of the marsh surface was measured with RTK-GPS to evaluate where the marsh falls within the current tidal frame. The historic marsh surface elevation was then reconstructed using the calculated age of each depth interval and its elevation, assuming that elevations within this shallow zone (less than 30 cm) have been preserved for the past century.
Data compilation of soil respiration, moisture, and temperature measurements from global warming experiments from 1994-2014
This dataset is the largest global dataset to date of soil respiration, moisture, and temperature measurements, totaling >3800 observations representing 27 temperature manipulation studies, spanning nine biomes and nearly two decades of warming experiments. Data for this study were obtained from a combination of unpublished data and published literature values.
This data release contains the compilation of multiple elevation products into a continuous digital elevation model at a resolution of 3-arcseconds (approximately 90 meters) from the terrestrial landscape to the seafloor for the contiguous U.S. and portions of Mexico and Canada, focused on the coastal interface.
Groundwater data were collected in the spring and fall of 2008 from three sites representing different geological settings and biogeochemical conditions within the surficial glacial aquifer of Long Island, NY.
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.
Natural climate solutions for the United States
Limiting climate warming to <2°C requires increased mitigation efforts, including land stewardship, whose potential in the United States is poorly understood. We quantified the potential of natural climate solutions (NCS)—21 conservation, restoration, and improved land management interventions on natural and agricultural lands—to increase...Fargione, Joseph E.; Bassett, Steven; Boucher, Timothy; Bridgham, Scott D.; Conant, Richard T.; Cook-Patton, Susan C.; Ellis, Peter W.; Falcucci, Alessandra; Fourqurean, James W.; Gopalakrishna, Trisha; Gu, Huan; Henderson, Benjamin; Hurteau, Matthew D.; Kroeger, Kevin D.; Kroeger, Timm; Lark, Tyler J.; Leavitt, Sara M.; Lomax, Guy; McDonald, Robert I.; Megonigal, Patrick; Miteva, Daniela A.; Richardson, Curtis J.; Sanderman, Jonathan; Shoch, David; Spawn, Seth A.; Veldman, Joseph W.; Williams, Christopher A.; Woodbury, Peter B.; Zganjar, Chris; Baranski, Marci; Elias, Patricia; Houghton, Richard A.; Landis, Emily; McGlynn, Emily; Schlesinger, William H.; Siikamaki, Juha V.; Sutton-Grier, Ariana; Griscom, Bronson W.
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
Geochemical conditions and nitrogen transport in nearshore groundwater and the subterranean estuary at a Cape Cod embayment, East Falmouth, Massachusetts, 2013–14
Nitrogen transport and transformation were studied during 2013 to 2014 by the U.S. Geological Survey, in cooperation with the U.S. Environmental Protection Agency, in a subterranean estuary beneath onshore locations on the Seacoast Shores peninsula, a residential area in Falmouth, Massachusetts, served by septic systems and cesspools, and adjacent...Colman, John A.; LeBlanc, Denis R.; Böhlke, John K.; McCobb, Timothy D.; Kroeger, Kevin D.; Belaval, Marcel; Cambareri, Thomas C.; Pirolli, Gillian F.; Brooks, T. Wallace; Garren, Mary E.; Stover, Tobias B.; Keeley, Ann
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
Carbon budget of tidal wetlands, estuaries, and shelf waters of eastern North America
Carbon cycling in the coastal zone affects global carbon budgets and is critical for understanding the urgent issues of hypoxia, acidification, and tidal wetland loss. However, there are no regional carbon budgets spanning the three main ecosystems in coastal waters: tidal wetlands, estuaries, and shelf waters. Here we construct such a budget for...Najjar, R.G.; Herrmann, M.; Alexander, Richard B.; Boyer, E.W.; Burdige, D. J.; Butman, D.; Cai, W.-J.; Canuel, E.A.; Chen, R.F.; Friedrichs, M. A. M.; Feagin, R.A.; Griffith, P. C.; Hinson, A.L.; Holmquist, J.R.; Hu, X.; Kemp, W.M.; Kroeger, Kevin D.; Mannino, A.; McCallister, S.L.; McGillis, W.R.; Mulholland, M.R.; Pilskaln, C. H.; Salisbury, J.; Signorini, S. R.; St. Laurent, P.; Tian, H.; Tzortziou, M; Vlahos, P.; Wang, Z. A.; Zimmerman, R. C.
The magnitude and origin of groundwater discharge to eastern U.S. and Gulf of Mexico coastal waters
Fresh groundwater discharge to coastal environments contributes to the physical and chemical conditions of coastal waters, but the role of coastal groundwater at regional to continental scales remains poorly defined due to diverse hydrologic conditions and the difficulty of tracking coastal groundwater flow paths through heterogeneous subsurface...Befus, Kevin; Kroeger, Kevin D.; Smith, Christopher G.; Swarzenski, Peter W.
Restoring tides to reduce methane emissions in impounded wetlands: A new and potent Blue Carbon climate change intervention
Coastal wetlands are sites of rapid carbon (C) sequestration and contain large soil C stocks. Thus, there is increasing interest in those ecosystems as sites for anthropogenic greenhouse gas emission offset projects (sometimes referred to as “Blue Carbon”), through preservation of existing C stocks or creation of new wetlands to increase future...Kroeger, Kevin D.; Crooks, Stephen; Moseman-Valtierra, Serena; Tang, Jianwu
Depth of the vadose zone controls aquifer biogeochemical conditions and extent of anthropogenic nitrogen removal
We investigated biogeochemical conditions and watershed features controlling the extent of nitrate removal through microbial dinitrogen (N2) production within the surficial glacial aquifer located on the north and south shores of Long Island, NY, USA. The extent of N2 production differs within portions of the aquifer, with greatest N2 ...Szymczycha, Beata; Kroeger, Kevin D.; Crusius, John; Bratton, John F.
Temperature response of soil respiration largely unaltered with experimental warming
The respiratory release of carbon dioxide (CO2) from soil is a major yet poorly understood flux in the global carbon cycle. Climatic warming is hypothesized to increase rates of soil respiration, potentially fueling further increases in global temperatures. However, despite considerable scientific attention in recent decades, the overall response...Carey, Joanna C.; Tang, Jianwu; Templer, Pamela H.; Kroeger, Kevin D.; Crowther, Thomas W.; Burton, Andrew J.; Dukes, Jeffrey S.; Emmett, Bridget; Frey, Serita D.; Heskel, Mary A.; Jiang, Lifen; Machmuller, Megan B.; Mohan, Jacqueline; Panetta, Anne Marie; Reich, Peter B.; Reinsch, Sabine; Wang, Xin; Allison, Steven D.; Bamminger, Chris; Bridgham, Scott D.; Collins, Scott L.; de Dato, Giovanbattista; Eddy, William C.; Enquist, Brian J.; Estiarte, Marc; Harte, John; Henderson, Amanda; Johnson, Bart R.; Steenberg Larsen, Klaus; Luo, Yiqi; Marhan, Sven; Melillo, Jerry M.; Penuelas, Josep; Pfeifer-Meister, Laurel; Poll, Christian; Rastetter, Edward B.; Reinmann, Andrew B.; Reynolds, Lorien L.; Schmidt, Inger K.; Shaver, Gaius R.; Strong, Aaron L.; Suseela, Vidya; Tietema, Albert
Carbon dioxide fluxes reflect plant zonation and belowground biomass in a coastal marsh
Coastal wetlands are major global carbon sinks; however, they are heterogeneous and dynamic ecosystems. To characterize spatial and temporal variability in a New England salt marsh, greenhouse gas (GHG) fluxes were compared among major plant‐defined zones during growing seasons. Carbon dioxide (CO2) and methane (CH4) fluxes were compared in two...Moseman-Valtierra, Serena; Abdul-Aziz, Omar I.; Tang, Jianwu; Ishtiaq, Khandker S.; Morkeski, Kate; Mora, Jordan; Quinn, Ryan K.; Martin, Rose M.; Egan, Katharine; Brannon, Elizabeth Q.; Carey, Joanna C.; Kroeger, Kevin D.
Observations of nearshore groundwater discharge: Kahekili Beach Park submarine springs, Maui, Hawaii
Study regionThe study region encompasses the nearshore, coastal waters off west Maui, Hawaii. Here abundant groundwater—that carries with it a strong land-based fingerprint—discharges into the coastal waters and over a coral reef.Study focusCoastal groundwater discharge is a ubiquitous hydrologic feature that has been shown to impact nearshore...Swarzenski, Peter W.; Dulai, H.; Kroeger, K.D.; Smith, C.G.; Dimova, N.; Storlazzi, C. D.; Prouty, N.G.; Gingerich, S.B.; Glenn, C. R.