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Coastal Aquifer Project II [CAPII]

Overview

Increasing population density and changing agricultural practices in coastal areas have led to releases of nutrients (and other contaminants) into the coastal environment from fertilizer use, industrial practices, and wastewater discharge. These increased nutrient releases have led to eutrophication in many coastal waters, which is a widespread concern. Yet, the role that groundwater-derived nutrients has played in coastal eutrophication is not well understood in many areas. The ecological and economic impacts of eutrophication have been substantial in many coastal regions, which demands a better understanding of the contribution of groundwater-derived nutrient fluxes. Management of wastewater treatment practices in coastal regions critically depends on accurate estimates of the flux and quality of ground water in the coastal zone. In addition, informed resource management requires an improved understanding of the geological framework of coastal aquifers, the pathways by which ground water travels to the coastal zone, the specific locations and dimensions of submarine discharge zones, and the geochemical transformations that take place prior to discharge. Basic science questions related to how fluid flux across ocean margins and fluid recirculation through ocean margin sediments affects elemental cycling at all scales are also scientific priorities of this research effort. Experiments that address more applied aspects of nutrient delivery can also yield information that is valuable for developing a more general understanding of land-ocean aquifer interactions.

Start/End Dates

10/1/2004 - 9/30/2018

Location

Western U.S. and Pacific, Northeastern U.S., and Southeasern U.S. and Gulf of Mexico

Investigators

• Pete Swarzenski, Project Chief
• Patricia Hartsing
• Kevin Kroeger
• Patricia Anne Mullan
• Janet Paquette
• Christopher G Smith

Web Site

Submarine Groundwater Discharge: http://walrus.wr.usgs.gov/sgd/

Objectives

These investigations are designed to quantify the relative role of ground water in the delivery of fresh water and nutrients to geologically distinct coastal areas. The five goals of this effort, as presented in the 2006 Submarine Groundwater Discharge Science Plan, are:

• Goal A. Geologic Controls: Describe regional geological controls on submarine groundwater flow and discharge.
• Goal B. Flow Measurement: Quantify flow and discharge rates of both fresh and saline groundwater to estuaries and to the coastal ocean, including temporal and spatial variability and climatic influences.
• Goal C. Geochemical Processes: Identify and assess rates and impacts of important geochemical, microbial, and physical transformations that take place along subsurface flow paths en route to coastal waters.
• Goal D. Ecosystem Effects: Quantify the ecological impacts of submarine groundwater discharge on critical coastal habitats, resources, and ecosystem functions.
• Goal E. Technology and Resources: Create the next generation of instruments and techniques needed to identify and quantify important submarine groundwater discharge processes and impacts.

Work in FY2010 (October 2009 - September 2010) included studies in collaboration with USGS Water and Biological Resource Discipline (WRD and BRD) scientists. Work was primarily carried out in New York, Massachusetts, Florida, Chesapeake Bay, and California. Additional complementary CMGP research in Hawaii was done under a separate project by scientists from the CMGP Santa Cruz office. Geophysical measurements will identifie likely locations of ground water discharge. Chemical analyses of natural tracers of coastal ground water discharge will be used to prepare water and nutrient discharge estimates from ground water for each study site. These estimates will provide an independent check on the flow model estimates of WRD scientists, and will provide complementary information for academic colleagues studying nutrient cycling in eutrophic embayments. In addition to addressing local management concerns, current study sites have been chosen as representatives of the mode of ground water discharge in four distinct hydrogeologic settings:

• glaciated coasts with thick drift (MA/NY);
• deep coastal plain estuaries (Chesapeake Bay);
• tectonically active coasts (CA); and
• carbonate platform (FL),

based on the theoretical typological approach described by Bokuniewicz et al. (2003).The multi-faceted nature of these problems quite naturally leads to interactions with scientists from other disciplines, including USGS-WRD and BRD, other agencies (NPS, NOAA, EPA, ACOE), as well as academics supported by NSF and other funding sources. These interdisciplinary approaches are being designed to yield information needed to improve hydrologic models, quantify sustainable rates of ground water withdrawal, and determine the importance and biological impacts of the fluxes of nutrients (especially nitrate and ammonium ion) from ground water into estuaries.

In FY-11, three CMG scientists developed a new science direction for the Coastal Aquifer Project (CAP), properly named CAPII. The project reflects the transition of the USGS from science disciplines to science themes. It cuts across themes, linking groundwater discharge within coastal zones to ecosystems function and in turn their influence on coastal vulnerability and stability. The Coastal Aquifer Project has traditionally been a multi-center project since its earlier conception. Primary management of the project during FY-12 and -13 will be based out of the Pacific Coastal and Marine Science Center, however, Woods Hole Science Center and St. Petersburg Coastal and Marine Science center will also be responsible for providing data and other information to the lead institution for dissemination throughout the USGS and public domain. To ensure proper data management, one employee (half-time) that currently resides on the project will be shared among the three centers. The persons responsibilities will be to record and maintain appropriate data and metadata for the project. These data will be published to a centrally-accessible database (SharePoint or other) and final data products will be available to internal and eventually external users through a web-accessible, mapping application (e.g. Google Maps-based interface). The goals of this approach are:

• to enhance exchange of information among project participants and collaborators,
• develop a comprehensive project-centric geo-database,
• facilitate interdisciplinary science

Approach

This research depends critically upon techniques that have been refined over the last 7 years as part of the original Coastal Aquifer Project. These techniques include qualitative mapping tools (e.g., radon-mapping, continuous resistivity profiling, shallow seismic, salinity mapping, etc) as well as quantitative passive and active techniques (e.g., radon times series, radium-quartet isotope models, seepage meters, well transects, and modeling). References for the techniques and application can be found in the primary products section and individual task products. The general long-term approach employed here to developing a regional perspective of submarine ground-water discharge is to carry out local studies at sites that are typologically representative of more general geological conditions and processes. In addition, consideration is given to mission and regional priorities of USGS (including WRD and BRD) and DOI, including management priorities of sister DOI bureaus and other federal agencies. To date, research has benefitted resource managers at Assateague Island, Cape Cod, and Fire Island National Seashores, as well as NSF-funded research partners.

Tasks and SubTasks

• CAPII coordination
  • one project member will record and maintain appropriate data and metadata for the project. These data will be published to a centrally-accessible database. Final data products will be available through a web-accessible, mapping application (e.g. Google Maps-based interface). The goals of this approach are
    1. to enhance exchange of information among project participants and collaborators,
    2. develop a comprehensive project-centric geo-database,and
    3. facilitate interdisciplinary science
• National Focus Sites: CMG collaborative evaluation of the role of groundwater discharge in ecosystems function and coastal hazards
  • A project meeting will be planned to facilitate the new direction of the Coastal Aquifer Project. Project members will solidify collaborations and partnerships, sampling strategies, and respective responsibilities of individual scientists, and will also refine sampling locations for the first field trip of FY-2012.
• Western U.S. and Pacific
  • Continued buildup of the analytical capabilities at PCMSC and and migration into the new labs
  • Continued project development on the geologic controls and ecosystem impacts of coastal aquifers
    1. San Francisco Bay
    2. Malibu, CA
    3. Puget Sound, WA
    4. Maui and Hawai`i (Big Island)
    5. Copano Bay, TX
    6. Younger Lagoon, Santa Cruz, CA
• Northeastern U.S.
1. Coastal Groundwater Discharges in Chesapeake Bay
2. Coastal Groundwater Discharges in Delaware Bays
3. Greenhouse Gas Fluxes in Coastal Ecosystems: Impacts of Eutrophication, Sea Level Rise, and Climate Change Add tag Coastal Groundwater Discharges on Long Island, New York and in Long Island Sound
• Southeast and Gulf of Mexico
  • continue to evaluate groundwater fluxes specifically to Saint Joseph Sound and adjacent Florida shelf (FL) and possibly Indian River Lagoon (FL)

Products, Results, and Publications

• Baskaran, M. and Swarzenski, P.W., 2007, Short-lived radionuclides as tracers of anthropogenic activity in Tampa Bay, FL Marine Chemistry, 104, 27-42
• Bowen, J. L., K. D. Kroeger, G. Tomasky, W. J. Pabich, M. L. Cole, R. H. Carmichael, and I. Valiela, 2007, A review of land-sea coupling by groundwater discharge of nitrogen to New England estuaries: Mechanisms and effects, Applied Geochemistry, 22:175-191
• Bratton, John F., 2007, The importance of shallow confining units to submarine groundwater flow, in A New Focus on Groundwater-Seawater Interactions: in, Sanford, W., Langevin, C., Polemio, M, and Povinec, P., eds., IAHS Publication 312, p. 28-36
• Bratton, John F., 2010, The three scales of submarine groundwater flow and discharge across passive continental margins, Journal of Geology, vol. 118, no. 5
• John F. Bratton, John Karl Böhlke, David E. Krantc, Craig R. Tobias, 2009, Flow and geochemistry of groundwater beneath a back-barrier lagoon: The subterranean estuary at Chincoteague Bay, Maryland, USA: Marine Chemistry Volume 113, Issues 1-2, 30 January 2009, Pages 78-92, doi:10.1016/j.marchem.2009.01.004
• Bratton, John F., Böhlke, J.K., Manheim, Frank T., Krantz, David E., 2004, Ground water beneath coastal bays of the Delmarva Peninsula: Ages and nutrients: Ground Water, vol. 42, no. 7, p. 1021-1034
• Bratton, John; Guntenspergen, Glenn; Taggart, B. E.; Wheeler, Douglas; Bjorklund, Lynn; Bothner, Michael; Kotra, Rama; Lent, Robert; Mecray, E. L.; Neckles, Hilary; Poore, Barbara; Rideout, Stephen; Russell-Robinson, Susan; Weiskel, P. K., 2003, Coastal ecosystems and resources framework for science: USGS Open-File Report 03-405
• Cole, M. L., K. D. Kroeger, J. W. McClelland, and I. Valiela. 2005. Macrophytes as indicators of land-derived wastewater: Application of a N stable isotopic method in aquatic systems. Water Resources Research. 41, W01014, doi:10.1029/2004WRR003269
• Cole, Marci L., Kevin D. Kroeger, J. W. McClelland, and I. Valiela, 2006, Effects of watershed land use on nitrogen concentrations and delta-15 nitrogen in groundwater, Biogeochemistry, 77:199-215.
• Cross, VeeAnn A., John F. Bratton, Emile Bergeron, Jeff K. Meunier, John Crusius, Dirk Koopmans, 2006, Continuous Resistivity Profiling Data from the Upper Neuse River Estuary, North Carolina, 2004-2005: USGS Open-File Report 2005-1306
• Crusius, J., Bratton, J., and Charette, M., 2004, Putting radon to work; identifying coastal groundwater discharge sites: USGS Open-File Report 2004-1381
• Crusius J. and Kenna T. C. (2007) Ensuring confidence in radionuclide-based sediment chronologies and bioturbation rates. Estuarine Coastal And Shelf Science 71(3-4), 537-544.
• Crusius J., Berg P., Koopmans D. J., and Erban L. (2008) Eddy correlation measurements of submarine groundwater discharge. Mar. Chem. 109(77-85).
• Crusius J., Koopmans D., Bratton J. F., Charette M. A., Kroeger K. D., Henderson P., Ryckman L., Halloran K., and Colman J. A., 2005, Submarine groundwater discharge to a small estuary estimated from radon and salinity measurements and a box model. Biogeosciences 2, 141-157.
• Garrison, V., Kroeger, K.D., Fenner, D., and Craig, P. 2007. Identifying nutrient sources to three lagoons at Ofu and Olosega, American Samoa using δ15N of benthic macroalgae. Marine Pollution Bulletin 54:1813-1838.
• Greenwood, WJ, Kruse,S and Swarzenski, PW (2006) Extending electromagnetic methods to map coastal pore-water salinities. Ground Water, 44, 292-299.
• Hu, C, Muller-Karger, F and PW Swarzenski (2006) Hurricanes, submarine ground-water discharge and west Florida's red tides. Geophys. Res. Lett., 33, L11601, doi:10.1029/2005GL025449
• Kim, G and Swarzenski, PW (2005) Submarine ground-water discharge (SGD) and associated nutrient fluxes to the coastal ocean. In, Carbon and Nutrient Fluxes in Continental Margins: A Global Synthesis. Eds., K.-K. Liu, L. Atkinson, R. Quinones, and L. Talaue-McManus, Springer-Verlag, New York.
• Krantz, David E., Frank T. Manheim, John F. Bratton, Daniel J. Phelan, 2004, Hydrogeologic setting and ground-water flow beneath a section of Indian River Bay, Delaware: Ground Water, , vol. 42, no. 7, p. 1035-1051.
• Kroeger, K.D. and Charette, M.A. (submitted), 2007, Submarine groundwater discharge: Nitrogen biogeochemistry of the discharge zone, Limnology and Oceanography
• Kroeger, K.D., Cole, M.L., and Valiela, I. 2006. Groundwater-transported dissolved organic nitrogen exports from coastal watersheds. Limnology and Oceanography 51: 2248-2261
• Kroeger, K.D., Swarzenski, P.W., Reich, C. and Greenwood, W.J. (2007) Submarine groundwater discharge to Tampa Bay: Nutrient fluxes and biogeochemistry of the coastal aquifer. Marine Chemistry, 104, 85-97,
• Kroeger, Kevin D., Marci L. Cole, Joanna K. York, and Ivan Valiela, 2006, Nitrogen loads to estuaries from waste water plumes: Modeling and isotopic approaches, Ground Water 44(2):188-200.
• Kroeger, K.D., Swarzenski, P.W., Crusius, J., Bratton, J.F. and Charette, M.A. 2007. Submarine groundwater discharge: Nutrient loading and nitrogen transformations: USGS Fact Sheet 2006-3110
• Manheim, Frank T., David E. Krantz, John F. Bratton, 2004, Studying ground water under Delmarva coastal bays using electrical resistivity: Ground Water, vol. 42, no. 7, p. 1052-1068
• Orem, William H.; Swarzenski, Peter W.; McPherson, Benjamin F.; Hedgepath, Marion; Lerch, Harry E.; Reich, Christopher; Torres, Arturo E.; Corum, Margo D.; Roberts, Richard E., 2007, Assessment of Groundwater Input and Water Quality Changes Impacting Natural Vegetation in the Loxahatchee River and Floodplain Ecosystem, Florida: USGS Open-File Report 2007-1304
• Shedlock, R.J., and Bratton, J.F., 2009, Groundwater contributes nutrients to the Coastal Bays, in Shifting Sands: Environmental & Cultural Change in Maryland's Coastal Bays, Dennison, W.C., Thomas, J.E., Cain, C.J., Carruthers, T.J.B., Hall, M.R., Jesien, R.V., Wazniak, C.E., and Wilson, D.E., eds., University of Maryland Center for Environmental Science, Integration and Application Network.
• Spruill, Timothy B., and John F. Bratton, 2008, Estimation of groundwater and nutrient fluxes to the Neuse River Estuary, North Carolina, Estuaries and Coasts, vol. 31, p. 501-520, doi: 10.1007/s12237-008-9040-0
• Swarzenski, P.W. (2007) U/Th series radionuclides as tracers of coastal groundwater. Chemical Reviews, 107(2), 663-674, DOI: 10.1021/cr0503761
• Swarzenski, P.W. and Baskaran, M. (2007) Uranium distributions in the coastal waters and pore waters of Tampa Bay, Florida. Marine Chemistry, Special Issue, Biogeochemical Cycles in Tampa Bay, Florida. Eds. P.W. Swarzenski and M Baskaran, 104, 43-57.
• Swarzenski, P.W., Reich, C., Kroeger, K. and Baskaran, M. (2007) Ra and Rn isotopes as natural tracers of submarine groundwater discharge in Tampa Bay, FL. Marine Chemistry, 104, 69-84,
• Swarzenski, PW, Orem, WG, McPherson, BF, Baskaran, M and Wan, Y. (2006) Biogeochemical transport in the Loxahatchee river estuary: The role of submarine groundwater discharge. Mar. Chem. 101, 248-265
• Swarzenski, P.W., Bratton, J.F., and Crusius, J., 2004a, Submarine ground-water discharge and its role in coastal processes and ecosystems: USGS Open-File Report 2004-1226
• Waldrop, WR, PW Swarzenski (2006) A new tool for quantifying flux rates between ground water and surface water. In, Coastal Hydrology and Processes. Eds VP Singh and YJ Xu. Water Resources Publications, pp 1-9

Cooperators

• University of Toledo
• Delaware Geological Survey
• Marine Biological Laboratory
• Monterey Bay Aquarium Research Institute
• National Park Service (NPS)/Assateague Island National Seashore
• National Park Service (NPS)/Atlanta NPS Southeast Region Headquarters [Regional Coastal Geomorphologist]
• National Park Service (NPS)/Cape Cod National Seashore
• State University of New York, Stonybrook
• University of California, Santa Cruz
• University of Delaware
• Woods Hole Oceanographic Institution/Dept. of Marine Chemistry and Geochemistry
• Maryland Department of Natural Resources/Maryland Coastal Bays Program
• Neuse River Foundation