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School of the Earth, Ocean and Environment

Faculty and Staff Directory

Willard Moore

Title: Distinguished Faculty Emeritus
Department: Earth Ocean and Environment
College of Arts and Sciences
Phone: 803-777-2262
Office: EWS, Room 411
Resources: School of the Earth, Ocean and Environment


  • B.S., 1962, Millsaps College; 
  • M.S., 1965, Columbia University; 
  • Ph.D., 1969, State University of New York at Stony Brook


The primary research of our laboratory is based on the use of natural radioisotopes as tracers of geological and oceanographic processes. By measuring precisely radioisotopes that result from the decay of uranium and thorium in the environment, we investigate such diverse topics as interactions of river water and sediments with sea water; flow of ground water through salt marshes; the mixing rate of the ocean; hydrothermal processes at ocean spreading centers; the internal structure of minerals; the ages, rates, and processes of formation of manganese nodules; the rate of growth of corals; and sea level changes. During the past decade our efforts have been focused on the following topics:

Groundwater Input to the Coastal Ocean: Submarine flow of groundwater (fresh and salty) directly into the coastal ocean has been documented, but there has been no means of quantifying the total flux on a regional scale. Groundwater inputs may be identified using chemical tracers. These tracers have high concentrations in the groundwater and low reactivity in the coastal ocean. The tracers integrate the groundwater signal over a large region. To translate the tracer distribution into a groundwater flux, we must also determine the tracer concentration in the groundwater and the rate of mixing of coastal waters. If the system is in balance, the rate at which the tracer is lost by mixing offshore must equal the rate at which it is being added near the coast. If we can measure the terms in this mass balance, we can establish the groundwater flux.
Our group has used four naturally-occurring radium isotopes as tracers of groundwater flux. Our tracer balance equations require substantial discharge of brackish and salty groundwater extending from salt marshes to the edge of the continental shelf along the southeastern coasts pf the U. S. and Brazil. The fluxes of salty groundwater rival river inputs along these coasts in terms of total volume and fluxes of nutrients. Other studies near the mouths of the Ganges-Brahmaputra and Mississippi-Atchafayla Rivers indicate that here also, groundwater inputs are important.
The subterranean groundwater flux to the ocean is important because it brings not only radium, but also large concentrations of nutrients, metals, organic compounds, and inorganic carbon. Evaluating the groundwater fluxes of these reactive species is a major challenge to chemical oceanography. On the other hand, the flux of freshwater from the underground system may not be important in all areas. Along the SE US coast most of the groundwaters that contain high tracer concentrations are salty, in fact their high ionic strength causes the high Ra concentrations. The fluxes we measure are the result of chemical reactions between the aquifer solids and a mixture of sea water and meteoric water. To emphasize the roles of mixing and chemical reactions in coastal aquifers, I call these systems subterranean estuaries.

Ocean Circulation and Mixing: Natural radioactive tracers, especially Ra isotopes, are released into the ocean when sea water contacts sediments. This occurs within coastal aquifers, at the mouths of major and minor rivers, along the continental shelf, and at the ocean floor. Measurements of these tracers enable us to model the circulation of the tagged waters as they move away from the source regions and mix with waters of the ocean interior. Here, our studies have been concentrated along the coasts of the SE US and Brazil and in the mixing zones of major rivers. To study mixing in these complex regions, we use four radium isotopes having half lives of 3.6 days, 11.4 days, 5.7 years, and 1600 years. The two short-lived isotopes decay almost completely between the shore and the edge of the shelf; the two long-lived isotopes decay hardly at all. Their distributions reveal patterns and rates of offshore mixing.

Interactions of Sediments and Sea Water at River Mouths: Chemical reactions which are initiated when river sediments enter the ocean alter the supply of dissolved elements from the land to the sea. Because major rivers such as the Amazon, Orinoco, Ganges- Brahmaputra, and Mississippi are so important in supplying the ocean with dissolved components and sediments, we have concentrated our efforts on understanding these systems.

Radiochemistry Laboratory:
The radiochemistry laboratory has four high resolution gamma spectrometer systems including one large volume intrinsic GE detector, one intrinsic germanium detector with a 1 cm diameter well, another intrinsic detector with a 2 cm diameter well and a low energy planar detector. These detectors are interfaced to a desktop computer through separate ORTEC Spectramasters. Data reduction is accomplished using the program Hypermet which we have adapted to run on our computers. We also operate 16 alpha spectrometer systems, 8 gas phase alpha scintillation counters to measure 222Rn as well as low background gross alpha and beta proportional counters. We have developed a delayed coincidence system to measure 223Ra and 224Ra; currently 8 systems are in use. A low background liquid scintillation counter is used to measure low levels of C-14 and tritium. These instruments allow us to measure all of the isotopes in the U and Th decay chains having half lives greater than a few minutes as well as gamma-emitting fallout and cosmic-ray produced isotopes.


Moore, W.S. and T. J. Shaw. Fluxes and behavior of radium isotopes, barium, and uranium in seven Southeastern US rivers and estuaries. Marine Chemistry 108, 236-254, 2008.

Moore, W.S. and J. de Oliveira, Determination of residence time and mixing processes of the Ubatuba, Brazil, inner shelf waters using natural Ra isotopes. Estuarine, Coastal, Shelf Science, 76, 512-521, 2008.

Burnett, W.C., R. Peterson, W.S. Moore, and J. de Oliveira; Radon and Radium Isotopes as Tracers of Submarine Groundwater Discharge – Results from the Ubatuba, Brazil SGD assessment intercomparison. Estuarine, Coastal, Shelf Science, 76, 501-511, 2008.

Charette, M., W. S. Moore, and W.C. Burnett, Uranium- and thorium-series nuclides as tracers of submarine groundwater discharge. In U/Th Series Radionuclides in Aquatic Systems, edited by S. Krishnaswami and J. K. Cochran, Elsevier Press, in press.

Moore, W.S. Submarine Groundwater Discharge. Encyclopedia of Ocean Sciences, in press.

Moore, W.S. Seasonal Distribution and Flux of Radium Isotopes on the Southeastern U.S. Continental Shelf, J. Geophys. Res. Oceans, 112, C10013, doi:10.1029/2007JC004199, 2007

Geibert, W., Charette, M., Kim, G., Moore, W.S., Paytan, A., Street, J., Young, M. The release of dissolved actinium to the ocean: a global comparison of different end-members. Marine Chemistry, doi:10.1016/j.marchem.2007.07.005, 2007.

Moore, W.S., Fifteen years experience in measuring 224Ra and 223Ra by delayed-coincidence counting. Marine Chemistry, doi:10.1016/j.marchem.2007.06.015, 2007.

Young, M. B., Meagan Eagle Gonneea, Derek A. Fong, Willard S. Moore, Jorge Herrera-Silveira, Adina Paytan, Characterizing sources of groundwater to a tropical coastal lagoon in a karstic area using radium isotopes and water chemistry. Marine Chemistry, doi:10.1016/j.marchem.2007.07.010, 2007.

Niencheski, L.F.H., H.L. Windom, W.S. Moore, & R.A. Jahnke. Submarine groundwater discharge of nutrients to the ocean along a coastal lagoon barrier, southern Brazil. Marine Chemistry 106, 546–561, 2007.

Moore, W.S., W. Ussler,III, C.K. Paull, Short-lived radium isotopes in the Hawaiian margin: Evidence for large fluid fluxes through the Puna Ridge. Marine Chemistry, doi:10.1016/j.marchem.2007.06.015, 2007.

Moore, W.S., Seasonal Changes in the Distribution Radium-226 on the Southeastern U.S. Continental Shelf: Implications for Changing Submarine Groundwater Discharge. In A New Focus on Groundwater–Seawater Interactions Ed. by W. Sanford, C. Langevin, M. Polemio & P. Povinec, IAHS Publ. 312, 134-141, 2007.

Windom, H.L., L.F. Niencheski, W.S. Moore, Influence of groundwater discharge through a coastal sandy barrier in southern Brazil on sea water metal chemistry. In A New Focus on Groundwater–Seawater Interactions Ed. by W. Sanford, C. Langevin, M. Polemio & P. Povinec, IAHS Publ. 312, 180-188, 2007.

Moore, W.S., J.O. Blanton, S. Joye, Estimates of Flushing Times, Submarine Groundwater Discharge, and Nutrient Fluxes to Okatee River, South Carolina, J. Geophys. Res., 111, C09006, doi:10.1029/2005JC003041, 2006.

Moore, W.S., Radium Isotopes as Tracers of Submarine Groundwater Discharge in Sicily. Continental Shelf Research, 26, 852-861, 2006.

Joye, S. B., D. A. Bronk, D. Koopmans, and W. S. Moore, Potential for groundwater-derived carbon, nitrogen and phosphorus inputs to coastal ecosystems in South Carolina and Georgia. In: Implications of Land Use Change to Coastal Ecosystems: Challenges to Effective Resource Management. (Eds) G.S. Kleppel, M.R. DeVoe, and M. Rawson. Springer Verlag, 2006.

Burnett, W.C., P.K. Aggarwal, H. Bokuniewicz, J.E. Cable, M.A. Charette, E. Kontar, S. Krupa, K.M. Kulkarni, A. Loveless, W.S. Moore, J.A. Oberdorfer, J. Oliveira, N. Ozyurt, P. Povinec, A.M.G. Privitera, R. Rajar, R.T. Ramessur, J. Scholten, T. Stieglitz, M. Taniguchi, J.V. Turner, Quantifying Submarine Groundwater Discharge in the Coastal Zone via Multiple Methods, Science of the Total Environment, 367, 498-543, 2006.

Benitez-Nelson, C. and W.S. Moore, Future applications of 234Th in aquatic ecosystems. Marine Chemistry, 100, 163-165, 2006.

Moore, W.S., The role of submarine groundwater discharge in coastal biogeochemistry. Journal of Geochemical Exploration, 88, 389-393, 2006.

Dulaiova, H., W.C. Burnett, J.P. Chanton, W.S. Moore, H.J. Bokuniewicz, M.A. Charette, and E. Sholkovitz, Assessment of groundwater discharges into West Neck Bay, New York, via natural tracers. Continental Shelf Research, 26, 1971-1983, 2006.

Windom, H.L., L.F. Niencheski, W.S. Moore, R. Jahnke. Submarine Groundwater Discharge: a Large, Previously Unrecognized Source of Dissolved Iron to the South Atlantic Ocean. Marine Chemistry, 102: 252-266, 2006.

Taniguchi, M., W.C. Burnett, H. Dulaiova, E.A. Kontar, P.P. Povince, Submarine groundwater discharge measured by seepage meters in Sicilian coastal waters. Continental Shelf Research, 26, 835-842, 2006.

Povince, P.P., P.K. Aggarwal, W.C. Burnett, E.A. Kontar, K.M. Kulkarni, W.S. Moore, R. Rajar, M. Taniguchi, J.-F. Comanducci, G. Cusimano, H. Dulaiova, L. Gatto, M. Groening, S. Hauser, I. Levy-Palomo, B. Oregioni, Y.R. Ozorovich, A.M.G. Privitera, M.A. Schiavo. Characterisation of submarine groundwater discharge offshore south-eastern Sicily. J. Environmental Radioactivity, 89, 81-101, 2006.

Moore, W.S. and A.M. Wilson, Advective flow through the upper continental shelf driven by storms, buoyancy, and submarine groundwater discharge. Earth and Planetary Science Letters 235, 564-576, 2005.

Paytan, Adina; Shellenbarger, G. G.; Street, H. J., Gonneea, E. M.; Davis, K.; Young, B. M.; Moore, W.S., Submarine Groundwater Discharge: An Important Source of New Nutrients to Coral Reef Ecosystems. Limnol. Oceo. 51, 343-348, 2005.

Murphy, K.; J. Boehme; P. Coble; J. Cullen; P. Field; W.S. Moore; E. Perry; R. Sherrell; and G. Ruiz. Verification of mid-ocean ballast water exchange using naturally occurring coastal tracers. Marine Pollution Bull., 48, 711–730, 2004.

Moore, W.S. and J.M. Krest, Distribution of 223Ra and 224Ra in the Plumes of the Mississippi and Atchafalaya Rivers and the Gulf of Mexico. Marine Chemistry, 86, 105-119, 2004.

Smoak, J.M., C. Benitez-Nelson, W.S. Moore, R.C. Thunell, Y. Astor, and F. Muller-Karger, Radionuclide fluxes and particle scavenging in Cariaco Basin. Cont. Shelf Res. 24, 1451-1463, 2004.

Cai, W.-J., Wang. Y., Krest, J., and Moore, W.S., The geochemistry of dissolved inorganic carbon in a surficial groundwater aquifer in North Inlet, South Carolina, and the carbon fluxes to the coastal ocean. Geochimica et Cosmochimica Acta, 67, 631-639, 2003.

Johnson, H. P., J. Baross, T. Bjorklund, W. Brazelton, C. Channing, J. Huber, M. Johnson, P. Kalk, M. Pruis, C. Kammerer, S. Lang, R. Light, W. Martin, M. McCarthy, F. McCroskey, M. Mehta, V. Miller, W. Moore, K. Roe, M. Sharma, J. Voight, Probing for Life in the Ocean Crust. EOS, 84, 109-116, 2003.

McCraith, B.M., L.R. Gardner, D.S. Wethey, and W.S. Moore, The effect of
fiddler crab burrowing on sediment mixing and radionuclide profiles along a topographic gradient in a southeastern salt marsh. Journal of Marine Research, 61, 359-390, 2003.

Moore, W.S., Sources and fluxes of submarine groundwater discharge delineated by radium isotopes. Biogeochemistry, 66, 75-93, 2003.

Burnett, W.C., H. Bokuniewicz, M. Huettel, W.S. Moore, M. Taniguchi, Groundwater and pore water inputs to the coastal zone. Biogeochemistry, 66, 3-33, 2003.

Splivallo, R., M.A. Charette, C. Herbold, M.S. Bollinger, and W.S. Moore, Salt Marsh submarine groundwater discharge as traced by radium isotopes. Marine Chemistry, 84, 113-121, 2003.

Crotwell, A.M. and W.S. Moore, Nutrient and Radium Fluxes from Submarine Groundwater Discharge to Port Royal Sound, South Carolina. Aquatic Geochemistry, 9, 191-208, 2003.

Shaw, T.J. and W.S. Moore, Analysis of 227Ac in seawater by delayed coincidence counting, Marine Chemistry, 78, 197-203, 2002.

Moore, W.S., J. Krest, G. Taylor, E. Roggenstein, S. Joye, & R. Lee, Thermal evidence of water exchange through a coastal aquifer: Implications for nutrient fluxes, Geophys. Res. Letters, 29, 10.1029/2002GL014923, 2002.

Burnett, W.C., J. Chanton, J. Christoff, E. Kontar, S. Krupa, M. Lambert, W. Moore, D. O'Rourke, R. Paulsen, C. Smith, L. Smith, and M. Taniguchi, 
Assessing methodologies for measuring groundwater discharge to the ocean. EOS, 83, p117-123, 2002.

Dickson, A., R. Bidigare, J. Hedges, K. Johnson, D. LeBlanc, C. Lee, A. McNichol, F. Millero, J. Moffet, W.S. Moore, E. Peltzer, and S. Van den Berg, Chemical Reference Materials: Setting the Standards for Ocean Science. National Research Council, National Academy Press, Washington, DC, 130pp, 2002.

Swarzenski, P.W., C.D. Reich, R.M. Spechler, J.L. Kindinger, and W.S. Moore, Using multiple geochemical and radionuclide tracers to characterize the hydrogeology of the submarine spring off Crescent Beach, Florida. Chemical Geology, 179, 187-202, 2001.

Moore, W.S., T. Liu, W.S. Broecker, R.C. Finkel, and A. Wright, Factors influencing 7Be accumulation on rock varnish, Geophys. Res. Lett., 28, 4475-4478, 2001.

Kim, Guebuem, W.C. Burnett, H. Dulaiova, P.W. Swarzenski, and W.S. Moore, Measurement of 224Ra and 226Ra activities in natural waters using a radon-in-air monitor, Envir. Sci. Tech., 35, 4680-4683, 2001.

Krest, J. M., W. S. Moore, L. R. Gardner, and J. Morris, Marsh nutrient export supplied by groundwater discharge: Evidence from Ra measurements. Global Biogeochemical Cycles, 14, 167-176, 2000.

Moore, W. S., Determining coastal mixing rates using radium isotopes. Cont. Shelf. Res., 20, 1993-2007, 2000.

Naehr, T.H., D.S. Stakes, and W. S. Moore, Mass wasting, ephemeral fluid flow and barite deposition on the California continental margin. Geology, 28, 315-318, 2000.

Moore, W. S., Ages of continental shelf waters determined from 223Ra and 224Ra. J. Geophys. Res., 105, 22117-22122, 2000.

Hancock, G.J., I.T. Webster, P.W. Ford and W.S. Moore, Using Ra isotopes to examine transport processes controlling benthic fluxes into a shallow estuarine lagoon. Geochimica et Cosmochimica Acta, 64, 3685-3699, 2000.

Smoak, J.M., W.S. Moore, and R.C. Thunell, Influence of boundary scavenging and focusing on 234Th, 238Th, and 210Pb fluxes in the Santa Barbara Basin. Estuarine, Coastal and Shelf Science, 51, 373-384, 2000.

Moore, W. S. and K. K. Falkner, Cycling of radium and barium in the Black Sea, J. Environmental Radioactivity 43, 247-254, 1999.

van der Loff, M. M. and W. S. Moore, Determination of Natural Radioactive Tracers in Methods of Seawater Analysis, Third Edition, ed by K. Grasshoff, K. Kremling, and M. Ehrhardt; Wiley-VCH Publishers, p 365-398, 1999.

Fleisher, M., T. Liu, W. S. Broecker, and W. S. Moore, A clue regarding the origin of rock varnish. Geophys. Res. Lett. 26, 103-106, 1999.

Krest, J. M., W. S. Moore, and Rama, 226Ra and 228Ra in the mixing zones of the Mississippi and Atchafalaya Rivers: Indicators of groundwater input, Marine Chemistry, 64, 129-152, 1999.

Moore, W. S., The subterranean estuary: a reaction zone of ground water and sea water, Marine Chemistry, 65, 111-126, 1999.

Mayer, L., E. Druffel, M. Bender, E. Boyle, R. Jahnke, W. Jenkins, C. Lee, G. Luther, and W. Moore, Even more interdisciplinary future lies ahead for ocean chemistry. EOS, 80, 207-210, 1999.

Smoak, J. M., W. S. Moore, R. C. Thunell, and T. J. Shaw, Comparison of 234Th, 228Th, and 210Pb fluxes with fluxes of major sediment components in the Guaymas Basin, Gulf of California, Marine Chemistry 65, 177-194, 1999.

Cohen, A. D., C. P. Gage, W. S. Moore, R. S. VanPelt, Combining organic petrography and palynology to assess anthropogenic impacts on peatlands: Part 1, an example from the northern Everglades of Florida. Int. J. Coal Geol., 39, 3-45, 1999.

Cohen, A. D., C. P. Gage, and W. S. Moore, Combining organic petrography and palynology to assess anthropogenic impacts on peatlands: Part 2, an example from a carolina bay wetland at the Savannah River Site in South Carolina. Int. J. Coal Geol., 39, 47-95, 1999.

Moore, W. S., B. Kjerfve, J. F. Todd, Identification of rain-freshened plumes in the coastal ocean using Ra isotopes and Si. J. Geophys. Res. 103, 7709-7717, 1998.

Moore, W. S. and T. J. Shaw, Chemical signals from submarine fluid advection onto the continental shelf. J. Geophys. Res. 103, 21543-21552, 1998.

Shaw, T. J., W. S. Moore, J. Kloepfer and M. A. Sochaski, The flux of Barium to the coastal waters of the southeastern United States: The importance of submarine groundwater discharge. Geochimica et Cosmochimica Acta 62, 3047-3052, 1998.

Moore, W. S., Application of 226Ra, 228Ra, 223Ra, and 224Ra in coastal waters to assessing coastal mixing rates and groundwater discharge to oceans. Proc. (Earth and Planet. Sci.) Indian Acad. Sci. 107, 1-7, 1998.

Moore, W. S. The effects of groundwater input at the mouth of the Ganges-Brahmaputra Rivers on barium and radium fluxes to the Bay of Bengal. Earth and Planetary Science Letters 150, 141-150, 1997.

Moore, W. S. 226Ra, 228Ra, 223Ra, and 224Ra in coastal waters with application to coastal dynamics and groundwater input. Radioprotection-Colloques 32, C2-137-146, 1997.

Kuehl, S. A., B. A. Levy, M. Allison, and W. S. Moore Subaqueous delta of the Ganges-Brahmaputra River system. Marine Geology 144, 81-96, 1997.

Lauerman, L., J. M. Smoak, T. J. Shaw, W. S. Moore, and K. Smith, Th-234 and Pb-210 evidence for rapid ingestion of settling particles by mobile epibenthic megafauna in the abyssal NE Pacific. Limnol. & Oceanog. 42, 589-595, 1997.

Moore, W. S. and Ralph Arnold, Measurement of 223Ra and 224Ra in coastal waters using a delayed coincidence counter, J. Geophys. Res. 101, p1321-1329, 1996.

Moore, W. S., Large groundwater inputs to coastal waters revealed by 226Ra enrichments, Nature 380, 612-614, 1996.

Moore, W. S., D. J. DeMaster, J. M. Smoak, B. A. McKee, and P. W. Swarzenski, Radionuclide tracers of sediment-water interactions on the Amazon shelf. Cont. Shelf Res. 16, 645-665, 1996.

Moore, W. S. and T. M. Church, Submarine Groundwater Discharge, reply to Younger. Nature 382, 122, 1996.

Rama and W. S. Moore, Using the radium quartet for evaluating groundwater input and water exchange in salt marshes, Geochim. Cosmochim. Acta 60, 4645-4652, 1996.

Paytan, A., W. S. Moore and M. Kastner, Sedimentation rate as determined by 226Ra activity in marine barite, Geochim. Cosmochim. Acta 60, 4313-4319, 1996.

Reyes, A. O., W. S. Moore, D. S. Stakes, 228Th/228Ra ages of a barite rich chimney from the Endeavour segment of the Juan de Fuca Ridge. Earth Planet. Sci. Lett. 131, 99-113, 1995.

Veeh, H. H., W. S. Moore and S. V. Smith, The behaviour of uranium and radium in an inverse estuary, Cont. Shelf Res. 15, 1569-1583, 1995.

Moore, W. S., H. Astwood and C. Lindstrom, Radium isotopes in coastal waters on the Amazon shelf. Geochim. Cosmochim. Acta 59: 4285-4298, 1995.

Hussain, N., T. M. Church, G. W. Luther III, and W. S. Moore, 210Pb and 210Po disequilibrium in the hydrothermal vent fluids and chimney deposits from the Juan de Fuca Ridge. Geophysical Research Letters 22, p3175-3178, 1995.

Challenge the conventional. Create the exceptional. No Limits.