James W. McClelland
Associate Professor, Department of Marine Science
Office: 361-749-6756; Email:
Land-Sea Coupling/Coastal Ecosystem Dynamics/Biogeochemistry
Effects of human activity on water, carbon, and nutrient fluxes from land to sea; responses of estuarine and coastal food webs to changes in land-derived resources; use of stable isotopes and other natural tracers to follow water and water-borne constituents across the land-sea interface.
Environmental changes as a consequence of human activity, including changes in land use, land cover, and global warming, provide the context for much of my work. These changes are having a profound influence on the transport of water and water-borne constituents from land to sea. In turn, changes in the fluxes of water, carbon, and nutrients to estuaries and the coastal ocean are altering fundamental ecosystem properties such as primary production and food web structure. Changes in land-sea fluxes have broader implications as well, including alteration of the global carbon budget and potential impacts of freshwater inputs on global ocean circulation and climate. To identify and explore changes in land-sea coupling I use a wide variety of approaches including analysis of historic data sets, field studies of biogeochemical cycling and constituent transport, and modeling. In my field studies, I frequently take advantage stable isotopes and other natural markers to track the fate of water, organic matter, and nutrients from land through estuarine and marine systems.
Holmes, R. M., J. W. McClelland, P. A. Raymond, B. B. Frazer, B. J. Peterson, and M. Stieglitz. 2008. Lability of DOC transported by Alaskan rivers to the Arctic Ocean. Geophys. Res. Lett., 35, L03402, doi:10.1029/2007GL032837.
McClelland, J. W., M. Stieglitz, F. Pan, R. M. Holmes, and B. J. Peterson. 2007. Recent changes in nitrate and dissolved organic carbon export from the upper Kuparuk River, North Slope, Alaska. J. Geophys. Res., 112, G04S60, doi:10.1029/2006JG000371.
Raymond, P. A., J. W. McClelland, R. M. Holmes, A. V. Zhulidov, K. Mull, B. J. Peterson, R. G. Striegl, G. R. Aiken, and T. Y. Gurtovaya. 2007. Flux and age of dissolved organic carbon exported to the Arctic Ocean: A carbon isotopic study of the five largest arctic rivers. Global Biogeochem. Cycles, 21, GB4011, doi:10.1029/2007GB002934.
Peterson, B.J., J. McClelland, R. Curry, R.M. Holmes, J.E. Walsh, and K. Aagaard. 2006. Trajectory shifts in the arctic and subarctic freshwater cycle. Science 313:1061-1066.
McClelland, J.W., S.J. Déry, B.J. Peterson, R.M. Holmes, and E.F. Wood. 2006. A pan-arctic evaluation of changes in river discharge during the latter half of the 20th century. Geophys. Res. Lett., 33, L06715, doi:10.1029/2006GL025753.
Cooper, L., R. Benner, J. McClelland, B. Peterson, R. Holmes, P.A. Raymond, D. Hansell, J.M. Grebmeier, and L.A. Codispoti. 2005. Linkage among runoff, dissolved organic carbon, and the stable oxygen isotope composition of seawater and other water mass indicators in the Arctic Ocean. J. Geophys. Res. 110, G02013, doi:10.1029/2005JG000031.
McClelland, J.W., R.M. Holmes, B.J. Peterson, and M. Stieglitz. 2004. Increasing river discharge in the Eurasian Arctic: Consideration of dams, permafrost thaw, and fires as potential agents of change. J. Geophys. Res. 109, D18102, doi:10.1029/2004JD004583.
McClelland, J.W., C.M. Holl, and J.P. Montoya. 2003. Attributing low δ15N values of zooplankton to an N2-fixing source in the tropical North Atlantic: Insights provided by stable isotope ratios of amino acids. Deep-Sea Res. I, 50:849-861.
Peterson, B.J., R.M. Holmes, J.W. McClelland, C.J. Vorosmarty, R.B. Lammers, A.I. Shiklomanov, I.A. Shiklomanov, and S. Rahmstorf. 2002. Increasing river discharge to the Arctic Ocean. Science 298:2171-2173.
Valiela, I., M. Geist, J. McClelland, and G. Tomasky. 2000. Nitrogen loadings from watersheds to estuaries: Verification of the Waquoit Bay Nitrogen Loading Model. Biogeochemistry 49:277-293.
McClelland, J.W. and I. Valiela. 1998. Linking nitrogen in estuarine producers to land-derived sources. Limnol. Oceanogr. 43:577-585.
McClelland, J.W. and I. Valiela. 1998. Changes in food web structure under the influence of increased anthropogenic nitrogen inputs to estuaries. Mar. Ecol. Prog. Ser. 168:259-271.
Contact: James W. McClelland