Biosciences Division

Staff

Patrick J. Mulholland

Patrick J. Mulholland

Carbon & Nutrient Biogeochemistry Group
Environmental Sciences Division
Oak Ridge National Laboratory
Oak Ridge, TN 37831-6036
Phone: (865) 574-7304
Fax: (865) 576-8543
mulhollandpj@ornl.gov

I am an aquatic ecologist in the Environmental Sciences Division of Oak Ridge National Laboratory in Oak Ridge, Tennessee. On this page you can find information about my educational background, research interests, recent publications, complete CV, and useful web links.

Background/Education

  • Ph.D., Environmental Biology, Department of Environmental Sciences and Engineering, University of North Carolina, Chapel Hill, NC 1979.
  • M.S., Environmental Engineering, Cornell University, Ithaca, NY, 1975.
  • B.S., Civil and Environmental Engineering, Cornell University, Ithaca, NY, 1973.

Research Interests

  • Reservoir greenhouse gas emissions
  • Ecology of streams (nutrient cycling, primary production, algal-herbivore interactions, carbon dynamics and energy flow)
  • Biogeochemistry and land/water interactions in forested catchments
  • Watershed hydrology
  • Wetland and riparian ecosystems
  • Climate change effects on freshwater ecosystems
  • Reservoir greenhouse gas emissions

Recent Publications (last 10 years)

  • Helton, A. M., G. C. Poole, J. L. Meyer, W. M. Wollheim, B. J. Peterson, P. J. Mulholland, J. A. Stanford, C. Arango, L.R. Ashkenas, L. W. Cooper, W. K. Dodds, S. V. Gregory, R. O. Hall, S. K. Hamilton, S. L. Johnson, W. H. McDowell, J. D. Potter, J. L. Tank, S. M. Thomas, H. M. Valett, J. R. Webster, and L. Zeglin. Thinking outside the channel: nitrogen cycling in networked river ecosystems. Frontiers in Ecology and the Environment (in press).
  • Kardol, P., D. E.Todd, P. J. Hanson, and P. J. Mulholland. 2010. Long-term successional forest dynamics: species and community responses to climatic variability. Vegetation Science (in press).
  • Bernot, M.J., D.J. Sobota, R.O. Hall, P.J. Mulholland, W.K. Dodds, J.R. Webster, J.L. Tank, L.R. Ashkenas, L. W. Cooper, C. N. Dahm, S. Findlay, S. V. Gregory, N. B. Grimm, S. K. Hamilton, S. L. Johnson, W. H. McDowell, J. L. Meyer, B. J. Peterson, G.C. Poole, H. M. Valett, C. Arango, J. J. Beaulieu, A. J. Burgin, C. Crenshaw, A.M. Helton, L. Johnson, J. Merriam, B. R. Niederlehner, J. M. O’Brien, J. D. Potter, R. W. Sheibley, S. M. Thomas, and K. Wilson. 2010. Inter-regional comparison of land-use effects on stream metabolism. Freshwater Biology (in press).
  • Mulholland, P. J., and J. R. Webster. 2010. Nutrient dynamics in streams and the role of J-NABS. Journal of the North American Benthological Society 29:100-117.
  • Koirala, S. R., R. W. Gentry, P. J. Mulholland, E. Perfect, and J. S. Schwartz. 2010. Time and frequency domain analyses of high-frequency hydrologic and chloride data in an east Tennessee watershed. Journal of Hydrology 387:256-264.
  • Webster, J. R., J. D. Newbold, S. A. Thomas, H. M. Valett, and P. J. Mulholland. 2009. Nutrient uptake and mineralization during leaf decay in streams - a model simulation. International Review of Hydrobiology 94:372-390.
  • Mulholland, P. J., B. J. Roberts, W. R. Hill, and J. G. Smith. 2009. Stream ecosystem responses to the 2007 spring freeze: unexpected effects of climate change. Global Change Biology 15:1767-1776.
  • Alexander, R. B., J. K. Bohlke, E. W.Boyer, M. B. David, J. W. Harvey, P. J. Mulholland, S. P. Seitzinger, C. R. Tobias, C. Tonitto, W. M. Wollheim. 2009. Simulating temporal variations of nitrogen losses in river networks with a dynamic transport model unravels the coupled effects of hydrological and biogeochemical processes. . Biogeochemistry doi: 10.1007/s10533-008-9274-8.
  • Mulholland, P. J, , R. O. Hall, Jr., D. J. Sobota, W. K. Dodds, S. Findlay, , N. B. Grimm, S. K. Hamilton, W. H. McDowell, J. M. O’Brien, J. L. Tank, L.R. Ashkenas, L. W. Cooper, C. N. Dahm, S. V. Gregory, S. L. Johnson, J. L. Meyer, B. J. Peterson, G. C. Poole, H. M. Valett, J. R. Webster, C. Arango, J. J. Beaulieu, M. J. Bernot, A. J. Burgin, C. Crenshaw, A. M. Helton, L. Johnson, B. R. Niederlehner, J. D. Potter, R. W. Sheibley, and S. M. Thomas.  2009.  Nitrate removal in stream ecosystems measured by 15N addition experiments: denitrification.  Limnology and Oceanography 54: 666-680.
  • Hall, R. O., Jr., J. L. Tank, D. J. Sobota, P. J. Mulholland, J. M. O’Brien, W. K. Dodds, J. R. Webster, H. M. Valett,  G. C. Poole, B. J. Peterson, J. L. Meyer, W. H. McDowell, S. L. Johnson, S. K. Hamilton, N. B. Grimm, S. V. Gregory, C. N. Dahm, L. W. Cooper, L.R. Ashkenas, S. M. Thomas, R. W. Sheibley, J. D. Potter, B. R. Niederlehner, L. Johnson, A. M. Helton, C. Crenshaw, A. J. Burgin, M. J. Bernot, , J. J. Beaulieu, C. Arango.  2009. Nitrate removal in stream ecosystems measured by 15N addition experiments: total uptake.  Limnology and Oceanography 54: 653-665.
  • Alexander, R. B., J. K. Bohlke, E. W.Boyer, M. B. David, J. W. Harvey, P. J. Mulholland, S. P. Seitzinger, C. R. Tobias,  C. Tonitto, W. M. Wollheim.  2009.  Simulating temporal variations of nitrogen losses in river networks with a dynamic transport model unravels the coupled effects of hydrological and biogeochemical processes.  Biogeochemistry doi: 10.1007/s10533-008-9274-8.
  • Mulholland, P. J., B. J. Roberts, W. R. Hill, and J. G. Smith.  2009.  Stream ecosystem responses to the 2007 spring freeze: unexpected effects of climate change.  Global Change Biology 15:1767-1776.
  • Fagre, D.B., C.W. Charles, C.D. Allen, C. Birkeland, F.S. Chapin III, P.M. Groffman, G.R. Gunternspergen, A.K. Knapp, A.D. McGuire, P.J. Mulholland, D.P.C. Peters, D.D. Roby, and G. Sugihara. 2009. Thresholds of Climate Change in Ecosystems. A report by the U.S. Climate Change Science Program and the Subcommittee on Global Change Research. U.S. Geological Survey, Reston, VA, USA. 156 pages.
  • Maloney, K.O., J. W. Feminella, R. M. Mitchell, S. A. Miller, P. J. Mulholland, and J. N. Houser.  2008. Land use legacies and small streams: the relationships between historic and contemporary land use patterns with present-day stream conditions. Journal of the North American Benthological Society 27:280-294.
  • Mulholland, P. J, A. M. Helton, G. C. Poole, R. O. Hall, Jr., S. K. Hamilton, B. J. Peterson, J. L. Tank, L.R. Ashkenas, L. W. Cooper, C. N. Dahm, W. K. Dodds, S. Findlay, S. V. Gregory, N. B. Grimm, S. L. Johnson, W. H. McDowell, J. L. Meyer, H. M. Valett, J. R. Webster, C. Arango, J. J. Beaulieu, M. J. Bernot, A. J. Burgin, C. Crenshaw, L. Johnson, B. R. Niederlehner, J. M. O’Brien, J. D. Potter, R. W. Sheibley, D. J. Sobota, and S. M. Thomas.  2008.  Stream denitrification across biomes and its response to anthropogenic nitrate loading. Nature 452:202-205 ; doi: 10.1038/nature06686.
  • Johnson, D. W., D. E. Todd, Jr., C. F. Trettin, and P. J. Mulholland. 2008. Decadal changes in potassium, calcium, and magnesium in a deciduous forest soil.  Soil Science Society of America Journal 72: 1795-1805.
  • Valett, H. M, S. A. Thomas, P. J. Mulholland, J. R. Webster, C. N. Dahm, C. S. Fellows, C. L. Crenshaw, and C. G. Peterson.  2008. Endogenous and exogenous control of ecosystem function: N cycling in headwater streams.  Ecology 89(12):3515-3527.
  • Roberts, B. J., P. J. Mulholland, and J. N. Houser.  2007.  Effects of upland disturbance and in-stream restorations on hydrodynamics and ammonium uptake in headwater streams.  Journal of the North American Benthological Society 26: 38-53.
  • Roberts, B. J., P. J. Mulholland, and W. R. Hill.  2007.  Multiple scales of temporal variability in ecosystem metabolism rates: results from two years of continuous monitoring in a forested headwater stream. Ecosystems 10:588-606. doi: 10.1007/s10021-007-9059-2.
  • Roberts B.J. and P. J. Mulholland.  2007.  In-stream biotic control on nutrient biogeochemistry in a forested headwater stream, West Fork of Walker Branch.  J. Geophys. Res 112:G04002 , doi: 10.1029/2007JG000422.
  • Jardine, P. M., M. A. Mayes, P. J. Mulholland, P. J. Hanson, J. R. Tarver, R. J. Luxmoore, J. F. McCarthy, and G. V. Wilson.  2006.  Vadose zone flow and transport of dissolved organic carbon at multiple scales in humid regimes.  Vadose Zone Journal 5: 140-152.
  • Mulholland, P. J., S. A. Thomas, H. M. Valett, J. R. Webster, and J. Beaulieu.  2006.  Effects of light on nitrate uptake in small forested streams: diurnal and day-to-day variations.  Journal of the North American Benthological Society 25: 583-595.
  • Steinman, A. D. and P. J. Mulholland.  2006.  Phosphorus limitation, uptake, and turnover in benthic stream algae, Chapter 9, pp 187-212.  In:  F. R. Hauer and G. A. Lamberti (eds),  Methods in Stream Ecology, 2nd edition, Academic Press.
  • Fellows, C. S., H. M. Valett, C. N. Dahm, P. J. Mulholland, and S. A. Thomas.  2006.  Coupling nutrient uptake and energy flow in headwater streams.  Ecosystems 9: 788-804.
  • Houser, J. N., P. J. Mulholland, and K. O. Maloney.  2006.  Upland disturbance affects headwater stream nutrients and suspended sediments during baseflow and stormflow.  Journal of Environmental Quality 35: 352-365.
  • Jardine, P. M., M. A. Mayes, P. J. Mulholland, P. J. Hanson, J. R. Tarver, R. J. Luxmoore, J. F. McCarthy, and G. V. Wilson.  2006.  Vadose zone flow and transport of dissolved organic carbon at multiple scales in humid regimes.  Vadose Zone Journal 5:140-152.
  • Steinman, A. D. and P. J. Mulholland.  2006.  Phosphorus limitation, uptake, and turnover in benthic stream algae, Chapter 9.  In:  F. R. Hauer and G. A. Lamberti (eds),  Methods in Stream Ecology, 2nd edition, Academic Press.
  • Houser, J. N., P. J. Mulholland, and K. O. Maloney.  2005.  Catchment disturbance and stream metabolism: patterns in stream respiration and gross primary production along a gradient of upland soil and vegetation disturbance.  Journal of the North American Benthological Society 24(3): 538-552.
  • Maloney, K. O, P.J. Mulholland, and J.W. Feminella.  2005.  The effects of catchment-scale military land use on stream physical and organic matter variables in small Southeastern Plains catchments (USA).  Journal of Environmental Management 35:677-691. 
  • Mulholland, P. J., J. N. Houser, and K. O. Maloney.  2005.  Stream diurnal dissolved oxygen profiles as indicators of in-stream metabolism and disturbance effects: Fort Benning as a case study.  Ecological Indicators 5:243-252.
  • Payn, R. A., J. R. Webster, P. J. Mulholland, H. M. Valett, and W. K. Dodds.  2005.  Estimation of stream nutrient uptake from nutrient addition experiments.  Limnology and Oceanography: Methods 3:174-182.
  • DeAngelis, D. L., and P. J. Mulholland.  2004. Dynamic consequences of allochthonous inutrient input to freshwater systems, pp. 12-24.  In: Food Webs at the Landscape Level, G. A. Polis, M. E. Power, and G. R. Huxel (eds.), The University of Chicago Press, Chicago, IL.
  • Mulholland, P. J., H. M. Valett, J. R. Webster, S. A. Thomas, L. N. Cooper, S. K. Hamilton, and B. J. Peterson.  2004.  Stream denitrification and total nitrate uptake rates measured using a field 15N isotope tracer approach.  Limnology and Oceanography 49(3): 809-820.
  • Dale, V H., Mulholland, P., Olsen, L. M., Feminella, J., Maloney, K., White, D. C., Peacock, A., and Foster, T., “Selecting a Suite of Ecological Indicators for Resource Management,” Landscape Ecology and Wildlife Habitat Evaluation: Critical Information for Ecological Risk Assessment, Land-Use Management Activities and Biodiversity Enhancement Practices, ASTM STP 1458, L. A. Kapustka, H. Gilbraith, M. Luxon, and G. R. Biddinger, Eds., ASTM International, West Conshohocken, PA, 2004.
  • Mulholland, P. J.  2004.  The importance of in-stream uptake for regulating stream concentrations and outputs of N and P from a forested watershed: evidence from long-term chemistry records for Walker Branch Watershed.  Biogeochemistry 70: 403-426.
  • Thomas, S. A., H. M. Valett, J. R. Webster, and P. J. Mulholland.  2003.  A regression approach to estimating reactive solute uptake in advective and transient storage zones of stream ecosystems.  Advances in Water Resources 26:965-976.
  • Mulholland, P. J.  2003.  Large scale patterns in DOC concentration, flux, and sources, pp. 139-159.  In: S. Findlay and R. Sinsabaugh (ed.), Aquatic Ecosystems: Interactivity of Dissolved Organic Matter, Elsevier Science.
  • Webster, J. R., P. J. Mulholland, J. L. Tank, H. M. Valett, W. K. Dodds, B. J. Peterson, W. B. Bowden, C. N. Dahm, S. Findlay, S. V. Gregory, N. B. Grimm, S. K. Hamilton, S. L. Johnson, E. Marti, W. H. McDowell, J. L. Meyer, D. D. Morrall, S. A. Thomas, W. M. Wollheim.  2003.  Factors affecting ammonium uptake in streams – an interbiome perspective.  Freshwater Biology 48:1329-1352.
  • Jones, J. B., Jr., E. H. Stanley, and P. J. Mulholland.  2003.  Long-term decline in carbon dioxide supersaturation in rivers across the contiguous United States.  Geophysical Research Letters 30 (10):1495-1499.
  • Jones, J. B., E. H. Stanley, and P. J. Mulholland.  2003.  Increased alkalinity in the Mississippi.  Science 302:985 (letter).
  • Mulholland, P. J., J. L. Tank, J. R. Webster, W. B. Bowden, W. K. Dodds, S. V. Gregory, N. B. Grimm, S. K. Hamilton, S. L. Johnson, E. Marti, W. H. McDowell, J. Merriam, J. L. Meyer, B. J. Peterson, H. M. Valett, and W. M. Wollheim.  2002.  Can uptake length in streams be determined by nutrient addition experiments? Results from an inter-biome comparison study.  Journal of the North American Benthological Society 21: 544-560.
  • Findlay, S., J. Tank, S Dye, H. M. Valett, P. Mulholland, W. H. McDowell, S. Johnson, S. K. Hamilton, J. Edmonds, W. K. Dodds, W. B. Bowden. 2002. A cross-system comparison of bacterial and fungal biomass in detritus pools of headwater streams.  Microbial Ecology 43:55-66.
  • Dodds, W. K., A. J. Lopez, W. B. Bowden, S. Gregory, N. B. Grimm, S. K. Hamilton, A. E. Hershey, E. Marti, W. H. McDowell, J. L. Meyer, D. Morrall, P. J. Mulholland, B. J. Peterson, J. L. Tank, H. M. Valett, J. R. Webster, and W. Wollheim.  2002.  Nitrogen uptake as a function of concentration in streams.  Journal of the North American Benthological Society 21:206-220.
  • Mulholland, P. J.  2002. Large scale patterns in DOC concentration, flux, and sources, Pages 139-159. In: S. Findlay (ed.),  Dissolved Organic Carbon in Aquatic Ecosystems, Academic Press.
  • Mulholland, P. J., C. S. Fellows, J. L. Tank, N. B. Grimm, J. R. Webster, S. K. Hamilton, E. Marti, L. Ashkenas, W. B. Bowden, W. K. Dodds, W. H. McDowell, M. J. Paul, and B. J. Peterson.  Inter-biome comparison of factors controlling stream metabolism.  2001.  Freshwater Biology 46:1503-1517.
  • Sanzone, D. M., J. L. Tank, P. J. Mulholland, J. L. Meyer, and S. E. G. Findlay.  2001.  Microbial incorporation of nitrogen in stream detritus.  Hydrobiologia 464:27-35.
  • Martin, L. A., P. J. Mulholland, J. R. Webster, and H. M. Valett.  2001.  Denitrification in sediments of headwater streams in the southern Appalachian Mountains, USA.    Journal of the North American Benthological Society 20:505-519.
  • Wilson, K. B., P. J. Hanson, P. J. Mulholland, D. D. Baldocchi, and S. D. Wullschleger. 2001. A comparison of methods for determining forest evapotranspiration and its components across scales: sap-flow, soil water budget, eddy covariance and catchment water balance.  Agricultural and Forest Meteorology 106:153-168. 
  • Peterson, B. J., W. M. Wollheim, P. J. Mulholland, J. R. Webster, J. L. Meyer, J. L. Tank, E. Marti, W. B. Bowden, H. M. Valett, A. E. Hershey, W. H. McDowell, W. K. Dodds, S. K. Hamilton, S. Gregory, and D. J. Morrall.  2001.  Control of nitrogen export from watersheds by headwater streams.  Science 292:86-90.
  • Hill, W. R., P. J. Mulholland, and E. R. Marzolf.  2001.  Stream ecosystem responses to forest leaf emergence in spring.  Ecology 82:2306-2319.
  • Thomas, S.A., H.M. Valett, J.R.Webster, P.J. Mulholland, C.S. Fellows, C.N. Dahm, and C.G. Peterson.  2001.  Nitrogen retention in headwater streamsthe influence of groundwater  surface water interaction.   In Optimizing Nitrogen Management in Food and Energy Production and Environmental ProtectionProceedings of the 2nd International Nitrogen Conference on Science and Policy. TheScientificWorld 1: 623-631.
  • Mulholland, P. J., J. L. Tank, D. M. Sanzone, W. M.. Wollheim, B. J. Peterson, J. R. Webster,  and J. L. Meyer.  2000.  Food Web Relationships in a Forested Stream Determined by Natural Abundance and Experimental 15N-Tracer Studies.  Journal of the North American Benthological Society 19:145-157.
  • Jones, J. G., Jr. and P. J. Mulholland.  2000.  Streams and Ground Waters.  Academic Press, San Diego.
  • Mulholland, P. J., J. L. Tank, D. M. Sanzone, W. M.. Wollheim, B. J. Peterson, J. R. Webster,  and J. L. Meyer. 2000. Nitrogen Cycling in a Forest Stream Determined by a 15N Tracer Addition.  Ecological Monographs 70(3): 471-493.
  • Tank, J. L., J. L. Meyer, D. M. Sanzone, P. J. Mulholland, J. R. Webster, B. J. Peterson, W. M. Wollheim, and N. E. Leonard.  2000. Analysis of nitrogen cycling in a forest stream during autumn using a 15N tracer addition.  Limnology and Oceanography 45:1013-1029.  ESD #5029.
  • Mulholland, P. J., J. L. Tank, D. M. Sanzone, J. R. Webster, W. Wollheim, B. J. Peterson, and J. L. Meyer.  2000.  Ammonium and nitrate uptake lengths in a small forested stream determined by 15N tracer and short-term nutrient enrichment experiments.  Verh. Internat. Verein Limnol. 27 :1320-1325.
  • Mulholland, P. J., and D. L. DeAngelis.  2000.  Effect of surface/subsurface exchange on nutrient dynamics and nutrient spiraling in streams, pp. 149-166.  In: J. B. Jones, Jr. and P. J. Mulholland (eds.), Streams and Ground Waters.  Academic, San Diego, CA.
  • Rosemond, A. D., P. J. Mulholland, and S. H. Brawley. 2000.  Seasonally shifting limitation of stream periphyton: response of algal populations and assemblage biomass and productivity to variation in light, nutrients, and herbivores.  Canadian Journal of Fisheries and Aquatic Sciences 57:66-75.
  • Meyer, J. L., M. J. Sale, P. J. Mulholland, and N. L. Poff. 1999.  Impacts of climate change on aquatic ecosystem functioning and health.  Journal of the American Water Resources Association 35:1373-1386.
  • Hart, D. R., P. J. Mulholland, E. R. Marzolf, D. L. DeAngelis, and S. P. Hendricks. 1999. Relationships between hydraulic parameters in a small stream under varying flow and seasonal conditions.  Hydrologic Processes 13:1497-1510. Jones, J. G., Jr., and P. J. Mulholland.  1998.  Influence of drainage basin topography and elevation on carbon dioxide and methane supersaturation of stream water.  Biogeochemistry 40: 57-72.
  • Jones, J. G., Jr., and P. J. Mulholland.  1998.  Carbon dioxide variation in a hardwood forest stream: an integrative measure of whole catchment ecosystem respiration.  Ecosystems 1: 183-196.
  • Jones, J. G., Jr., and P. J. Mulholland. 1998. Methane input and evasion in a hardwood forest stream: effects of subsurface flow from shallow and deep pathways.  Limnology and Oceanography 43: 1243-1250. Mulholland, P. J., and M. J. Sale.  1998.  Impacts of climate change on water resources: findings of the IPCC Regional Assessment of Vulnerability for North America.  Water Resources Update, Universities Council on Water Resources, Issue No. 112, pages10-15, Summer 1998.

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