• In understanding the environment as an integrated system, WSAG explores the physical, chemical and biological processes that shape hydrological systems, with emphasis on the unique role of humans as agents of change. Our research and educational programs cross the boundaries of traditional scientific disciplines to foster interdisciplinary understanding of environmental change. Through field monitoring, whole ecosystem experiments, novel in situ sensor deployments, and dynamic hydrological and ecosystem modeling, we attempt to understand hydrological and biogeochemical dynamics at scales ranging from individual ecosystems, to whole river systems, to the global systems of inland waters. Built on strong collaborations that are national and international in scope, our group also serves as a teaching platform for the next generation of ecosystem and earth system scientists.

    The success of the Water Systems Analysis Group reflects a rapidly emerging scientific field which pursues integrative studies of hydrology, biogeochemistry, and human-water interactions that is necessary to analyze the full dimension of anthropogenic change at local, regional, and global scales.
  • Publications

    Academic Article

    Year Title
    2018 River network saturation concept: factors influencing the balance of biogeochemical supply and demand of river networksBiogeochemistry.  141:503-521. 2018
    2018 Influences of agricultural land use composition and distribution on nitrogen export from a subtropical watershed in China.Science of the Total Environment.  642:21-32. 2018
    2018 Lateral Marsh Edge Erosion as a Source of Sediments for Vertical Marsh AccretionJournal of Geophysical Research Biogeosciences.  123:2444-2465. 2018
    2018 Controls of Chloride Loading and Impairment at the River Network Scale in New England.Journal of Environmental Quality.  47:839-847. 2018
    2018 Continental-scale decrease in net primary productivity in streams due to climate warmingNature Geoscience.  11:415-+. 2018
    2018 The impact of flooding on aquatic ecosystem services.Biogeochemistry.  141:439-461. 2018
    2017 Nitrification increases nitrogen export from a tropical river networkFreshwater Science.  36:698-712. 2017
    2017 Aquatic Nitrate Retention at River Network Scales Across Flow Conditions Determined Using Nested In Situ SensorsWater Resources Research.  53:9740-9756. 2017
    2017 A longer vernal window: the role of winter coldness and snowpack in driving spring transitions and lags.Global Change Biology.  23:1610-1625. 2017
    2017 Stream tracer breakthrough curve decomposition into mass fractions: A simple framework to analyze and compare conservative solute transport processesLimnology and Oceanography: Methods.  15:140-153. 2017
    2017 A coupled terrestrial and aquatic biogeophysical model of the Upper Merrimack River watershed, New Hampshire, to inform ecosystem services evaluation and management under climate and land-cover changeEcology and Society Conservation Ecology.  22. 2017
    2016 Dissolved organic carbon uptake in streams: A review and assessment of reach-scale measurementsJournal of Geophysical Research Biogeosciences.  121:2019-2029. 2016
    2016 Longer thaw seasons increase nitrogen availability for leaching during fall in tundra soilsEnvironmental Research Letters.  11:064013-064013. 2016
    2016 Baseflow physical characteristics differ at multiple spatial scales in stream networks across diverse biomesLandscape Ecology.  31:119-136. 2016
    2015 An index to characterize the spatial distribution of land use within watersheds and implications for river network nutrient removal and exportGeophysical Research Letters.  42:6688-6695. 2015
    2015 Removal of terrestrial DOC in aquatic ecosystems of a temperate river networkGeophysical Research Letters.  42:6671-6679. 2015
    2015 Urban Evolution: The Role of WaterWater (Switzerland).  7:4063-4087. 2015
    2015 Causes and Consequences of Ecosystem Service Regionalization in a Coastal Suburban WatershedEstuaries Chesapeake Science Estuaries and Coasts.  38:S19-S34. 2015
    2014 A Scale-Explicit Framework for Conceptualizing the Environmental Impacts of Agricultural Land Use ChangesSustainability.  6:8432-8451. 2014
    2014 Climate variability masks the impacts of land use change on nutrient export in a suburbanizing watershedBiogeochemistry.  121:45-59. 2014
    2014 Ecosystem metabolism and nutrient uptake in an urban, piped headwater streamBiogeochemistry.  121:167-187. 2014
    2014 Tracking evolution of urban biogeochemical cycles: past, present, and futureBiogeochemistry.  121:1-21. 2014
    2014 The Lotic Intersite Nitrogen Experiments: an example of successful ecological research collaborationFreshwater Science.  33:700-710. 2014
    2014 Nitrate uptake dynamics of surface transient storage in stream channels and fluvial wetlandsBiogeochemistry.  120:239-257. 2014
    2014 Temperature and peat type control CO2 and CH4 production in Alaskan permafrost peats.Global Change Biology.  20:2674-2686. 2014
    2014 Characterizing storm-event nitrate fluxes in a fifth order suburbanizing watershed using in situ sensors.Environmental Science & Technology.  48:7756-7765. 2014
    2013 Extreme rainfall, vulnerability and risk: a continental-scale assessment for South America.Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences.  371:20120408. 2013
    2013 Controls on dissolved organic carbon quantity and chemical character in temperate rivers of North AmericaGlobal Biogeochemical Cycles.  27:492-504. 2013
    2013 History of nutrient inputs to the northeastern United States, 1930-2000Global Biogeochemical Cycles.  27:578-591. 2013
    2013 Horizontal cooling towers: riverine ecosystem services and the fate of thermoelectric heat in the contemporary Northeast USEnvironmental Research Letters.  8:025010-025010. 2013
    2013 Riverine ecosystem services and the thermoelectric sector: strategic issues facing the Northeastern United StatesEnvironmental Research Letters.  8:025017-025017. 2013
    2012 Effects of suburbanization on foodweb stoichiometry of detritus-based streamsFreshwater Science.  31:1202-1213. 2012
    2012 Hotbeds of Biogeochemical Diversity: Insights from Urban Long-Term Ecological Research SitesElements.  8:435-438. 2012
    2012 Coastal eutrophication as a driver of salt marsh loss.Nature Nature: New biology.  490:388-392. 2012
    2012 Legacy Effects in Material Flux: Structural Catchment Changes Predate Long-Term StudiesBioScience.  62:575-584. 2012
    2012 Taking the pulse of snowmelt: in situ sensors reveal seasonal, event and diurnal patterns of nitrate and dissolved organic matter variability in an upland forest streamBiogeochemistry.  108:183-198. 2012
    2011 Separation of river network-scale nitrogen removal among the main channel and two transient storage compartmentsWater Resources Research.  47. 2011
    2011 Residence time distributions in surface transient storage zones in streams: Estimation via signal deconvolutionWater Resources Research.  47. 2011
    2011 Thinking outside the channel: modeling nitrogen cycling in networked river ecosystemsFrontiers in Ecology and the Environment.  9:229-238. 2011
    2011 Nitrous oxide emission from denitrification in stream and river networks.Proceedings of the National Academy of Sciences of the United States of America.  108:214-219. 2011
    2010 Millennium Ecosystem Assessment scenario drivers (1970-2050): Climate and hydrological alterationsGlobal Biogeochemical Cycles.  24:n/a-n/a. 2010
    2010 Surface and hyporheic transient storage dynamics throughout a coastal stream networkWater Resources Research.  46. 2010
    2009 The biogeochemical influences of NO(3)(-), dissolved O(2), and dissolved organic C on stream NO(3)(-) uptakeJournal of the North American Benthological Society.  28:894-907. 2009
    2009 Dynamic modeling of nitrogen losses in river networks unravels the coupled effects of hydrological and biogeochemical processesBiogeochemistry.  93:91-116. 2009
    2009 The regional and global significance of nitrogen removal in lakes and reservoirsBiogeochemistry.  93:143-157. 2009
    2008 Dynamics of N removal over annual time periods in a suburban river networkJournal of Geophysical Research.  113. 2008
    2008 Global N removal by freshwater aquatic systems using a spatially distributed, within-basin approachGlobal Biogeochemical Cycles.  22:n/a-n/a. 2008
    2008 The application of electrical conductivity as a tracer for hydrograph separation in urban catchmentsHydrological Processes.  22:1810-1818. 2008
    2006 The Role of Snowmelt and Spring Rainfall in Inorganic Nutrient Fluxes from a Large Temperate Watershed, the Androscoggin River Basin (Maine and New Hampshire)Biogeochemistry.  80:191-203. 2006
    2006 Relationship between river size and nutrient removalGeophysical Research Letters.  33. 2006
    2005 N retention in urbanizing headwater catchmentsEcosystems.  8:871-884. 2005
    2004 Spatial Distribution of Land Type in Regression Models of Pollutant Loading.Biological Bulletin.  207:173. 2004
    2004 Role of wetlands and developed land use on dissolved organic nitrogen concentrations and DON/TDN in northeastern U.S. rivers and streamsLimnology and Oceanography.  49:910-918. 2004
    2004 Role of wetlands and developed land use on dissolved organic nitrogen concentrations and DON/TDN in northeastern US rivers and streamsLimnology and Oceanography.  49:910-918. 2004
    2004 A stable isotope tracer study of nitrogen uptake and transformation in an old-growth forest streamEcology.  85:1725-1739. 2004
    2003 Factors affecting ammonium uptake in streams - an inter-biome perspectiveFreshwater Biology.  48:1329-1352. 2003
    2002 Can uptake length in streams be determined by nutrient addition experiments? Results from an interbiome comparison studyJournal of the North American Benthological Society.  21:544-560. 2002
    2002 N uptake as a function of concentration in streamsJournal of the North American Benthological Society.  21:206-220. 2002
    2002 Characterizing nitrogen dynamics, retention and transport in a tropical rainforest stream using an in situ N-15 additionFreshwater Biology.  47:143-160. 2002
    2001 Control of nitrogen export from watersheds by headwater streams.Science The Scientific monthly.  292:86-90. 2001
    2001 Influence of stream size on ammonium and suspended particulate nitrogen processingLimnology and Oceanography.  46:1-13. 2001
    2000 Quantification of the Nitrogen Cycle in a Prairie StreamEcosystems.  3:574-589. 2000
    2000 Nitrogen cycling in a forest stream determined by a N-15 tracer additionEcological Monographs.  70:471-493. 2000
    2000 Analysis of nitrogen cycling in a forest stream during autumn using a N-15-tracer additionLimnology and Oceanography.  45:1013-1029. 2000
    2000 Food resources of stream macroinvertebrates determined by natural-abundance stable C and N isotopes and a N-15 tracer additionJournal of the North American Benthological Society.  19:145-157. 2000
    1999 A coupled field and modeling approach for the analysis of nitrogen cycling in streamsJournal of the North American Benthological Society.  18:199-221. 1999
    1997 Oxygen, organic matter, and sediment granulometry as controls on hyporheic animal communities fig: 5 tab: 3Archiv f�r Hydrobiologie Fundamental and Applied Limnology.  140:131-144. 1997
    1996 Effects of macrophyte growth forms on invertebrate communities in saline lakes of the Wyoming High PlainsHydrobiologia Journal of Aquatic Ecosystem Stress and Recovery.  323:83-96. 1996
    1995 An endemic groundwater fauna in unglaciated eastern North AmericaCanadian Journal of Zoology.  73:502-508. 1995


    Year Title
    2016 Chapter 8 From Headwaters to Rivers to River Networks Scaling in Stream Ecology.  349-388. 2016
    2016 From Headwaters to Rivers to River Networks: Scaling in Stream Ecology.  349-388. 2016

    Principal Investigator On

  • Collab Proposal:MRA:Linking Land-to-Water Transport & Stream Carbon Cycling to Inform Macrosystem Carbon Balance  awarded by National Science Foundation (NSF) 2020 - 2023
  • Collab Proposal:MSA:Controls on Coupled Nitrogen & Carbon Cycles of Watersheds Across Eco-Regions  awarded by National Science Foundation (NSF) 2020 - 2022
  • LTER-Plum Island Ecosystems: Dynamics of a Coastal Ecosystem in a Region of Rapid Climate Change  awarded by Marine Biological Laboratory 2016 - 2022
  • Estimating Spatially Explicit Water Quality Benefits throughout River Systems: Development of Next Generation Stated Preference Methods Using National Probability Samples  awarded by Clark University 2016 - 2021
  • Nutrient Sensor Action Challenge Stage 2  awarded by Environmental Protection Agency (EPA) 2020 - 2021
  • Nutrient Sensor Action Challenge Stage 1  awarded by Environmental Protection Agency (EPA) 2017 - 2019
  • The PIE-LTER: Interactions Between External Drivers, Humans and Ecosystems in Shaping Ecological Process in a Mosaic of Coastal Landscapes and Estuarine Seascapes  awarded by Marine Biological Laboratory 2012 - 2017
  • SCALER Stream Consumers  awarded by National Science Foundation (NSF) 2011 - 2017
  • A Regional Earth System Model of the Northeast Corridor: Analyzing 21st Century Climate and Environment  awarded by City College of New York 2011 - 2015
  • Impact of Climate Change and Variability on the Nation's Water Quality  awarded by City College of New York 2009 - 2014
  • Tracking Dissolved Organic Carbon and its Absorbtion Characteristics along the Aquatic Continuum over Time using a Remote Sensing Based Approach  awarded by National Aeronautics and Space Administration (NASA) 2009 - 2014
  • ETBC: Controls on the Flux, Age and Composition of Terrestrial Carbon Exported by Rivers to the Ocean  awarded by Woods Hole Oceanographic Institution 2009 - 2014
  • EPA-ULTRA Climate Project  awarded by Univ of Massachusetts Amherst 2012 - 2014
  • Plum Island Ecosystem LTER  awarded by Marine Biological Laboratory 2010 - 2013
  • How Does Changing Seasonality Affect the Capacity of Arctic Stream Networks to Influence Nutrient Fluxes from the Landscape to the Ocean?  awarded by National Science Foundation (NSF) 2009 - 2013
  • Suburbanization, Water-use, Nitrogen Cycling and Euthophication in the 21st Century: Interactions, Feedbacks and Uncertainties in a Massachusetts Coastal Zone  awarded by Clark University 2008 - 2013
  • Plum Island Sound Comparative Ecosystem Study  awarded by Marine Biological Laboratory 2004 - 2011
  • Understanding the Scaling of N Cycle Controls Throughout a River Network  awarded by National Science Foundation (NSF) 2006 - 2010
  • Teaching Activities

  • Environmental Modeling Taught course 2020
  • Environmental Modeling Taught course 2020
  • Freshwater Resources Taught course 2020
  • Freshwater Resources Taught course 2020
  • Freshwater Resources Taught course 2020
  • Freshwater Resources Taught course 2020
  • Freshwater Resources Taught course 2019
  • Freshwater Resources Taught course 2019
  • Freshwater Resources Taught course 2019
  • Freshwater Resources Taught course 2019
  • Grant Writing Taught course 2019
  • Investigations Taught course 2018 - 2019
  • Aquatic Ecosystems Taught course 2018
  • Aquatic Ecosystems Taught course 2018
  • Environmental Modeling Taught course 2018
  • Environmental Modeling Taught course 2018
  • Grant Writing Taught course 2018
  • Inv/Sediment Control Fluxes Taught course 2018
  • Aquatic Ecosystems Taught course 2017
  • Aquatic Ecosystems Taught course 2017
  • Sem/ Science Denialism Taught course 2017
  • Grant Writing Taught course 2017
  • Proj/Environmental Science I Taught course 2017
  • Adv Rsrch Exp/Natural Resource Taught course 2016
  • Environmental Modeling Taught course 2016
  • Environmental Modeling Taught course 2016
  • Grant Writing Taught course 2016
  • Aquatic Ecosystems Taught course 2015
  • Aquatic Ecosystems Taught course 2015
  • Grant Writing Taught course 2015
  • Aquatic Ecosystems Taught course 2014
  • Aquatic Ecosystems Taught course 2014
  • Environmental Modeling Taught course 2014
  • Grant Writing Taught course 2014
  • Education And Training

  • B.S. Natural Resources, Cornell University
  • M.S. Zoology/Physiology, University of Wyoming
  • Ph.D. Earth Sciences, University of New Hampshire
  • Full Name

  • Wilfred Wollheim