The Influence of Climate-Induced Alterations in Dissolved Organic Matter on Metal Toxicity and UV Radiation in Rocky Mountain Streams

EPA Grant Number: R829640
Title: The Influence of Climate-Induced Alterations in Dissolved Organic Matter on Metal Toxicity and UV Radiation in Rocky Mountain Streams
Investigators: Clements, William , Baron, Jill S. , McKnight, Diane M. , Meyer, Joseph S.
Institution: Colorado State University , University of Colorado at Boulder , University of Wyoming
EPA Project Officer: Hiscock, Michael
Project Period: April 1, 2002 through April 1, 2005
Project Amount: $896,212
RFA: Assessing the Consequences of Global Change for Aquatic Ecosystems: Climate, Land Use, and UV Radiation (2001) RFA Text |  Recipients Lists
Research Category: Global Climate Change , Ecological Indicators/Assessment/Restoration , Water , Ecosystems , Climate Change


The goal of this research is to investigate the influence of climate-induced changes in hydrology and dissolved organic material (DOM) on responses of stream ecosystems to other anthropogenic disturbances. We hypothesize that changes in climate and ultraviolet radiation (UVR) will alter the quality and quantity of DOM in Rocky Mountain streams. Because DOM regulates light attenuation and metal bioavailability in these systems, we predict that exposure to UVR and metals will increase as a result of these changes in DOM.


We will integrate climate and hydrologic modeling with an intensive field monitoring and experimental program to test the hypothesis that changes in DOM increase bioavailability of metals and exposure to UV-B radiation. We will estimate effects of climate-induced alterations in stream hydrology on the timing and export of DOM using a GIS-based, hydroecological model (RHESSys) that simulates carbon, water, and nutrient flux to streams. We will characterize metal-binding capabilities and light attenuation of DOM from different sources (e.g., allochthonous versus autochthonous) in the laboratory after exposure to a full-spectrum solar simulator. Finally, we will conduct field and microcosm experiments to test the hypothesis that reductions in DOM concentration and binding capabilities will increase exposure of benthic communities to heavy metals and UV-B radiation.

Expected Results:

Because DOM regulates bioavailability and light attenuation, we expect that alterations in quality and quantity of DOM will increase exposure of aquatic organisms to metals and UVR. Ultimately, we predict that benthic communities from metal-polluted streams will show greater susceptibility to UV-B radiation than those from unpolluted streams.

Publications and Presentations:

Publications have been submitted on this project: View all 20 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 5 journal articles for this project

Supplemental Keywords:

Dissolved organic carbon; ecological effects; monitoring; modeling; microcosms; UV-B; Rocky Mountain streams., RFA, Scientific Discipline, Air, Geographic Area, Water, Hydrology, Water & Watershed, climate change, State, Atmospheric Sciences, Ecological Risk Assessment, Watersheds, EPA Region, water resources, metal toxicity, dissolved organic matter, wetlands, environmental monitoring, global change, regional hydrologic vulnerability, aquatic food web, hydrologic models, climate models, Rocky Mountains, Rocky Mountain Streams, UV radiation, vulnerability assessment, aquatic ecosystems, watershed sustainablility, land and water resources, aquatic ecology, climate variability, climatic models, Global Climate Change, stream ecosystem, Colorado (CO), land use

Progress and Final Reports:

  • 2002 Progress Report
  • 2003 Progress Report
  • Final Report