Grantee Research Project Results
2003 Progress Report: Interactive Effects of Climate Change, Wetlands, and Dissolved Organic Matter on UV Damage to Aquatic Foodwebs
EPA Grant Number: R829643Title: Interactive Effects of Climate Change, Wetlands, and Dissolved Organic Matter on UV Damage to Aquatic Foodwebs
Investigators: Bridgham, Scott D. , Shmagin, Boris A. , Johnston, Carol A. , Lamberti, Gary A. , Maurice, Patricia A. , Lodge, David M.
Current Investigators: Bridgham, Scott D. , Shmagin, Boris A. , Johnston, Carol A. , Lamberti, Gary A. , Maurice, Patricia A. , Frost, Paul C , Lodge, David M.
Institution: University of Notre Dame , University of Oregon , South Dakota State University
Current Institution: University of Oregon , Natural Resources Research Institute , Trent University , University of Notre Dame
EPA Project Officer: Packard, Benjamin H
Project Period: June 24, 2002 through June 23, 2005 (Extended to June 23, 2006)
Project Period Covered by this Report: June 24, 2003 through June 23, 2004
Project Amount: $897,307
RFA: Assessing the Consequences of Global Change for Aquatic Ecosystems: Climate, Land Use, and UV Radiation (2001) RFA Text | Recipients Lists
Research Category: Aquatic Ecosystems , Ecological Indicators/Assessment/Restoration , Water , Climate Change
Objective:
The objectives of this research project are to: (1) relate dissolved organic matter (DOM) concentration and chemical characteristics in various tributaries of a relatively pristine watershed in the Lake Superior drainage basin (Ontonagon River in northern Michigan) to discharge, wetland landscape characteristics, upland landscape characteristics, and stream order via multivariate analysis; (2) determine interactions among ultraviolet radiation (UVR) intensity and DOM chemistry, photodegradation, photoaggregation, and biodegradation; and (3) determine the response of stream food webs to the interactions among UVR intensity and DOM quantity and quality. We have met or exceeded all goals and objectives for Year 2 of the project, as detailed below.
Progress Summary:
Watershed Analyses
We sampled water chemistry (including DOM) a dozen times over a 2-year period and determined discharge in 35 subwatersheds in the Ontonagon watershed. Additionally, we did an initial survey of 60 sampling locations within the Ontonagon River watershed in September 2003. Thus, we have developed an extensive spatial and temporal data set of water chemistry over the Ontonagon River watershed. The second component of our watershed analysis is to relate DOM concentration and chemical characteristics in tributaries of the Ontonagon River to discharge, landscape characteristics, and stream order with multivariate statistics. We have entered the landscape characteristics within of each of the 35 subwatersheds into a geographical information systems (GIS) database.
Many of the streams in this region originate as lake outflows, so we have extended our original project objectives to compare DOM and UVR dynamics in streams with and without upstream lakes. We have studied longitudinal changes in DOM characteristics and UVR penetration in several streams from their lake outlet, for several miles downstream. We also have incorporated GIS landscape variables into this analysis. Furthermore, in one stream, we intensively measured changes in DOM characteristics with distance from the lake outflow throughout this past summer, including several sets of diurnal measurements.
UVR Mapping
Three main UV mapping activities were completed during the summer of 2004. The first project measured UV flux using plastic dosimetry strips in eight streams across a 100-m transect. Plastic dosimetry strips allow for integrated UV measurements at different depths within a stream and under different forest canopy types. A second project measured the attenuation coefficients (Kd) of UVR in six streams throughout the summer. A third project compared Kd values for more streams but less intensively than in the second project.
Hydrologic Research
The objectives of the hydrologic research are to: (1) understand the forces driving the water balance for the Ontonagon watershed, including its interannual and seasonal dynamics; and (2) evaluate the hydrology of the Ontonagon watershed in relation to climate. We did a literature review and have begun a more indepth evaluation of a number of basin-scale hydrology models to model discharge and DOM concentration throughout the Ontonagon watershed. Our second task is to describe the multiscale landscape influence on the spatial-temporal distribution of the components of the water balance using factor analysis of hydrologic characteristics at four spatial levels (the conterminous United States, Great Lakes Basin, upper Michigan, and the Ontonagon watershed) using different sets of hydrologic data obtained from U.S. Geological Survey gauging station records. The work focused primarily on the upper Michigan and Ontonagon watersheds and the interconnection of all four levels. The hydrologic regime for the conterminous United States and the Great Lakes Basin are being connected with global climatic processes with the use of teleconnection indices (Atlantic oscillation, Antarctic oscillation, North Atlantic oscillation, and North Pacific oscillation).
Biodegradation Experiments
We are currently 6 months into a long-term DOM biodegradation experiment in which we are asking three questions: (1) How do DOM concentration and quality interact to affect DOM biodegradation rates? (2) Does low nutrient availability constrain DOM biodegradation in some streams? (3) Is the effect of photodegradation on DOM biodegradation rates dependent on the DOM source? To answer these questions, we are examining DOM biodegradation in water from six streams subjected to three treatments: (1) plus nutrients; (2) no nutrients; and (3) photodegraded and then biodegraded, with five replicates of each stream-treatment combination. We are measuring both short-term and long-term DOM biodegradation, microbial growth, and nutrient mineralization.
Food Web Experiments
We constructed a large artificial stream facility at the University of Notre Dame Environmental Research Center, at the southern edge of the Ontonagon watershed, to examine experimentally how DOM and UVR interact in controlling food web structure in streams. We conducted two artificial stream experiments in each of the 2003 and 2004 summers. This past summer, we manipulated both light quantity and quality and tracked the accumulation of organic matter for 1 month. A second experiment compared the responses of periphyton to the same concentrations of DOM from a stream with a wetland-dominated watershed and a stream downstream of a lake outlet.
Future Activities:
Many of the field components have been completed, and we are in the process of analyzing the data and writing manuscripts. We will collect additional data from some sites in the coming year to improve stage and discharge curves. If resources allow, we will examine the relationship between DOM and soil C/N ratios in the Ontonagon watershed. The continuing tasks for the hydrologic analyses are described above. Ultimately, we will use the hydrological model as a tool to synthesize the many aspects of this project so that we can predict the effects of climate and landscape on DOM concentration and UVR penetration into the water column within the Ontonagon watershed. We may undertake one more food web experiment in the summer of 2005, probably incorporating higher trophic levels.
Journal Articles on this Report : 4 Displayed | Download in RIS Format
| Other project views: | All 56 publications | 14 publications in selected types | All 13 journal articles |
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Frost PC, Larson JH, Kinsman LE, Lamberti GA, Bridgham SD. Attenuation of ultraviolet radiation in streams of northern Michigan. Journal of the North American Benthological Society 2005;24(2):246-255. |
R829643 (2003) R829643 (2004) R829643 (Final) |
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Frost PC, Larson JH, Johnston CA, Young KC, Maurice PA, Lamberti GA, Bridgham SD. Landscape predictors of stream dissolved organic matter concentration and physicochemistry in a Lake Superior river watershed. Aquatic Sciences – Research Across Boundaries 2006;68(1):40-51. |
R829643 (2003) R829643 (2004) R829643 (Final) |
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Young KC, Maurice PA, Docherty KM, Bridgham SD. Bacterial degradation of dissolved organic matter from two northern Michigan streams. Geomicrobiology Journal 2004;21(8):521-528. |
R829643 (2003) R829643 (Final) |
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Young KC, Docherty KM, Maurice PA, Bridgham SD. Degradation of surface-water dissolved organic matter: influences of DOM chemical characteristics and microbial populations. Hydrobiologia 2005;539(1):1-11. |
R829643 (2003) R829643 (2004) R829643 (Final) |
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Supplemental Keywords:
water, watersheds, groundwater, land, soil, sediments, global climate, ecological effects, organism, stressor, organics, ecosystem, scaling, terrestrial, aquatic, environmental chemistry, biology, ecology, hydrology, geology, limnology, monitoring, surveys, Great Lakes, Midwest, Michigan, MI, U.S. EPA Region,, RFA, Air, Scientific Discipline, Geographic Area, Water, Ecological Risk Assessment, EPA Region, State, Watersheds, Atmospheric Sciences, Hydrology, climate change, Water & Watershed, hydrologic models, vulnerability assessment, Global Climate Change, water quality, global change, aquatic food web, aquatic ecology, environmental monitoring, climate models, climate variability, land and water resources, regional hydrologic vulnerability, vegetation models, Region 5, UV radiation, wetlands, land use, ecological research, Lake Superior, dissolved organic matter, aquatic ecosystems, Michigan (MI), water resources, anthropogenic processesProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.