Grantee Research Project Results
2000 Progress Report: An Integrative Aquatic Ecosystem Indicator
EPA Grant Number: R826591Title: An Integrative Aquatic Ecosystem Indicator
Investigators: Stemberger, Richard S. , Miller, Eric K.
Institution: Dartmouth College
EPA Project Officer: Packard, Benjamin H
Project Period: October 1, 1998 through June 30, 2003
Project Period Covered by this Report: October 1, 1999 through June 30, 2000
Project Amount: $888,661
RFA: Ecological Indicators (1998) RFA Text | Recipients Lists
Research Category: Ecological Indicators/Assessment/Restoration , Aquatic Ecosystems
Objective:
In this project, we establish a relationship between the dissolved and particulate sources of carbon (C), nitrogen (N), and phosphorus (P) in lake water and tributary sources with watershed land use and forest cover. Our goal is to integrate watershed, lake, and pelagic zooplankton assemblages in a multi-tier ecological indicator for monitoring lake integrity. Complex species assemblages are aggregated into simple consumer guilds that reflect relative N and P intracellular requirements of species. Element supply ratios correlate to a variety of potential risks to lake ecosystem function such as loss of the cool-water refuge, bioaccumulation of toxins, algal turbidity, acidification and UV/B toxicity. These risks are associated with zooplankton assemblage structure along a gradient from high to low lake water N:P ratios.
Objectives of the project include the following:
- Evaluate metrics based on the C, N, and P supply of the total dissolved plus seston fraction of lake water as indicators of the character of lake zooplankton assemblage.
- Establish the strength of the relationship between the relative C, N, and P supply from the watershed to the C, N, and P supply to the lake. We will test the hypothesis that N:P, C:N, C:P ratios in lake water and watershed C, N, P supply to lakes are significantly influenced by landscape factors related to human land use activity, forest ecosystem composition, and regional air pollution gradients.
- Conduct a landscape characterization analysis of features in the lake-watershed basins which, in conjunction with concurrent watershed-associated stream and groundwater measurements, will be used to develop proxy measures for expected relative C, N, P supply conditions for lake water.
- Establish zooplankton assemblage-derived variables that reflect risks to ecosystem function, structure, or human health as a function of the elemental supply gradient. These risks include food web simplification reflected by assemblage-derived structural indices like chain length and linkages, the availability of oxic cold-water habitat, algal turbidity, UV/B and aluminum toxicity, and bioaccumulation and transfer efficiency of toxins.
- Conduct a thorough analysis of the sensitivity of zooplankton metrics using the spatially extensive data set in this study and from the existing lake data sets. These analyses will establish statistical confidence and power to detect change for measures of lake integrity. We expect to demonstrate that the proposed relative C, N, P supply indicator can provide a simple, inexpensive and practical approach to evaluating aquatic ecosystem integrity within the context of the terrestrial environment.
- Develop a hierarchical, ecological-indicator analysis tool designed to aid resource managers in assessment, monitoring and prediction of aquatic ecosystem integrity, sustainability and associated ecosystem risks.
Progress Summary:
Objectives 1-2. In our two field seasons, we conducted 80 lake visits, including 24 revisits and sampled 158 tributaries in Adirondack Mountain and Saint Lawrence Valley Regions of New York, Vermont, and New Hampshire. At each lake visit physical profiles were collected (CTD, DO, pH, Turbidity). Water samples were collected from the epilimnion, metalimnion and hypolimnion and from all tributary streams of each lake. Dissolved and suspended fractions were separated. Plankton tows were conducted for both enumeration and chemical analysis. Sediment samples were collected from mid-lake and tributary mouths. Chemical analysis of 1999 water and sediment samples is complete. Analysis of 2000 samples is well underway and should be complete by spring.
Enumeration of the 2000 zooplankton samples should be completed early this spring. We have completed enumeration and biomass estimates of zooplankton from 37 lakes from the 1999 survey and from an additional 40 lakes from the 1991-1996 EMAP pilot survey which are also part of the current field sample. Zooplankton population data are being converted to biomass/carbon using length-weight regression. Biomass measures allow us to integrate the soluble and particulate fractions of C, N, and P in lake and stream water with the comprising zooplankton taxa. This conversion program uses high resolution gray-scale images of the zooplankton and provides a permanent image archive of the lake zooplankton. The program is written in NIH Image language that is available from the NIH website (http://rsb.info.nih.gov/nih-image). It gives many useful data such as magnification, measurement line marks, time stamps on images and measurements useful for QA assessment, and a variety of descriptive statistics (N, standard deviation, and coefficient of variation of length and biomass of individual taxa). All data and images are saved as tab-delimited text files for later manipulation and cross-referencing in spreadsheet programs. This program will eventually be available for interested users at the NIH web site.
Objective 2 (Experimental Evaluation). Using 1000L mesocosms we evaluated taxonomic and body size responses of zooplankton to additions of nitrogen, phosphorus, and fish. Nutrients had striking effects on taxonomic structure of the assemblages: phosphorus stimulated the abundance of cladocerans and rotifers while nitrogen increased the abundance of copepod nauplii, cyclopoid copepodites, and rotifers. Fish reduced body sizes of crustacean zooplankton independent of taxonomic grouping. Populations of microzooplankton like copepod nauplii, cyclopoid copepodites, small cladocerans, and rotifers also increased significantly with fish. Observed taxonomic responses to nutrient additions are consistent with mineral limitation on growth rates presumably mediated through the nitrogen-to-phosphorus supply ratio.Objectives 2 and 4 (Empirical Evaluation). We evaluated zooplankton assemblages of northeastern U.S. lakes with respect to 17 environmental factors including those tested in the above experiment. The results of this analysis identified a major gradient which contrasted low N:P ratio taxa (small cladocerans, cyclopoid copepodites, nauplii, and rotifers) with high N:P ratio taxa (calanoid copepods). The primary explanatory variable was chlorophyll a which was positively and significantly correlated to nitrogen and phosphorus concentrations (i.e., decreasing N:P ratios). The analysis of field populations generally corroborated the results from the experiment- fish and the nitrogen-to-phosphorus ratio were significant factors but subordinate to chlorophyll a, total dissolved aluminum, pH, and dissolved organic carbon (DOC). The results from the experiment and analysis of natural assemblages support nutrients and their supply ratios as significant factors controlling broad taxonomic structure in lakes. The analysis also provides strong statistical correspondence among zooplankton metrics with risk factors such as aluminum toxicity and low pH.
Objective 3. The landscape characterization task involves both field and GIS-analysis components. During fall 1999, ten forested tributary riparian zone locations were visited for extensive field characterizations that included vegetation survey, leaf-litter sampling, and soil characterization and sampling. Preliminary results indicate significant variation in soluble, transportable (measured by incubation and extraction) N and P in soils as a function of dominant forest species. Soils occupied by forest species adapted to low nitrogen environments (e.g., red spruce) had higher transportable (soluble + extractable) P, while soils occupied by some deciduous species (e.g. American beech) had higher transportable N and lower P. This produced a range of N:P ratios of readily transportable materials in soil from 79 to 1070. Our observations are consistent with expectations based on the relative nutrient demand of different forest species. These results support the idea that variation in forest composition and forest nutrient cycling is partially responsible for landscape scale variation in N and P supply to aquatic systems. We have continued to develop the foundation data layers (topographic factors, land cover, forest type, soils, hydrology, climate, and atmospheric deposition) of a regional GIS that will be used for characterization of the study watersheds. The generation of watershed and riparian zone overlays for our study systems is in progress. Software for collecting statistics from the GIS was written.
Objective 5. A sensitivity analysis of zooplankton indicators proposed in this study was undertaken using data provided by the Environmental Monitoring and Assessment Program (EMAP). Assemblage indicators reflected presumptive nitrogen and phosphorus tissue demands. Indicators were evaluated for their ability to give precise estimates of status or condition and to detect trends on several geographic spatial scales. Sensitivity greatly increased for some of the indicators as a function of specific geographic region. Calanoid copepods were the most sensitive indicators having up to 95 percent of their variance attributed to the lake component. Therefore, this group would be especially useful for use in regional assessment of lake condition. Rotifers, cyclopoid copepods, small cladocerans, and minor zooplankton groups had low sensitivity irrespective of spatial scale. This suggests that other environmental factors must be evaluated in partitioning the data such as lake water nutrients and watershed influences.
Future Activities:
Work will continue in support of Objectives 1-5. Chemical analysis of 2000 survey lake, plankton, sediment and soil samples should be completed by the spring of 2001. The lake survey will be selectively expanded in the remaining field seasons (2001) to include lakes that extend the range in nitrogen and phosphorus concentrations and/or their supply ratios in the current lake sample. We will also make an effort to undertake chemical analyses of key zooplankton species for which their internal tissue nutrient measures are unknown. We will continue to revisit the current study lakes for purposes of estimating temporal and spatial variance of zooplankton, nutrient, and landscape indicators. GIS development, analysis and modeling will continue through 2001 and we will begin more formal analysis of the zooplankton assemblages data with lake and stream water nutrient size fraction data in relation to watershed land use and land cover variables. Development of indicator analysis tools (objective 6) will primarily take place during 2001 with complete of the field survey.Journal Articles on this Report : 8 Displayed | Download in RIS Format
Other project views: | All 27 publications | 12 publications in selected types | All 11 journal articles |
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Type | Citation | ||
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Allen AP, Whittier TR, Larsen DP, Kaufmann PR, O'Conner RJ, Hughes RM, Stemberger RS, Dixit SS, Brinkhurst RO, Herlihy AT, Paulsen SG. Concordance of taxonomic composition patterns across multiple lake assemblages: effects of scale, body size, and land use. Canadian Journal of Fish and Aquatic Science 1999;56(11):2029-2040. |
R826591 (2000) |
not available |
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Allen AP, Whittier TR, Kaufmann PR, Larsen DP, O'Conner RJ, Hughes RM, Stemberger RS, Dixit SS, Brinkhurst RO, Herlihy AT, Paulsen SG. Concordance of taxonomic richness patterns across multiple assemblages in lakes of the northeastern United States. Canadian Journal of Fisheries and Aquatic Sciences 1999;56(5):739-747. |
R826591 (1999) R826591 (2000) |
not available |
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Chen CY, Stemberger RS, Klaue B, Blum JD, Pickhardt PC, Folt CL. Accumulation of heavy metals in food web components across a gradient of lakes. Limnology and Oceanography 2000;45(7):1525-1536. |
R826591 (1999) R826591 (2000) R826591 (2001) R826591 (2002) |
not available |
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Evans CA, Miller EK, Friedland AJ. Nitrogen mineralization associated with birch and fir under different soil moisture regimes. Canadian Journal of Forest Research 1998;28(12):1890-1898. |
R826591 (1999) R826591 (2000) |
Exit |
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Friedland AJ, Miller EK. Major element cycling in a high-elevation Adirondack forest: patterns and change, 1986-1996. Ecological Applications 1999;9(3):958-967 |
R826591 (1999) R826591 (2000) |
Exit Exit |
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Miller EK, Friedland AJ. Local climate influences on precipitation, cloud water, and dry deposition to an Adirondack subalpine forest: insights from observations 1986-1996. Journal of Environmental Quality 1999;28(1):270-277. |
R826591 (1999) R826591 (2000) |
Exit Exit |
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Stemberger RS, Miller EK. A zooplankton- N:P-ratio indicator for lakes. Environmental Monitoring and Assessment 1998;51(1-2):29-51. |
R826591 (1999) R826591 (2000) R826591 (2001) R826591 (2002) R826591 (Final) |
not available |
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Stemberger RS, Chen CY. Fish tissue metals and zooplankton assemblages of northeastern U.S. lakes. Canadian Journal of Fisheries and Aquatic Sciences 1998;53:339-352. |
R826591 (1999) R826591 (2000) |
Exit |
Supplemental Keywords:
air, water, watersheds, limnology, ecology, ecological effects, ecosystem, indicators, aquatic, terrestrial, EMAP, modeling, GIS, northeast., RFA, Scientific Discipline, Water, Ecosystem Protection/Environmental Exposure & Risk, Water & Watershed, Nutrients, Ecology, Hydrology, Ecosystem/Assessment/Indicators, Ecosystem Protection, exploratory research environmental biology, Environmental Chemistry, Ecological Effects - Environmental Exposure & Risk, Air Deposition, Drinking Water, Geology, Watersheds, Ecological Indicators, nutrient transport, aquatic ecosystem, environmental monitoring, nutrient supply, ecological effects, ecological exposure, risk assessment, EMAP, carbon cycling, algae, multi-level indicators, bioavailability, other - risk assessment, algal growth, chemical transport, ecosystem indicators, terrestrial, aquatic ecosystems, phosphorus, carbon storage, integrative indicators, lake ecosystem, landscape characterization, land use, nitrogen, atmospheric depositionRelevant Websites:
http://rsb.info.nih.gov/nih-image
Progress 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.