Final Report: Anthropogenic Pollutant Effects on Aquatic Ecosystems Impacts of Atmospheric Nitrogen Deposition on Phytoplankton Dynamics and Eutrophication

EPA Grant Number: R825243
Title: Anthropogenic Pollutant Effects on Aquatic Ecosystems Impacts of Atmospheric Nitrogen Deposition on Phytoplankton Dynamics and Eutrophication
Investigators:
Institution: University of North Carolina at Chapel Hill , Rutgers University - New Brunswick
EPA Project Officer: Chung, Serena
Project Period: October 1, 1996 through September 30, 1999
Project Amount: $382,789
RFA: Air Quality (1996) RFA Text |  Recipients Lists
Research Category: Air Quality and Air Toxics , Water Quality , Air

Objective:

The main objective of this research project was to evaluate ecosystem sensitivity to pollutant stress by examining phytoplankton community responses to atmospherically derived nitrogen compounds.

Summary/Accomplishments (Outputs/Outcomes):

Biweekly river sampling of physical, chemical, and biological parameters was conducted at 17 locations in Project Year 3 to characterize short (weeks) to long-term (annual) changes in environmental variables and their effects on natural phytoplankton communities. Although our sampling interval is biweekly, the North Carolina Department of the Environment and Natural Resources - Division of Water Quality (DENR-DWQ) and the Weyerhaeuser Company took samples on alternating weeks. Data from this collaborative effort was transferred to IMS after collection via the Internet. Our overall results show a high degree of temporal and spatial variability in chemical, physical, and biological parameters measured in this estuary.

We continued sampling in Project Year 3 for measurement of wet deposition (rain/snow) at sites in the Neuse watershed. The material has been characterized chemically for nitrate, ammonium, and TKN on a weekly basis. Weekly collections have been completed according to National Atmospheric Deposition Program (NADP) protocol at three locations in the Neuse River Basin, including a near-estuarine site at the U.S. Forest Service Croatan National Forest headquarters near New Bern, Lenoir Community College near Kinston, and a North Carolina State Highway Patrol site near Goldsboro. We also have recently established a collection site near Cedar Island, NC. These stations are complemented by the NADP NC-41 location in Wake County. The dissolved inorganic nitrogen/dissolved organic nitrogen (DIN/DON) concentrations in rainfall have been analyzed on a continuous basis for 2 years from the three established locations. Weekly depositional fluxes were highly variable, but were significantly higher in the spring and summer months. This pattern is not driven by precipitation patterns and may be driven by seasonal changes in Nitrogen (N) source emissions, as well as the direction of dominant air flow patterns and fronts passing over the research area. Typically, continental rainfall exhibits elevated DIN/DON concentrations, while oceanic fronts contain the lowest concentrations (as well as total deposition rates) of both N forms (Paerl, et al., 1999).

Short-term (2d) nutrient addition bioassays were used to assess the impacts of DIN/DON components (nitrate, ammonium, and urea) on phytoplankton community structure (i.e., species composition and abundance) and function (i.e., productivity). Phytoplankton growth and productivity were N-limited during much of the study period, but the potential existed for colimitation by phosphorus when ambient N concentrations were high, and by light when incident irradiance was low. Nitrogen additions generally resulted in an increase in diatom biomass and a decrease in cyanobacteria biomass, but there were no consistent shifts in composition due to different forms of N, i.e, there were no consistent significant differences between effects of nitrate versus ammonium versus urea (Harrington, 1999).

Mesocosm bioassays were conducted to examine long-term (up to 6 d) changes in phytoplankton community structure following nutrient manipulations. We conducted two series of mesocosm experiments. Experiments in Series 1 were conducted in November 1997, February 1998, June 1998, and December 1998. Experiments in Series 2 were conducted in March 1999, May 1999, August 1999, and November 1999. During each series, we addressed photophysiological and community structural responses to manipulations of both nutrients and light. All mesocosm experiments incorporated a two-factor (mixing, nutrient addition) experimental design using 66 liter mesocosm tanks. Natural phytoplankton communities were collected from a mesohaline station in the estuary. The results from Series 1 showed that the relative effects of nutrient additions and water column mixing on phytoplankton community structure and function at this site varied between experiments. Overall, we found no significant effect of N form (nitrate vs. ammonium) on phytoplankton community structure and function in any experiment. All nutrient additions significantly increased total community biomass (as measured by chl a) in the June 1998 experiment only, indicating that the community was N-limited at this time. The increase in total biomass was due to increases in the contributions of chlorophytes and diatoms to the community.

In all experiments, significant differences were found between mixed and static incubations. In November 1997, the absolute and relative contribution of diatoms to total community biomass and rates of primary productivity were significantly higher in mixed incubations than in tanks left static. In the June 1998 experiment, static tanks had significantly higher absolute and relative contributions of cyanobacteria to overall community biomass than tanks that were mixed. In December, static incubations showed significantly higher absolute and relative abundances of cryptophytes than mixed tanks. We concluded that temporal variability in the effects of nutrient additions, temporal variations in water column structure, and the potential limiting or colimiting effects of light were all important determinants of phytoplankton community structure and function and should be considered in estuarine nutrient management plans. (Richardson et al., 1999). The results of Series 2 of our mesocosm experiments still are being analyzed. We examined responses of Neuse phytoplankton communities to various forms of N (nitrate, ammonium, and urea) under irradiance conditions that were more representative of those of a turbid estuary than experiments in Series 1.

Photophysiological responses were examined during both series of mesocosm experiments. We determined the synergistic interactions of light and nutrients on the maximum quantum yield of stable charge separation at photosystem II (Fv/Fm) for natural phytoplankton communities collected from the Neuse River Estuary. A full suite of pigmentation, absorption, total carbon fixation, and Fv/Fm data were collected. The results of Series 1 show that both mixing and nutrient treatments were found to be statistically significant (p = .05), with the addition of nitrogen resulting in a 40 percent increase in Fv/Fm values within 24 hours. No significant differences were observed between additions of the different forms of nitrogen (i.e. nitrate vs. ammonium). Additional preliminary data suggests that nutrient addition enhanced carbon fixation. This supports previous work suggesting that the Neuse River is nitrogen limited. Strong diurnal trends in Fv/Fm exhibited an inverse relationship to instantaneous light. Collected data suggests the large diurnal variability reflected physiological responses to bright light. Accordingly, chlorophyll specific spectral absorption and pigmentation data indicated acclimation to high light conditions.

During the mesocosm study of May 1999, we deployed the self contained underwater photosynthesis apparatus (SUPA) in the mesocosm pond at the Institute of Mathematical Statistics (IMS) to collect high time resolution measures of photosynthetic responses to vertical mixing. Samples from the experimental treatment including additions of nitrate, ammonium, and phosphorus (NAP) were compared to the control (no nutrient additions). Dissolved oxygen, pH, temperature, and spectral irradiance in each sample were recorded every minute during the daytime on May 5 and 7. During each of those days, the sample chambers were lowered and raised through the pond (0.5 m) on an approximate 1 hour cycle to simulate water column mixing. These time series, when converted to rates of oxygen production and carbon uptake, allow examination of the effects of eutrophication on the average rates of net productivity during the daytime, as well as on the short-period responses to mixing through potential light stress. Analysis indicated that the NAP enriched phytoplankton community achieves higher net productivity than the control community at all levels in the water column. The NAP community also was able to more quickly recover from light stress experienced when mixing placed it at the surface of the water column. Completion of this analysis and synthesis, with results from the mesocosm experiments, will help provide some physiological basis for the eutrophication effects detected.


Journal Articles on this Report : 16 Displayed | Download in RIS Format

Other project views: All 63 publications 19 publications in selected types All 16 journal articles
Type Citation Project Document Sources
Journal Article Bergmann T, Richardson TL, Paerl HW, Pinckney JL, Schofield O. Synergy of light and nutrients on the photosynthetic efficiency of phytoplankton populations from the Neuse River Estuary, North Carolina. Journal of Plankton Research 2002;24(9):923-933. R825243 (1999)
R825243 (Final)
  • Abstract: Oxford Journals Abstract
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  • Journal Article Borsuk ME, Stow CA, Luettich Jr. RA, Paerl HW, Pinckney JL. Modelling oxygen dynamics in an intermittently stratified estuary: estimation of process rates using field data. Estuarine, Coastal and Shelf Science 2001;52(1):33-49. R825243 (1999)
    R825243 (Final)
    R826938 (2001)
    R826938 (Final)
    R827957 (Final)
  • Full-text: ScienceDirect-Full Text HTML
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  • Abstract: ScienceDirect-Abstract
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  • Other: ScienceDirect-Full Text PDF
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  • Journal Article Kirkpatrick GJ, Millie DF, Moline MA, Schofield O. Optical discrimination of a phytoplankton species in natural mixed populations. Limnology and Oceanography 2000;45(2):467-471. R825243 (Final)
    R827085 (2000)
    R827085 (2001)
    R827085 (Final)
  • Full-text: ASLO-PDF
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  • Abstract: ASLO - Abstract
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  • Journal Article Paerl HW. Coastal eutrophication and harmful algal blooms: importance of atmospheric deposition and groundwater as "new" nitrogen and other nutrient sources. Limnology and Oceanography 1997;42(5 Part 2):1154-1165. R825243 (Final)
  • Other: ASLO Full-text pdf
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  • Journal Article Paerl HW. Structure and function of anthropogenically altered microbial communities in coastal waters. Current Opinion in Microbiology 1998;1(3):296-302. R825243 (Final)
  • Abstract from PubMed
  • Journal Article Paerl HW, Pinckney JL, Fear JM, Peierls BL. Ecosystem responses to internal and watershed organic matter loading: consequences for hypoxia in the eutrophying Neuse River Estuary, North Carolina, USA. Marine Ecology Progress Series 1998;166:17-25. R825243 (Final)
  • Abstract: Marine Ecology-Progress Series Abstract
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  • Other: Marine Ecology-Progress Series Full-text pdf
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  • Journal Article Paerl HW, Willey JD, Go M, Peierls BL, Pinckney JL, Fogel ML. Rainfall stimulation of primary production in western Atlantic Ocean waters: roles of different nitrogen sources and co-limiting nutrients. Marine Ecology Progress Series 1999;176:205-214. R825243 (1999)
    R825243 (Final)
  • Abstract: Marine Ecology Progress Series Abstract
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  • Other: Marine Ecology Progress Series Full-text pdf
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  • Journal Article Paerl HW. Cultural eutrophication of shallow coastal waters: coupling changing anthropogenic nutrient inputs to regional management approaches. Limnologica-Ecology and Management of Inland Waters 1999;29(3):249-254. R825243 (Final)
  • Abstract: Science Direct Abstract
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  • Journal Article Paerl HW, Whitall DR. Anthropogenically-derived atmospheric nitrogen deposition, marine eutrophication and harmful algal bloom expansion: is there a link? Ambio 1999;28(4):307-311. R825243 (1999)
    R825243 (Final)
  • Abstract: JSTOR Abstract
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  • Journal Article Paerl HW, Pinckney, JL, Fear JM, Peierls BL. Fish kills and bottom-water hypoxia in the Neuse River and Estuary: reply to Burkholder et al. Marine Ecology Progress Series 1999;186:307-309. R825243 (1999)
    R825243 (Final)
  • Other: Marine Ecology-Progress Series Full-text pdf
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  • Journal Article Pinckney JL, Paerl HW, Harrington MB. Responses of the phytoplankton community growth rate to nutrient pulses in variable estuarine environments. Journal of Phycology 1999;35(6):1455-1463. R825243 (1999)
    R825243 (Final)
  • Abstract: Blackwell Synergy Abstract
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  • Journal Article Pinckney JL, Paerl HW, Haugen E, Tester PA. Responses of phytoplankton and Pfiesteria-like dinoflagellate zoospores to nutrient enrichment in the Neuse River Estuary, North Carolina, USA. Marine Ecology Progress Series 2000;192:65-78. R825243 (1999)
    R825243 (Final)
  • Abstract: Marine Ecology Progress Series Abstract
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  • Other: Marine Ecology Progress Series Full-text pdf
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  • Journal Article Richardson TL, Pinckney JL, Paerl HW. Responses of estuarine phytoplankton communities to nitrogen form and mixing using microcosm bioassays. Estuaries and Coasts 2001;24(6):828-839. R825243 (1999)
    R825243 (Final)
    R826938 (Final)
  • Abstract: Estuaries and Coasts Abstract
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  • Other: Estuaries and Coasts Full-text pdf
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  • Journal Article Schofield O, Gryzmski J, Bissett WP, Kirkpatrick GJ, Millie DF, Moline M, Roesler CS. Optical monitoring and forecasting systems for harmful algal blooms: possibility or pipe dream? Journal of Phycology 1999;35(6):1477-1496. R825243 (1999)
    R825243 (Final)
    R827085 (2000)
    R827085 (2001)
    R827085 (Final)
  • Full-text: Cal Poly - PDF
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  • Abstract: Wiley Online
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  • Journal Article Whitall DR, Paerl HW. Spatiotemporal variability of wet atmospheric nitrogen deposition to the Neuse River Estuary, North Carolina. Journal of Environmental Quality 2001;30(5):1508-1515. R825243 (Final)
    R826938 (2000)
    R826938 (Final)
  • Abstract from PubMed
  • Full-text: JEQ Full Text
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  • Other: JEQ Full Text pdf
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  • Journal Article Willey JD, Paerl HW, Go M. Impact of rainwater hydrogen peroxide on chlorophyll a content of surface Gulf Stream seawater off North Carolina, USA. Marine Ecology Progress Series 1999;178:145-150. R825243 (Final)
  • Abstract: Marine Ecology Progress Series Abstract
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  • Other: Marine Ecology Progress Series Full-text pdf
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  • Supplemental Keywords:

    watersheds, precipitation, bioavailability, indicators, stress, ecology, modeling, MidAtlantic, North Carolina, NC, agriculture., RFA, Scientific Discipline, Geographic Area, Water, Ecosystem Protection/Environmental Exposure & Risk, Nutrients, Water & Watershed, Ecosystem/Assessment/Indicators, Ecosystem Protection, State, Monitoring/Modeling, Ecological Effects - Environmental Exposure & Risk, Atmospheric Sciences, Ecological Risk Assessment, Watersheds, Ecological Indicators, anthropogenic processes, atmospheric processes, precipitation, nutrient transport, eutrophication, aquatic ecosystem, anthropogenic stress, ecological exposure, biodiversity, nutrient sensitive ecosystems, atmospheric nitrogen deposition, ADN compounds, nutrient stress, phytoplankton dynamics, atmospheric nitrogen deposits, aquatic ecosystems, North Carolina (NC), rainfall

    Relevant Websites:

    http://www.marine.unc.edu/neuse/modmon/homepage.html Exit

    Progress and Final Reports:

    Original Abstract
  • 1997
  • 1998