The fate of nitrogen and phosphorus at the land-sea margin of the North Atlantic Ocean

Nixon, Scott W.; Ammerman, James W.; Atkinson, Larry P.; Berounsky, Veronica M.; Billen, Gilles; Boicourt, William C.; Boynton, W. R.; Church, Thomas M.; DiToro, Dominic M.; Elmgren, Ragnar; Garber, Jonathan; Giblin, Anne E.; Jahnke, Richard A.; Owens, Nick; Pilson, Michael E. Q.; Seitzinger, Sybil P.

doi:10.1007/978-94-009-1776-7_4

Cited by 234 publications

(200 citation statements)

References 75 publications

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“…Total N exported or N denitrified is a function of hydraulic residence time (Nixon et al 1996;Dettmann 2001). In the Adirondack lakes, total N, NO 3 À or DON drainage loss, total N or NO 3 À net hydrologic flux, or the fraction of total N or NO 3 À net hydrologic flux was not significantly related to the log mean hydraulic residence time alone (p > 0.05).…”

Section: In-lake Processesmentioning

confidence: 77%

“…In lakes and rivers (Howarth et al 1996) and estuaries (Nixon et al 1996), the percentage of N retention (or N exported) is a function of the ratio of mean depth to water residence time, based on a model of Kelly et al (1987) for NO 3 À . In the Adirondack lakes, the ratio of mean depth to water residence time (z/t) on the log-arithmetic scale was positively related with the NO 3 À drainage loss (R 2 = 0.20, p = 0.001) and inversely related with the net NO 3 À hydrologic flux and the fraction of net NO 3 À hydrologic flux (R 2 = 0.22, p = 0.0009 ( Figure 5) and R 2 = 0.21, p = 0.001, respectively, excl.…”

Section: In-lake Processesmentioning

confidence: 99%

“…Further, the concentrations or fluxes of N solutes and DOC can be altered within ponded waters. The N removal or retention increases with increasing hydraulic residence time in lakes or rivers (Kelly et al 1987;Howarth et al 1996;Nixon et al 1996;Dettman 2001) and denitrification plays an important role in this N removal process (Kelly et al 1987;Seitzinger 1987). In comparison with drainage lake-watersheds, the contributions of atmospheric N deposition or inflow from wetlands are expected to be more important in seepage lake-containing watersheds and the seepage lake-containing watersheds may respond to atmospheric N deposition differently in addition to the effect of differences in hydraulic residence time.…”

Section: Introductionmentioning

confidence: 96%

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Nitrogen input–output budgets for lake-containing watersheds in the Adirondack region of New York

et al. 2005

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The Adirondack region of New York is characterized by soils and surface waters that are sensitive to inputs of strong acids, receiving among the highest rates of atmospheric nitrogen (N) deposition in the United States. Atmospheric N deposition to Adirondack ecosystems may contribute to the acidification of soils through losses of exchangeable basic cations and the acidification of surface waters in part due to increased mobility of nitrate (NO 3 À ). This response is particularly evident in watersheds that exhibit 'nitrogen saturation.' To evaluate the contribution of atmospheric N deposition to the N export and the capacity of lake-containing watersheds to remove, store, or release N, annual N input-output budgets were estimated for 52 lake-containing watersheds in the Adirondack region from 1998 to 2000. Wet N deposition was used as the N input and the lake N discharge loss was used as the N output based on modeled hydrology and measured monthly solute concentrations. Annual outputs were also estimated for dissolved organic carbon (DOC). Wet N deposition increased from the northeast to the southwest across the region. Lake N drainage losses, which exhibited a wider range of values than wet N deposition, did not show any distinctive spatial pattern, although there was some evidence of a relationship between wet N deposition and the lake N drainage loss. Wet N deposition was also related to the fraction of N removed or retained within the watersheds (i.e., the fraction of net N hydrologic flux relative to wet N deposition, calculated as [(wet N deposition minus lake N drainage loss)/wet N deposition]). In addition to wet N deposition, watershed attributes also had effects on the exports of NO 3 À , ammonium (NH 4 + ), dissolved organic nitrogen (DON), and DOC, the DOC/DON export ratio, and the N flux removed or retained within the watersheds (i.e., net N hydrologic flux, calculated as [wet N deposition less lake N drainage loss]). Elevation was strongly related with the lake drainage losses of NO 3 À , NH 4 + , and DON, net NO 3 À hydrologic flux (i.e., NO 3 À deposition less NO 3 À drainage loss), and the fraction of net NO 3 À hydrologic flux, but not with the DOC drainage loss. Both DON and DOC drainage losses from the lakes increased with the proportion of watershed area occupied by wetlands, with a stronger relationship for DOC. The effects of wetlands and forest type on NO 3 À flux were evident for the estimated NO 3 À fluxes flowing from the watershed drainage area into the lakes, but were masked in the drainage losses flowing out of the lakes. The DOC/DON export ratios from the lake-containing watersheds were in general lower than those from forest floor leachates or streams in New England and were intermediate between the values of autochthonous and allochthonous dissolved organic matter (DOM) reported for various lakes. The DOC/ DON ratios for seepage lakes were lower than those for drainage lakes. In-lake processes regulating N exports may include denitrification, planktonic depletion, degradation of ...

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Section: In-lake Processesmentioning

confidence: 77%

Section: In-lake Processesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

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Nitrogen input–output budgets for lake-containing watersheds in the Adirondack region of New York

et al. 2005

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“…In a global analysis, Green et al (2004) show that on a basin-wide scale there was an average loss/sequestration of 18% (range 0-100%) of the Nr through the combined effects of soil, lake/reservoir, wetland, and riverine systems, based on residency time and temperature differences across watersheds. For Nr that enters estuaries, 10-80% can be denitrified, depending primarily on the residence time and depth of water in the estuary (Seitzinger 1988;Nixon et al 1996).…”

Section: Surface Watersmentioning

confidence: 99%

Nitrogen Cycles: Past, Present, and Future

et al. 2004

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This paper contrasts the natural and anthropogenic controls on the conversion of unreactive N 2 to more reactive forms of nitrogen (Nr). A variety of data sets are used to construct global N budgets for 1860 and the early 1990s and to make projections for the global N budget in 2050. Regional N budgets for Asia, North America, and other major regions for the early 1990s, as well as the marine N budget, are presented to highlight the dominant fluxes of nitrogen in each region. Important findings are that human activities increasingly dominate the N budget at the global and at most regional scales, the terrestrial and open ocean N budgets are essentially disconnected, and the fixed forms of N are accumulating in most environmental reservoirs. The largest uncertainties in our understanding of the N budget at most scales are the rates of natural biological nitrogen fixation, the amount of Nr storage in most environmental reservoirs, and the production rates of N 2 by denitrification.

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“…While benthic denitrification is an important sink in the global nitrogen cycle (see below) and in some ecosystems (see, e.g., Seitzinger 1988;Nixon et al 1996), its contribution to benthic carbon oxidation is in most cases low: less than 10 percent of the total (Thamdrup 2000;Canfield et al 2005). Larger contributions are possible particularly when the process is fuelled by nitrate from the bottom water.…”

Section: Targets For Identification Of Nitrogen-metabolizing Bacteriamentioning

confidence: 99%

Nitrogen Cycling in Sediments

Thamdrup

Dalsgaard²

2008

Microbial Ecology of the Oceans

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The fate of nitrogen and phosphorus at the land-sea margin of the North Atlantic Ocean

Cited by 234 publications

References 75 publications

Nitrogen input–output budgets for lake-containing watersheds in the Adirondack region of New York

Nitrogen input–output budgets for lake-containing watersheds in the Adirondack region of New York

Nitrogen Cycles: Past, Present, and Future

Nitrogen Cycling in Sediments

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