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Effects of watershed land use on nitrogen concentrations and δ15 nitrogen in groundwater

Biogeochemistry

By:
, , , and
DOI: 10.1007/s10533-005-1036-2

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Abstract

Eutrophication is a major agent of change affecting freshwater, estuarine, and marine systems. It is largely driven by transportation of nitrogen from natural and anthropogenic sources. Research is needed to quantify this nitrogen delivery and to link the delivery to specific land-derived sources. In this study we measured nitrogen concentrations and δ 15N values in seepage water entering three freshwater ponds and six estuaries on Cape Cod, Massachusetts and assessed how they varied with different types of land use. Nitrate concentrations and δ 15N values in groundwater reflected land use in developed and pristine watersheds. In particular, watersheds with larger populations delivered larger nitrate loads with higher δ 15N values to receiving waters. The enriched δ 15N values confirmed nitrogen loading model results identifying wastewater contributions from septic tanks as the major N source. Furthermore, it was apparent that N coastal sources had a relatively larger impact on the N loads and isotopic signatures than did inland N sources further upstream in the watersheds. This finding suggests that management priorities could focus on coastal sources as a first course of action. This would require management constraints on a much smaller population.

Study Area

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Effects of watershed land use on nitrogen concentrations and δ15 nitrogen in groundwater
Series title:
Biogeochemistry
DOI:
10.1007/s10533-005-1036-2
Volume
77
Issue:
2
Year Published:
2006
Language:
English
Publisher:
Springer
Description:
17 p.
First page:
199
Last page:
215
Country:
United States
State:
Massachusetts
Other Geospatial:
Cape Cod
Online Only (Y/N):
N
Additional Online Files(Y/N):
N