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Denitrification Enzyme Activity of Fringe Salt Marshes in New England (USA)
Author(s) -
Wigand Cathleen,
McKinney Richard A.,
Chintala Marnita M.,
Charpentier Michael A.,
Groffman Peter M.
Publication year - 2004
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2004.1144
Subject(s) - salt marsh , hydric soil , marsh , wetland , watershed , environmental science , estuary , groundwater , hydrology (agriculture) , soil water , brackish marsh , denitrification , water quality , bay , ecology , oceanography , geology , soil science , biology , chemistry , nitrogen , geotechnical engineering , organic chemistry , machine learning , computer science
ABSTRACT Coastal salt marshes are a buffer between the uplands and adjacent coastal waters in New England (USA). With increasing N loads from developed watersheds, salt marshes could play an important role in the water quality maintenance of coastal waters. In this study we examined seasonal relationships between denitrification enzyme activity (DEA) in salt marshes of Narragansett Bay, Rhode Island, and watershed N loadings, land use, and terrestrial hydric soils. In a manipulative experiment, the effect of nutrient enrichment on DEA was examined in a saltmeadow cordgrass [ Spartina patens (Aiton) Muhl.] marsh. In the high marsh, DEA significantly ( p < 0.05) increased with watershed N loadings and decreased with the percent of hydric soils in a 200‐m terrestrial buffer. In the low marsh, we found no significant relationships between DEA and watershed N loadings, residential land development, or terrestrial hydric soils. In the manipulation experiment, we measured increased DEA in N‐amended treatments, but no effect in the P‐amended treatments. The positive relationships between N loading and high marsh DEA support the hypothesis that salt marshes may be important buffers between the terrestrial landscape and estuaries, preventing the movement of land‐derived N into coastal waters. The negative relationships between marsh DEA and the percent of hydric soils in the adjacent watershed illustrate the importance of natural buffers within the terrestrial landscape. Denitrification enzyme activity appears to be a useful index for comparing relative N exposure and the potential denitrification activity of coastal salt marshes.