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EFFECT OF NUTRIENT LOADING ON BIOGEOCHEMICAL AND MICROBIAL PROCESSES IN A NEW ENGLAND HIGH SALT MARSH, SPARTINA PATNES, (AITON MUHL)
Citation:
Caffrey, M C. Murrell, C Wigand, AND R A. McKinney. EFFECT OF NUTRIENT LOADING ON BIOGEOCHEMICAL AND MICROBIAL PROCESSES IN A NEW ENGLAND HIGH SALT MARSH, SPARTINA PATNES, (AITON MUHL). BIOGEOCHEMISTRY. Springer, New York, NY, , 251-264, (2007).
Impact/Purpose:
to examine the effects of nitrogen (N) and phosphorus (P) fertilization on biogeochemical and microbial processes
Description:
Coastal marshes represent an important transitional zone between uplands and estuaries and can assimilate nutrient inputs from uplands. We examined the effects of nitrogen (N) and phosphorus (P) fertilization on biogeochemical and microbial processes during the summer growing season in a Spartina patens (Aiton (Muhl.)) marsh in the Narragansett Bay National Estuarine Research Reserve on Prudence Island (RI). Quadruplicate 1 m2 plots were fertilized with N and P additions, N only, P only or no additions. Sediment oxygen consumption and denitrification measured in intact cores were higher in the N+P treatment although rates were not statistically significant due to core-to-core variation. Most of the denitrification occurring in sediments was coupled to nitrification because overlying water NO3- concentrations were low (< 5 ?M). P fertilization led to increased pore water DIP concentrations and DIP release from sediments while no additions or N-only treatments had significant P uptake. Nitrogen only addition stimulated bacterial production and pore water NH4+ and NO3- concentrations. Heterogeneity in the availability of nitrate and organics as well as the oxidation-reduction status of the sediments may mask fertilization effects on some microbial processes.