Nutrient fluxes within a small north temperate salt marsh

The water exchange between a small (4.1 hectare) salt marsh adjoining the Great Bay Estuary system of New Hampshire, USA was sampled during 16 tidal cycles between July, 1976 and November, 1977. Tidal amplitude, temperature, salinity, nutrient concentrations (ammonia-N, nitrate-N, nitrite-N, orthophosphate-P, total-P, silicates) and suspended particulates were measured. Conspicuous tidal hydrographic patterns were observed. Mean concentrations of nitrate-N and silicates varied with season. The tidal information, combined with volume determinations, was extrapolated to determine the net flux of hydrographic parameters on monthly and yearly bases. Ammonia-N showed a pronounced seasonality of net exchange by regression analyses. Ammonia-N and suspended particulates had a statistically significant import into the marsh. However, the net fluxes of the other materials were not statistically different from O.Published with the approval of the Director of the New Hampshire Agricultural Experiment Station as Scientific Contribution No. 930Scientific Contribution No. 69 of the Jackson Estuarine Laboratory