Aquatic Sciences Meeting, Albuquerque 2001

CS04 Benthic-Pelagic Coupling: Seasonality, Pulses, and Flux

Date: Thursday, February 15, 2001, Time: 4:30:00 PM

Location: Mesilla

DiDonato, G, T, US EPA, Gulf Breeze, FL, USA, didonato.guy@epa.gov

Lores, E, M, US EPA, Gulf Breeze, FL, USA,

Smith, L, M, US EPA, Gulf Breeze, FL, USA,

NUTRIENT FLUX AT THE SEDIMENT-WATER INTERFACE IN ESCAMBIA BAY, FL, A NORTHERN GULF OF MEXICO ESTUARY

Nutrient flux at the sediment-water interface is an integral component of estuarine dynamics, and the benthos may represent a significant source or sink for material cycling. Benthic flux rates (umol/ m2 h) for NH4, NO2+NO3, PO4, and Si were quantified between June and October, 2000, at stations within Escambia Bay, a component of northwestern Florida?s Pensacola Bay system. Benthic cores (15 cm diameter, 30 cm high) and site water were collected in the field. Cores served as laboratory microcosms while site water was used to maintain flow-through conditions within experimental chambers. Chambers were incubated in the dark for 10-12 hours, and samples were collected at 2.5-3.5 hour intervals, with flux calculated from the difference between inflow and outflow nutrient concentrations. NH4 and Si showed either no net flux or a positive net flux (from sediment to water column). Average NO2+NO3 flux was close to 0 but showed significant spatial variability. PO4 flux was also close to 0. These data are crucial for developing a nutrient budget for Escambia Bay.

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Aquatic Sciences Meeting, Albuquerque 2001

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