Community structure and productivity of the Cornwallis Estuary, Minas Basin

Preliminary results of a seasonal study of the pelagic community at a station on the outer edge of the Cornwallis Estuary suggest that the seasonal variation in plankton community respiration (PCR) is related to organic inputs from nearby salt marshes. Annual phytoplankton production is low (<30 g C m⁻² y⁻¹) and exhibits a seasonal cycle very different from PCR. There is no indication that resuspension of benthic diatoms is an important energy input to the pelagic system. PCR, however, is quite high and exhibits a seasonal trend similar to the export of salt marsh detritus. Zooplankton densities (5–200 l⁻¹) and biomass (<0.4 g m⁻³) appear to be much greater than could be supported by phytoplankton alone. The Cornwallis Estuary may be an estuarine system exhibiting a net export of organic matter to nearby offshore waters.