Community oxygen metabolism in a shallow tidal estuary

Comprehensive sampling of a shallow tidal estuary was performed hourly for 14 days, at three-month intervals throughout the annual temperature cycle. The project took place in the Newport River estuary located inside the Outer Banks of North Carolina, U.S.A. In all 26 parameters were monitored at a single station, including meteorology, hydrology, water chemistry and phytoplankton production physiology. The estuarine character in colder months was dominated by riverine input, while in warmer months the estuary was lagoonal, having limited input and exchange with the sea. A holistic evaluation of estuarine community O 2 metabolism was developed using diffusion-corrected changes in O 2 concentration. These data indicated positive integrated diel production (autotrophy) only in winter (February). The estuary was functionally heterotrophic during warmer months (May, August, November). Integrated short-term radiocarbon productivity estimates compared favorably with measurements of oxygen based diel gross production rates. Community O 2 based respiration rates (heterotrophy) exhibited a strong positive relationship with water temperature. During summer, rates of heterotrophic metabolism and associated nutrient regeneration appeared to control autotrophic production.