Effects of river discharge and vertical circulation on aquatic primary production in a turbid Louisiana (USA) estuary
Randall, J.M.; Day Jr., J.W. (1987). Effects of river discharge and vertical circulation on aquatic primary production in a turbid Louisiana (USA) estuary. Neth. J. Sea Res. 21(3): 231-242
In: Netherlands Journal of Sea Research. Netherlands Institute for Sea Research (NIOZ): Groningen; Den Burg. ISSN 0077-7579; e-ISSN 1873-1406, meer
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| Auteurs | | Top |
- Randall, J.M.
- Day Jr., J.W.
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| Abstract |
Aquatic primary production was measured in stationary and moving bottles with the light/dark oxygen method at two sites in Fourleague Bay, a shallow, turbid estuary on the central Louisiana coast receiving flow from the Atchafalaya River. Riverflow strongly influenced spatial and seasonal patterns of production. Annual net production increased from 382.5 g O2·m-2 (119.5 g C·m-2) at an upper bay site near the river mouth to 1015.7 g O2·m-2 (317.4 9 C·m-2) at a lower bay site distant from the river. Net production was negatively correlated with seasonal changes in riverflow at both sites. Maximum production rates occurred at intermediate salinities. At low salinities, production was apparently lightlimited because of the extreme turbidity of the riverwater. At high salinities, production declined despite greater water clarity, apparently due to nitrogen limitation. At the upper bay areal production estimates from moving incubations were significantly lower than estimates from stationary incubations, but no consistent differences were found at the lower bay and in the bay as a whole. This is the first report of moving incubations yielding significantly lower estimates most of the time. The productivity differences between moving incubations and stationary incubations were significantly correlated with relative light penetration and we suggest that this was because of at least two distinct time-dependent production-versus-irradiance phenomena whose influences varied as conditions changed. |
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