Barranguet, C. C. University of Amsterdam/ARISE,
Kromkamp, J. J. Netherlands Institute of Ecology,
Herman, P. P. Netherlands Institute of Ecology,
Peene, J. J. Netherlands Institute of Ecology,

In the frame of a project studying the eco-metabolism of a tidal flat, the importance of microphytobenthos in the carbon uptake of the sediments was studied. The tidal flat is located in the Schelde Estuary, the Netherlands, and presents a range of sediment grain size and hydrodynamic energy levels. Microphytobenthos biomass and diversity, as well as its degradation, was studied by HPLC. Benthic microalgae were composed mainly by motile and attached diatoms, the proportion of which varied depending on the sediment composition and degree of exposure. Primary production was studied at two kinds of sediments composed mainly of sands and muddy sands. The photosynthetic capacities were comparable at the two stations, but reveled different mechanisms of regulation. Light and temperature played an important role in determining the production rates, especially in the muddy sediments; where changes in the photoacclimation index were correlated to temperature. Vertical migration of diatoms showed to be an essential mechanism regulating primary production during ebb tide. The results supplied by P-I curves constructed with 14C data, and Pulse Amplitude Modulated fluorescence (PAM) are compared with those obtained with oxygen microelectrodes, which take into account the true photic zone and the vertical migration of diatoms.
Day: Friday, Feb. 5
Time: 11:00 - 11:15am
Location: Eldorado Hotel
Code: SS46FR1100E