|Excretie en produktie van de benthische microflora op de Wadden in het westelijk deel van de Waddenzee|
Canters, K.J. (1972). Excretie en produktie van de benthische microflora op de Wadden in het westelijk deel van de Waddenzee. NIOZ-rapport, 1972(5). Nederlands Instituut voor Onderzoek der Zee: Texel. 33 pp.
Part of: NIOZ-rapport. Netherlands Institute for Sea Research (NIOZ): Den Burg. ISSN 0923-3210, more
During the first half of 1971 the methods of WATT and others for measuring excretion by algae during fotosynthesis were adapted to microbenthic algae. Excretion as used here is defined as that part of the algal production which passes through a membrane filter of 0,15 µpore-diameter. Liquid scintillation was used for measuring C-14 activity of algae and excretion products. The method was tested in the laboratory. One of the pitfalls in excretion measurements appeared to be the impossibility to remove all added 14CO2 from the filtrate. Therefore a rest-activity has to be substracted from the filtrate activity. This seems to have been overlooked by earlier workers. Excretion proved to amount to some 3% of the primary production in situ by the macrobenthic algae. This means that earlier measurements of primary production on the tidal flats need only a small correction.Furthermore this implies that contribution of dissolved organic C to the Waddensea by microbenthic algae is low. Annual production amounts to some 100gC/m2/year; excretion (3%) amounts to 3gC/m2/year. For the Waddensea with 150km2 of tidal flats this will give 0.45x106 kg dissolved org.C/year. DUURSMA (1961) concluded that 32 x 106 kg dissolved org.C was formed in the western Waddensea annually, which means that contribution by benthic microalgae is only 1,4%. Therefore dissolved org.C will be largely the product of other processes (consumption of algae, bacterial breakdown of organic matter).