Biomass and production of periphyton attached to dead reed stems in Lake Maarsseveen

Abstract

Seasonal changes of periphytic biomass attached to dead reed stems were measured during two successive years. Biomass was compared at the bankside, the lakeside, and the center of a reed-belt. The biomass was high in winter; subsequently it decreased and remained low during summer (maximum and minimum values being, respectively, 49.52 ± 5.61 and 5.22 ± 2.88 g ash-free dry weight m^-2 substratum). Preliminary results of periphytic production measurements in situ (O₂-method) are discussed.

The response of carbon fixation rate to light was studied in the laboratory (¹⁴C-method). The ¹⁴C-fixation response curves showed an inhibition of C-fixation rate under high light intensities. In summer, when the periphyton was ‘shade-adapted’, this inhibition was less in comparison with responses found in spring and late summer. These results may indicate that factors other than light are responsible for the observed inhibition.