Removal and Excretion of Dissolved Organic Matter by Periphyton Community Grown in Eutrophic River Water

Abstract

Removal and excretion activities of dissolved organic substances by periphyton communities were examined using artificial substrata submerged in the water of the eutrophic River Tamagawa and laboratory recirculating streams. These activities changed with the progress of biofilm development. High removal activity of dissolved organic substances was observed in the early stage of the biofilm development, while high excretion rate was found in the mature stage. A maximum exertion rate was 580 mgC.m-2.d-1 Organic substances removed from the water were biologically labile compounds which can be determined by BOD, and excreted organic substances were regarded as microbiologically stable compounds. Decomposition products formed at the inside of periphyton biofilm were considered to be an important source as well as photosynthetic products by sessile algae for the excretion of organic substances from the periphyton community in the mature stage of biofilm development. Copyright © 1985, The Japanese Society of Limnology. All rights reserved.