Planktonic food chains of a highly humic lake

摘要: The development and metabolism of epilimnetic plankton from a highly humic lake was followed in late summer, when the predominant Zooplankton species, Daphnia longispina, very abundant (ca. 200 ind. 1-1 ). experiment made two tanks: one with an unaltered assemblage larger removed. scarce phytoplankton community also simple, consisting mainly Cryptomonas Mallomonas species. abundance species composition smaller heavily influenced by grazing Daphnia. In particular, biomass heterotrophic flagellates increased after removal production bacterio-plankton were not affected, remained several times higher than that phytoplankton. Bacterial on bacteria balanced, removed its activity compensated flagellates. did affect respiration or net plankton. Among organisms Zooplankton, seemed to be responsible for most respiration. consistently negative even at water surface, indicating allochthonous carbon source. results suggest primary insufficient secondary study lake. food requirements as well flagellates, each exceeded supplied production. simple chains this it possible reveal functioning so completely dissolved organic matter is certainly comparable exceeds importance energy source webs