Decomposition of Cladophora. III. Heterotroph Populations and Phosphatase Activity Associated with in vitro Phosphorus Mineralisation

Abstract

Changes in phosphatase activities and bacterial heterotroph populations were examined in long term (to 114 days) and short term (7 days or less) studies on the decomposition of the benthic alga, Cladophora. Initial phosphatase activities were high and inversely correlated with orthophosphate concentrations. These activities were associated with fine particulate matter, and were the result of newly synthesized and secreted enzymes. The population of heterotrophic bacteria isolated consisted mainly of Gram-negative rods and were frequently pigmented. The count increased sharply at day 114; this was consistant with light microscopical observations. A build-up in the population of Beggiatoa- and Thiothrix-like filamentous organisms was shown using scanning electron microscopy.