Onset and persistence of cyanobacterial blooms in a large impounded tropical river, Australia

摘要: The dynamic interplay between physical, chemical and biological factors in the development persistence of cyanobacterial blooms impounded rivers is an important topic. Over a 3-year study period, variable climatic conditions were recorded Fitzroy River, Queensland, Australia, which typical, lowland tropical river. Post-flood turbidity reduced available light well-mixed water column to levels insufficient for growth. Only when stratified slowly sinking particles dropped from surface layer did ratio mixed depth euphotic approach 1, allowing By time climate became favorable, most dissolved nutrients had been scavenged by settling or sequestered fringing macrophytes other biogeochemical processes. Cyanobacterial dominated Cylindrospermopsis raciborskii persisted several months until next flood flushed system. species dominating that environment very small high specific phosphorus uptake rates. Their nutrient requirement was met transfer across oxycline driven regular wind mixing events, entraining nutrient-rich bottom waters. Nutrient fluxes sediments into anoxic sufficient replace lost layer.