Physico-chemical influences on Cladophora blooms in a Natural Stream, Korea

Cladophora is ubiquitous macroalga which grows attached to hard rocks in freshwaters. This filamentous green algal blooms may result in decrease in aesthetic value of waters and play a role in providing nutrients to harmful water-borne bacteria. In a natural stream, which flows along a natural ecosystem conservation area in Korea, Cladophora blooms have occurred since 2016. Therefore, the objective of this study was to investigate influences of physico-chemical variables on the Cladophora blooms. Two monitoring events were conducted in June and July, 2018, respectively. Water samples were collected at seven stations along the stream. Various physical and chemical variables such as rainfall, water velocity and depth, water temperature, dissolved oxygen, pH, conductivity, suspended solid, nutrient concentrations, chlorophyll-a, and macroalgae biomass, etc were measured. Based on the results, physical variables were seen to be critical to formation of Cladophora blooms. This study can be useful information for developing strategies to reduce and manage the Cladophora blooms in a natural stream.