Keanekaragaman Plankton di Perairan Sungai Asahan Sumatera Utara

Abstract

Plankton are organisms living water floating and movement is strongly influenced by water movement. As is the case with the benthos, plankton are also divided into phytoplankton (plankton organisms are plants) and zooplankton (animal plankton that is). The existence of plankton in the waters is largely determined by the physical and chemical conditions of the water. plankton have a certain tolerance limits to environmental parameters so that diversity will be different on the condition of the physical and chemical parameters are different. This research was conducted from April to May 2013. Samples were taken from four observation stations, at each station observations were made 4 replications. Sampling point is determined using purposive random sampling method., As the results, seven classes of phytoplankton were found. They were Bacillariophyceae, Chlorophyceae, Conjugatophyceae, Coscinodiscophyceae, Cyanophyceae, Eulenophyceae, Ulvophyceae and 12 classes of zooplankton namely Branchiopoda, Cladocera, Clitellata, Copepoda, Crustaceae, Filosia, Gastropods, Lobosea, Monogonta, Oligotrichea, Tubulinea, and Turbellarian, The highest value of plankton abundance was at station 4 is 2043.707 ind/l and the lowest value of found in station 3 is 1519,707 ind/l. The highest of index (H') founded at stastion 3 is 1.206 and lowest at station 4 is 0,929 Pearson correlation analysis showed flow, BOD5, phosphate and nitrate was positively correlated with the diversity of plankton while the temperature, brightness, DO, and pH were negatively correlated with the diversity of plankton.