Indeks Keanekaragaman Dan Indeks Saprobik Plankton Dalam Menilai Kualitas Perairan Laut Bangka Di Sekitar FSO Laksmiati PT. MEDCO E & P INDONESIA, Kabupaten Bangka Barat, Propinsi Bangka Belitung

Diversity and saprobic indices of plankton community had been analysis acording to research results about composition dan abundance of plankton species have been carried out to water samples from sea waters around FSO (Floating Storage Operation) Laksmiati Tanker Ship PT. MEDCO E & P INDONESIA at Bangka Straits on March 2007. According to the observation and researching in laboratory can be found 40 species of plankton organism consist of 30 species were phytoplankton and 10 species were zooplankton. There were nine grups of taxonomic categories which can be found in these study namely Cyanophyceae, Chlorophyceae, Desmidiaceae, Bacillariophyceae, Flagellata, Rhizopoda, Rotifera, Copepoda and Ostracoda. The abundance of plankton community were 37 individuals/liter (seawaters around 1000 m backside of FSO) upto 55 individuals/liter (seawaters around 500 m backside FSO). The aim of calculating of plankton community diversity and saprobic indeces useful for determinating the levels of pollution in waters ecosystem. The results of research point out that diversity index of plankton commnunity for five research sampling location were lowest 2,42 (Loading Host FSO location) upto 2,98 (500 m backside FSO). The range of plankton diversity index for five location were 2,42 – 2,98 means the condition of plankton community include into stable upto almost very stable (> 2,00 - < 3,00) so that able assessed the levels of pollution was low in rank. The saprobic index of plankton community for five research location had range of 1,17 lowest (1000 m ahead FSO) upto + 1,47 (500 m ahead of FSO) highest. Assessment of saprobic index + 1,17 – 1,47 for five research location prooved that the levels of pollutions was low and view organic or anorganic matters into phase of mesosaprobic/oligosaprobic. Those condition related to parameters of phisics and chemicals almost everage in environment standart value. For example, pH at 500 m ahead FSO and 1000 m backside FSO each 8,55 and 8,51 respectively were view over environment standart value, but naturally situation. The parameter BOD (Biochemical Oxygen Demand) average for five location were 20,40 – 25,52 mg/l, while the environment standart value was <20 mg/l. The increasingly a view BOD above environment standart value give indication that the quality of sea waters in around of study location to become bad or low quality, caused saprobic index become a view low