Epipelic Diatom Communities in Pengilon Lake Dieng, Central Java

Diatom communities in the lake have an advantage of environmental assessment and paleo reconstruction study, due to the ability of diatom preserved in the sediment. There are only limited studies about taxonomy, ecology, and diversity of diatom flora in tropical areas, especially Indonesia. The main objective of the research is to describe the structure of benthic diatom communities in Pengilon Lake, together with physical chemical variables. Sediment samples were collected at an altitude of more than 2,000 msal habitats with pH around 5.40-6.86. A total of 83 diatom species identified as belonging to 16 families. The diversity index ranges from about 2.25 to 3.01 indicated the ecosystem that naturally stable with none diatom dominant. The most abundant genera were Eunotia with high diversity around 14 taxa. The composition of Eunotia assemblages was different among habitat and season variation. Eunotia has a wide tolerance of pH because of its ability to survive in an area with an acidic environment and circumneutral water. The most dominance diatom species in Pengilon Lake were Eunotia paludosa (Grunow) 39.2%, Nitzschia frustulum (Kutzing) 28.1%, P innularia viridis (Krammer & Lange-Bertalot) and Pinnularia divergentissima (Grunow) 24.6%.