Distribusi Bakteri Nitrifikasi di Danau Paparan Banjir Studi Kasus: di Suaka Perikanan Danau Loa Kang, Kalimantan Timur

Lake Loa Kang is a fishery reserve located in a floodplain system of River Mahakam. This floodplain lakes consists of several habitat types among the others are backswamp deposit lakes represented by Lake Loa Kang and Lake Balikpapan. This two floodplain lakes exchange water with River Mahakam and one of its tributary, the River Pela. Nitrification is one key of microbiological process of nitrogen cycle in inland water. The nitrifying bacteria functional group that mediated the process can be detected and identified by enrichment culture. This study was aimed to reveal feature of nitrification process in several floodplain habitat types of Lake Loa Kang Fishery Reserve (LLFR) system with emphasize on the spatial distribution pattern of nitrifying bacteria. The results of the study will be utilized as limnological data base for development of conservation and restoration ofPesut habitat. Water samplings are conducted for three times in 2003, those were in dry season (June), transitional (August) and the rainy (Sept.). Results of the study showed that the number of nitrifying bacteria is highest at connecting channel between floodplain lakes (L. Balik Papan) and River Mahakam and the lowest in small size ephemeral pond in LLFR (Lopak). Ex situ simulation of this biogeochemical cycle indicate a duration of 13 - 21 days to complete the nitrification process. The number of nitritation and nitratation bacteria in Lake Loa Kang in the dry season is smaller compared to the number in rainy season. The duration of nitrification process in LLFR suspected to be influenced by the number of bacteria, organic material and season. Jurnal Biologi Indonesia, Vol. 4, No. 2. Hal. 87-97