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

Abstract

ABSTRACT
Distribution of Nitrifying Bacteria in Floodplain Lake. Case Study in Lake Loa
Kang Fishery Reserve, East Kalimantan. 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 ofthe study will be utilized
as limnological database for development of conservation and restoration of Pesut 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.
Key words: Distribution,Floodplain, Lake Loa Kang Fishery Reserve, Nitrifying bacteria