Primary productivity in tropical oxbow lakes in Central Kalimantan, Indonesia

摘要

Kalimantan (Borneo) Island is the third largest island on earth. On this island are many small oxbow and floodplain lakes along large rivers (MACKINNON et al. 1996). Although these small lakes have extreme limnological features, such as brownish water color, low pH, low transparency and low dissolved oxygen concentration (HARTOTO 2000), they also have high fish biodiversity (HARTOTO 2000) and high fishery harvest (KOTTELAT WHITTEN 1996). Therefore, these lakes seem to a have unique food web structure. Recent studies showed dominance of benthic invertebrate (IWAKUMA GUMIRI 2002) and small zoo-plankton (GUMIRI IWAKUMA 2002) in these lakes; however, little is known about the source of organic matter that supports heterotrophic organisms. The purpose of this study was to measure primary production and oxygen consumption rate and show general characteristics of lake water to discuss possible material flow in humic tropical oxbow lakes.