The biophysical environment of Separi River on Kutai Kartanegara District

Abstract

This study was conducted at six sampling sites in Separi River flow area. Results showed that at all sampling sites the diversity of water biota (as nekton, plankton and benthos) was categorized low to moderate, its homogeneity was low to evenly distributed, and both dominant and not dominant species were found. Linear regression equation to show the relationship between fish species, plankton species and benthos species with some water quality parameters as temperature (X1), TSS (X2), TDS (X3), colour (X4), and turbidity (X5) was applied. The equation to show relationship with fish species is Y = 8,657–0,101 X1 -0,002 X2 –0,013 X3 -0,008 X4+ 0,021 X5 (r = 0,792; R = 62,48 %); with plankton species is Y = 2551,355 – 69,582 X1 - 0,101 X2 + 0,256 X3 + 0,128 X4- 0,362 X5 (r = 0,372; R = 0,139%); and with benthos species is Y = 1356,461–21,310 X1-0,816 X2+0,153 X3+0,012 X4 -0,248 X5 (r = 0,444; R = 19,7 %). Relationship between fish species and some other water quality parameters as pH (X1), DO (X2), COD (X3), and BOD5 (X4) is shown by equation Y = - 8,503 –1,105 X1 + 2,054 X2 + 0,043 X3 + 3,501 X4 (r = 0,648; R = 41,9 %). Phytoplankton from the class of Chlorophyceae, Cyanophyceae, and Crysophyceae can be used as bio-indicators to predict water pollution. The quality status of water at all sample sites based on physical, chemical, and biological parameters in average was included in Class 4 which means that the water can only be utilized for crop irrigation or for other uses with similar requirements