Hydrobiological Assessment of Lake Lanao Subsequent to Its Unusual Greening in 2006

Abstract

The biological, chemical, and physical parameters of Lake Lanao were investigated for two sampling periods in October and November 2006 at three stations namely, Kialdan, Lake Center, and Sugod. Findings revealed that the plankton composition was dominated by a filamentous diatom, Melosira sp.. The massive growth of this alga caused the shallow Secchi disc transparency of the lake and its apparent eutrophication. Such large phytoplankton biomass resulted in the presumed assimilation and consequent negligible quantities of N03-N, NH3-N, and P04-P of the lake water. Coliform analysis showed that there is no site in the lake where one can get potable water.