The waters transparency model of Lake Laut Tawar, Aceh, Indonesia

Lake Laut Tawar in Aceh Province, Indonesia is an important ecosystem that has several endemic biotas such as Rasbora tawarensis and Poropuntius bargensis. Eutrophication is a potential problem in Lake Laut Tawar. To evaluate the trophic state needed the value of water transparency. This study aims to formulate a model for estimating the transparency of Lake Laut Tawar waters. The dependent variable was water transparency, and the predictors variable was the chlorophyll-a concentration, total suspended solids, and total dissolved solids. Observations and sampling were conduct starting from October 2016 to September 2017. Data analysis was using simple regression, multiple regression, and one-way ANOVA. The result showed a decrease in waters transparency (SD) was caused by increased phytoplankton density (Chl-a), suspended material (TSS), and dissolved material (TDS). But the dissolved matter did not have a partial effect if the values of other variables are constant. The model to estimate the water transparency of Lake Laut Tawar is Log SD = 1.414 – 0.322 Log Chl-a – 0.406 Log TSS. The average values of water transparency did no differential between the seven observation stations. It is presumably because the waters of Lake Laut Tawar are easily mixed.