Persebaran Diatom Epipelik secara Vertikal pada Ekosistem Mangrove Muara Sungai Banjir Kanal Timur Semarang

Diatom is a widespread and cosmopolite micro alga, some can used as bio-indicator of the past environmental change because of its sensivity to its habitat condition and because it is well fossilized. This study has been done on the estuary of Banjir Kanal Timur Semarang which has ecosystem mangrove; this region is often affected by coast abrasion, flooded by spring-tide inundation water, rain, and freshwater inflow of the river. The study was aimed to examine relative abundance difference, diversity, and vertically variety level of diatom per 2 cm per sediment layer. Sampling method used in the research was “Judgemental Random Sampling”. The result shows that diatom in the mangrove ecosystem of Banjir Kanal Timur Estuary is stable in the upper layer sediment and midle from lower layer and the mangrove ecosystem of Banjir Kanal Timur Estuary is affected by freshwater estuary, based on the domination of the existence of freshwater diatoms (Navicula radiosa, Synedra ulna, Meridion circulare, Sellaphora bacillum, and Eunotia lunula) on the 8-20 layer

Diversity of Plankton Bio-indicators on Water Quality of Lutan Lake, Palangka Raya, Central Kalimantan, Indonesia

Lutan Lake in Palangkaraya is one of the most important oxbow lakes for the people of Palangka Raya. The many water resources with high economic value in Lutan Lake require sustainable management to maintain their quality. One of the indicators for determining lake water quality is the analysis of bio-indicators and water’s physical and chemical quality. The purpose of this study was to analyze the quality of lake water using the presence of biological indicators such as plankton and water quality parameters. This study used a quantitative descriptive method with a survey approach. The sampling was carried out at four stations with two-time variations, i.e., at 04.00 p.m. and 10.00 p.m. Based on the study’s results, it was found that the quality of Lutan lake water for classes I, III, and IV were included in the lightly polluted category. For class II, it was in the moderately polluted category. The plankton parameter shows that the index of phytoplankton and zooplankton diversity looks low with an indication of an unstable aquatic ecosystem due to the dominance of species which indicated the condition of the waters of Lake Luta has been polluted