Structure Community of Phytoplankton as a Bioindicator of Water Quality in Situ Rawa Dongkal, East Jakarta, Indonesia

Situ Rawa Dongkal is one of the radical urban lakes in the village of
Cibubur, East of Jakarta, Indonesia. This urban lake plays a vital role in
water conservation, biodiversity, nurseries and recreational facilities.
Currently, Situ Rawa Dongkal is facing pressure originating from nature and
human activities, causing changes in water quality. Phytoplankton as an
environmental bioindicator can be used to measure the water quality of this
lake. Thus, a quantitative study was conducted to address the water quality
in Situ Rawa Dongkal based on chemical, physical and phytoplankton
factors as reference material on the usefulness of water for tourism.
Parameters of pH, temperature, BOD, COD, DO, nitrates, phosphates and
phytoplankton were measured. Sampling was conducted three times at four
stations. In addition, diversity, uniformity and dominance were determined
for the analysis of the phytoplankton community structure. Some results of
physico-chemical measurements, such as temperature, pH, nitrates and
phosphates indicate a good condition, supporting the life of organisms,
especially phytoplankton. While values of BOD and COD were higher than
the quality standard. 22 genera were detected from 6 classes; namely,
Bacclilariophyta, Chlorophyta, Ochrophyta, Chrysophyta and Euglenophyta,
with the most dominant number from the class Chlorophyta. Generally, the
phytoplankton diversity values are low-medium, and the saprobity index
values fall into the / - Mesosaprobic to - Meso / oligo saprobic categories.
These results indicate that the Situ Rawa Dongkal ecosystem is less stable
but slightly polluted, thus it is still recommended for tourism activities.