Botryococcus braunii in Putrajaya Lake.

The phytoplankton communities in the lake and wetland are low in terms of its densities and diversity as recorded by the biological monitoring exercises. Chlorophyta, Bacillariophyta and Cyanophyta were the important components of phytoplankton communities in this wetland system.

Isolated algae bloom in localized areas in the lake has become more frequent and this created a negative impact To the water quality of the lake as well as a threat to its aesthetic value. A serious algae bloom event in the wetland (upstream) is the Euglena sanguinea bloom that happened in 2003 due to lack of maintenance of the sewage treatment plant of a university’s students hostel. Moreover, every now and then the green algae (Botryococcus braunii) bloom occurs due to mostly from the leakage of the underground sewerage lines. Blooms of Botryococcus braunii have been shown to be toxic to other micro-organisms and fishes. 

The other negative impact when algae bloom happens is the diminishing quantities of dissolve oxygen (DO) in the water. This may cause fish death. It is expected that the growing algae demand more oxygen and this makes the water becoming more turbid and at the same time will cause the DO to be depleted. In that sense, it is of great concern to the management to ensure that this problem could be detected as soon as possible i.e. before major damage done to the overall ecological settings of the lake and wetland. 

Online monitoring equipments installed at the incoming water sources can be very helpful since it can activate the alarm system. Algae monitoring for determining its species diversity and indicator species need to be done at least once or twice a year. The dual purpose of this exercise is to observe the diversity of the algae species and the early detection of problematic algae in the system.