Monitoring harmful algal blooms in Singapore: Developing a HABs observing system

The increase in frequencies and the noxious effects of HABs in global coastal waters have led to enhanced interest in monitoring and detecting of such blooms. In December 2009, a toxic bloom hit Singapore waters along East Johor Strait causing massive fish kills and great economic losses. Interdisciplinary approach involving robotic network adaptation, multi-scale-sensing using autonomous vehicles and in-situ and real time multidisciplinary data acquisition using unmanned and wireless network was utilized to study and monitor HABs in Singapore waters. The present study managed to collect high spatial resolution data using ASV around station S2 located at Johor Strait. Distinct biological and physical patterns were observed from the data collected from the ASV. Low salinity was observed near the mouth of the reservoir, and the salinity increased with increasing distance from the reservoir mouth. In contrast, high phytoplankton biomass was observed near the reservoir mouth, while lower concentration was found further away from the mouth. This information could assist in defining bloom parameters and enhance our ability in determining and detecting pre-bloom condition. In addition, the ASV platform used in this study could assist in collecting high spatial resolution data set, which was not possible with point sampling. The information provided by the present study can assist in refining of bio-optical models for detecting and monitoring of HABs.