Application of a Telemetry System to Studying Microalgal Dynamics and Red Tides in Hong Kong

Abstract

A real time, continuous monitoring system for water quality parameters and meteorological conditions has been pilot-tested at Crooked Island (also known as Kat O), Hong Kong. Using an innovative telemetry system, the microalgal dynamics were studied with the aim of developing an early warning system for red tides. Data collected in situat the fish culture zone were transferred to the campus of The University of Hong Kong through the system by remote control. During the study period, incidents of red tides were detected and the system was found to be successful in alerting the study team based on changes in one of the prime parameters, Chlorophyll-a in surface waters. A preliminary survey also suggested that the system could be applied in other fish culture waters for evaluating microalgal dynamics. However, the real time monitoring system should be supplemented by frequent sampling of microalgae for accurate simulation and reporting, because field surveys revealed that microalgal diversity changes significantly over even short periods of time. 36 genera (including 60 species) of dinoflagellates and diatoms have been recorded and all of them showed strong seasonal succession. Instead of using solely dissolved oxygen as the assessment parameter for the system (which has been applied in this system since 1993), parameters such as chlorophyll-a and biodiversity changes should be incorporated into the real time monitoring to suit the special features in subtropical waters such as Hong Kong.