Real-time monitoring of harmful algal blooms in the southern Benguela

  • A Fawcett
  • S Bernard
  • GC Pitcher
  • TA Probyn
  • A du Randt
Keywords: Benguela, bio-optical, buoy, harmful algal bloom, monitoring, mooring


The southern Benguela Current region off South Africa is subject to frequent harmful algal blooms (HABs), which can have serious impacts — both through the introduction of toxins into the ecosystem and the collapse of high-biomass blooms leading to anoxia. As part of the Benguela Current Large Marine Ecosystem Programme, a bio-optical buoy has been developed for monitoring HABs in the region, providing both real-time and time-series data. Considerations in developing the buoy were that it should be small, cost effective and robust, allowing for field calibration of the sensors and servicing from a small boat. The instrument package on the buoy consists of two hyperspectral radiometers (providing remote sensing reflectance), a thermistor chain, a fluorometer and an Acoustic Doppler Current Profiler. A half-hourly acquisition regime collects data from the instruments, which are transmitted in real time using cellular phone telemetry. A website is updated with these data, when available, along with satellite data and shellfish warnings, to provide near real-time information on conditions in the area. Demonstration data from the buoy, related to observed blooms of dinoflagellates and the ciliate Mesodinium rubrum, are presented.

Journal Identifiers

eISSN: 1814-2338
print ISSN: 1814-232X