Development of an autonomous bioluminescence buoy (BioBuoy) for long-term ocean measurements

The temporal variability of coastal and oceanic bioluminescence remains largely unknown. Few studies have attempted to measure this phenomenon over any appreciable time scale because of the limitation of the number of available instruments, the platforms from which to measure for an extended period of time, and the cost in terms of time. Similarly, the seasonal and annual characteristics of bioluminescence have been observed in only a handful of studies. Bioluminescence is important because it is a sensitive indicator of marine environmental health. The distribution of bioluminescence has been of interest to the U.S. Navy because of its potential impact on operational issues. Bioluminescence correlates with toxicity, biomass, and even red tides, an important coastal phenomenon that can be associated with bioluminescent plankton (dinoflagellates). Recently, we modified a buoy mounted oil spill sensor to house a bioluminescence sensor and a transmissometer. Bioluminescence is measured by activating a small electric pump that pulls seawater into a light-tight chamber. The agitation and shear associated with the water flow stimulates the bioluminescent dinoflagellates to emit light. Water clarity is also measured with a red (680 nm) transmissometer. Data are automatically collected twice an hour, transmitted by a spread spectrum (900 MHz) RF link to a lab-based computer, and posted to a secure Internet browser. The buoy is providing, for the first time, autonomous long-term bioluminescence measurements in San Diego Bay.