Postprint version. Published in Deep Sea Research Part II: Topical Studies in Oceanography, Volume 56, Issue 3-5, February 1, 2009, pages 232-245. Copyright © 2009 Elsevier. The definitive version is available at http://dx.doi.org/10.1016/j.dsr2.2008.08.002.
Ecosystem function will in large part be determined by functional groups present in biological communities. The simplest distinction with respect to functional groups of an ecosystem is the differentiation between primary and secondary producers. A challenge thus far has been to examine these groups simultaneously with sufficient temporal and spatial resolution for observations to be relevant to the scales of change in coastal oceans. This study takes advantage of general differences in the bioluminescence flash kinetics between planktonic dinoflagellates and zooplankton to measure relative abundances of the two groups within the same-time space volume. This novel approach for distinguishing these general classifications using a single sensor is validated using fluorescence data and exclusion experiments. The approach is then applied to data collected from an autonomous underwater vehicle surveying >500 km in Monterey Bay and San Luis Obispo Bay, CA during the summers of 2002–2004. The approach also reveals that identifying trophic interaction between the two planktonic communities may also be possible.