OLI Grant: A submersible imaging-in-flow instrument to monitor nano- and microphytoplankton
Grant Funded: 2003
Plankton account for almost all the primary productivity and a majority of the biomass in the ocean, and the structure of the microbial community determines in large part that of higher trophic levels, including the production available for human consumption. Although we are beginning to appreciate the potential effects of human activities and climate change on plankton community structure, a fundamental understanding of the complex interaction between physical and biological factors that regulate community structure requires more detailed and sustained observations. We have begun to continuously monitor the smallest phytoplankton at the MVCO using FlowCytobot (a submersible flow cytometer), and the plankton at the other end of the size spectrum (mainly zooplankton >100 µm) will soon be monitored with the Video Plankton Recorder. However, neither of these instruments will sample well the phytoplankton in the size range 10-100 µm. This represents a serious gap because phytoplankton in this size range, which includes many diatoms and dinoflagellates, can be especially important in coastal blooms.
The goal of this proposal, therefore, is to develop an in situ instrument to characterize these large phytoplankton cells. We propose to use a combination of flow cytometric and video technology to both capture images of cells for identification and measure chlorophyll fluorescence associated with each image. We also propose to utilize a recently-developed optical technique called wavefront coding to increase our imaging depth of field and hence increase the rate at which we can examine water samples. The data from this instrument, in conjunction with the other plankton-monitoring instruments and other data collected at the MVCO, will help us to better understand how coastal plankton communities are regulated.