Sensors for Characterization of Phytoplankton Size and Taxonomic Composition Using Spectral Fluorescence Signatures and Imaging Multivariate Optical Computing

University South Carolina Research Foundation, Columbia SC

Investigators

Abstract

The PI's request funding take what they learned in the NSF funded demonstration project and develop a new field instrument for in situ measurement of phytoplankton abundance, size and taxonomic composition. The proposed instrument will be compact, inexpensive and will require low power. It will be suitable for broad deployment on fixed platforms or on mobile observing vehicles such as gliders or tethered or autonomous underwater vehicles. The technological basis, "imaging multivariate optical computing (IMOC)", uses multivariate discrimination of unique components of a cell's fluorescence excitation spectra to create interference filters (Multivariate Optical Elements, or "MOEs") that code for different phytoplankton species. Target phytoplankton cells are excited with a light source filtered through a rotating series of MOEs. The fluorescence response produces a classifying bar code in the image. Information on phytoplankton size is acquired by the instrument's use of imaging in a "streak camera" mode. Together, these will provide sufficient morphological and spectral analysis for classification and quantification. In this next phase of the research they will: 1) field test of the shipboard instrument using natural phytoplankton populations, 2) continue production of interference filters for a wider range of phytoplankton taxa (for which we have already identified discriminant functions), and 3) acquire fluorescence excitation spectra that capture a wider range of variability in ambient light, macronutrient, and micronutrient environment. Risk: an instrument that is successful in the simple lab environment may not be capable of discriminating amongst phytoplankton taxa in the more complex natural environment, or operations may be too difficult to allow commercialization. Reward: If successful, this instrument would revolutionize our ability to study the base of the ocean food web, with affordable sensors available for all ocean moorings, gliders and AUVs. Such in-situ observations would be transformative for ecosystem studies in coastal and open ocean settings Broader Impacts: This instrument has potential applications in both biological and chemical oceanography. Outside the societal benefits, the broader educational impacts of this work include the training of two undergraduate students, three graduate students, one postdoctoral fellow, and community outreach lectures. The undergraduates will be chosen on a competitive basis as part of the University of South Carolina Marine Science Program's Summer Undergraduate Research Assistant Program. Students will have a major role in the project work-load and would be provided with cross-discipline training opportunities.