Date of Award

Fall 2018

Document Type

Open Access Dissertation


Chemistry and Biochemistry

First Advisor

Michael L. Myrick


The development of methods for real-time characterization of phytoplankton community structure has important implications for environmental monitoring and the prediction of harmful algal blooms. Our research group has developed an instrument, the Fluorescence Imaging Photometer (FIP), which is capable of rapid classification of phytoplankton via imaging single-cell chlorophyll a fluorescence under different excitation conditions. Discrimination of cells from different taxonomic groups is achieved using optical bandpass filters that have been chosen to selectively excite pigments which occur in characteristic ratios that vary from one group to the next. The relative fluorescence intensity emitted by cells under these different excitation conditions can be used to distinguish between different species. Originally, the design of filters used to modulate excitation light was accomplished by generating filter designs with transmission profiles that mimicked linear discriminant (LD) vectors produced through analysis of single-cell fluorescence excitation spectra. Due to an unforeseen source of fluorescence yield variability, however, filters produced using this approach underperformed in real-world systems. We have recently developed a novel approach to filter design that remedies many of the shortcomings of the LD- based approach. In conjunction with the implementation of a new filter wheel design that offers improved fluorescence measurement precision, the use of these filters offers significantly improved discrimination of phytoplankton from different species. This work will detail the theoretical underpinnings of the new filter design approach, detail other instrumental improvements, and demonstrate methods for using FIP measurements to obtain information about the composition of phytoplankton communities.

Included in

Chemistry Commons