Abstract
Traditional laboratory methods exist for the measurement of phytoplankton abundance and taxonomic distribution, but they are 1) costly, 2) require large sample volumes, and 3) they are time-consuming – it can take months for results to be available. Optical measurements like sensors that measure fDOM and chlorophyll-a provide rapid results and are increasingly being used to measure water quality. Measuring the fraction of light absorbed at specific wavelengths and subsequently released at longer wavelengths (that is, fluorescence) is diagnostic of DOM type and amount. Spectral fluorometers measure the relative abundance of phytoplankton pigments by emitting various wavelengths of light and measuring the resulting fluorescence. Fluorometers, such a s the bbe FluroProbe (bbe Moldanke, GmBH, Germany) are designed for the analysis of chlorophyll with instantaneous algal class determination, thus, reducing the need for traditional multiday laboratory processes. The objective of this study is to validate the use of the bbe FluoroProbe during high-speed mapping surveys in the Sacramento - San Joaquin River Delta. I hypothesize that the data generated by the bbe FluoroProbe is highly correlated to data collected using traditional microscope counts for taxonomical analyses. Thus, reduce the need for discrete sample collection, lab analysis, and overall sampling expense. Lastly, this study will improve our fundamental understanding and confidence in our ability to make phytoplankton measurements with the bbe FluoroProbe and enhance our understanding of the Bay-Delta's phytoplankton dynamics in time and space. A correlation analysis will be conducted on bbe FluoroProbe and discrete sample data collected over a total of 18 days during high-speed mapping surveys spanning three months in 2018 and 2020 (May, July, and October). Discrete samples are analyzed for nutrients, pigments, and phytoplankton taxonomy. Eleven sites are sampled on each of the eighteen mapping days, providing a rich data set of phytoplankton taxonomic data to compare against the bbe FluoroProbe.