Project II.2.3c: Characterizing communities - Analysis of fluorescence signatures from phytoplankton DOC
Project Name: II.2.3c: Characterizing communities - Analysis of fluorescence signatures from phytoplankton DOC
Project Leads: Tawnya Peterson and Joseph Needoba
Project Description
This project seeks to identify signatures of colored dissolved organic matter (CDOM) produced by several species of marine and freshwater algae and will form part of a larger study aimed at characterizing the dynamics of DOC in the Columbia and Willamette Rivers and the Columbia River estuary. The main activity will be the culturing of several species of algae. This will be initiated by Peterson and carried out by J. Goldman (PhD student, CMOP) as part of her thesis work. The protocol will consist of growing algae at known temperature and irradiances until they reach exponential phase. Once they are in exponential phase, they will be harvested and the dissolved matter (filtered through a combusted 0.7 µm Glass Fiber Filter) will be stored in combusted, acid-cleaned amber glass bottles prior to analysis using a FluoroMaxIV scanning spectrofluorometer. Needoba will oversee the fluorescence measurements and subsequent data analysis using PARAFAC (Matlab program to identify spectral signatures from 3-dimensional excitation-emission plots). Once these basic measurements are made, the cultures will be grown at different nutrient concentrations and ratios to test whether growth conditions impact CDOM signatures.
Fit in program
(a) This project focuses on dissolved organic carbon, an important and poorly understood carbon pool that is particularly rich in the Columbia River and Estuary. The project builds on data gained through the comprehensive LMER program in the 1990’s using novel tools (a powerful scanning spectrofluorometer available to the EBS department). (b) This project will allow us to better understand the sources of DOC to the Columbia River and Estuary and is thus synergistic with the goals of the microbiology team. (c) The project complements the goals outlined in a second project focused on CDOM (II.2.2a) which focuses on analyzing field samples for CDOM signatures. The present charter describes a mechanism to truth field data.
Outcomes
The anticipate outcome are 3-dimensional signatures of dissolved organic carbon compounds from several species of algae important to the Columbia River and Estuary (Excitation-Emission Matrices, EEM), to determine whether different phytoplankton species produce distinct EEMs.
