Hawaii Ocean Time-series (HOT)
in the School of Ocean and Earth Science and Technology at the University of Hawai'i
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FLUOROMETRIC ANALYSIS OF CHLOROPHYLL A. AND PHAEOPIGMENTS
SUMMARY: Concentrations of chlorophyll a and phaeopigments, considered an index of the phytoplankton standing stock, are measured by fluorometry after particulate sample concentration by vacuum filtration and extraction in 100% acetone.
Historically chlorophyll a (chl a) has been used as a measure of phytoplankton standing stock. Also, when related to photosynthetic carbon production, the concentration of chl a and distribution in the water column allows one to estimate an index of the efficiency of phytoplankton in harvesting light.
Fluorescence is produced by atoms or molecules that, under exited state, return to their state of minimum energy (or ground state) by losing energy in the form of light. The absorption of blue light by chlorophylls and phaeopigments produces emission of red light. In a sample, the fraction of light transformed is proportional to the amount of pigment. Hence, by knowing the amount of incident light and by measuring the light emitted at a second wavelength, it is possible to estimate the concentration of these pigments in the sample.
2. Sampling, Filtration, Extraction and Storage
3. Standard Preparation and Analysis
4. Data Reduction and Calculations