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Article
Optical Fractionation of Chlorophyll and Primary Production for Coastal Waters of the Southern Ocean
Polar Biology
  • Mark A. Moline, California Polytechnic State University - San Luis Obispo
  • Barbara B. Prezelin, University of California - Santa Barbara
Publication Date
1-1-2000
Abstract

Our objective was to quantify the potential variability in remotely sensed chlorophyll a (Chl a) and primary productivity in coastal waters of the Southern Ocean. From data collected throughout the springs/summers of 1991–1994, we calculated the proportion of water column Chl a and primary productivity within the upper optical attenuation length (K −1 par) and the satellite-weighted depth. The temporal variability was resolved every 2–3 days and was observed to be greater within years than between years. Three-year averages (n=223) revealed that 10.2 ± 3.6% of total Chl a and 14.8 ± 6.5% of production occurred within satellite-weighted depth in predominantly Case I waters. The average values were twice as high within K −1 par, 24.1 ± 8% of total Chl a and 34 ± 9% of production respectively. Masked in these long-term averages are very large changes occurring on short time scales of seasonal blooms. We observed that the patterns of Chl a vertical distribution within blooms are also subject to taxonomic influence and dependent upon the physiological state of the phytoplankton. Highest proportions of water column Chl a in the first optical depth were measured during the rapid onset of surface cryptophyte blooms each year, i.e. 50% within K −1 par and 30% above the satellite-weighted depth. Lowest fractions, 6% and 2% of biomass within K −1 par and satellite-weighted depth respectively, were associated with peak bloom conditions independent of taxonomy. Our analyses suggest that satellite-dependent models of Chl a and subsequent chlorophyll-dependent primary production will be challenging to develop for the near-shore Southern Ocean, especially given the potentially high natural variability in the vertical distribution of Chl a driven by physical forcing, the photoadaptive abilities of polar phytoplankton, and taxonomic influences.

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Citation Information
Mark A. Moline and Barbara B. Prezelin. "Optical Fractionation of Chlorophyll and Primary Production for Coastal Waters of the Southern Ocean" Polar Biology Vol. 23 Iss. 2 (2000) p. 129 - 136
Available at: http://works.bepress.com/mmoline/21/