Photosynthate partitioning by natural phytoplankton populations in a shallow coastal front
Emilio Fernández, Iosu de Madariaga, Pablo Serret
Photosynthateradiocarbon labelling patterns measured in a shallow coastal front showed thatthe greatest proportion of 14C was incorporated into the lipid andlow molecular weight metabolite (LMWM) fractions. Carbon incorporation intoprotein continued overnight whereas incorporation into other products decreasedor remained constant. Dark 14Creallocation appeared to bethe main source of variability in carbon metabolism as revealed by an analysisof variance performed on the original data. Statistically significantinteractions were observed between irradiance and sampling station with regardto the 14C flow into protein and lipid. Although the highest levelsof primary production were measured at the innermost station, growth rateindicators such as the protein to LMWM synthesis ratio (PMSR) or the protein tostorage products synthesis ratio (PSSR) were higher at the frontal margin andat the offshore pycnocline. Our results support the conclusion that a clearrelationship between short-term primary production and growth rate can notalways be observed and that active phytoplankton growth occurs at frontalmargins.
Keywords: Phytoplankton, primary production, photosynthetic carbon metabolism,frontal systems, Ría of Eo (Northern Spain).
Sci. Mar. 55(4) : 599-604
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