Chlorophyll natural fluorescence response to upwelling events in the Southern Ocean

• Main Authors: Letelier, Ricardo M., Abbott, Mark R., Karl, David M.
• Other Authors: College of Oceanic and Atmospheric Sciences
• Format: Article in Journal/Newspaper
• Language: English; unknown
• Published: American Geophysical Union
• Subjects: Antarctic; Southern Ocean; The Antarctic; Antarc*
• Online Access: https://ir.library.oregonstate.edu/concern/articles/sq87bv92n

Variability of solar-induced (natural) fluorescence and chlorophyll were measured on scales of hours to weeks in the upper layer of a cyclonic eddy located south of the Antarctic Polar Front using a free-floating drifter. The fluorescence signal was analyzed both in terms of chlorophyll concentration and as an indicator of energy distribution in the photosynthetic apparatus. Long-term trends in fluorescence parallel changes in chlorophyll concentration. Considering a significant positive correlation between fluorescence and the relative depth of the eddy upper layer we hypothesize that the observed short-term variations in natural fluorescence are a physiological response of phytoplankton to changes in the supply of limiting nutrients. This interpretation is consistent with the Southern Ocean iron limitation hypothesis.