Summary of Abstract Submission

Abstract Submission No. IO50-09-0034PresentationPoster

PHYTOPLANKTON PHYSIOLOGICAL STATUS ASSOCIATED WITH TEMPERATURE FRONTS IN THE NORTHEASTERN ARABIAN SEA DURING WINTER

Jagadish S. Patil*1, Arga Chandrashekar Anil2, D.V. Desai2, Smita Mitbavkar2

1 CSIR-National Institute of Oceanography, Dona Paula, Goa, , India
2 CSIR-National Institute of Oceanography, Dona Paula, Goa,, India

ABSTRACT :

Temperature fronts have been recognized as regions of high biological production and occur significantly during winter in the northern Arabian Sea. However, information on the physiological response of the phytoplankton community in such unique environments is limited. The capability of fast repetition rate fluorometer to measure chlorophyll variable fluorescence (Fv=Fm-F0), quantum-yield (Fv/Fm) and functional-absorption-cross-section (σPSII) in real time provides considerable insight into the phytoplankton photosynthetic physiology particularly the structure and function of Photosystem-II. In order to examine the variations in phytoplankton physiological status within and outside fronts, a study was carried out in the northeastern Arabian Sea during February-2014. Observations were made during night time from a total of 54 stations located along seven transects in different geographic locations (oceanic, coastal and oligotrophic). Environmental data revealed that the frontal zones are relatively cooler (by 0.4 to 1.2oC), saltier (by 0.03 to 0.14) and nutrient rich compared to non-frontal zones. Irrespective of the geographic locations and phytoplankton composition, high Fv (0.25 to 0.83 relative units) and Fv/Fm (0.27 to 0.41 dimensionless) values were observed in frontal zones than in non-frontal zones (Fv: 0.11 to 0.54 relative units and Fv/Fm: 0.15 to 0.38). These results suggest that although maximum photosynthetic efficiency i.e. Fv/Fm=0.65 was not attained, the phytoplankton were relatively more photosynthetically efficient in frontal zones than in non-frontal zones.