Meridional variation in low light adaptability of phytoplankton in the south-west atlantic sector of the antarctic ocean

摘要

Bio-optical data collected from three summer cruises in the south-west Atlantic sector of the Antarctic Ocean were analyzed to assess the interrelationship between the beam and diffuse attenuation properties of biological particulates. The covariance between optical depth at 488 nm, K(488 nm)Z_e, and pigment-specific beam attenuation coefficient C_p~* (660 nm) was identified to be a stable parameter to spatially delineate distribution of low light adaptability to phytoplankton. Large variation in C_p~* with almost no change in K(488)Z_e along one meridional transect (45 deg W), extending from 50 deg S to 62 deg S was analyzed to assess meridional extent of magnitude of low light adaptability of Antarctic phytoplankton. An examination of horizontal as well as vertical distribution of temperature and sigma-t along 45 deg W transect further revealed lower C_p~* values to be a characteristic of waters with low temperature and high density and vice versa. C_p~* was also temperatur eand high density and vice versa. C_p~* was also found to have strong inverse relationship with meridional distribution of silicate. Lower C_p~* values were detected in waters with depletion of silicate.