Phytoplankton production characteristics in the southern Atlantic and the Atlantic sector of the Southern Ocean in the austral summer of 2009–2010

Abstract

In December-January of 2010 the spatial distribution of the phytoplankton production charac� teristics was studied along transects in the vicinity of the Greenwich meridian (I) and in the Drake Passage (II). On transect I, the surface chlorophyll a concentration and primary production varied from 0.11 up to 3.57 mg/m 3 and from 4.38 up to 37.47 mgC/m 3 per day, respectively. The chlorophyll a in the photosynthetic layer and the integrated primary production varied from 10.7 up to 66.1 mg/m 2 and from 83 to 646 mgC/m 2 per day, respectively. On transect II in the surface layer, the chlorophyll a concentration changed within the range of 0.09-1.02 mg/m 3 and the primary production ranged from 2.08 to 9.49 mgC/m 3 . The integrated val� ues ranged from 6.32 to 38.29 mg/m 2 and from 41 to 221 mgC/m 2 per day, respectively. The moderate means of themaximum quantum yield (Fv/Fm) on transects I and II (0.41 and 0.35, respectively) testify to the low activity of the phytoplankton's photosynthetic apparatus. The studied water areas in the Southern Ocean dif� fered both in the phytoplankton biomass expressed in the chlorophyll a concentration values and in the con� ditions of the primary production formation.