Large contribution of small phytoplankton at Marian Cove, King George Island, Antarctica, based on long-term monitoring from 1996 to 2008

Abstract

To detect and monitor coastal marine ecosystem responses to current environmental changes, the phytoplankton assemblage, salinity, and macro-nutrients were monitored daily at a fixed coastal site in Marian Cove, Antarctica, from 1996 to 2008. The monthly average water temperature at the site was highest (2.14 ± 0.36 °C) during the summer period (December？February) and lowest (？1.80 ± 0.22 °C) during the winter period (July？September). The salinity levels exhibited the opposite trend with the lowest values (30.9 ± 0.68 psu) during summer and the highest values (35.2 ± 1.15 psu) during winter. The concentrations of major nutrients were always high enough for phytoplankton growth, indicating the nutrients are not a main controlling factor for phytoplankton growth. Total chlorophyll-a generally started to increase from late November with a peak (1.14 ± 1.41 mg chl-a m？3) around January when the water temperature was the warmest during the year. Within the phytoplankton communities, the average contribution of small (nano- plus pico-) phytoplankton (