Seawater nutrient and chlorophyll α distributions near the Great Wall Station, Antarctica

We examined the influences upon nutrient, temperature, salinity and chlorophyll a distributions in Great Wall Cove(GWC) and Ardley Cove(AC), near the Chinese Antarctic Great Wall Station, using measurements taken in January 2013 and other recent data. Nutrient concentrations were high, with phosphate concentrations of 1.94(GWC) and 1.96(AC) μmol·L-1, DIN(dissolved inorganic nitrogen) concentrations of 26.36(GWC) and 25.94(AC) μmol·L-1 and silicate concentrations of 78.6(GWC) and 79.3(AC) μmol·L-1. However, average concentrations of chlorophyll a were low(1.29 μg·L-1, GWC and 1.08 μg·L-1, AC), indicating that this region is a high-nutrient and low-chlorophyll(HNLC) area. Nutrient concentrations of freshwater(stream and snowmelt) discharge into GWC and AC in the austral summer are low, meaning freshwater discharge dilutes the nutrient concentrations in the two coves. Strong intrusion of nutrient-rich water from the Bransfield Current in the south was the main source of nutrients in GWC and AC. Low water temperature and strong wind-induced turbulence and instability in the upper layers of the water column were the two main factors that caused the low phytoplankton biomass during the austral summer.