Limnological features of the saline lakes of the Bunger Hills (Wilkes Land, Antarctica)

Abstract

Twelve saline lakes 5-35m above sea level in Bunger Hills (66°10'S, 101°00'E) were investigated from January to April in 1987-89. Some lakes may be relict and all were subject to wind-borne marine salts with present salinities between 3.4-79.0°/‰ and δ¹⁸O values mostly between -10 to -14%. Temperatures up to 17.7°C were measured at the bottom of Lake Polest where a sharp thermohalocline was observed during the period of open water. Mg²⁺ dominated over Ca²⁺ in all the lakes. Phosphates concentration was 3-10 μgP I^-1 and total phosphorus 8-16 μgP I^-1. The concentrations of nitrates and nitrites were often equal, ranging between 1-4 μgN I^-1. Dissolved O₂ was usually near saturation levels but peaked at more than 230% of saturation in the hypolimnion of Lake Polest as a result of temperature-enhanced photosynthesis with an assimilation rate of 23.9 mgC (mg Chl a)^-1h^-1. The values for chlorophyll a were 0.26-1.93 mg m^-3 and for primary production 0.013-0.171 gCm^-3d^-1, the latter being an order of magnitude higher than in the fresh water lakes of the Bunger Hills.