Interannual meteorological variability and its effects on a lake from maritime Antarctica

Abstract

The present study shows the occurrence of remarkable interannual variation in the meteorological conditions at Byers Peninsula (Livingston Island, South Shetlands Islands, Antarctica), in which one of the summers was significantly colder than the others. Within this climatic scenario, a limnological study was carried out at Lake Limnopolar during three consecutive summer seasons (2001/2002, 2002/2003 and 2003/2004). The year-to-year meteorological variation observed during this period resulted in marked differences in the timing and duration of the ice-free period. As a result, physical and chemical conditions changed and were followed by variations in the biological characteristics of the lake. More significant dissimilarities took place during summer 2003/2004 relative to the preceding years. This season was characterized by a delay of 55 or 25 days in the ice-out timing compared to 2001/2002 or 2002/2003, respectively, and also a much shorter ice-free period. Higher algal and bacterial abundances in the surface layers occurred at the onset of ice melting due to increases in nutrients and light availability. The trophic interactions could also be affected by ice-out timing, as a consequence of the prolongation of the ice-cover period. From our findings, we describe links between the meteorological variations during those 3 years and the shifts in the water bodies, pointing out their high sensitivity to environmental changes that may occur at different time-scales. Furthermore, our results emphasize how the interannual meteorological variability needs to be investigated as a triggering factor of the limnological variations to understand the effects of global change on limnetic ecosystems in Maritime Antarctica.