Mid-Holocene palaeolimnological record of a Southern Hemisphere subtropical lake spanning the last ~6000 years: Lake Jennings, Fraser Island, Australia

Abstract

The study of climate mechanisms in the Southern Hemisphere during the Holocene remains an area of active research that lacks the spatial and temporal connectivity characteristic of Northern Hemisphere research. The subtropical/temperate climate transition zone of eastern Australia provides a unique location to investigate long-term environmental changes during the Holocene. Lake Jennings on Fraser Island was used to investigate climate change in this transition zone using palaeolimnological techniques. The beginning of the Lake Jennings record (~6000 to 3500 cal. yBP), is characterised by fluctuations in geochemical signals, an abundance of sponge spicules, and a lack of diatom species. Results suggest gradually increasing precipitation and water depth, which affect nutrient cycling. However, the biological functioning of the lake is difficult to interpret due to the absence of diatoms, possibly a result of turbidity, dissolution and/or predation by freshwater sponges. During the late Holocene, ~3500 cal....