Description
Summary:Public Summary of AAS project 4156 - High resolution reconstructions of climate and ecosystem variability in the sub-Antarctic during the last two millennia Our understanding of global climate and ability to predict future changes is limited by a lack of long-term (palaeoclimate) data from the Southern Hemisphere (SH). Sub-Antarctic islands are the only landmasses between Antarctica and the mid latitudes where terrestrial palaeoclimate records exist, making them crucial locations for linking data from the mid and high latitudes. Using lake sediments from sub-Antarctic islands, we will examine how the climate and ecosystems have changed over the last 2000 years. This will contribute vital information to understand SH climate and ecosystem variability Taken from the abstract of the referenced paper: Sub-Antarctic islands are ideally placed to reconstruct past changes in Southern Hemisphere westerly wind behaviour. They lie within their core belt (50-60 degrees South) and the strong winds deliver sea salt ions to the islands resulting in a west to east conductivity gradient in their water bodies. This means that the stronger (or weaker) the winds, the higher (or lower) the conductivity values measured in the water bodies. A survey of the water chemistry and diatom assemblages of lakes and ponds on sub-Antarctic Campbell Island (52 degrees 32 minutes S, 169 degrees 8 minutes E) revealed that, similar to other sub-Antarctic islands, conductivity was the most important, statistically significant ecological variable explaining turnover in diatom community structure. Based on this, a diatom-conductivity transfer function was developed (simple weighted averaging with inverse deshrinking). This transfer function will be applied to lake sediment cores from the western edge of the Campbell Island plateau to reconstruct past conductivity/sea spray and therefore directly reconstruct changes in Southern Hemisphere westerly wind strength within their core belt.