The biogeochemistry of a Salt Lake

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Principal investigator

Lake Tyrrell is a large salt lake in outback Australia . We aim to make the lake one of the most completely understood hypersaline ecosystems in the world. To achieve this, we are combining environmental genomics where the genome of all predominant microorganism in the lake water are sequenced (>1 billion base pairs) with biomarker geochemistry where we will quantify the entirety of all lipids and pigments.

Once the biological origins of lipids and pigments are known by assigning them to genes of individual organism, we will trace them back in time more than 100,000 years by studying the fossil remains of the pigments in the 6 meters of mud that have accumulated in the lake bed. The 1 billion base pairs of environmental genome will give a very detailed view of how the microbial community in Lake Tyrrell is constructed and how the ecosystem works; from the molecular fossil record we will learn how microbial communities evolved through time through changes of climate and salinity.

Lake Tyrrell is a large salt lake in outback Victoria . It was chosen as our study site as it is the hydrologically best understood salt lake in Australia and contains a well preserved sedimentary record of the past ~120,000 years. In winter, the lake contains ~50 cm water, but in summer, the water evaporates, leaving a salt crust up to 7 cm thick. However, around 120,000 years ago, Tyrrell was a ~13 meter deep freshwater (?) lake. During subsequent climate changes, the water level dropped dramatically and the lake went through cycles of drying and partial refilling. The history of Lake Tyrrell is representative of the region. It may hold valuable information about climatic changes in the southern hemisphere and the desiccation of the Australian continent.

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