Ms Yuexiao Shao1, Dr Juraj Farkaš1, Prof Luke Mosley1, Mr Henri Wong2, Dr Moneesha Samanta3, Dr Jonathan Tyler1, Prof Chris Holmden4, Prof Bronwyn Gillanders1, Ms Ana Kolevica5, Prof Anton Eisenhauer5
1University of Adelaide, Adelaide, Australia, 2ANSTO, Sydney, Australia, 3Australian National University, Canberra, Australia, 4University of Saskatchewan, Saskatoon, Canada, 5GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstr, Germany
Coastal environments, including lagoon-estuarine systems, represent a land-ocean interface whose physico-chemical properties are sensitive indicators of climate change and anthropogenic perturbations. These environments typically involve dynamic hydrological and geochemical processes and water mixing phenomena, resulting in large gradients in salinity, mineral saturation state and chemical/isotope composition of local waters. In turn, these parameters are critical for calcium carbonate (CaCO3) cycling in coastal waters, which is an important but currently poorly constrained component of the global carbon cycle and often concerned in “blue carbon” studies. In order to understand these coastal processes, we calibrate novel isotope tracers of alkaline earth metals, specifically stable strontium (δ88/86Sr) and calcium (δ44/40Ca) isotope tracers based on analyses in water and carbonate samples from the Coorong, Lower Lakes and Murray Mouth Estuary – an unique hydrological system in South Australia with large water salinity gradient ranging from fresh to hypersaline (from ~0 to over 100PSU). Preliminary results show a correlation between δ88/86Sr and δ44/40Ca, both of which show a systematically increasing trend with increasing salinity, complemented by increasing water carbonate saturation. Furthermore, this multi-proxy isotope approach can also be used to constrain water source mixing and changes in carbonate formation/dissolution in coastal systems, where the latter is relevant to blue carbon cycle and particularly its inorganic C or carbonate (CaCO3) component.
I have started my PhD at University of Adelaide since August 2017, with particular interest in biogeochemistry and non-traditional isotopes (e.g. Sr and Ca isotopes) and application of these tracers to constrain hydrological/geochemical variability in coastal environments, such as changes in water source inputs, salinity, and carbonate fluxes controlled by evaporation or biological processes. Furthermore, these tracers are explored for reconstruction of paleo-environments. Personally, I love travelling, seeing different nature and cultures, it has taught me to think in various ways, and to respect and appreciate the environments and resources given by our incredible planet.