Understanding connections between groundwater, caves and climate

UNSW’s Baker Lab Group is at the front line of research related to groundwater processes, cave and karst science, organic matter characterisation and speleothem paleoclimatology—the study of how cave formations can help us to understand Earth’s climate in the past.

Led by Dr Andy Baker—a member of UNSW’s Connected Waters Initiative Research Centre with a PhD from the University of Bristol and over 25 years of research experience—the  Baker Lab Group takes an interdisciplinary scientific approach, researching between the subject areas of environmental earth science and engineering with foci in organic and inorganic geochemistry and surface and subsurface hydrology.

Caves, organic matter and groundwater hold many clues about Earth’s climate—past, present and future. In a study published recently in the prestigious journal Nature Communications, the Baker Lab Group led a  world-first global analysis of cave drip waters, showing where stalagmites can provide vital clues towards understanding past rainfall patterns.

The Baker Lab Group, which is made up of members of UNSW’s Connected Waters Initiative Research Centre, led a study which compared the oxygen isotope composition of the drip water to that of rainfall as well as that expected in groundwater recharge. The results of this study have enabled climate thresholds on cave drip water composition to be determined for the first time.

In cool climates, it was established that cave drip water oxygen isotope composition is similar to that of rainfall, meaning that stalagmite oxygen isotopes might best preserve past rainfall in these regions. In warmer climates and strongly seasonal climates, however, cave drip water oxygen isotope composition is similar to that of modelled groundwater recharge.

With this knowledge, Dr Baker says we can better understand just how important rainfall is in the replenishment of our precious groundwater resources.  

Dr Baker and his team, in collaboration with Dr Pauline Treble from Australia’s Nuclear Science and Technology Organisation and Dr Andreas Hartman from the University of Freiburg in Germany, have also been undertaking long-term  karst hydrology monitoring at four sites across Australia: the Margaret River region in Western Australia; Yarrangobilly in the Snowy Mountains; Wellington in the NSW Central West and the Macleay in the NSW mid-north coast.  This project seeks to determine what controls groundwater recharge across different climate and vegetation types, and how understanding might then be used to interpret stalagmite records of past groundwater recharge. 

Dr Baker is a former member of UNSW’s Water Research Centre and remains a regular visitor to the Water Research Laboratory at Manly Vale. His research interest in organic matter characterisation affiliates him to the UNSW Biomass Group.  He has published over 230 papers in journals which include Nature and Science. He is an Associate Editor of the journal Water Research.
Dr Baker and the Baker Lab Group are active on Facebook and Twitter, and more information on their research and publications can be found on the Baker Lab Group website.

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