Monday, 20 February 2017

Investigating Climate and Environmental Change in Eastern Australia (Part 2)...by Melanie Leng

The field team made up of researchers from University of Adelaide,
the Queensland government and Melanie Leng  (BGS/University
of Nottingham) and Andy Henderson (Newcastle).
In May 2016 Melanie blogged about her role in a project led by Dr John Tibby and Dr Cameron Barr (from University of Adelaide) on understanding climate change in eastern Australia. This is difficult because few archives of climate change exist in eastern Australia. The team developed a climate record based on the chemistry (carbon isotope ratios) of the broad-leaved paperbark tree, which they correlated to water stress. As a result of that research, Melanie was invited to the University of Adelaide to discuss future collaboration on recent climate change in eastern Australia and visit North Stradbroke Island which was the focus of the original study. Here Mel tells us about her trip…… 

NASA World Wind Landsat
montage of Stradbroke Island
courtesy of Wikipedia.  
Following on from our recent paper in Global Change Biology, I was invited to visit the University of Adelaide to see what expertise we at the British Geological Survey and the University of Nottingham could provide in studying recent climate change along the eastern Australia coastal margin. Climate change is a current hot topic in Australia as it potentially could lead to significant environmental and economic impacts in water security, agriculture, coastal communities and infrastructure. It is important to understand past climate change especially the causes of past increases in frequency and intensity of extreme weather events.

Scientists from the University of Adelaide are working on the past frequency of climate extremes by undertaking research from the records in lake sediments. The first week in Adelaide was spent in meetings, talking to researchers about their projects, but probably the most important was the work being done on North Stradbroke Island (locally referred to as Straddie). Straddie is the second largest sand island in the world (24 x 7 miles), and lies off the Brisbane coast. The sand island contains both large and small aquifers of water and where these aquifers intersect the sand surface they form small lakes. Sediments have accumulated in these lakes over tens and up to hundreds of thousands of years! We visited several of these lakes to discuss their potential to accumulate sediments (many contain 10s of metres of organic rich muds). These muds contain information through time, the oldest being at the bottom of sediment cores extracted from the lakes, while the youngest are at the top. We are (and will be) analysing some of these sediments for geochemical and biological parameters at the British Geological Survey. These parameters will tell us about changing water quality in the past that is related to water stress (or how dry the climate was in the past).

From L-R: Swallow Lake on Stradbroke Island, one of the contenders to provide a long climate history of eastern Australia;
Fieldwork on 'Straddie' Island, here testing the depth of the sediments within this (currently) dried up lake (Welsby Lagoon).
We visited several lakes including Swallow Lake (the site of the original work on the paperbark tree) as well as Brown Lake (perhaps it got its name from leaching of organic compounds from the peats as the sediments accumulated), and the remarkably resilient Blue Lake which is thought to be untouched by climate change and due to its spectacular setting has been hypothetically referred to as “God’s Bathtub” thanks to Cameron Barr.
One of the locals of a field notebook (note the scale), a fairly
harmless orb-weaver spider.
Through our future collaboration we hope that the team involving staff from the University of Adelaide, the British Geological Survey and the University of Nottingham will be able to make inferences about the controls (local, global, man-made) on the past and future climates of eastern Australia.

The fieldwork was headed by Dr John Tibby and Dr Cameron Barr but included staff from Queensland Department of Science, Information Technology and Innnovation, as well as Melanie and Dr Andy Henderson (University of Newcastle)

Melanie Leng is the Director of the Centre for Environmental Geochemistry at the BGS and University of Nottingham. Follow Mel on twitter @MelJLeng.

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