Sediment timeline reveals climate change influence on Kimberley
By: Jo Myers, CSIRO
The remote Kimberley coast of northwestern Australia is one of the few marine environments on earth largely unaffected by human use. However, the region is undergoing increasing economic importance as a destination for tourism and significant coastal developments associated with oil and gas exploration.
A team of researchers, which included scientists from CSIRO, Edith Cowan University, La Rochelle University and the Chinese Academy of Sciences, collected sediment cores from three coastal locations in the Kimberley region, to provide an indication of the level of variability and change in water quality over the last 100 years.
The study locations of Koolama Bay (King George River), Cygnet Bay and Roebuck Bay in the southern, central and northern Kimberley were selected as each offered a different perspective in comparison of levels of human use or natural environmental variability.
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| Collecting sediment cores at Cygnet Bay (CSIRO) |
The team found that for the Kimberley in general, climate change, in particular temperature increases have had, and may continue to have, a significant influence on phytoplankton biomass.
Analysis of cores from the Broome site lent general support to other studies which have indicated increased nutrient pollution levels in Roebuck Bay.
At Cygnet Bay, where pearl farming has occurred since the 1960s, there were small but detectable, gradual changes in the environment evident over the long term.
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| Sediment cores indicated increased nutrient pollution levels in Roebuck Bay. |
The project also undertook a pilot study using the King George River cores, which indicated that coastal sediment cores could reveal long-term patterns of bush fires in different catchments in the Kimberley.
Links:
Yuan Z, Liu D, Keesing, J K, Zhao M, Guo S, Peng Y, Zhang H (2018) Paleoecological evidence for decadal increase in phytoplankton biomass off northwestern Australia in response to climate change. Ecology and Evolution doi:10.1002/ece3.3836
The project report Sediment Records in the Kimberley_WAMSI KMRP Report 2.2.9_Keesing et al 2017_FINAL is available at www.wamsi.org.au/sediment-record
The $30 million Kimberley Marine Research Program is funded through major investment supported by $12 million from the Western Australian government co-invested by the WAMSI partners and supported by the Traditional Owners of the Kimberley.