Coral record of southeast Indian Ocean marine heatwaves with intensified Western Pacific temperature gradient
journal contributionposted on 2019-10-22, 14:01 authored by J Zinke, A Hoell, JM Lough, M Feng, AJ Kuret, H Clarke, V Ricca, K Rankenburg, MT McCulloch
Increasing intensity of marine heatwaves has caused widespread mass coral bleaching events, threatening the integrity and functional diversity of coral reefs. Here we demonstrate the role of inter-ocean coupling in amplifying thermal stress on reefs in the poorly studied southeast Indian Ocean (SEIO), through a robust 215-year (1795–2010) geochemical coral proxy sea surface temperature (SST) record. We show that marine heatwaves affecting the SEIO are linked to the behaviour of the Western Pacific Warm Pool on decadal to centennial timescales, and are most pronounced when an anomalously strong zonal SST gradient between the western and central Pacific co-occurs with strong La Niña's. This SST gradient forces large-scale changes in heat flux that exacerbate SEIO heatwaves. Better understanding of the zonal SST gradient in the Western Pacific is expected to improve projections of the frequency of extreme SEIO heatwaves and their ecological impacts on the important coral reef ecosystems off Western Australia.
We acknowledge the Australian Institute of Marine Science coral core sampling campaign conducted using the RV Solander under the leadership of Dr Tim Cooper. J.Z. was supported by an Indian Ocean Marine Research Centre UWA/AIMS/CSIRO collaborative assistant professorial fellowship and a Honorary Fellowship with the University of the Witwatersrand (South Africa). M.F. is supported by the CSIRO Oceans and Atmosphere Flagship and also partly by the Australian Climate Change Science Program (ACCSP) and Western Australia Marine Science Institute (WAMSI). This research is partly funded by the Gorgon Barrow Island Net Conservation Benefits Fund, which is administered by the WA Department of Parks and Wildlife. M.T.M. and J.M.L. activities are conducted under the auspices of the ARC Centre of Excellence for Coral Reef Studies. J.M.L. was supported by AIMS. M.T.M. was a recipient of a Western Australian Premiers Fellowship kindly provided by the WA Premiers Department and an ARC Laureate Fellowship. Laboratory facilities were constructed using funds provided by an ARC LIEF grant 100100203, UWA and partner institutions. We thank the West Australian Biogeochemistry Centre, in particular G. Skrzypek and P. Grierson, for stable isotope measurements. We thank Andrew Heyward and James Gilmour (AIMS), and Tim McClanahan (Wildlife Conservation Society) for discussions on the paper. Kirsty Brooks from UWA helped mill the samples. Eric Matson (AIMS) provided skilled technical support for coral core collection and sample preparation.
CitationNature Communications, 2015, volume 6, Article number: 8562
Author affiliation/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/School of Geography, Geology and the Environment
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