Articles | Volume 13, issue 20
Biogeosciences, 13, 5827–5847, 2016
Biogeosciences, 13, 5827–5847, 2016

Research article 25 Oct 2016

Research article | 25 Oct 2016

A sea surface temperature reconstruction for the southern Indian Ocean trade wind belt from corals in Rodrigues Island (19° S, 63° E)

Jens Zinke1,2,3,4, Lars Reuning5, Miriam Pfeiffer5, Jasper A. Wassenburg6, Emily Hardman7, Reshad Jhangeer-Khan7, Gareth R. Davies8, Curtise K. C. Ng9, and Dick Kroon10 Jens Zinke et al.
  • 1Department of Environment and Agriculture, Curtin University of Technology, Kent Street, Bentley WA 6102, Australia
  • 2Division of Paleontology, Freie Universität Berlin, Malteserstrasse 74–100, 12249 Berlin, Germany
  • 3Australian Institute of Marine Science, Nedlands WA 6009, Australia
  • 4School of Geography, Archaeology and Environmental Studies, University of Witwatersrand, Johannesburg, South Africa
  • 5Geological Institute, RWTH Aachen University, Wuellnerstrasse 2, 52056 Aachen, Germany
  • 6Institute for Geosciences, Johannes Gutenberg University of Mainz, Johann-Joachim-Becher-Weg 21, 55128 Mainz, Germany
  • 7SHOALS Rodrigues, Rodrigues, Mauritius
  • 8Geology & Geochemistry, VU University Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, the Netherlands
  • 9Department of Medical Radiation Sciences, Curtin University of Technology, Kent Street, Bentley WA 6102, Australia
  • 10University of Edinburgh, School of GeoSciences, The King's Buildings, West Mains Road, Edinburgh, EH9 3JW, UK

Abstract. The western Indian Ocean has been warming rapidly over recent decades, causing a greater number of extreme climatic events. It is therefore of paramount importance to improve our understanding of links between Indian Ocean sea surface temperature (SST) variability, climate change and sustainability of tropical coral reef ecosystems. Here we present monthly resolved coral Sr ∕ Ca records from two different locations from Rodrigues Island (63° E, 19° S) in the south-central Indian Ocean trade wind belt. We reconstruct SST based on a linear relationship with the Sr ∕ Ca proxy with records starting from 1781 and 1945, respectively. We assess relationships between the observed long-term SST and climate fluctuations related to the El Niño–Southern Oscillation (ENSO), the Subtropical Indian Ocean Dipole Mode (SIOD) and the Pacific Decadal Oscillation (PDO) between 1945 and 2006, respectively. The reproducibility of the Sr ∕ Ca records is assessed as are the potential impacts of diagenesis and corallite orientation on Sr ∕ Ca–SST reconstructions. We calibrate individual robust Sr ∕ Ca records with in situ SST and various gridded SST products. The results show that the SST record from Cabri provides the first Indian Ocean coral proxy time series that records the SST signature of the PDO in the south-central Indian Ocean since 1945. We suggest that additional records from Rodrigues Island can provide excellent records of SST variations in the southern Indian Ocean trade wind belt to unravel teleconnections with the SIOD/ENSO/PDO on longer timescales.

Short summary
Our work provides a new coral proxy-based reconstruction of sea surface temperature (SST) from the coral reefs of Rodrigues Island, located in the poorly studied south-central Indian Ocean trade wind belt. This site is well located to study the SST history of the subtropical Indian Ocean and its teleconnections with the Pacific over long timescales. Our results provide insights into biases in coral Sr / Ca-based SST reconstructions and how to avoid them.
Final-revised paper