TY - JOUR
T1 - Using past interglacial temperature maxima to explore transgressions in modern Maldivian coral and Amphistegina bleaching thresholds
AU - Stainbank, Stephanie
AU - Kroon, Dick
AU - de Leau, Erica S.
AU - Spezzaferri, Silvia
N1 - Funding Information:
This work was funded by the Swiss National Science Foundation (SNSF) through grant number 200021_165852/1 awarded to S.Sp. Additionally DK acknowledges funding support from the Natural Environment Research Council (NERC) through grant number NERC-NE/N012739/1. The authors would like to thank the International Ocean Discovery Program (IODP) for supplying the samples used in this study. Both Colin Chilcott, from the University of Edinburgh, and Dr. Jacek Raddatz, from the Goethe-University of Frankfurt are thanked for their help with the stable isotopic and Mg/Ca measurements. The image of a bleached coral in Fig. 2a is credited to The Ocean Agency/ XL Catlin Seaview Survey and Richard Vevers/The Ocean Agency and the living coral image to Dr. Marine Fau from the University of Fribourg.
Publisher Copyright:
© 2021, The Author(s).
PY - 2021/5/13
Y1 - 2021/5/13
N2 - Tropical corals and Amphistegina, an example genus of symbiont-bearing larger benthic foraminifera, are presently living close to their thermal bleaching thresholds. As such, these essential reef-building organisms are vulnerable to the future prospect of more frequent sea surface temperature (SST) extremes. Exploring the earth’s paleo-climatic record, including interglacials warmer than present, may provide insights into future oceanographic conditions. We analyse foraminiferal shell geochemical compositions, from Recent surface sediments and Marine Isotope stage (MIS) 9e and MIS11c aged sediments, from the International Ocean Discovery Program Expedition 359 Site U1467 drilled in the Inner Sea of the Maldives. We illustrate through traditional (pooled) geochemical analysis (δ18O, Mg/Ca) that tropical temperatures were indeed marginally warmer during MIS9e and MIS11c in comparison to the modern ocean. Individual foraminiferal analysis (IFA) from the Recent (representing the last few hundred years) and MIS9e samples shows SSTs occasionally breached the coral bleaching threshold similarly to the modern-day. Significantly, the number of transgressions was four times higher during MIS11c, a recognised analogue for a warmer modern world. This new knowledge and novel IFA insight and application is invaluable given thermal stress is already obvious today with an increasing number of bleaching events over the last few decades.
AB - Tropical corals and Amphistegina, an example genus of symbiont-bearing larger benthic foraminifera, are presently living close to their thermal bleaching thresholds. As such, these essential reef-building organisms are vulnerable to the future prospect of more frequent sea surface temperature (SST) extremes. Exploring the earth’s paleo-climatic record, including interglacials warmer than present, may provide insights into future oceanographic conditions. We analyse foraminiferal shell geochemical compositions, from Recent surface sediments and Marine Isotope stage (MIS) 9e and MIS11c aged sediments, from the International Ocean Discovery Program Expedition 359 Site U1467 drilled in the Inner Sea of the Maldives. We illustrate through traditional (pooled) geochemical analysis (δ18O, Mg/Ca) that tropical temperatures were indeed marginally warmer during MIS9e and MIS11c in comparison to the modern ocean. Individual foraminiferal analysis (IFA) from the Recent (representing the last few hundred years) and MIS9e samples shows SSTs occasionally breached the coral bleaching threshold similarly to the modern-day. Significantly, the number of transgressions was four times higher during MIS11c, a recognised analogue for a warmer modern world. This new knowledge and novel IFA insight and application is invaluable given thermal stress is already obvious today with an increasing number of bleaching events over the last few decades.
U2 - 10.1038/s41598-021-89697-0
DO - 10.1038/s41598-021-89697-0
M3 - Article
C2 - 33986381
AN - SCOPUS:85105796942
SN - 2045-2322
VL - 11
JO - Scientific Reports
JF - Scientific Reports
IS - 1
M1 - 10267
ER -