Dataset Information

Pulses of South Atlantic water into the tropical North Atlantic since 1825 from coral isotopes.

ABSTRACT: Decadal and multidecadal changes in the meridional overturning circulation may originate from either the subpolar North Atlantic or the Southern Hemisphere. New records of carbon and oxygen isotopes from an eastern Martinique Island (Lesser Antilles) coral reveal irregular, decadal, double-step events of low ∆¹⁴C and enhanced vertical mixing, high δ¹⁸O and high δ¹³C values starting in 1885. Comparison of the new and published ∆¹⁴C records indicates that the last event (1956-1969) coincides with a widespread, double-step ∆¹⁴C low of South Atlantic origin from 32°N to 18°S, associated with a major slowdown of the Caribbean Current transport between 1963 and 1969. This event and the past Martinique ∆¹⁴C lows are attributed to pulses of northward advection of low ∆¹⁴C Sub-Antarctic Mode Waters into the tropical Atlantic. They are coeval with changes of the tropical freshwater budget and likely driven by meridional overturning circulation changes since ~1880.

SUBMITTER: Paterne M

PROVIDER: S-EPMC10848734 | biostudies-literature | 2023 Dec

REPOSITORIES: biostudies-literature

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Pulses of South Atlantic water into the tropical North Atlantic since 1825 from coral isotopes.

Paterne Martine M Druffel Ellen R M ERM Guilderson Thomas P TP Blamart Dominique D Moreau Christophe C Weil-Accardo Jennifer J Feuillet Nathalie N

Science advances 20231215 50

Decadal and multidecadal changes in the meridional overturning circulation may originate from either the subpolar North Atlantic or the Southern Hemisphere. New records of carbon and oxygen isotopes from an eastern Martinique Island (Lesser Antilles) coral reveal irregular, decadal, double-step events of low ∆14C and enhanced vertical mixing, high δ18O and high δ13C values starting in 1885. Comparison of the new and published ∆14C records indicates tha ...[more]

PMID: 38100584

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Project description:The North Atlantic Oscillation (NAO) has been hypothesized to drive interannual variability in Bermudan coral extension rates and reef-scale calcification through the provisioning of nutritional pulses associated with negative NAO winters. However, the direct influence of the NAO on Bermudan coral calcification rates remains to be determined and may vary between species and reef sites owing to implicit differences in coral life history strategies and environmental gradients across the Bermuda reef platform. In this study, we investigated the connection between negative NAO winters and Bermudan Diploria labyrinthiformis, Pseudodiploria strigosa, and Orbicella franksi coral calcification rates across rim reef, lagoon, and nearshore reef sites. Linear mixed effects modeling detected an inverse correlation between D. labyrinthiformis calcification rates and the winter NAO index, with higher rates associated with increasingly negative NAO winters. Conversely, there were no detectable correlations between P. strigosa or O. franksi calcification rates and the winter NAO index suggesting that coral calcification responses associated with negative NAO winters could be species-specific. The correlation between coral calcification rates and winter NAO index was significantly more negative at the outer rim of the reef (Hog Reef) compared to a nearshore reef site (Whalebone Bay), possibly indicating differential influence of the NAO as a function of the distance from the reef edge. Furthermore, a negative calcification anomaly was observed in 100% of D. labyrinthiformis cores in association with the 1988 coral bleaching event with a subsequent positive calcification anomaly in 1989 indicating a post-bleaching recovery in calcification rates. These results highlight the importance of assessing variable interannual coral calcification responses between species and across inshore-offshore gradients to interannual atmospheric modes such as the NAO, thermal stress events, and potential interactions between ocean warming and availability of coral nutrition to improve projections for future coral calcification rates under climate change.

Dataset Information

Pulses of South Atlantic water into the tropical North Atlantic since 1825 from coral isotopes.

Publications

Pulses of South Atlantic water into the tropical North Atlantic since 1825 from coral isotopes.

Similar Datasets

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