Calcium isotopes link ocean acidification to Aptian-Albian foraminiferal extinctions.
basic_science · Level V
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- Record sourced from PubMed, PMID 42531381.
- Also identified by DOI 10.1126/science.aed9359.
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Abstract
The second-largest extinction event in the evolutionary history of planktic foraminifera occurred at the Aptian-Albian boundary. This extinction may reflect ocean acidification (OA) associated with Oceanic Anoxic Event 1b. As calcium isotope ratios (δ<sup>44/40</sup>Ca) can track how biocalcification rates respond to OA, we measured δ<sup>44/40</sup>Ca records for planktic and benthic foraminifera, bulk carbonates, and authigenic calcite across the Aptian-Albian boundary in the South Atlantic. Benthic and bulk δ<sup>44/40</sup>Ca data display a distinct sequence of negative and positive excursions, similar to δ<sup>44/40</sup>Ca variations across other OA events. Planktic δ<sup>44/40</sup>Ca values increase markedly, tracking a reduction in calcification rates coincident with decreases in the size, diversity, and shell thickness of planktic foraminifera. These results suggest that OA drove extinctions of planktic foraminifera at the Aptian-Albian boundary.
Medical subject headings
- Calcium Isotopes
- Extinction, Biological
- Foraminifera
- Ocean Acidification
- Seawater