Algal δ<sup>13</sup>C reveals climate changes during the Cambrian Explosion.
basic_science · Level V
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- Record sourced from PubMed, PMID 42331839.
- Also identified by DOI 10.1038/s41467-026-74516-9.
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Abstract
Carbon dioxide is a fundamental atmospheric component that regulates Earth's climate. However, atmospheric CO<sub>2</sub> levels (pCO<sub>2</sub>) during the Cambrian Explosion remain poorly constrained. Here we report pCO<sub>2</sub> variations reconstructed via carbon isotope signatures of algal fossils from eight fossil deposits across the Ediacaran-Cambrian transition (~553 to ~508 Ma). Results reveal an increase in pCO<sub>2</sub> (±1σ) from ~3-9 to ~9-21 PAL during ~553-529 Ma, followed by a progressive decline to ~5-17 PAL and ~3-8 PAL at ~517 Ma and ~508 Ma, respectively. These temporal pCO<sub>2</sub> changes coincide with shifts in marine strontium isotope values, which, together, are most consistent with tectonically driven changes in the carbon and strontium cycles, as supported by the results of Earth system biogeochemical box modelling. Tectonic modulation over a three-stage greenhouse-hypergreenhouse-greenhouse climate could have profoundly influenced marine environments in ways that impacted the early diversification of animals.