Survival of cyanobacteria and mitigation of Fe(II) toxicity effects in a silica-rich Archean ocean.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41723153.
- Also identified by DOI 10.1038/s41467-026-69826-x and PMC identifier 12932812.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Banded iron formations (BIF) were deposited abundantly between 2.7-2.4 Ga from iron- and silica-rich oceans, with cyanobacterial oxygen (O<sub>2</sub>) as a possible oxidant for Fe(II)<sub>(aq)</sub> oxidation and Fe(III) oxyhydroxide precipitation. However, toxic reactive oxygen species (ROS) from Fe(II)/O<sub>2</sub> interactions might have inhibited cyanobacterial growth, contributing to the delay between cyanobacterial evolution (>3.0 Ga) and the Great Oxidation Event (2.5 Ga). Here, we explored the impact of Fe(II)<sub>(aq)</sub> and SiO<sub>2(aq)</sub> on Synechococcus sp. PCC 7002. High Fe(II)<sub>(aq)</sub> ( > 500 µM) increased ROS formation, but elevated SiO<sub>2(aq)</sub> (2200 µM) suppressed ROS formation, promoting growth and O<sub>2</sub> production. Diel light cycles further reduced ROS formation compared to continuous illumination. Modelling O<sub>2</sub> distribution based on experimental rates revealed oxygenated surface waters at relevant upwelling rates. Together, our results indicate that high SiO<sub>2(aq)</sub> and day-night-light cycles in Archean oceans mitigated ROS stress, enabling cyanobacterial proliferation and enhancing their role in Earth's oxygenation and BIF deposition.
Medical subject headings
- Silicon Dioxide
- Synechococcus
- Seawater
- Ferrous Compounds
- Cyanobacteria
- Iron