Enhanced phosphorus recycling during past oceanic anoxia amplified by low rates of apatite authigenesis.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 35776794.
- Also identified by DOI 10.1126/sciadv.abn2370 and PMC identifier 10883373.
- 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
Enhanced recycling of phosphorus as ocean deoxygenation expanded under past greenhouse climates contributed to widespread organic carbon burial and drawdown of atmospheric CO<sub>2</sub>. Redox-dependent phosphorus recycling was more efficient in such ancient anoxic marine environments, compared to modern anoxic settings, for reasons that remain unclear. Here, we show that low rates of apatite authigenesis in organic-rich sediments can explain the amplified phosphorus recycling in ancient settings as reflected in highly elevated ratios of organic carbon to total phosphorus. We argue that the low rates may be partly the result of the reduced saturation state of sediment porewaters with respect to apatite linked to ocean warming and acidification and/or a decreased availability of calcium carbonate, which acts as a template for apatite formation. Future changes in temperature and ocean biogeochemistry, induced by elevated atmospheric CO<sub>2</sub>, may similarly increase phosphorus availability and accelerate ocean deoxygenation and organic carbon burial.