Transient fertilization of a post-Sturtian Snowball ocean margin with dissolved phosphate by clay minerals

Ernest Chi Fru (1) , Jalila Al Bahri , Christophe Brosson , Olabode Bankole (2) , Jérémie Aubineau (3) , Abderrazzak El Albani (2) , Alexandra Nederbragt , Anthony Oldroyd , Alasdair Skelton , Linda Lowhagen , David Webster , Wilson Fantong , Benjamin Mills , Lewis Alcott (4) , Kurt Konhauser (5) , Timothy Lyons (6)

1 School of Earth, Ocean and Planetary Sciences [Cardiff]
2 IC2MP [Poitiers] - Institut de chimie des milieux et matériaux de Poitiers [UMR 7285]
3 Géosciences Montpellier
4 Yale University [New Haven]
5 University of Alberta
6 UC Riverside - University of California [Riverside]

Abstract Marine sedimentary rocks deposited across the Neoproterozoic Cryogenian Snowball interval, ~720-635 million years ago, suggest that post-Snowball fertilization of shallow continental margin seawater with phosphorus accelerated marine primary productivity, ocean-atmosphere oxygenation, and ultimately the rise of animals. However, the mechanisms that sourced and delivered bioavailable phosphate from land to the ocean are not fully understood. Here we demonstrate a causal relationship between clay mineral production by the melting Sturtian Snowball ice sheets and a short-lived increase in seawater phosphate bioavailability by at least 20-fold and oxygenation of an immediate post-Sturtian Snowball ocean margin. Bulk primary sediment inputs and inferred dissolved seawater phosphate dynamics point to a relatively low marine phosphate inventory that limited marine primary productivity and seawater oxygenation before the Sturtian glaciation, and again in the later stages of the succeeding interglacial greenhouse interval.

Domaines: Sciences de la Terre

Ernest Chi Fru, Jalila Al Bahri, Christophe Brosson, Olabode Bankole, Jérémie Aubineau, et al.. Transient fertilization of a post-Sturtian Snowball ocean margin with dissolved phosphate by clay minerals. Nature Communications, 2023, 14 (1), pp.8418. ⟨10.1038/s41467-023-44240-9⟩. ⟨hal-04520815⟩