Coastal El Niño triggers rapid marine silicate alteration on the seafloor

Sonja Geilert; Daniel A Frick; Dieter Garbe-Schönberg; Florian Scholz; Stefan Sommer; Patricia Grasse; Christoph Vogt; Andrew W Dale

doi:10.1038/s41467-023-37186-5

Coastal El Niño triggers rapid marine silicate alteration on the seafloor

Nat Commun. 2023 Mar 25;14(1):1676. doi: 10.1038/s41467-023-37186-5.

Authors

Sonja Geilert¹, Daniel A Frick², Dieter Garbe-Schönberg^{3

4}, Florian Scholz⁵, Stefan Sommer⁵, Patricia Grasse^{5

6}, Christoph Vogt⁷, Andrew W Dale⁵

Affiliations

¹ GEOMAR Helmholtz Centre for Ocean Research Kiel, 24148, Kiel, Germany. sgeilert@geomar.de.
² GFZ German Research Centre for Geosciences, Section Earth Surface Geochemistry, Telegrafenberg, 14473, Potsdam, Germany.
³ Institute of Geosciences, University of Kiel, 24118, Kiel, Germany.
⁴ Department of Physics and Earth Sciences, Jacobs University Bremen, 28759, Bremen, Germany.
⁵ GEOMAR Helmholtz Centre for Ocean Research Kiel, 24148, Kiel, Germany.
⁶ German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, 04103, Leipzig, Germany.
⁷ Faculty of Geosciences/Crystallography and Geomaterials & MARUM, University of Bremen, 28359, Bremen, Germany.

Abstract

Marine silicate alteration plays a key role in the global carbon and cation cycles, although the timeframe of this process in response to extreme weather events is poorly understood. Here we investigate surface sediments across the Peruvian margin before and after extreme rainfall and runoff (coastal El Niño) using Ge/Si ratios and laser-ablated solid and pore fluid Si isotopes (δ³⁰Si). Pore fluids following the rainfall show elevated Ge/Si ratios (2.87 µmol mol^-1) and δ³⁰Si values (3.72‰), which we relate to rapid authigenic clay formation from reactive terrigenous minerals delivered by continental runoff. This study highlights the direct coupling of terrestrial erosion and associated marine sedimentary processes. We show that marine silicate alteration can be rapid and highly dynamic in response to local weather conditions, with a potential impact on marine alkalinity and CO₂-cycling on short timescales of weeks to months, and thus element turnover on human time scales.