GEOMAR Helmholtz Centre for Ocean Research Kiel, 24148, Kiel, Germany.
GFZ German Research Centre for Geosciences, Section Earth Surface Geochemistry, Telegrafenberg, 14473, Potsdam, Germany.
Nat Commun. 2023 Mar 25;14(1):1676. doi: 10.1038/s41467-023-37186-5.
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 (δSi). Pore fluids following the rainfall show elevated Ge/Si ratios (2.87 µmol mol) and δSi 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 CO-cycling on short timescales of weeks to months, and thus element turnover on human time scales.
海洋硅酸盐的蚀变在全球碳和阳离子循环中起着关键作用，尽管人们对这一过程响应极端天气事件的时间尺度还了解甚少。在这里，我们利用 Ge/Si 比值和激光烧蚀固体及孔隙流体硅同位素（δSi），研究了秘鲁大陆架边缘极端降雨和径流（沿海厄尔尼诺现象）前后的表层沉积物。降雨后的孔隙流体表现出较高的 Ge/Si 比值（2.87 µmol/mol）和 δSi 值（3.72‰），我们认为这与陆源径流带来的反应性陆源矿物快速形成自生粘土有关。本研究强调了陆地侵蚀与相关海洋沉积过程的直接耦合。我们表明，海洋硅酸盐的蚀变可以对当地的天气条件迅速且高度活跃，这可能对海洋碱度和 CO 循环产生影响，其影响时间尺度为数周到数月，从而对人类时间尺度上的元素周转率产生影响。
