Revisiting the dissolution of biogenic Si in marine sediments: a key term in the ocean Si budget

• 作者: Patrick Frings
• 来源期刊: 地球化学学报(英文）
• 关键词: Biogenic silica Diatoms Ocean Si cycle Dissolution
• 年，卷（期）: 2017,（3）
• 页码范围: 429-432
• 页数: 3页
• 语种: 英文
• DOI: 10.1007/s11631-017-0183-1

摘要

Of the ~ 240×1012 mol year-1 of biogenic silica (bSi) produced by diatoms and other silicifying organisms, only roughly 3%-4% escapes dissolution to be permanently buried. At the global scale, how, where and why bSi is preserved in sediment is not well understood. To help address this, I compile 6245 porewater dissolved Si concentrations from 453 sediment cores, to derive the concentration gradient at the sediment-water interface and thus diffusive fluxes out of the sediment. These range from <0.002 to 3.4 mol m-2 year-1, and are independent of temperature, depth and latitude. When classified by sediment lithology, predominantly siliceous sediments unsurprisingly have higher mean diffusive fluxes than predominantly calcareous or clay-rich sediment. Combined with the areal extent of these lithologies, the'best-guess'global sedimentary bSi recycling flux is 69×1012 mol year-1.