Isotopic composition of oceanic dissolved black carbon reveals non-riverine source
Isotopic composition of oceanic dissolved black carbon reveals non-riverine source
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DOI：
10.1038/s41467-019-13111-7
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发表时间：
2019-11-07
影响因子：
16.6
通讯作者：
Stubbins, Aron
中科院分区：
文献类型：
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作者：
Wagner, Sasha;Brandes, Jay;Stubbins, Aron
在陆地上燃烧过程中产生的一部分木炭和烟灰（例如，野火，燃烧化石燃料）进入水生系统的溶解黑碳（DBC）。就质量通量而言，河流是已确定的排入海洋的DBC的主要来源。由于DBC被认为是难降解碳库的代表，因此限制海洋DBC的来源是了解碳在全球海洋中长期存在的关键。在这里，我们使用特定化合物的稳定碳同位素（δ C-13）来揭示，与主要河流输出的DBC相比，海洋中的DBC类似于富含C-13的千分之六。这种同位素差异表明，大多数河流DBC在到达公海之前就被隔离和/或迅速降解。因此，我们认为，海洋DBC并不主要来自河流，而是可能来自另一个来源的同位素签名类似的海洋浮游植物。
A portion of the charcoal and soot produced during combustion processes on land (e.g., wildfire, burning of fossil fuels) enters aquatic systems as dissolved black carbon (DBC). In terms of mass flux, rivers are the main identified source of DBC to the oceans. Since DBC is believed to be representative of the refractory carbon pool, constraining sources of marine DBC is key to understanding the long-term persistence of carbon in our global oceans. Here, we use compound-specific stable carbon isotopes (delta C-13) to reveal that DBC in the oceans is similar to 6 parts per thousand enriched in C-13 compared to DBC exported by major rivers. This isotopic discrepancy indicates most riverine DBC is sequestered and/or rapidly degraded before it reaches the open ocean. Thus, we suggest that oceanic DBC does not predominantly originate from rivers and instead may be derived from another source with an isotopic signature similar to that of marine phytoplankton.