Global Ocean Sediment Composition and Burial Flux in the Deep Sea
Global Ocean Sediment Composition and Burial Flux in the Deep Sea
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DOI：
10.1029/2020gb006769
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发表时间：
2021-04-01
影响因子：
5.2
通讯作者：
Zhang, Jing
中科院分区：
文献类型：
--
作者：
Hayes, Christopher T.;Costa, Kassandra M.;Zhang, Jing
关于海底沉积成分埋藏的定量知识对海洋科学（从全球气候到大陆风化）具有广泛的影响。 Th-230 归一化通量的使用减少了许多先前研究所面临的不确定性，因为它考虑了底部水流沉积物重新分布的影响，并最大限度地减少了年龄模型不确定性的影响。在这里，我们采用最近编译的 Th-230 归一化通量全球数据集以及更新的海底表面沉积物成分数据库来导出碳酸钙、生物蛋白石、总有机碳 (TOC)、非生物物质、铁、汞和过量钡 (Ba-xs) 的深海埋藏通量图集。主要成分埋藏的空间模式主要与之前的工作一致，但新的定量估计允许对深海预算进行评估。我们的综合深海埋藏通量为 136 Tg C/年 CaCO3、153 Tg Si/年蛋白石、20Tg C/年 TOC、220 Mg Hg/年和 2.6 Tg Ba-xs/年。这种蛋白石通量大约比之前的估计增加了 2 倍，对全球硅循环具有重要影响。沉积铁通量反映了多种来源，包括成岩物质、热液输入和自生相。一些常用的古生产力指标（TOC、生物蛋白石和 Ba-xs）的通量在地理上与基于卫星的生产力估计值没有很好的相关性。我们新的沉积通量汇编提供了详细的区域和全球信息，这将有助于加深对沉积物保存的理解。
Quantitative knowledge about the burial of sedimentary components at the seafloor has wide-ranging implications in ocean science, from global climate to continental weathering. The use of Th-230-normalized fluxes reduces uncertainties that many prior studies faced by accounting for the effects of sediment redistribution by bottom currents and minimizing the impact of age model uncertainty. Here we employ a recently compiled global data set of Th-230-normalized fluxes with an updated database of seafloor surface sediment composition to derive atlases of the deep-sea burial flux of calcium carbonate, biogenic opal, total organic carbon (TOC), nonbiogenic material, iron, mercury, and excess barium (Ba-xs). The spatial patterns of major component burial are mainly consistent with prior work, but the new quantitative estimates allow evaluations of deep-sea budgets. Our integrated deep-sea burial fluxes are 136 Tg C/yr CaCO3, 153 Tg Si/yr opal, 20Tg C/yr TOC, 220 Mg Hg/yr, and 2.6 Tg Ba-xs/yr. This opal flux is roughly a factor of 2 increase over previous estimates, with important implications for the global Si cycle. Sedimentary Fe fluxes reflect a mixture of sources including lithogenic material, hydrothermal inputs and authigenic phases. The fluxes of some commonly used paleo-productivity proxies (TOC, biogenic opal, and Ba-xs) are not well-correlated geographically with satellite-based productivity estimates. Our new compilation of sedimentary fluxes provides detailed regional and global information, which will help refine the understanding of sediment preservation.