Long-chain diols and BIT index in surface sediments and cores GeoB7702-3 and 64PE304-80

The study of past sedimentary records from coastal margins allows us to reconstruct variations in terrestrial input into the marine realm and to gain insight into continental climatic variability. There are numerous organic proxies for tracing terrestrial input into marine environments but none that strictly reflect the input of river-produced organic matter. Here, we test the fractional abundance of the C32 alkane 1,15-diol relative to all 1,13- and 1,15-long-chain diols (FC32 1, 15) as a tracer of input of river-produced organic matter in the marine realm in surface and Quaternary (0-45 ka) sediments on the shelf off the Zambezi and nearby smaller rivers in the Mozambique Channel (western Indian Ocean). A Quaternary (0-22 ka) sediment record off the Nile River mouth in the eastern Mediterranean was also studied for long-chain diols. For the Mozambique Channel, surface sediments of sites most proximal to Mozambique rivers showed the highest F1, 15 - C32 (up to 10 k%). […]

研究沿海边缘过去的沉积记录，使我们能够重构陆地输入到海洋领域的变化，并洞察大陆气候的变异性。在追踪陆地输入到海洋环境方面，存在众多有机替代指标，但没有任何一种能够严格反映河流产生的有机物质的输入。在本研究中，我们以C32烷烃1,15-二醇相对于所有1,13-和1,15长链二醇的丰度分数（FC32 1, 15）为指标，测试其在海洋领域表面和第四纪（0-45千年前）沉积物中作为河流产生有机物质输入的示踪剂。对于莫桑比克海峡，研究还包括了东地中海尼罗河河口第四纪（0-22千年前）沉积记录中的长链二醇。在莫桑比克海峡，靠近莫桑比克河流的地点的表面沉积物显示了最高的F1,15-C32（高达10千%）含量。