2020年12月17日出版的《科学》杂志发表了美国加州大学圣塔芭芭拉分校M. R. Raven研究组的最新研究成果。他们的研究揭示了海洋沉积颗粒物中微生物硫酸盐的还原和有机硫的形成。

在本研究中，研究人员发现在东热带太平洋北部的缺氧区沉没颗粒内存在“神秘的”微生物硫酸盐还原，并且某些微生物产生的硫化物会迅速反应形成有机酸并可抵抗酸水解。发生在颗粒物中的硫化作用可以增强缺氧地带水下沉积物中碳的保留，并形成缺氧区扩张和大气CO2之间的稳定反馈。

类似的机制可能有助于解释在地球形成过程中，与海洋缺氧有关许多有机碳保存的极端情况。

据介绍，气候变化推动海洋缺氧地带的扩大，这可能会改变全球碳、硫、氮和微量金属循环。 但是，当前人们对缺氧如何影响有机碳循环和沉积的理解有限。

附：英文原文

Title: Microbial sulfate reduction and organic sulfur formation in sinking marine particles

Author: M. R. Raven, R. G. Keil, S. M. Webb

Issue&Volume: 2020/12/17

Abstract: Climate change is driving an expansion of marine Oxygen Deficient Zones, which may alter the global cycles of carbon, sulfur, nitrogen, and trace metals. Currently, however, we lack a full mechanistic understanding of how oxygen deficiency affects organic carbon cycling and burial. Here, we show that ‘cryptic’ microbial sulfate reduction occurs within sinking particles from the Eastern Tropical North Pacific Oxygen Deficient Zone, and that some microbially-produced sulfide reacts rapidly to form organic S that is resistant to acid hydrolysis. Particle-hosted sulfurization could enhance carbon preservation in sediments underlying O2-deficient water columns and serve as a stabilizing feedback between expanding anoxic zones and atmospheric CO2. A similar mechanism may help explain more extreme instances of organic carbon preservation associated with marine anoxia in Earth history.

DOI: 10.1126/science.abc6035

Source: https://science.sciencemag.org/content/early/2020/12/16/science.abc6035