The biogeochemistry of ferruginous lakes and past ferruginous oceans
The biogeochemistry of ferruginous lakes and past ferruginous oceans
复制标题
DOI：
10.1016/j.earscirev.2020.103430
复制
发表时间：
2020-12
影响因子：
12.1
通讯作者：
E. Swanner;N. Lambrecht;C. Wittkop;C. Harding;S. Katsev;J. Torgeson;S. Poulton
中科院分区：
文献类型：
--
作者：
E. Swanner;N. Lambrecht;C. Wittkop;C. Harding;S. Katsev;J. Torgeson;S. Poulton
在太古界大部分地区出现的低氧大气下，海洋中普遍存在缺氧和富铁(含铁)的条件。虽然在元古界，常氧条件(即缺氧和富含硫化氢的水域)变得更加常见，但在深水中，铁质条件仍然存在。含铁的海洋区域将是一个主要的生物圈和地球表面的储存库，元素作为其全球生物地球化学循环的一部分通过这些储存库。了解关键的生物事件，如大气中氧气的上升，甚至从含铁海洋到富氧或含氧条件的转变，需要了解含铁海洋中发生的生物地球化学过程，以及它们在岩石记录中的指示。在含铁和含氧或正辛酸条件之间转换的重要类似物是古含铁湖泊；它们的沉积物通常含有菱铁矿和钙碳酸盐，这是前寒武纪碳循环的重要记录。过去含铁的湖泊，或具有神秘铁循环的正辛湖，也可能有助于理解元古代浅海和中深海域铁质和正辛质条件之间的转换。现代含铁混生湖泊拥有各种厌氧微生物群落，越来越多地被用作古代含铁海洋的生物地球化学类似物。这样的湖泊被认为是罕见的，但地区和地质因素表明，它们可能比之前认为的更常见。尽管湖泊和海洋中的物理混合过程明显不同，但许多化学和生物过程是相似的。因此，含铁湖泊的大小、分层和水化学的多样性可以被用来探索一系列海洋系统中的生物地球化学控制：近岸、离岸、硅质盆地，或那些以陆地或热液元素来源为主的盆地。铁质系统，包括现存的和灭绝的，湖泊和海洋，拥有一系列生物地球化学过程，突出了铁在地球表面环境演变中的重要作用。
Anoxic and iron-rich (ferruginous) conditions prevailed in the ocean under the low-oxygen atmosphere that occurred through most of the Archean Eon. While euxinic conditions (i.e. anoxic and hydrogen sulfide-rich waters) became more common in the Proterozoic, ferruginous conditions persisted in deep waters. Ferruginous ocean regions would have been a major biosphere and Earth surface reservoir through which elements passed through as part of their global biogeochemical cycles. Understanding key biological events, such as the rise of oxygen in the atmosphere, or even the transitions from ferruginous to euxinic or oxic conditions, requires understanding the biogeochemical processes occurring within ferruginous oceans, and their indicators in the rock record. Important analogs for transitions between ferruginous and oxic or euxinic conditions are paleoferruginous lakes; their sediments commonly host siderite and Ca-carbonates, which are important Precambrian records of the carbon cycling. Lakes that were ferruginous in the past, or euxinic lakes with cryptic iron cycling may also help understand transitions between ferruginous and euxinic conditions in shallow and mid-depth oceanic waters during the Proterozoic. Modern ferruginous meromictic lakes, which host diverse anaerobic microbial communities, are increasingly utilized as biogeochemical analogues for ancient ferruginous oceans. Such lakes are believed to be rare, but regional and geological factors indicate they may be more common than previously thought. While physical mixing processes in lakes and oceans are notably different, many chemical and biological processes are similar. The diversity of sizes, stratifications, and water chemistries in ferruginous lakes thus can be leveraged to explore biogeochemical controls in a range of marine systems: near-shore, off-shore, silled basins, or those dominated by terrestrial or hydrothermal element sources. Ferruginous systems, both extant and extinct, lacustrine and marine, host a continuum of biogeochemical processes that highlight the important role of iron in the evolution of Earth’s surface environment.