Manganese Cycling in the Oceans
Manganese Cycling in the Oceans
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DOI：
10.1002/9781119300762.wsts0065
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发表时间：
2019-12
期刊：
影响因子：
--
通讯作者：
B. Tebo;G. Luther
中科院分区：
文献类型：
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作者：
B. Tebo;G. Luther
锰（Mn）是生命的必需元素。虽然它的浓度在整个海洋中处于（亚）纳摩尔水平，但它会影响海洋的氧浓度，因为它是光系统中心II中光合作用形成双氧（O2）的中心。Mn输入海洋的途径主要有大气颗粒物的迁移和溶解，以及河流、沉积物和热液喷口的溶解Mn通量。锰的主要去除机制是粉尘和有机质中的颗粒态锰向沉积物的迁移。锰的环境化学主要集中在+2、+3和+4氧化态。最近的数据表明，Mn（II）是溶解的，Mn（IV）是颗粒状MnO 2，Mn（III）在与有机络合物结合时可以是颗粒状或溶解的[表示为Mn（III）-L]。Mn（II）主要通过微生物过程氧化，而MnO 2通过非生物和生物过程还原。光化学处理有助于表面沃茨的氧化还原循环。在溶解氧浓度低于3 μ M的亚氧区，氧化和还原过程都可能发生，但通常发生在不同的深度。在亚氧区，溶解锰也从有机质中释放出来，在其分解和二氧化锰还原。
Manganese (Mn) is an essential element for life. Although its concentration is at (sub)nanomolar levels throughout the ocean, it affects the oxygen concentration of the ocean because it is central to the photosynthetic formation of dioxygen, O2, in photosystem center II. Mn inputs into the ocean are from atmospheric transport of particles and their dissolution to form dissolved Mn, and from the flux of dissolved Mn from rivers, sediments and hydrothermal vents. The main removal mechanism is transport of particulate Mn from dust and organic matter to the sediments. The environmental chemistry of manganese centers on its +2, +3 and +4 oxidation states. Most recent data show that Mn(II) is dissolved, that Mn(IV) is particulate MnO2, and that Mn(III) can be particulate or dissolved when bound to organic complexes [denoted as Mn(III)-L]. Mn(II) is oxidized primarily by microbial processes whereas MnO2 is reduced by abiotic and biotic processes. Photochemical processing aids redox cycling in surface waters. In suboxic zones, which are defined as areas with dissolved O2 concentrations below 3 M, both oxidation and reduction processes can occur but usually at different depths. In suboxic zones, dissolved Mn is also released from organic matter during its decomposition and from MnO2 reduction.