Biogenic manganese oxides as reservoirs of organic carbon and proteins in terrestrial and marine environments
Biogenic manganese oxides as reservoirs of organic carbon and proteins in terrestrial and marine environments
复制标题
DOI：
10.1111/gbi.12195
复制
发表时间：
2017-01-01
期刊：
影响因子：
3.7
通讯作者：
Hansel, C. M.
中科院分区：
文献类型：
--
作者：
Estes, E. R.;Andeer, P. F.;Hansel, C. M.
锰（Mn）氧化物参与与有机碳（OC）的一系列相互作用，可能导致碳降解或保存。在这里，我们研究了与生物和环境锰氧化物相关的OC的丰度和组成，以阐明锰氧化物作为碳库的作用及其对特定碳物种的选择性分区的潜力。与含有低1-2个数量级的OC的锰铁洞穴沉积物相比，在天然微咸水沃茨中以及由Mn（II）-氧化海洋细菌和陆地真菌沉淀的锰氧化物具有相当水平的有机碳（4.1-17.0 mol OC/kg矿物）。光谱分析表明，锰氧化物相关的OC从微生物培养物的化学组成是均匀的细菌锰氧化物托管主要蛋白质碳和真菌锰氧化物含有蛋白质和脂多糖样碳。细菌锰氧化物宿主蛋白质参与锰（II）氧化和金属结合这些细菌物种，并可能参与矿物成核过程以及。相比之下，与自然环境（半咸水沃茨，特别是洞穴铁锰岩石涂层）中形成的锰氧化物相关的OC组成在空间和化学上更加不均匀。洞穴锰氧化物相关的有机物质富含脂肪族C，这与较低的碳浓度一起，指向更广泛的微生物或矿物加工的碳在这个系统中相对于其他系统在这项研究中，并将在贫营养洞穴环境中预期。这项研究强调锰氧化物作为碳在不同环境中的水库。在生物和天然锰氧化物的蛋白质碳的存在，并在某些情况下占主导地位，可能有助于优先保存沉积物中的蛋白质和蛋白质依赖的代谢在地下生物圈的优势。
Manganese (Mn) oxides participate in a range of interactions with organic carbon (OC) that can lead to either carbon degradation or preservation. Here, we examine the abundance and composition of OC associated with biogenic and environmental Mn oxides to elucidate the role of Mn oxides as a reservoir for carbon and their potential for selective partitioning of particular carbon species. Mn oxides precipitated in natural brackish waters and by Mn(II)-oxidizing marine bacteria and terrestrial fungi harbor considerable levels of organic carbon (4.1-17.0 mol OC per kg mineral) compared to ferromanganese cave deposits which contain 1-2 orders of magnitude lower OC. Spectroscopic analyses indicate that the chemical composition of Mn oxide-associated OC from microbial cultures is homogeneous with bacterial Mn oxides hosting primarily proteinaceous carbon and fungal Mn oxides containing both protein-and lipopolysaccharide-like carbon. The bacterial Mn oxide-hosted proteins are involved in both Mn(II) oxidation and metal binding by these bacterial species and could be involved in the mineral nucleation process as well. By comparison, the composition of OC associated with Mn oxides formed in natural settings (brackish waters and particularly in cave ferromanganese rock coatings) is more spatially and chemically heterogeneous. Cave Mn oxide-associated organic material is enriched in aliphatic C, which together with the lower carbon concentrations, points to more extensive microbial or mineral processing of carbon in this system relative to the other systems examined in this study, and as would be expected in oligotrophic cave environments. This study highlights Mn oxides as a reservoir for carbon in varied environments. The presence and in some cases dominance of proteinaceous carbon within the biogenic and natural Mn oxides may contribute to preferential preservation of proteins in sediments and dominance of protein-dependent metabolisms in the subsurface biosphere.