Methane excess production in oxygen-rich polar water and a model of cellular conditions for this paradox
Methane excess production in oxygen-rich polar water and a model of cellular conditions for this paradox
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DOI：
10.1016/j.polar.2015.05.001
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发表时间：
2015-09-01
期刊：
影响因子：
1.8
通讯作者：
Kattner, G.
中科院分区：
文献类型：
--
作者：
Damm, E.;Thoms, S.;Kattner, G.
北冰洋夏季海冰覆盖面积在过去十年中有所减少，使海面暴露在无法预见的环境变化之下。融化的海冰增加了水的分层，并导致营养限制，这也是众所周知的在含氧地表水甲烷的形成中发挥关键作用。我们报告的过量甲烷在边缘冰区在西部弗拉姆海峡。我们的研究是基于测量的氧气，甲烷，DMSP，硝酸盐和磷酸盐的浓度，以及浮游植物的组成和光传输，进行沿着79度N的海洋样带，在西部的弗拉姆海峡和东北水Polynya地区格陵兰岛。在大西洋水从南部进入的弗拉姆海峡东部和极地水从北部进入的弗拉姆海峡西部之间，发生了不同的营养限制，因此建立了不同的水华条件。持续的海冰融化增强了两个水团之间的环境差异，并启动再生生产在西部弗拉姆海峡。我们表明，在这个地区甲烷是在原位产生的，而DMSP（二甲基磺基丙酸酯）从海冰释放可能作为甲烷形成的前体。尽管在这个水团中氧气浓度很高，甲烷的产生还是发生了。由于单细胞生物的代谢活动（呼吸）解释了细胞环境中厌氧条件的存在，我们提出了一个理论模型，该模型解释了细菌细胞内甲烷形成的厌氧条件的维持，尽管环境中的氧浓度增加。(C)2015 Elsevier B.V.和NIPR。All rights reserved.
Summer sea ice cover in the Arctic Ocean has undergone a reduction in the last decade exposing the sea surface to unforeseen environmental changes. Melting sea ice increases water stratification and induces nutrient limitation, which is also known to play a crucial role in methane formation in oxygenated surface water. We report on an excess of methane in the marginal ice zone in the western Fram Strait. Our study is based on measurements of oxygen, methane, DMSP, nitrate and phosphate concentrations as well as on phytoplankton composition and light transmission, conducted along the 79 degrees N oceanographic transect, in the western part of the Fram Strait and in Northeast Water Polynya region off Greenland. Between the eastern Fram Strait, where Atlantic water enters from the south and the western Fram Strait, where Polar water enters from the north, different nutrient limitations occurred and consequently different bloom conditions were established. Ongoing sea ice melting enhances the environmental differences between both water masses and initiates regenerated production in the western Fram Strait. We show that in this region methane is in situ produced while DMSP (dimethylsulfoniopropionate) released from sea ice may serve as a precursor for the methane formation. The methane production occured despite high oxygen concentrations in this water masses. As the metabolic activity (respiration) of unicellular organisms explains the presence of anaerobic conditions in the cellular environment we present a theoretical model which explains the maintenance of anaerobic conditions for methane formation inside bacterial cells, despite enhanced oxygen concentrations in the environment. (C) 2015 Elsevier B.V. and NIPR. All rights reserved.