Rapid, oxygen-dependent microbial Mn(II) oxidation kinetics at sub-micromolar oxygen concentrations in the Black Sea suboxic zone
Rapid, oxygen-dependent microbial Mn(II) oxidation kinetics at sub-micromolar oxygen concentrations in the Black Sea suboxic zone
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DOI：
10.1016/j.gca.2008.12.023
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发表时间：
2009-04-01
影响因子：
5
通讯作者：
Tebo, Bradley M.
中科院分区：
文献类型：
--
作者：
Clement, Brian G.;Luther, George W., III;Tebo, Bradley M.
微生物锰（II）氧化动力学响应氧浓度进行了评估，在整个黑海的六个站点在亚氧区水。Mn（II）的氧化速率随着氧浓度的增加而逐渐增加，与Michaelis-Menten酶动力学一致。环境半饱和常数，K-E，Mn（II）去除（氧化）变化从0.30至10.5 μ M溶解氧，而最大的环境速率，VE-最大，范围从4至50 nM h（-1）。这些参数变化的空间和时间，在黑海催化锰氧化物生产的酶的多样性人口相一致。受影响的网站产生较低的K-E和较高的VE-最大常数相对于西部和东部环流网站。在博斯普鲁斯海峡地区，Mn（II）的停留时间计算使用我们的K-E和VE-最大值与0.1 μ M的氧气是4天，25倍，比以前的估计。我们的研究结果（i）表明，在黑海的低氧区，Mn（II）快速氧化为固相Mn氧化物是由远低于目前海洋学方法可靠检测到的3-5 μ M浓度的氧浓度刺激的，（ii）表明存在多种多样的Mn（II）氧化酶，（iii）与之前计算的Mn（II）在低氧区中的停留时间相一致，以及（iv）进一步怀疑存在将固相Mn氧化物生产与除氧之外的电子受体偶联的所提出的反应。(c)2009爱思唯尔有限公司版权所有。
Microbial Mn(II) oxidation kinetics in response to oxygen concentration were assessed in suboxic zone water at six sites throughout the Black Sea. Mn(II) oxidation rates increased asymptotically with increasing oxygen concentration, consistent with Michaelis-Menten enzyme kinetics. The environmental half-saturation constant, K-E, of Mn(II) removal (oxidation) varied from 0.30 to 10.5 mu M dissolved oxygen while the maximal environmental rate, VE-max, ranged from 4 to 50 nM h(-1). These parameters varied spatially and temporally, consistent with a diverse population of enzymes catalyzing Mn oxide production in the Black Sea. Coastally-influenced sites produced lower K-E and higher VE-max constants relative to the Western and Eastern Gyre sites. In the Bosporus Region, the Mn(II) residence time calculated using our K-E and VE-max values with 0.1 mu M oxygen was 4 days, 25-fold less than previous estimates. Our results (i) indicate that rapid Mn(II) oxidation to solid phase Mn oxides in the Black Sea's suboxic zone is stimulated by oxygen concentrations well below the 3-5 mu M concentration reliably detected by current oceanographic methods, (ii) suggest the existence of multiple, diverse Mn(II)-oxidizing enzymes, (iii) are consistent with shorter residence times than previously calculated for Mn(II) in the suboxic zone and (iv) cast further doubt on the existence of proposed reactions coupling solid phase Mn oxide production to electron acceptors other than oxygen. (c) 2009 Elsevier Ltd. All rights reserved.