Fine-scale variability in methanol uptake and oxidation: from the microlayer to 1000 m
Fine-scale variability in methanol uptake and oxidation: from the microlayer to 1000 m
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DOI：
10.5194/bg-9-2961-2012
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发表时间：
2012-01-01
期刊：
影响因子：
4.9
通讯作者：
Nightingale, P. D.
中科院分区：
文献类型：
--
作者：
Dixon, J. L.;Nightingale, P. D.
这项研究的目的是使第一个深度剖面的微生物同化的甲醇碳及其氧化为二氧化碳和使用作为能源从微层到1000米。在微层和紧邻的下沃茨（10厘米深）中偶尔会发现一些报告的最高甲醇氧化速率常数（0.5-0.6 d（-1）），尽管与深度达1000米的其他深度相比，这些样品也表现出最大的异质性。在微层样品中，甲醇吸收到颗粒相中的比例非常低，这表明在这种环境中微生物利用的任何甲醇都是用于产生能量的。海洋表面微层和10厘米深度也表现出较高比例的细菌与低DNA含量，和细菌亮氨酸吸收率在表面微层样品小于或等于那些在下面的10厘米层。然而，在整个取样深度，平均甲醇氧化率和微粒率在统计上是相同的，尽管后者在近地表0.25-2米处与更深处相比变化很大。在甲醇摄取到颗粒中和细菌亮氨酸掺入之间显示的统计学显著关系表明，许多异养细菌可以使用甲醇碳进行细胞生长。平均而言，甲醇细菌生长效率（BGE（m））在顶部25米的水柱是6%，并随深度下降。虽然，对于微层和10厘米深的样品，BGE（m）小于近表面25-217厘米，可能反映了环境紫外线压力的增加，导致维护成本增加，即生存所需的能量。我们的结论是，微生物的甲醇吸收率，即从海水中的损失，是高度可变的，特别是接近海水表面，这可能会显着影响海水浓度，因此，海气通量。
The aim of this research was to make the first depth profiles of the microbial assimilation of methanol carbon and its oxidation to carbon dioxide and use as an energy source from the microlayer to 1000 m. Some of the highest reported methanol oxidation rate constants of 0.5-0.6 d(-1) were occasionally found in the microlayer and immediately underlying waters (10 cm depth), albeit these samples also showed the greatest heterogeneity compared to other depths down to 1000 m. Methanol uptake into the particulate phase was exceptionally low in microlayer samples, suggesting that any methanol utilised by microbes in this environment is for energy generation. The sea surface microlayer and 10 cm depth also showed a higher proportion of bacteria with a low DNA content, and bacterial leucine uptake rates in surface microlayer samples were either less than or the same as those in the underlying 10 cm layer. The average methanol oxidation and particulate rates were however statistically the same throughout the depths sampled, although the latter were highly variable in the near-surface 0.25-2 m compared to deeper depths. The statistically significant relationship demonstrated between uptake of methanol into particles and bacterial leucine incorporation suggests that many heterotrophic bacteria could be using methanol carbon for cellular growth. On average, methanol bacterial growth efficiency (BGE(m)) in the top 25 m of the water column is 6% and decreases with depth. Although, for microlayer and 10 cm-depth samples, BGE(m) is less than the near-surface 25-217 cm, possibly reflecting increased environmental UV stress resulting in increased maintenance costs, i.e. energy required for survival. We conclude that microbial methanol uptake rates, i.e. loss from seawater, are highly variable, particularly close to the seawater surface, which could significantly impact upon seawater concentrations and hence the air-sea flux.