Bringing methanotrophy in rivers out of the shadows
Bringing methanotrophy in rivers out of the shadows
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DOI：
10.1002/lno.10569
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发表时间：
2017-11
影响因子：
4.5
通讯作者：
Felicity C Shelley;Nicola L. Ings;A. Hildrew;M. Trimmer;J. Grey
中科院分区：
文献类型：
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作者：
Felicity C Shelley;Nicola L. Ings;A. Hildrew;M. Trimmer;J. Grey
甲烷氧化产生的生物质是消费者颗粒碳的潜在来源，并且是光合生产的补充。我们评估了甲烷营养和光合生产在不同条件下的光和甲烷浓度。我们测量了甲烷氧化和光合作用的砾石沉积物从邻近的阴影和无阴影的延伸15白垩河在英格兰南部，也在30个人工渠道中，我们操纵光和甲烷实验。甲烷氧化的能力是78%以上的阴影比unshaded地区，表明密度更大，或更活跃，甲烷营养组合的阴影河床，差异是最明显的甲烷浓度高时。在15条河流中，甲烷氧化生产量范围为16至650 nmol C cm−2 d−1，净光合生产量范围为256至35，750 nmol C cm−2 d−1。甲烷营养对它们的总产量的相对重要性（即，光合作用和甲烷营养）随甲烷浓度的增加而增加，在无阴影和阴影区域分别为0.1-2.4%和0.2-13%。在一条河流的年周期中，甲烷氧化菌在阴凉处对夏季高甲烷浓度的反应是开放的2.5倍;在冬季，对甲烷氧化没有影响。甲烷营养对人工渠道中的遮荫和甲烷浓度的响应与河流中的相似。甲烷氧化对这些溪流中颗粒碳的产生做出了不可忽视的贡献（这里高达13%），在阴影中不成比例地更大，并构成了可用于其食物网的独特碳途径。
Methane oxidation produces biomass that is a potential source of particulate carbon for consumers, and is in addition to photosynthetic production. We assessed methanotrophy and photosynthetic production under differing conditions of light and methane concentration. We measured methane oxidation and photosynthesis in gravel sediments from adjacent shaded and unshaded stretches of 15 chalk rivers in southern England, and also in 30 artificial channels in which we manipulated light and methane experimentally. The capacity for methane oxidation was 78% higher in the shade than unshaded areas, indicating a denser, or more active, methanotrophic assemblage on shaded riverbeds, and the difference was most pronounced when methane concentration was high. Across the 15 rivers, methanotrophic production ranged from 16 to 650 nmol C cm−2 d−1 and net photosynthetic production from 256 to 35,750 nmol C cm−2 d−1. The relative importance of methanotrophy to their total production (i.e., photosynthetic and methanotrophic) increased with methane concentration and ranged from 0.1–2.4% and 0.2–13% in unshaded and shaded areas, respectively. Over an annual cycle in one river, the response of the methanotrophs in the shade to a high summer methane concentration was ∼ five times greater than in the open; in winter, there was no effect of shading on methane oxidation. The response of methanotrophy to shading and methane concentration in the artificial channels resembled that found in the rivers. Methanotrophy makes a non‐negligible (here up to ∼ 13%) contribution to particulate carbon production in these streams, is disproportionately greater in the shade, and constitutes a distinct carbon pathway available for their food webs.