Methane production by three widespread marine phytoplankton species: release rates, precursor compounds, and potential relevance for the environment
Methane production by three widespread marine phytoplankton species: release rates, precursor compounds, and potential relevance for the environment
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DOI：
10.5194/bg-16-4129-2019
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发表时间：
2019-10-28
期刊：
影响因子：
4.9
通讯作者：
Keppler, Frank
中科院分区：
文献类型：
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作者：
Klintzsch, Thomas;Langer, Gerald;Keppler, Frank
海洋混合层中甲烷（CH 4）的产生是一种普遍现象，但其机制仍存在争议。海洋藻类可能是导致好氧沃茨中甲烷过饱和的原因之一，但迄今为止，海洋藻类产生甲烷的直接证据仅限于球石藻Emiliania huxleyi。huxleyi，其他广泛分布的附着菌，即，球形棕囊藻和Chrysochromulina属。我们进行了CH 4生产和稳定碳同位素测量，并提供明确的证据表明，所有三个调查的海洋藻类参与生产的CH 4在好氧条件下。速率范围为1.9 +/- 0.6至3.1 +/- 0.4 μ g CH 4/g POC（颗粒有机碳）/天，Chrysochromulina sp.和E. huxleyi分别显示了最低和最高的比率。细胞CH 4产生速率范围从16.8 +/- 6.5（球形毕赤酵母）到62.3 +/- 6.4 ag CH 4细胞（-1）d（-1）（E. huxleyi; ag D 10（-18）g）。在用C-13标记的碳酸氢盐处理的培养物中，δ（CH 4）-C-13值随孵育时间增加，这是由于C-13-碳酸氢盐转化为（CH 4）-C-13。添加C-13标记的二甲硫醚，二甲亚砜和甲硫氨酸亚砜-已知的藻类代谢物，是普遍存在于海洋表层-导致C-13富集的甲烷在培养的E。huxleyi，清楚地表明甲基化硫化合物也是CH 4的前体。通过比较藻类甲烷生产率从我们的实验室实验与以前报道的结果在两个领域的研究，太平洋和波罗的海，我们可能会得出结论，藻类介导的甲烷释放是促进甲烷过饱和在好氧沃茨。因此，我们建议，附着植物介导的甲烷生产可能是一个共同的和重要的过程，在海洋表面沃茨。
Methane (CH4) production within the oceanic mixed layer is a widespread phenomenon, but the underlying mechanisms are still under debate. Marine algae might contribute to the observed CH4 oversaturation in oxic waters, but so far direct evidence for CH4 production by marine algae has only been provided for the coccolithophore Emiliania huxleyi.In the present study we investigated, next to E. huxleyi, other widespread haptophytes, i.e., Phaeocystis globosa and Chrysochromulina sp. We performed CH4 production and stable carbon isotope measurements and provide unambiguous evidence that all three investigated marine algae are involved in the production of CH4 under oxic conditions. Rates ranged from 1.9 +/- 0.6 to 3.1 +/- 0.4 mu g of CH4 per gram of POC (particulate organic carbon) per day, with Chrysochromulina sp. and E. huxleyi showing the lowest and highest rates, respectively. Cellular CH4 production rates ranged from 16.8 +/- 6.5 (P. globosa) to 62.3 +/- 6.4 ag CH4 cell(-1) d(-1) (E. huxleyi; ag D 10(-18) g). In cultures that were treated with C-13-labeled hydrogen carbonate, delta(CH4)-C-13 values increased with incubation time, resulting from the conversion of C-13-hydrogen carbonate to (CH4)-C-13. The addition of C-13-labeled dimethyl sulfide, dimethyl sulfoxide, and methionine sulfoxide - known algal metabolites that are ubiquitous in marine surface layers - resulted in the occurrence of C-13-enriched CH4 in cultures of E. huxleyi, clearly indicating that methylated sulfur compounds are also precursors of CH4. By comparing the algal CH4 production rates from our laboratory experiments with results previously reported in two field studies of the Pacific Ocean and the Baltic Sea, we might conclude that algae-mediated CH4 release is contributing to CH4 oversaturation in oxic waters. Therefore, we propose that haptophyte mediated CH4 production could be a common and important process in marine surface waters.