Institute of Earth Sciences , Heidelberg University , Im Neuenheimer Feld 236 , D-69120 Heidelberg , Germany.
Department of Biosciences , Swansea University , Swansea SA2 8PP , U.K.
Environ Sci Technol. 2020 Feb 4;54(3):1451-1463. doi: 10.1021/acs.est.9b03182. Epub 2020 Jan 22.
The discovery of methane (CH) accumulation in oxic marine and limnic waters has redefined the role of aquatic environments in the regional CH cycle. Although CH accumulation in oxic surface waters became apparent in recent years, the sources are still subject to controversial discussions. We present high-resolution in situ measurements of CH concentration and its stable isotope composition in a stratified mesotrophic lake. We show that CH accumulation in surface waters originates from a highly dynamic interplay between (oxic) CH production and emission to the atmosphere. Laboratory incubations of different phytoplankton types and application of stable isotope techniques provide a first unambiguous evidence that major phytoplankton classes in Lake Stechlin per se produce CH under oxic conditions. Combined field and lab results show that the photoautotroph community is an important driver for CH production and its highly dynamic accumulation in oxic surface waters.
在有氧海洋和淡水环境中发现甲烷 (CH) 积累，重新定义了水生环境在区域 CH 循环中的作用。尽管近年来有氧地表水的 CH 积累变得明显，但来源仍存在争议。我们在一个分层的中营养湖中进行了 CH 浓度及其稳定同位素组成的高分辨率原位测量。结果表明，地表水的 CH 积累源于（有氧）CH 产生和向大气排放之间高度动态的相互作用。不同浮游植物类型的实验室培养和稳定同位素技术的应用提供了第一个明确的证据，表明施泰因湖中的主要浮游植物类群本身在有氧条件下会产生 CH。结合现场和实验室的结果表明，自养生物群落是 CH 产生及其在有氧地表水高度动态积累的重要驱动因素。
