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Photosynthesis‐driven methane production in oxic lake water as an important contributor to methane emission
Author(s) -
Günthel Marco,
Klawonn Isabell,
Woodhouse Jason,
Bižić Mina,
Ionescu Danny,
Ganzert Lars,
Kümmel Steffen,
Nijenhuis Ivonne,
Zoccarato Luca,
Grossart HansPeter,
Tang Kam W.
Publication year - 2020
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.1002/lno.11557
Subject(s) - environmental chemistry , algae , methane , photosynthesis , environmental science , anoxic waters , phytoplankton , bicarbonate , water column , phosphorus , cyanobacteria , chemistry , nutrient , oceanography , ecology , biology , geology , biochemistry , organic chemistry , genetics , bacteria
Recent discovery of methane (CH 4 ) production in oxic waters challenges the conventional understanding of strict anoxic requirement for biological CH 4 production. High‐resolution field measurements in Lake Stechlin, as well as incubation experiments, suggested that oxic‐water CH 4 production occurred throughout much of the water column and was associated with phytoplankton especially diatoms, cyanobacteria, green algae, and cryptophytes. In situ concentrations and δ 13 C values of CH 4 in oxic water were negatively correlated with soluble reactive phosphorus concentrations. Using 13 C‐labeling techniques, we showed that bicarbonate was converted to CH 4 , and the production exceeded oxidation at day, but was comparable at night. These experimental data, along with complementary field observations, indicate a clear link between photosynthesis and the CH 4 production‐consumption balance in phosphorus‐limited epilimnic waters. Comparison between surface CH 4 emission data and experimental CH 4 production rates suggested that the oxic CH 4 source significantly contributed to surface emission in Lake Stechlin. These findings call for re‐examination of the aquatic CH 4 cycle and climate predictions.