Constraints on methane oxidation in ice-covered boreal lakes. Denfeld, B. A., Ricão Canelhas, M., Weyhenmeyer, G. A., Bertilsson, S., Eiler, A., & Bastviken, D. Journal of Geophysical Research: Biogeosciences, 121(7):2016JG003382, July, 2016.
Constraints on methane oxidation in ice-covered boreal lakes [link]Paper  doi  abstract   bibtex   
Boreal lakes can be ice covered for a substantial portion of the year at which time methane (CH4) can accumulate below ice. The amount of CH4 emitted at ice melt is partially determined by the interplay between CH4 production and CH4 oxidation, performed by methane-oxidizing bacteria (MOB). Yet the balance between oxidation and emission and the potential for CH4 oxidation in various lakes during winter is largely unknown. To address this, we performed incubations at 2°C to screen for wintertime CH4 oxidation potential in seven lakes. Results showed that CH4 oxidation was restricted to three lakes, where the phosphate concentrations were highest. Molecular analyses revealed that MOB were initially detected in all lakes, although an increase in type I MOB only occurred in the three lake water incubations where oxidation could be observed. Accordingly, the increase in CO2 was on average 5 times higher in these three lake water incubations. For one lake where no oxidation was measured, we tested if temperature and CH4 availability could trigger CH4 oxidation. However, regardless of incubation temperatures and CH4 concentrations, ranging from 2 to 20°C and 1–500 μM, respectively, no oxidation was observed. Our study indicates that some lakes with active wintertime CH4 oxidation may have low emissions during ice melt, while other and particularly nutrient poor lakes may accumulate large amounts of CH4 below ice that, in the absence of CH4 oxidation, will be emitted following ice melt. This variability in CH4 oxidation rates between lakes needs to be accounted for in large-scale CH4 emission estimates.
@article{denfeld_constraints_2016,
	title = {Constraints on methane oxidation in ice-covered boreal lakes},
	volume = {121},
	issn = {2169-8961},
	url = {http://onlinelibrary.wiley.com.proxy.ub.umu.se/doi/10.1002/2016JG003382/abstract},
	doi = {10.1002/2016JG003382},
	abstract = {Boreal lakes can be ice covered for a substantial portion of the year at which time methane (CH4) can accumulate below ice. The amount of CH4 emitted at ice melt is partially determined by the interplay between CH4 production and CH4 oxidation, performed by methane-oxidizing bacteria (MOB). Yet the balance between oxidation and emission and the potential for CH4 oxidation in various lakes during winter is largely unknown. To address this, we performed incubations at 2°C to screen for wintertime CH4 oxidation potential in seven lakes. Results showed that CH4 oxidation was restricted to three lakes, where the phosphate concentrations were highest. Molecular analyses revealed that MOB were initially detected in all lakes, although an increase in type I MOB only occurred in the three lake water incubations where oxidation could be observed. Accordingly, the increase in CO2 was on average 5 times higher in these three lake water incubations. For one lake where no oxidation was measured, we tested if temperature and CH4 availability could trigger CH4 oxidation. However, regardless of incubation temperatures and CH4 concentrations, ranging from 2 to 20°C and 1–500 μM, respectively, no oxidation was observed. Our study indicates that some lakes with active wintertime CH4 oxidation may have low emissions during ice melt, while other and particularly nutrient poor lakes may accumulate large amounts of CH4 below ice that, in the absence of CH4 oxidation, will be emitted following ice melt. This variability in CH4 oxidation rates between lakes needs to be accounted for in large-scale CH4 emission estimates.},
	language = {en},
	number = {7},
	urldate = {2017-05-27},
	journal = {Journal of Geophysical Research: Biogeosciences},
	author = {Denfeld, Blaize A. and Ricão Canelhas, Monica and Weyhenmeyer, Gesa A. and Bertilsson, Stefan and Eiler, Alexander and Bastviken, David},
	month = jul,
	year = {2016},
	keywords = {\#nosource, 0458 Limnology, 4806 Carbon cycling, 4930 Greenhouse gases, Methanotrophs, ice-covered lakes, methane oxidation},
	pages = {2016JG003382},
}

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