@article {robison_dominance_2022,
	title = {Dominance of {Diffusive} {Methane} {Emissions} {From} {Lowland} {Headwater} {Streams} {Promotes} {Oxidation} and {Isotopic} {Enrichment}},
	journal = {Frontiers in Environmental Science},
	volume = {9},
	year = {2022},
	pages = {791305},
	abstract = {Inland waters are the largest natural source of methane (CH 4 ) to the atmosphere, yet the contribution from small streams to this flux is not clearly defined. To fully understand CH 4 emissions from streams and rivers, we must consider the relative importance of CH 4 emission pathways, the prominence of microbially-mediated production and oxidation of CH 4 , and the isotopic signature of emitted CH 4 . Here, we construct a complete CH 4 emission budgets for four lowland headwater streams by quantifying diffusive CH 4 emissions and comparing them to previously published rates of ebullitive emissions. We also examine the isotopic composition of CH 4 along with the sediment microbial community to investigate production and oxidation across the streams. We find that all four streams are supersaturated with respect to CH 4 with diffusive emissions accounting for approximately 78{\textendash}100\% of total CH 4 emissions. Isotopic and microbial data suggest CH 4 oxidation is prevalent across the streams, depleting approximately half of the dissolved CH 4 pool before emission. We propose a conceptual model of CH 4 production, oxidation, and emission from small streams, where the dominance of diffusive emissions is greater compared to other aquatic ecosystems, and the impact of CH 4 oxidation is observable in the emitted isotopic values. As a result, we suggest the CH 4 emitted from small streams is isotopically heavy compared to lentic ecosystems. Our results further demonstrate streams are important components of the global CH 4 cycle yet may be characterized by a unique pattern of cycling and emission that differentiate them from other aquatic ecosystems.},
	issn = {2296-665X},
	doi = {10.3389/fenvs.2021.791305},
	url = {https://www.frontiersin.org/articles/10.3389/fenvs.2021.791305/full},
	author = {Robison, Andrew L. and Wollheim, Wilfred M. and Perryman, Clarice R. and Cotter, Annie R. and Mackay, Jessica E. and Varner, Ruth K. and Clarizia, Paige and Ernakovich, Jessica G.}
}
