@article{8024593116bc4712a549f118c9cd0fa4,
title = "Clumped Isotopes Link Older Carbon Substrates With Slower Rates of Methanogenesis in Northern Lakes",
abstract = "The release of long-stored carbon from thawed permafrost could fuel increased methanogenesis in northern lakes, but it remains unclear whether old carbon substrates released from permafrost are metabolized as rapidly by methanogenic microbial communities as recently produced organic carbon. Here, we apply methane (CH4) clumped isotope (Δ18) and 14C measurements to test whether rates of methanogenesis are related to carbon substrate age. Results from culture experiments indicate that Δ18 values are negatively correlated with CH4 production rate. Measurements of ebullition samples from thermokarst lakes in Alaska and glacial lakes in Sweden indicate strong negative correlations between CH4 Δ18 and the fraction modern carbon. These correlations imply that CH4 derived from older carbon substrates is produced relatively slowly. Relative rates of methanogenesis, as inferred from Δ18 values, are not positively correlated with CH4 flux estimates, highlighting the likely importance of environmental variables other than CH4 production rates in controlling ebullition fluxes.",
author = "Douglas, {Peter M.J.} and {Gonzalez Moguel}, Regina and {Walter Anthony}, {Katey M.} and Martin Wik and Crill, {Patrick M.} and Dawson, {Katherine S.} and Smith, {Derek A.} and Ella Yanay and Lloyd, {Max K.} and Stolper, {Daniel A.} and Eiler, {John M.} and Sessions, {Alex L.}",
note = "Funding Information: We thank Nami Kitchen for help with Δ analyses, Sarah Murseli for help with C analyses, and Nathan Dalleska for help with CH concentration measurements. Victoria Orphan and Jared Leadbetter provided laboratory facilities for culture experiments. This research was partially supported by funds from the Trottier Institute for Science and Public Policy to PMJD, from Royal Dutch Shell to JME and ALS, from the Agouron Institute to MKL, from the Heising‐Simons Foundation to DA Stolper, and from Vetenskapsr{\aa}det 2013‐5562 to PC. Data supporting this article are available at https://doi.org/10.6084/m9.figshare.11831340.v1 . 18 14 4 Funding Information: We thank Nami Kitchen for help with ?18 analyses, Sarah Murseli for help with 14C analyses, and Nathan Dalleska for help with CH4 concentration measurements. Victoria Orphan and Jared Leadbetter provided laboratory facilities for culture experiments. This research was partially supported by funds from the Trottier Institute for Science and Public Policy to PMJD, from Royal Dutch Shell to JME and ALS, from the Agouron Institute to MKL, from the Heising-Simons Foundation to DA Stolper, and from Vetenskapsr?det 2013-5562 to PC. Data supporting this article are available at https://doi.org/10.6084/m9.figshare.11831340.v1. Publisher Copyright: {\textcopyright}2020. American Geophysical Union. All Rights Reserved.",
year = "2020",
month = mar,
day = "28",
doi = "10.1029/2019GL086756",
language = "English (US)",
volume = "47",
journal = "Geophysical Research Letters",
issn = "0094-8276",
publisher = "American Geophysical Union",
number = "6",
}