Methane Munching Microbes: calculated consumption or blowout bender?

Numerous seafloor emissions of methane have been identified spanning a wide range of oceanographic conditions. A fundamental question when assessing the transport and fate of this released greenhouse gas is "how much is biodegraded vs. dispersed and diluted in ocean waters?" For decades, measurements of natural stable isotopes have been used to answer this question since isotopic values of methane systematically change during biodegradation but not dispersion. However, this process is not straight-forward when microbial populations grow up in response to increased methane emissions. Laboratory experiments are showing that this isotopic change varies substantially while models suggest this variability can be ignored. The answer to this debate may be revealed in the Deepwater Horizon incident where seawater microbes bloomed in response to the released methane; if the insights gained here prove robust, a more quantitative framework will be established for assessing the fate of future greenhouse gas releases in seawater be them natural or industrial.

Speaker: John Kessler, Univ. of Rochester