How methane studies on Earth could inform the search for alien life in our solar system

Space.com report stated, "Elsewhere in the solar system, previous research has suggested methane on Mars originates from hydrothermal reactions. On Titan, which is Saturn's largest moon, scientists think the gas originated from its building blocks since the early solar system. Saturn's moon Enceladus and Jupiter's Europa, arguably the current best places to search for life, are thought to host methane clathrates as well. Findings from the new study suggest that if microbes exist on other worlds, they might create similar molecules to create and stabilize methane clathrates, which in turn affects the composition of ocean waters and the atmospheres of those worlds. Thus, to find alien life, maybe we need to follow the methane clathrate trail."

My note, reports for methane on Mars goes back sometime. Here is a report from 2013 as an example.

Curiosity Rover Samples Air for a Taste of Mars History, http://www.scientificamerican.com/article.cfm?id=curiosity-mars-atmosphere

“It’s time to update the list of ingredients in Martian air. In late 2012 NASA’s Curiosity rover drew air into its onboard laboratory and analyzed Mars’s atmospheric composition with a pair of spectrometers. The results of the investigation, published July 19 in Science, revise decades-old data on the makeup of Red Planet air and paint a broad picture of how the atmosphere has changed since the planet’s formation... “We know that the Allan Hills meteorite is four billion years old,” Webster says. “It traps gas from that early Martian atmosphere.” Curiosity, on the other hand, can determine the precise makeup of the atmosphere today. “So we now have enough confidence and enough accuracy in the measurements to make that comparison. The overarching result is that the atmosphere has changed very little in four billion years.” In other words, it appears the bulk of Mars’s atmosphere was lost relatively shortly after the planet’s formation 4.5 billion years ago. That does not mean there hasn’t been any recent variation. Methane, a gas that some planetary scientists expect to change greatly over time, is notably absent from the new studies. In recent years, measurements from Earth have indicated the appearance and disappearance of methane plumes on Mars that might spew from geologic—or even biological—sources. Those observations have stirred controversy, which Curiosity ought to help settle. The rover has yet to detect the gas, but that does not necessarily mean it is absent from the Martian atmosphere. The precise upper limits on methane abundance that rover scientists can infer from Curiosity’s nondetection will appear in a later study. “That’s a big story, so we decided to separate it,” Webster says. “We have a result that’s very interesting,” he adds, which has been submitted to Science for publication. “We have no definitive detection of methane—I can tell you that.” It remains to be seen if Curiosity’s limits on methane abundance strongly conflict with the levels expected in the presence of seasonal methane belches from the Red Planet. If they do, the supposed plumes of mysterious origin may be consigned—alongside the purported fossils in the Allan Hills meteorite—to the long list of Martian mirages, much to the dismay of optimistic astrobiologists and an excited public. “It’s not a message people want to hear,” Webster says. “They don’t really want to hear that there’s no methane on Mars.”

My note. Concerning astrobiology (founded upon abiogenesis doctrine), no life confirmed in our solar system or somewhere else in the universe still stands in nature.