Daily Science Dose

Methane was in the news this week, after it was finally confirmed that methane plumes are present on Mars and in another study, decaying plants were found not to contribute methane to the air, but instead transpire methane from other sources, such as microbes in the soil.

Methane plumes are red and yellow in this NASA-produced image.

Mars’ Methane Madness

NASA announced this past week that scientists have confirmed the presence of infamous greenhouse gas methane on the lonely redrock planetary neighbor. Plumes of methane have been detected at three different locations on Mars, and the plumes only occur during the summer. My question now is what exactly is a Martian summer? Does Mars enjoy a tilt like Earth, or is it when the planet is closest the sun in its elliptical orbit?

The answer is that Mars has an axial tilt of about 25 degrees, similar to Earth’s 23ish degrees.

So methane is there, but what is it that produces this gas? On Earth, methane is produced by certain microbes that live, well, everywhere…even in your stomach. Methane is the major component of our own natural gas.

So does this mean that there is life on Mars? Maybe. Maybe not. Methane is also a product of volcanic activity. Volcanoes release the gas into the atmosphere, and that gas may have been trapped underground for quite some time. On Earth, methane is trapped under heavier ocean water as well as the permafrost in the arctic and antarctic regions of the Earth. So it may mean that there could have been microbial life on Mars some time ago, or it could mean that Mars also has a goodly amount of methane trapped under its volcanically active surface.

Methane Doesn’t Come from Decaying Plants…Kind of.

Ok, methane may come from plant matter, but it’s not the plant’s fault. A few years ago, Frank Keppler ran a test to see if plant matter produces methane. His experiment concluded yes, but it made other scientists question the experiment. So some other scientists ran another experiment.

“This finding was shocking,” recalls Euan Nisbet of Royal Holloway, University of London, in Egham, U.K. If true, both plant biochemistry and global methane budget would need a major reexamination. It could also mean that the human contribution to global warming is less than previously thought.

Nisbet’s team set about to investigate Keppler’s findings by growing the same plants, including celery (Apium graveolens) and a type of rice (Oryza sativa), in the absence of external sources of the greenhouse gas. The group found no trace of methane, suggesting that the plants alone cannot make the gas. In a separate experiment, the team placed the plants in water containing dissolved methane. Sure enough, the roots drew up the methane-soaked water and the leaves then pushed out the gas and water vapor–a process known as transpiration. –Science

The same group of scientists also tested some chemical paths that could allow the plant to create methane, but nada, the plant’s did not have the same pathways that methane-producing microbes have. Keppler gives the new science a nod to the transpiration of methane finding, but still holds on to the idea that an unidentified pathway exists.

methane, Mars, plants, NASA, science, greenhouse gas, atmosphere, emissions, decomposition, microbes, chemical, transpiration,