Въглероден диоксид + Водород -> Метан
orly?
Most people have heard of the water cycle, in which water evaporates into
the air, returns to Earth and then evaporates again. Many other substances,
including methane, cycle this way too. There are many sources that release
methane (CH4) into the atmosphere. There are also sinks or ways that
methane is trapped or destroyed.
The methane cycle begins in the soil where methane gas is created by
microbes. Soil methane is consumed by methanotrophs, microorganisms that
feed on methane. Methanogens make more methane that methanotrophs
consume. Methanotrophs live in drier soil layers above the deep, wet oxygen
poor soils of swamps. Their “food” bubbles past them on its way to the
surface, releasing methane into the atmosphere. This methane joins methane
from other sources, such as landfills, livestock and exploitation of fossil
fuels.
The main mechanism for removal of methane from the earth’s atmosphere
is oxidation within the troposphere by the hydroxyl radical (OH). A hydroxyl
radical is a negatively charged oxygen atom bonded to a hydrogen atom (OH).
Hydroxyl radicals are a form of “sink” because they “scrub” the atmosphere
clean of pollutant molecules and break them down. For this reason OH is
known as the ‘cleanser of the atmosphere’.
After reacting with OH,
atmospheric methane is converted to CO2 by a long series
of chemical reactions.) Some of the methane present in the troposphere passes
into the stratosphere where the same process scrubs the atmosphere clean of
methane there.
In an ideal world, methane sources would be balanced with methane sinks, as
with CO2, however, global atmospheric methane concentrations are rising as
a result human activities. Scientists are worried because as the planet
warms, even more methane will to be released from soils or other places
adding to the global warming problem.https://gml.noaa.gov/education/info_activities/pdfs/CTA_the_methane_cycle.pdf