Pakistani geologists find mud
volcanoes due to methane emission near Makaran Coast
According to the scientists,
the Makran coastal belt is reported to have extensive reserves of frozen methane
that exist in the form of gas hydrates (crystalline water-based solids
physically resembling ice which were formed under conditions of relatively high
pressures and low temperatures) hundreds of metres below the sea floor. And
whenever this highly pressured gas finds a weak space to release some of its
energy, a dome-like structure (island) is created within the waters or it
emerges on the sea surface.
Scientists studying the water and sediment samples collected from the
one-square-kilometer island that emerged off the Makaran coast last year has
found well-preserved shells of certain marine organisms that are known to
survive on sulphur and methane.
Methane (CH4) is a greenhouse gas that remains in the atmosphere for
approximately 9-15 years. Methane is over 20 times more effective in trapping
heat in the atmosphere than carbon dioxide (CO2) over a 100-year period and is
emitted from a variety of natural and human-influenced sources. Human-influenced
sources include landfills, natural gas and petroleum systems, agricultural
activities, coal mining, stationary and mobile combustion, wastewater treatment,
and certain industrial process.
Methane is also a primary constituent of natural gas and an important energy
source. As a result, efforts to prevent or utilize methane emissions can provide
significant energy, economic and environmental benefits. In the United States,
many companies are working with EPA in voluntary efforts to reduce emissions by
implementing cost-effective management methods and technologies.
Methane is not toxic; however, it is extremely flammable and may form explosive
mixtures with air. Methane is created near the Earth's surface, primarily in
soils, rivers/seas and in animal innards. It is carried into the stratosphere by
rising air in the topics.
Uncontrolled build-up of methane in the atmosphere is naturally checked —
although human influence can upset this natural regulation — by methane's
reaction with hydroxyl radicals formed from singlet oxygen atoms and with water
vapor.
According to new calculations, the impacts of methane on climate warming may be
double the standard amount attributed to the gas. The new interpretations reveal
methane emissions may account for a third of the climate warming from well-mixed
greenhouse gases between the 1750s and today. The methane’s affects once it
exists in the atmosphere, states that methane increases in our atmosphere
account for only about one sixth of the total effect of well-mixed greenhouse
gases on warming.
“This is the first time that we have found rocks and boulders with burrows and
holes that indicates the forceful eruption of the mass. Also, the presence of
huge rocks on the island led us to assume that this time the island had emerged
with greater pressure, though we are not sure about the exact depth from where
the mass has erupted,” said Dr A.R. Tabriz, the director general of the National
Institute of Oceanography (NIO).
All data pointed to the presence of microbiologically generated bacterial
methane, excluding thermo genic gas.
Other findings of the samples’ testing showed dominant presence of clay minerals
such as muscovite and chlorite with quartz and calcite. The elemental
composition of the sediments was dominated by silicates, aluminium, calcium and
iron. “The shells are probably of the calyptogena species, which is known to
survive on sulphur and methane. A strong correlation was found between the
sediments of the offshore island and the onshore mud volcanoes,” said Dr Asif
Inam, the director continental shelf project at the NIO.