North of the Arctic Circle, west of Spitsbergen, methane gas is effervescing out of the seabed.
But why? Is this an indication that methane hydrates in the seabed are dissolving due to global warming? And how concerned should we be?
These are questions that researchers at Germany’s Geomar – Helmholtz Centre for Ocean Research Kiel are trying to answer.
An expedition, utilising the German research vessel Maria S Merian and the Jago submersible, hope to come up with at least clues as to what the answers might be.
The expedition started out from Iceland last month.
Average atmospheric and oceanic temperatures are rising and already impacting the environment.
The transitional zones between shallow shelf seas and the deep sea at continental slopes store a huge amount of methane hydrates in the sea bed, including in the North Atlantic and Arctic Sea.
These specific, ice-like compounds only forms at low temperatures and under high pressure. When the water temperature directly above the sea bed rises, some of the methane hydrates could dissolve and release the previously bound methane.
They are both a threat and a possible commercial opportunity for the oil and gas industry.
“This scenario incorporates two fears: Firstly that enormous amounts of this very powerful greenhouse gas will be released into the atmosphere, and secondly that continental slopes may become unstable.
The expedition builds on research conducted by marine scientists from Kiel who worked in this area of the sea in 2008. Back then they found over 250 places where gas was escaping the sea bed.
“These spots lie directly on the border of the area of stable hydrates” said Professor Christian Berndt, leader of the current expedition.
“Therefore we presume that the hydrates are dissolving from the rim inwards.”
With the help of sophisticated acoustic systems, the expedition is searching for gas sources in order to determine the total amount of escaping hydrocarbon in water depths to 400m.
Parallel to this, geophysicists, lead by Professor Sebastian Krastel, are investigating the slopes under the gas outlet spots for signs of instability using acoustic and seismic methods.
“The methane hydrates act like binding cement on these slopes. If they dissolve, chances are that parts of the slopes will slide,” added Prof Krastel.