Deep down, beneath the icy edges of the Greenland Sea, a remarkable and previously undiscovered geological and biological complex has been found by scientists.
This topographic anomaly exists deep in the sea, where light is scarce, and high pressure and low temperatures are prevalent.
extends our understanding of what is known about the oceanography of the Arctic.
The findings are particularly relevant given the recent surge in scientific interest in the Earth’s poles, which is linked to a better understanding of global climate processes.
The observation of a level of biological and geological interaction in one of the most remote ocean regions on Earth contributes important information to what is known about the physical characteristics of the Arctic.
Why methane hydrate mounds forming deep beneath the Arctic Ocean
The most notable aspect of the discovery is that it consists of a number of gas hydrate mounds along the Molloy Ridge, a tectonic boundary that lies deep beneath the Greenland Sea.
A gas hydrate is a molecule that consists of a large amount of trapped methane, all held together with crystalline ice.
The existence of these hydrates at a depth of some 3,640 metres is one of the deepest known hydrate formation sites that have been discovered so far.
According to the research paper that was published in Nature Communications,
Researchers discovered high-resolution images showing the extent of these hydrate mounds along the ridge with the help of a remotely operated robotic vehicle.
Until now, we have largely associated gas hydrates with continental slopes and the shallower margins of the Arctic.
The question of how life survives without sunlight on the Arctic sea floor is intriguing.
The ecologists surrounding the hydrate mountains recorded the existence of a dense population of chemosynthetic organisms.
Such organisms receive energy from chemicals instead of sunlight.
Based on the fact that the area is lightless, the organisms receive energy from the methane seeping from beneath the seafloor.
The organisms form the base of the food chain, in turn supporting other life forms.
Scientists recorded tube worms and crustaceans, as well as a dense mat of microbes aggregated in areas surrounding the seeps.
The organisms exhibit specific adaptations to withstand high pressures as well as near-freezing temperatures.
The organisms’ metabolism is specifically attuned to take advantage of the methane as well as sulphide compounds seeping from the sediments.
The finding shows the existence of life in the deepest parts of the Arctic Ocean utilising available energy in the area.
What role does the Molloy Ridge play in processes occurring on the deep Arctic sea floor?
Molloy Ridge is recognised as one of the deepest mid-ocean ridges in the world and is characterised by tectonic plates that are gradually drifting apart.
The tectonic activities in this process result in the creation of cracks and channels in the Earth’s crust that facilitate methane gas flowing from deeper to upper layers.
When methane gas reaches lower temperatures close to the ocean floor, it either becomes trapped in its hydrate form or seeps out gradually.
This tectonic interaction directly links the observed process to biological activities on the ocean floor.
The mid-ocean ridge functions both as a channel and as a supporting structure that determines hydrate and biologically active zones.
The process of interaction in this study is very advantageous in gaining an understanding of deep-sea ecosystems’ maintenance at a deeper level for extended periods.
What this discovery means for Arctic methane stability
Methane has a crucial role within the carbon cycle, and what happens to it under the ocean floor is closely tracked because it can affect the climate.
The methane hydrate mounds under the Greenland Sea support a long-term trap that holds methane under stable conditions.
At present, the conditions on the Molloy Ridge support a stable environment to retain methane, hindering massive amounts of methane from entering the water body. Still,
Recognising such systems is critical to predicting their reaction to potential warming in ocean currents or temperatures.
The findings provide scientists a chance to observe and measure methane within a system that has been under-represented within climate models to predict climatic changes.
The findings validate the crucial role of the deep basins in the Arctic in managing carbon under the Earth’s surface and in the ocean.
Why the deep Arctic Ocean is becoming a focus of scientific research
The discovery of hydrate mounds and their ecosystems in the Greenland Sea is one such finding that showcases the effect that advances in technology are having on deep oceanography.
The use of remotely operated vehicles with sophisticated sensors and imaging systems is enabling scientists to explore regions that were hitherto unexplored.
With every new expedition, new layers of complexity are being found under the Arctic Ocean, from unexpected topographical features to new ecosystems.
The Molloy Ridge finding indicates that perhaps such regions are to be found elsewhere on deep tectonic margins, waiting to be located and studied.
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