Oslo: A study lead by University in Tromso (UIT) The Arctic University of Norway has claimed that the moon has a role to play in controlling the amount of methane gas released by the Arctic Ocean.
The Arctic Ocean, according to various researches leaks enormous amounts of the potent greenhouse gas methane which have been ongoing for thousands of years but could be intensified by a future warmer ocean.
The potential for this gas to escape the ocean, and contribute to the greenhouse gas budget in the atmosphere, is an important mystery that scientists are trying to solve.
A recent paper in Nature Communications reveals that the total amount of methane in the atmosphere has increased immensely over the past decades, and the moon can play a vital role to control that.
Small pressure changes affect methane release and the moon controls one of the most formidable forces in nature like the tides that shape coastlines. Tides, in turn, significantly affect the intensity of methane emissions from the Arctic Ocean seafloor.
Co-author of the paper Andreia Plaza Faverola said, “We noticed that gas accumulations, which are in the sediments within a meter from the seafloor, are vulnerable to even slight pressure changes in the water column. Low tide means less of such hydrostatic pressure and higher intensity of methane release. High tide equals high pressure and lower intensity of the release.”
Meanwhile, another co-author Jochen Knies revealed that it was the first time that an observation has been made in the Arctic Ocean which showed that slight pressure changes can release significant amounts of methane.
The observation proved to be a game-changer for the study that unveiled new facts about the same.
Faverola told that the observations were made by placing a tool called a piezometer in the sediments and leaving it there for four days.
It measured the pressure and temperature of the water inside the pores of the sediment. Hourly changes in the measured pressure and temperature revealed the presence of gas close to the seafloor that ascends and descends as the tides change.
The measurements were made in an area of the Arctic Ocean where no methane release has previously been observed but where massive gas hydrate concentrations have been sampled.
“This tells us that gas release from the seafloor is more widespread than we can see using traditional sonar surveys. We saw no bubbles or columns of gas in the water. Gas burps that have a periodicity of several hours won’t be identified unless there is a permanent monitoring tool in place, such as the piezometer,” said Faverola.
These observations implied that the quantification of present-day gas emissions in the Arctic may be underestimated. High tides, however, seem to influence gas emissions by reducing their height and volume.
“What we found was unexpected and the implications are big. This is a deep-water site. Small changes in pressure can increase the gas emissions but the methane will still stay in the ocean due to the water depth. This approach needs to be done in shallow Arctic waters as well, over a longer period. In shallow water, the possibility that methane will reach the atmosphere is greater,” said Knies.
The scientists also noted that high sea-level influenced gas emissions by potentially reducing their height and volume.
The question that remained unsolved was whether sea-level rise due to global warming might partially counterbalance the effect of temperature on submarine methane emissions.
Faverola revealed that Earth systems are interconnected in ways that they are still deciphering, “Our study revealed one of such interconnections in the Arctic: The moon causes tidal forces, the tides generate pressure changes, and bottom currents that in turn shape the seafloor and impact submarine methane emissions. Fascinating!”