Scientists are studying about the impact of volcanoes deep within the sea and it has been revealed that they have a prominent influence on climate change. Sea-floor volcanoes expelling molten rock have been found to be associated with historical changes in the orbit and environment of the Earth. According to a scientist at the Joint Institute for the Study of Atmosphere and the National Oceanic and Atmospheric Administration, Edward Baker, “We don’t usually think of eruptions as being affected by very small changes-astronomical changes and sea levels rising and falling, and the Earth spinning around the sun at different distances. It’s another way of understanding how the Earth works.”
Geophysicist, Maya Tolstoy from Columbia University’s Lamont-Doherty Earth Observatory explained that such volcanic eruptions were once thought to be slow and steady but they actually erupt in the form of bursts, lasting from two weeks to 100,000 years and having a regular pattern. Owing to their steady state, these deep-sea volcanoes were assumed to have small impact. However, volcanoes at mid-ocean ridges are influenced by both large and small forces and a closer look at their impact is required.
The new study was carried out with the aim of determining the frequency of underwater volcanic eruptions and the factors behind them. Tolstoy found that these volcanoes were associated with the changes in the movement of Earth around the Sun. These changes take place in 100,000 year cycles, leading to ice ages and warm periods. Among the factors responsible for worldwide climate change, the underwater eruptions are not considered. The study also discovered that the eruptions coincided with low tides.
During the ice ages, the sea level was lower as the sea water converted into ice. The low level of sea was also accompanied by more volcanic activity in the sea. According to the researchers, the icecaps building on land increases the pressure on volcanoes which in turn suppress eruptions. Melting of ice leads to increased volcanic eruptions on land. Carbon dioxide expelled by the volcanoes causes warming of the atmosphere which significantly influence the climate. The warming air also causes further volcanic eruptions.
In case of both land and sea, sufficient pressure on the volcano results in limited volcanic activity. When the pressure reduces, due to melting of ice on land or low tides in the ocean, the volcanoes start erupting. Evidences of a 100,000 year cycle in seafloor maps of the Pacific have been found by the researchers. When the sea level was low, large hills of lava formed on the East Pacific Rise. Volcanic activity increased due to low water pressure on the ridge. The patterns of volcanic activity were found to be associated with the ice sheets formation and melting approximately every 100,000 years for the last two to three million years. In every 100,000 years, a cycle of the Earth’s orbit gets more or less elliptical and the patterns are paced up. Tolstoy opines that underwater eruptions probably do not just follow the 100,000 year cycle but they might also influence the climate.