Seafloor Volcano Pulses May Impact Earth's Climate

It turns out that seafloor volcanoes may cause climate change. Scientists have taken a closer look at the way seafloor volcanoes flare up from time to time and have found that the pulses may actually help trigger natural climate swings.

"People have ignored seafloor volcanoes on the idea that their influence is small-but that's because they are assumed to be in a steady state, which they're not," said Maya Tolstory, the study's author, in a news release. "They respond to both very large forces, and to very small ones, and that tells us that we need to look at them much more closely."

Volcanically active mid-ocean ridges crisscross Earth's seafloors like stitching on a baseball. In fact, they stretch a total of 37,000 miles. These are the growing edges of giant tectonic plates; lava pushes outward and forms new areas of seafloor. Although scientists though that these regions produce seafloor at a fairly constant rate, new research suggests that they actually work in pulses instead. In fact, if volcanic activity were to stir a bit more, their CO2 output would shoot up.

In order to better understand undersea volcanic eruptions, the researchers monitored 10 submarine eruption sites using sensitive new seismic instruments. They also created new high-resolution maps showing outlines of pass lava flows.

The long-term eruption data, spread over more than 700,000 years, revealed that during the coldest times, when sea levels were low, undersea volcanism surged. However, when things warmed up and sea levels rose, lava erupted more slowly, creating bands of lower topography. This could be due to the weight of the ocean impacting eruptions. In addition, it could also be related to changes in the earth's orbit; when the orbit is more elliptical, Earth is squeezed and unsqueezed by the sun's gravitational pull at a rapidly varying rate as it spins daily. This tends to massage undersea magma upward. When the orbit is circular, though, the squeezing effect is minimized and there are fewer eruptions.

"If you look at the present-day eruptions, volcanoes respond even to much smaller forces than the ones that might drive climate," said Tolstoy.

The findings reveal a bit more about how our climate system is interlinked. In addition, it shows how a surge in volcanic activity could increase the release of CO2 and impact our climate.

The findings are published in the journal Geophysical Research Letters.

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