Ocean Volcanoes Stirred by Ice Age Cycles

Scientists studying the seafloor along mid-ocean ridges have found a strong connection between climate change and underwater volcanic activity. Research indicates that fluctuations in polar ice volume and subsequent sea-level changes over the last 49,000 years have made these undersea volcanoes more active.

The study focused on the Carlsberg Ridge in the Indian Ocean, a slow-spreading ridge. By analyzing rust-colored coatings on seafloor samples, scientists identified lead isotopes that revealed the intensity of past volcanic activity. These coatings act as chemical sponges, absorbing signatures from magma and land dust.

Findings show that lower sea levels during glacial periods, such as the one around 60,000 years ago, reduced hydrostatic pressure. This reduction spurred increased volcanism over the Carlsberg Ridge, releasing more heat and carbon dioxide into the ocean.

This research demonstrates that hydrothermal systems at slow-spreading ridges are highly sensitive to global climate shifts. These systems play a vital role in transporting crucial trace metals from Earth's interior to the deep ocean, influencing marine life and overall ocean chemistry across glacial cycles.