Anyone who has faced flood warnings resulting from high tides in recent weeks will be in no doubt as to the impact they can have, but far fewer will understand the effect they are having on volcanic eruptions and, ultimately, on the world’s climate. Rising sea levels are undoubtedly causing more problems with coastal flooding, but could what lies beneath the sea also be contributing to the changes to the oceans and the world as a whole?
A new study that has just been published in the Geophysical Research Letters journal has revealed that undersea volcanoes, which spew greenhouse gases into the atmosphere, are very sensitive to the ocean’s tides. In fact, they are surprisingly susceptible to the effects of low tides.
Marine geophysicist Maya Tolstoy, of the Lamont-Doherty Earth Observatory at Columbia University in the US, studied seismic records from 10 eruptions on the seafloor, along with associated tide times. The eruptions were found to be most likely to happen around times of fortnightly neap tides, which reduced the weight on the undersea volcanoes and encouraged some small earthquakes that are often associated with eruptions. The eruptions also happened during the first half of the year. This is a time when the tidal pull from the sun is lowering, which is also known to be associated with volcanic eruptions.
Tolstoy actually found that this kind of eruption could influence the world’s ice age cycles and also highlighted the amounts of CO2 which are released into the oceans after eruptions, some of which eventually reaches the atmosphere. Other experts have pointed out, however, that the volume of greenhouse gasses released by the world’s volcanoes is still swamped by the sheer volume of gases entering the atmosphere as a result of the burning of fossil fuels by man.
