Hotspot volcanoes

The unknown world of underwater volcanoes

ROV Jason studies an underwater hydrothermal vent (NOAA)

Posted on Dec 17, 2021 3:53 PM by

Brian Gicheru Kinyua

Volcanic activity is emblematic of the destructive power of nature. When they occur on land, volcanic eruptions leave a trail of property destruction and loss of life. In 2015, about eight percent of the world’s population lived within 60 miles of a volcano with at least one significant eruption. They are both a source of risk and prosperity: the fertile soils created by volcanic ash can support agriculture, and the heat from volcanic activity can be exploited for the production of electricity (geothermal energy).

Current scientific knowledge of volcanoes is largely based on eruptions seen on land, but scientists say volcanology can also help nuance ocean research. Specifically, underwater volcanoes are increasingly helping marine scientists understand marine biogeochemical cycles – how nutrients move through the oceans. The foundation of the productivity of the oceans, and therefore of the fisheries it can sustain, rests on this cycle.

“It is strange that despite their importance and flair for the dramatic, underwater volcanoes have not found their place in the zeitgeist,” writes Dr Robin George in his new book, “Super Volcanoes”.

We now know more about outer space than about the submerged seamounts that harbor some of the most unique habitats for life on Earth.

“One of Earth’s most underappreciated biodiverse habitats is, for now, mostly a mystery. It has left a chasm in the collective understanding of the full extent of our largely detrimental effects on the aquatic realms of the world. and the threats these habitats face, from warming oceans to commercial fishing to a controversial and nascent deep-sea mining industry, are increasing,” Dr. Robin added in an article he wrote for Vox. .com.

The Pacific islands of Nauru and Kiribati, themselves from volcanism, have petitioned the International Seabed Authority (ISA) to expedite approval for the start of deep-sea mining operations. Many scientists consider this as reckless, especially given the limited knowledge of deep ocean ecosystems.

At a recent World Conservation Summit hosted by the International Union for Conservation of Nature (IUCN), thousands of conservationists, scientists and diplomats voted overwhelmingly in favor of a moratorium on deep sea mining and new exploration contracts until there is evidence that marine ecosystems can be effectively protected.

Humans have only explored a tiny fraction of the deep sea, which is home to most of Earth’s volcanoes. If all these submarine volcanoes were merged, their total area would be roughly equivalent to that of Europe and Russia combined. So deep sea mining becomes scary in the sense that it targets these deep sea habitats – abyssal plains, seamounts and hydrothermal vents – to extract minerals. No one can characterize the level of potential impacts it would have on these fragile ecosystems teeming with marine life. The vast majority of species there remain unknown precisely because of the cost, expertise and technology required to do so.

Remarkably, seamounts have proven to be way stations for marine life making journeys across the oceans. Simply put, they are ocean outposts where life can seek refuge, refuel, and raise offspring before continuing its journey.

For example, sea turtles coming from the Great Barrier Reef use Kavachi (an active underwater volcano in the Solomon Islands) as a transit point to feed before leaving.

“Underwater volcanoes can even protect life from climate change. The shallow depths are warming and acidifying faster as we continue to pump greenhouse gases into the sky. Deeper seamounts will likely act as castles for biodiversity,” says Dr Robin.

If you cruise about 300 miles west of the Oregon coast, you’ll float above Axial Seamount, where scientists have established a global model of an underwater volcanic observatory. Scientists wired the active volcano with hundreds of sensors and cameras, sending gigantic amounts of data back to shore. The goal is to gain continued insight into the pyrotechnics of volcanic activity hidden in the dark recesses of the ocean – and to begin to answer some of the long-standing questions about how this activity is affecting our planet.