Source: Oceans Deeply
Author: Todd Woody
Hydrothermal vent fields on the seabed are rich in copper, gold and other valuable metals, but scientists have found that some are home to unique animals found nowhere else on Earth.
At the bottom of the ocean lie hydrothermal “chimneys” the height of 10-story buildings that spew superheated chemical fluids into an oxygen-deprived, lightless void. These hydrothermal vents nourish communities of otherworldly creatures – such as 6ft (1.8m)-long tubeworms that lack mouths and digestive tracts – and create untold mineral wealth now coveted by countries and corporations.
The mineral deposits laid down over the eons by the sulfides emitted by hydrothermal vents contain copper, zinc, silver and gold. Over the next three weeks, the International Seabed Authority is meeting in Jamaica to, among other things, draft environmental regulations to govern the mining of the deep sea. The mission: to fulfill the United Nations-chartered organization’s mandate to preserve the biological diversity of the mostly unexplored seabed while allowing the extraction of metals that make possible smartphones, solar panels and other products used by the most committed environmentalist and rapacious industrialist alike.
That job just got harder.
A new discovery appears to blow a hole in a major premise of seabed mining – that if a marine ecosystem reliant on one hydrothermal vent field is destroyed, life will go on at adjacent vents and, over time, the mined site could be recolonized by the same species. Deep-sea expeditions led by scientists affiliated with the Monterey Bay Aquarium Research Institute (MBARI) have found that hydrothermal vent fields as close as 45 miles (75km) to each other have spawned unique animal life based on local geology and the particular chemistry of the fluids flowing through the hydrothermal chimneys. The Alarcon Rise vent field at the southern end of the Gulf of California off Mexico, for instance, shares just seven of 61 animal species with the Pescadero Basin vent field less than 50 miles to the north, according to the study published in the Proceedings of the Royal Society B.
“Someone might want to mine the Alarcon Rise for precious metals and would say the Pescadero Basin is right next door so there will be a movement of animals between the two. But that’s not the case,” said the study’s lead author, Shana Goffredi, a marine biologist at Occidental College in Los Angeles who works with MBARI.
In fact, the Pescadero Basin hydrothermal vent field and its marine life are unlike any yet discovered.
Similar to other hydrothermal vent fields, the Alarcon Rise, discovered on a 2012 MBARI expedition, lies at a depth of about 7,550ft (2,300m) and is covered in geologically young lava that spew sulfide-rich liquids at temperatures as high as 680F (360C).
Pescadero, on the other hand, lies at a depth of 12,000ft (3,700m) and hydrothermal fluid flows through thick seafloor mud, creating pools of methane and hydrocarbons.
“This combination of habitat characteristics is unlike any seen on Earth,” said Goffredi of the Pescadero vent field, which MBARI discovered on a 2015 expedition. “There’s the possibility that these sites are unique but there’s also the possibility that as we explore other sites, we’ll find others like it or other unique sites.”