Scientists have found an alien, inhospitable world not in the far reaches of the galaxy, but on the bottom of the Gulf of Mexico -- about a day’s boat ride from New Orleans. Dubbed the “Jacuzzi of Despair,” this pool of super-salty brine kills any unfortunate creature that happens to wonder in -- mainly benthic crabs, amphipods and an occasional fish.
The circular pool -- about 100 feet in circumference and about 12 feet deep -- lies nearly 3,300 feet below the surface of the Gulf. It contains water that is four or five times saltier than the surrounding seawater. As a result, the brine is so dense that it sits on the bottom, forming an underwater cauldron of toxic chemicals that include methane gas and hydrogen sulfide that doesn’t mix with surrounding seawater.
The brine pool -- and a nearby flowing brine river -- were formed as normal seawater seeped into cracks in the seabed, mixed with the region’s subsurface salt formations, then were forced up by methane gas percolating from the seafloor.
“It was one of the most amazing things in the deep sea,” said Erik Cordes, associate professor of biology at Temple University who discovered the site along with several colleagues, and published a report on the findings in the journal Oceanography. “You go down into the bottom of the ocean and you are looking at a lake or a river flowing. It feels like you are not on this world.”
Cordes -- who studies deep-sea corals -- and others first found the formations in 2014 using a remotely-operated underwater robot called Hercules. They returned the following year with the three-person research sub Alvin to get a closer look.
After closing the hatch of the Alvin on the E/V Nautilus ship, the two scientists and pilot took almost an hour to descend to the bottom. A video of their journey can be found on the Nautilus website.
“We were able to see the first opening of a canyon,” Cordes recalls. “We kept up this steep slope and it opened up and we saw all these mud flows. We got closer and we saw the brine falling over this wall like a dam. It was this beautiful pool of red white and black colors.”
This undersea “deadpool” was contained with a living mat of bacteria and salt deposits. The rim was littered with carcasses of deep-sea crabs that had wandered into the pool looking for food. Giant mussels with a symbiotic bacteria living in their gills were feeding off the hydrogen sulfide and methane gas surrounded the pool. They also found specially adapted shrimp and tube worms.
Scott Wankel, a biogeochemist at the Woods Hole Oceanographic Institution, said the brine “Jacuzzi of Despair” water measured about 65 degrees Fahrenheit, quite a nice bath compared to the 39 degrees of the surrounding seawater. It’s the warmth that drew in the unsuspecting marine life, including laptop-sized isopods.
“It’s warm, but super salty,” Wankel said. “When they fall in they die and get pickled and preserved.”
Cordes says these pools are rare in the world’s oceans. One was discovered in the Mediterranean in 2011, but it didn’t have such a lively ecosystem living just on its edge.
When the Alvin arrived on the scene, it used its robot arms to take samples of the dense gas and water in the pool, stirring up the poisonous brew.
“If you muck around in the lake, you can make waves of brine that break on the shore,” Cordes said.
The team retrieved some samples of microbial life that are adapted to handle the high salinity and low oxygen levels of the brine pool. Cordes believes that these creatures could resemble life on planets in our solar system, or beyond.
“There’s a lot of people looking at these extreme habitats on Earth as models for what we might discover when we go to other planets,” Cordes said.
“The technology development in the deep sea is definitely going to be applied to the worlds beyond our own.”
Similar ecosystems of hardy marine “extremophiles” also have found around deep-sea hydrothermal vents, but this is the first time such a community has been found around a brine pool.
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