This Bizarre Underwater Lake Kills Almost Anything That Enters It — Scientists Finally Know Why

There’s a whole world left to explore underwater. Life thrives in the harshest of conditions but some may be too lethal to sustain life. A team of scientists discovered a deadly pool of brine at the bottom of the Gulf of Mexico, thousands of feet below the sea level, that not only kills any and all life that enters it but also embalms them. Nautilus Live (@EVNautilus) documented an expedition through a remotely operated vehicle (ROV) Hercules deployed to examine cold seeps in 2015. 

The scientists eventually stumbled upon this cold seep, a toxic brine pool, dubbed the "Hot Tub of Despair," that saw countless crabs and other amphipods lying dead with their bodies preserved intact. “So there’s a dead amphipod. That’s what we mean by the 'Jacuzzi of Despair.' These types of bigger, larger organisms really don’t like to be in this fluid,” a researcher said in the video. He even joked if the pool was a place where these creatures came to die. Dark humor there. 

The brine pool is located about 3,300 feet below the surface of the water with a 100 feet circumference. The depth of the brine pool measured at about 12 feet containing water that is four times more salty and way denser than regular seawater, according to a 2016 study published in the journal Oceanography. The temperature inside the pool goes as high as 66 degrees Fahrenheit (19 degrees Celsius) which creates a fatal environment for life in combination with the high salinity. 

Cold seeps are essentially locations where hydrocarbons escape from the seafloor and interact with the water column of the sea atmosphere. These areas are identified as a resource pool of oil and gas, fundamentally made from hydrocarbons. Shifting slabs of salt in the Earth’s crust release these compounds in the gulf. However, the toxic brine pool does not mix with the larger seawater due to the difference in densities as well as the steep wall engineered by the biological communities. The high levels of methane and hydrogen sulfide are advantageous for some creatures like mussels who help in keeping the wall of the pool intact. 

"The mussels, they've done a really standup job at keeping the walls intact,” one of the researchers said in the video. The researchers also spotted an outflow of the brine pouring into the sea from a salt drainage in the wall. The video’s description stated that the expedition was conducted in two cruise legs during the May 2015 E/V Nautilus field season and later analyzed water samples, conducted high-resolution mapping, and completed visual surveys to accumulate data on these site salty sites. 

According to a report by Nautilus Live, some cold seep sites feature seawater interacting with ancient salt deposits from depths of the seafloor. This process results in an extremely saline fluid called brine, which does not easily mix with seawater and in turn, forms lakes and pools deep under the sea. At present, the Gulf is a deep basin but it was once a shallow sea that was separated from the world ocean and eventually dried out during the middle Jurassic period, as per a NOAA report. All it left behind was a layer of thick salts and minerals, about 8 kilometers thick. With time, the region reopened a connection with the ocean and now exists as underwater salt lakes. 

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