A lake at the bottom of the sea seems like the stuff of fantasy, but the Jacuzzi of Despair is definitely not. The lake was discovered by a San Pedro based research vehicle known as E/V Nautilus in 2015. The researchers sent a remotely operated underwater vehicle known as the Hercules to get information about the lake and collect samples for examination. Named the Jacuzzi of Despair or the Pit of Despair, the extreme salinity of the water and the dissolved methane gas kills any and all life that is unfortunate enough to enter the lake.

The Jacuzzi of Despair is about 100 feet in circumference, dammed 12 feet high and lies on the ocean floor almost 3,300 feet below the surface of the Gulf of Mexico.

The salinity of the water is four to five times higher than its surroundings, and is brewed by the methane and hydrogen sulfide that seeps from its floor.

The underwater lake was formed over a few millions of years ago when the Gulf of Mexico was relatively shallow and the water evaporated leaving behind massive sediments of salt beds. Every time these beds got shifted or cracked, the oil and gas trapped in the shale would escape allowing the sea water to enter and mix with the sediments.

The overflowing lake water formed waterfalls with cascading tiny crates at its border. The lake is also connected too what seems to be a brine river that flows over the ocean bed. If its surface is disturbed, the brine solution breaks up into waves.

The high salinity of the water makes it so dense and viscous that it doesn’t mix with the water around it. It also makes for a toxic environment for ocean life that unwittingly enters the water, hence the name Jacuzzi of Despair.

At 10 feet the lake is 46⁰ F (7.8⁰ C) and as Hercules’ sensor was sent down further the temperature rose and reached 66⁰ F (19⁰ C), much warmer than the 39⁰ F (3.8⁰ C) of the surrounding waters.

The warmth attracts the marine life looking for food. The lake is scattered with the dead bodies of benthic crabs, amphipods and fish that have tried to either swim in or cross across the water, getting literally “pickled” in brine.

Despite the inevitable death trap that is the lake, life thrives at its borders. In a symbiotic chemosynthesis, the bacteria that live on the shells of these mussels convert the methane and hydrogen sulfide at the borders to feed the mussels.

The researchers believe that understanding extreme places such as this lake and the technology developed to study these systems will help in the exploration of the worlds on other planets.

The Hercules’ robotic arm working at the lake’s border. 

Video of the Hercules exploring the lake.