Rare deep-sea brine pools discovered in the Red Sea may hold clues to environmental upheavals in the region that span millennia, and could even shed light on the origins of life on Earth, a new study finds.
Scientists have discovered a 10-feet long brine pool at the bottom of the Red Sea that is lethal to most sea creatures and humans. Rare brine pools in the Red Sea are extremely salty. They cannot sustain marine life forms because they are devoid of any oxygen whatsoever.
The ‘death pool’ was discovered by a team of scientists from the University of Miami. Professor Sam Purkis, who was part of that team, explained the brine pool doesn’t have any oxygen and can immediately stun or kill any sea creature.
Deep-sea brine pools are extraordinarily salty or “hypersaline” lakes that form on the seafloor. They are among the most extreme environments on Earth, yet despite their exotic chemistry and complete lack of oxygen, these rare pools teem with life and may offer insights into how life on Earth began — and how life could evolve and thrive on water-rich worlds other than our own.
The team discovered the pool at a depth of 1,770 meters using a remotely operated underwater vehicle (ROV). “At this great depth, there is ordinarily not much life on the seabed. However, the brine pools are a rich oasis of life. Thick carpets of microbes support a diverse suite of animals,” said Professor Purkins.
“Our current understanding is that life originated on Earth in the deep sea, almost certainly in anoxic — without oxygen — conditions,” study lead author Sam Purkis, a professor and chair of the Department of Marine Geosciences at the University of Miami, told Live Science. “Deep-sea brine pools are a great analog for the early Earth and, despite being devoid of oxygen and hypersaline, are teeming with a rich community of so-called ‘extremophile’ microbes. Studying this community hence allows a glimpse into the sort of conditions where life first appeared on our planet, and might guide the search for life on other ‘water worlds’ in our solar system and beyond.”
These pools might also yield microbial discoveries that could contribute to the development of novel medicines, Purkis added. “Molecules with antibacterial and anticancer properties have previously been isolated from deep-sea microbes living in brine pools,” he said.
While the pool may be bad news for unsuspecting marine creatures, they’re rich in biodiversity and also a food reserve for predators who feed on the ‘unlucky fish’.
Perkins told Live Science that the discovery could lep scientists in the future to find how oceans were formed on our planet millions of years ago.
“Our discovery of a rich community of microbes that survive in extreme environments can help trace the limits of life on Earth and can be applied to the search for life elsewhere in our solar system and beyond,” he said.
“Until we understand the limits of life on Earth, it will be difficult to determine if alien planets can host any living beings,” he added.
Scientists know of just a few dozen deep-sea brine pools in the entire world, which range in size from a few thousand square feet to about a square mile (2.6 square kilometers). Only three bodies of water are known to host deep-sea brine pools: the Gulf of Mexico, the Mediterranean Sea and the Red Sea.
The Red Sea possesses the highest known number of deep-sea brine pools. These are thought to arise from dissolving pockets of minerals deposited during the Miocene epoch (about 23 million to 5.3 million years ago) when the sea level in the region was lower than it is today.
The researchers discovered the pools during a 2020 expedition onboard the marine exploration organization OceanX’s research vessel OceanXplorer. The expedition investigated the Red Sea coastline of Saudi Arabia, “an area which has so far received little attention,” Purkis said.
What happens in a brine pool, stays in a brine pool:
Because the brine lacks oxygen, the pool keeps out the usual animals that live in and on the seabed, such as burrowing shrimp, worms, and mollusks. “Ordinarily, these animals bioturbate or churn up the seabed, disturbing the sediments that accumulate there,” Purkis said. “Not so with the brine pools. Here, any sedimentary layers that settle to the bed of the brine pool remain exquisitely intact.”
Core samples that the researchers extracted from the newfound brine pools “represent an unbroken record of past rainfall in the region, stretching back more than 1,000 years, plus records of earthquakes and tsunami,” Purkis said. Their findings suggest that in the past 1,000 years, major floods from serious rain “occur about once every 25 years, and tsunamis [take place] about once every 100 years.”
These findings regarding the risk of tsunamis and other disasters may have “very important lessons for the massive infrastructure projects that are presently being built on the coastline of the Gulf of Aqaba,” Purkis said. “Whereas the coastline of the Gulf of Aqaba has traditionally been sparsely populated, it is now urbanizing at an astounding rate.”
In the future, “we aim to work with the other countries that border the Gulf of Aqaba to widen the assessment of earthquake and tsunami risk,” Purkis said. In addition, “we hope to return to the brine pools with more sophisticated coring equipment to try to extend our reconstruction back beyond 1,000 years, deeper into antiquity.“
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