“Unlucky” creatures that enter rare brine pools in the Red Sea are immediately stunned to death

Rare deep-sea brine pools discovered in the Red Sea may hold clues to environmental upheavals in the region that span millennia, and may even shed light on the origins of life on Earth, according to a new report. study.

Deep-sea brine pools are extraordinarily salty or “hypersaline” lakes that form on the seabed. They are among the most extreme environments on Earth, but despite their exotic character chemistry and complete lack of oxygen, these rare pools teem with life and may offer insight into how life on Earth began – and how life may have evolved and thrived on water-rich worlds other than our own.

“Our current understanding is that life originated on Earth in the open ocean, almost certainly under anoxic conditions – without oxygen -,” lead study author Sam Purkis, professor and director of the Department of marine geosciences from the University of Miami. Science. “Brine pools of the deep sea are an excellent analogue of early Earth and, although they are oxygen-deprived and hypersaline, are teeming with a rich community of so-called ‘extremophile’ microbes. Studying this community allows therefore to gain insight into the kind of conditions where life first appeared on our planet, and could guide the search for life on other “aquatic worlds” in our solar system and beyond.”

These pools could also yield microbial findings that could aid in the development of new drugs, Purkis added.

“Molecules with antibacterial and anticancer properties have already been isolated from deep-sea microbes living in brine pools,” he said.

Related: Photos: 2,300-year-old fortress discovered along the Red Sea

Scientists know of only a few dozen deep-sea brine ponds worldwide, ranging 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 has the largest known number of deep water brine pools. These are thought to result from the dissolution of pockets of minerals deposited during the Miocene epoch (about 23 million to 5.3 million years ago) when sea levels in the area were lower than it is today.

Until now, all known deep brine pools in the Red Sea have been located at least 15.5 miles (25 km) offshore. Now scientists have discovered the first such pools in the Gulf of Aqaba, a northern pocket of the Red Sea, where submerged salt lakes lie just 2 km from shore.

Researchers discovered the pools during a 2020 expedition aboard marine exploration organization OceanX’s OceanXplorer research vessel. The expedition surveyed Saudi Arabia’s Red Sea coastline, “an area that has so far received little attention,” Purkis said.

Using a remotely operated underwater vehicle (ROV), scientists discovered the pools 1.77 km below the surface of the Red Sea, naming them NEOM Brine Pools after the Saudi development company that funded the research. The largest pool was approximately 107,000 square feet (10,000 square meters) in diameter, while three smaller pools were less than 107 square feet (10 square meters) in diameter.

“At this great depth, there’s usually not a lot of life on the seafloor,” Purkis said. “However, brine pools are a rich oasis of life. Thick carpets of microbes support a diverse retinue of animals.”

Most interesting among these “were fish, shrimp and eels that seem to use brine to hunt,” Purkis said. The brine is devoid of oxygen, so “any animal that strays into the brine is immediately stunned or killed,” he explained. Predators lurking near the brine “prey on the unlucky,” he noted.

The proximity of these pools to the coast means that they could have accumulated terrestrial runoff, incorporating terrestrial minerals into their chemical composition. They could therefore potentially serve as a unique archive preserving traces of tsunamis, floods and earthquakes in the Gulf of Aqaba for thousands of years, 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 mud shrimp, worms, and molluscs. “Ordinarily, these animals bioturbate or stir up the seabed, disturbing the sediment that accumulates there,” Purkis said. “This is not the case with brine ponds. Here, all the sedimentary layers that settle on the bed of the brine pond remain perfectly intact.”

The baseline samples the researchers extracted from the new brine pools “represent an unbroken record of past rainfall in the region, dating back more than 1,000 years, as well as earthquake and tsunami records,” Purkis said. . Their findings suggest that over the past 1,000 years, major floods from heavy rains “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 currently being built on the Gulf of Aqaba coastline,” Purkis said. “While the Gulf of Aqaba coastline has always been sparsely populated, it is now urbanizing at a staggering rate.”

Going forward, “we aim to work with the other countries bordering the Gulf of Aqaba to expand earthquake and tsunami risk assessment,” Purkis said. Additionally, “we hope to return to the brine pools with more sophisticated coring equipment to try to extend our reconstruction beyond 1,000 years, deeper into antiquity.”

The scientists detailed their findings online June 27 in the journal Earth and Environment Communications (opens in a new tab).

Originally posted on Live Science.

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