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.
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 on how life on Earth began — and how life could evolve and thrive on water-rich worlds other than our own.
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.
Until now, all known deep-sea brine pools in the Red Sea were 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 the submerged salty lakes lie just 1.25 miles (2 km) from shore.
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.
"At this great depth, there is ordinarily not much life on the seabed," Purkis said. "However, the brine pools are a rich oasis of life. Thick carpets of microbes support a diverse suite of animals."
Most interesting among those "were the fish, shrimp and eels that appear to use the 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. The predators that lurk near the brine "feed on the unlucky," he noted.
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."
The scientists detailed their findings online June 27 in the journal Communications Earth and Environment.
Originally published on Live Science.
