The discovery of a huge field of hydrothermal vents in the depths of the eastern Pacific Ocean

There is still much to be discovered about deep-sea vents along the global ridge in the middle of the ocean, both in terms of their location and in terms of their geological, geochemical and biological characteristics.

An enormous field of mysterious hydrothermal vents on the sea floor, specifically in the dark depths of the eastern Pacific Ocean. The field was discovered by a team of researchers from Lehigh University in the United States, and they say it is the hottest and largest discovered in the region so far.

The field is located about 200 miles off the coast of western Mexico, in a place where scientists did not expect to find active thermal vents, let alone an entire system of them, hundreds of meters from the center of a volcanic ridge.

The field covers a football field, and its candelabra-like chimneys are as high as a three-story building in a mountain range on the ocean floor known as the East Pacific Rise. The team published the results of the study of the discovered field in the Proceedings of the National Academy of Sciences (PNAS) on July 21.

Sulfide structures in the YBW-Sentry vent field have iron yellow staining, and host white lobster.  Image source 01: Woods Hole Oceanographic Institution, National Deep Diving Facility, Jason RV Team, WHOI-MISO Facility, National Science Foundation.

A hydrothermal vent field located about 322 km off the coast of western Mexico (Woods Hole Oceanographic Institution)

The hydrothermal vents are home to some of the most amazing ecosystems on Earth. They are vents on the sea floor that spew heat and chemicals from our planet's crust, and are usually associated with volcanic activity.

Huge towers in the depths of the sea

According to a report on the university’s website , Ross Parnell Turner, a geophysicist at the Scripps Institution of Oceanography in California, and co-author of the research, explained that the bathymetric surveys near the bottom that the research team conducted between 2018 and 2021 with a spacecraft. The Sentry (AUV), an autonomous underwater vehicle provided by the Woods Hole Oceanographic Institution (WHOI), has produced high-resolution maps showing the characteristics of the seafloor over very small areas (one metre).

Through it, the team was able to monitor an area of ​​huge towers up to 3 floors at a depth of 2560 meters below the surface in permanent darkness. During this survey, the team found the tops of a huge thermal vent field located 750 meters east of the known ridge axis, and 5 to 7 km north of the nearest previously known active axial vents.

The team was able to monitor an area of ​​​​the huge towers up to 3 stories high (Woods Hole Oceanographic Institution)

Samples from 9 vents revealed temperatures of 368°C, with elements indicating higher temperatures with a minimum of 437°C given the observed iron and manganese ratio.

Water vents outside and inside the axis

"We were amazed that not only was the field active, but it was larger in area and hotter in temperature than any other known hydrothermal vent field along this part of the East Pacific Rise that was created," marine geologist Daniel Fornari of Woods Hole Oceanographic Institution said. studies over the past 30 years.

"The mapping provides a detailed picture of the sea floor so that we can monitor and measure the changes that occur when the next volcanic eruption occurs along this part of the eastern Pacific rise axis," McDermott of Lehigh University explained.

Scientists believe the vents may help recharge nearby hydrothermal ecosystems after volcanic eruptions. There have been two volcanic eruptions in the height of the eastern Pacific Ocean in recent decades, one from 1991 to 1992, and another in 2005 to 2006, and other eruptions are expected to occur within a few years.

"There is still much to be discovered about deep-sea vents along the global mid-ocean ridge, both in terms of their location and in terms of their geological, geochemical and biological characteristics," McDermott said.

"I hope our study will stimulate future research efforts to target mapping of off-axis regions along the crest of the global mid-ocean ridge in order to better quantify the extent of off-axis hydrothermal venting versus on-axis hydrothermal venting," he added.