Hundreds of hydrothermal nozzles undulating the seabed

The new underwater map reveals towering towers and hydrothermal vents rising from the sea floor in the dark off the Pacific Northwest.

Hydrothermal vents of all sizes in the ocean floor off the US coast. Photo: MBARI.

Nozzles emit superheated water heated by magma deep in the Earth. The field of hydrothermal vents extends along the sea floor in the Juan de Fuca Plate in the northwestern coastal state of Washington, in an area called Endeavor Segment.

The study of Endeavor spray circuit started in the 1980s. Previously, scientists identified 47 nozzles in 5 large fields. But recent expeditions by underwater automatic means (AUV), operated by the Monterey Bay Aquarium Research Institute (MBARI), reveal that there are more than 500 orifice concentrated in an area 14 km long and 2 km wide. .

Deep-sea vents that form around hydrothermal vessels from mineral deposits are pushed to the surface by hot liquids up to 400 degrees Celsius. When hot liquids meet salty sea water, minerals settle around the geysers, forming towers with impressive heights.

In Endeavor Segment, abundant and intense hydrothermal activity has transformed the sea floor in about 2,300 years. Strong tremors also worsened the region, according to the MBARI research team published on April 14 in the journal Geochemistry, Geophysics, Geosystems. The mouths rising from Endeavor are among the highest in the middle of the ocean. The largest tower ever recorded is "Godzilla", rising 45 m from the sea floor but collapsed in 1995.

Previous expeditions had difficulty identifying the undersea structure at great depths in the darkness of the geysers. Sound waves from surface ships and diving robots cannot map the area with a resolution high enough for researchers to count each nozzle, according to geologist and volcanologist David Clague, Endeavor research leader. Segment. This time, Clague and colleagues took a closer look at the nozzle of D. Allan B, AUV shaped 5 meters long yellow torpedoes and can map with multi-beam sound waves with a meter resolution.

This AUV sample conducted four surveys in 2008 from the Atlantis research facility and three surveys from the Zephyr research facility in 2011, allowing scientists to map an area of ​​62 km2. The team of researchers counted 572 nozzles higher than 3 m high, high enough to distinguish them from other topographic features. Most of the mouth is lower than 8 m while the highest is 27 m.

Most spray nozzles are quiet. If minerals accumulate over the geyser, super hot water rushes to another crack and the nozzle stops growing, even though they may stay there for centuries. Only 47 nozzles in Endeavor are still active.