Kaleidoscope of Deep-Sea Life Found Near Hydrothermal Vents Off Mexican Coast

In the Gulf of California off the coast of La Paz, Mexico, a deep-sea expedition discovered a thriving hydrothermal vent ecosystem, complete with six new possible species of arrow worms, mollusks, crustaceans, and roundworms, reports Molly Taft for Gizmodo.

A remotely operated vehicle (ROV) captured stunning images of the ecosystem’s calcite spires, hydrothermal mirror pools, and iridescent scale worms. With the ROV, researchers studied various hydrothermal vents, some reaching temperatures up to 549 degrees Fahrenheit, per a statement.

The 33-day long expedition aboard the research vessel Falkor included researchers from both Mexico and the United States. During this time, the researchers focused on mapping the seafloor, exploring tectonic processes, measuring heat flow, sampling microbes, and geophysics of the hydrothermal vents in the Gulf, a statement reports.

The Gulf of California is a body of water filled with diverse sea life that falls about half a mile deep with a few depressions reaching greater depths. The gulf formed 12.5 million years ago when the Baja Peninsula started to pull away from the rest of North America along the San Andreas Fault system. Compared to other geological features in the area, it's actually considered quite young.

Hydrothermal vents form when two tectonic plates move away from each other and form a fissure at the bottom of the ocean. Water will then seep through these cracks into Earth’s red-hot mantle below. When the water touches the mantle, it will shoot back towards the surface, creating a vent of rushing, steaming hot water, Live Science reports.

Underwater sea vents were only recently discovered in the 1970s, and scientists are still learning about life that thrives from them, per Gizmodo.

“The deep ocean is still one of the least explored frontiers in the solar system,” one of the expedition’s lead researchers Robert Zierenberg, a geologist at the University of California, Davis, said in a statement from a 2018 expedition. “Maps of our planet are not as detailed as those of Mercury, Venus, Mars, or the moon, because it is hard to map underwater. This is the frontier.”

Previous expeditions from 2012, 2015, and 2018 laid the groundwork and mapped the seafloor for exploration in 2021. First, researchers used a yellow torpedo-shaped robot called an autonomous underwater vehicle (AUV) to map out the seafloor and the features of the sea vents. To get a closer look at the hidden sea world, researchers used yellow a mini van–sized ROV named SuBastian, which allowed them to determine that the ducts are active.

Hydrothermal vents can actually expel various colors of liquid. For example, vents called black smokers expel sooty-colored plumes because the liquid encounters basaltic rocks and iron metals as the water rushes towards the surface. But researchers on this recent expedition discovered a vent that expels a clear, sparkling liquid in the Pescadero Basin at the south end of the Gulf of California. Scientists suspect sediment from Mexico’s mainland ends up in the vent, which in turn filters out basalts and other metals, leaving behind only shimmering minerals, reports Nicoletta Lanese for Live Science.

The floating mineral forms ledge-like deposits called flanges. The vent’s liquid pools underneath these structures at times, creating a type of reverse waterfall or upside-down lake effect. When water accumulates in these small ledges, they will at times collapse, creating small mounds. The minerals can also form tall structures dubbed chimneys, per Live Science.

Aside from discovering the fascinating geology of the Gulf’s floor, the team also found diverse sea life thriving on or near the vents and their mineral structures. Some animals even seemed to gravitate toward certain vents. Sites towards the south had more shining blue worms, for example. Researchers also spotted Oasisia tubeworms living on or near other vents, Gizmodo reports.

Until another expedition is organized, the team plans to examine the bacterial mats and other sea life samples to understand their genetics and morphology—and determine whether these creatures can be categorized as a new species.

“This expedition has simultaneously built on our past exploration of the Alarcon and Pescadero basins and enabled further exploration in the adjacent, but poorly known Farallon and Carmen Basins,” David Caress, an engineer at the Monterey Bay Aquarium Research Institute, said in a statement.

Elizabeth Gamillo | | READ MORE

Elizabeth Gamillo is a correspondent for Smithsonian and a science journalist based in Milwaukee, Wisconsin. She has written for Science magazine as their 2018 AAAS Diverse Voices in Science Journalism Intern.