Hot and Cold Chile

Each year scientists learn more about the mysterious creatures that make their living in the harsh conditions of the planet’s hydrothermal vent systems, where heated water gushes from the seafloor. Researchers also have made progress in accumulating data about organisms that flourish at cold areas where methane rises, or “seeps” from the deep ocean bottom.

Scientists at Scripps Institution of Oceanography at UC San Diego are leading investigations off the coast of Chile where the strange organisms of hot hydrothermal vent and cold methane seep biological communities are thought to meet—a deep and dark region unique to the planet.

A 24-day research cruise supported by UC Ship Funds aboard Scripps Institution of Oceanography’s research vessel Melville is conducting operations on a continental margin that features some of the planet’s largest earthquakes and massive reservoirs of methane (Note: On Feb. 27, just three days after departing from the southern Chilean port city of Puerto Montt, one of the largest earthquakes in recorded history ruptured in Chile while researchers aboard Melville conducted research off the Chilean coast; Thankfully the vessel was out of harm’s way and all aboard were safe. See: cruise log entry by Scripps graduate student Ben Maurer).

One expedition site is the Chile Triple Junction, where three of the planet’s tectonic plates meet. Here the spreading center that typically features hot vents is being dragged into a subduction zone, forcing it under a continental margin with methane seeps. The scientists also will visit the Concepción methane seep, El Quisco methane seep, and the southern end of the Peru Chile Trench.

Chief scientist and Scripps graduate student Andrew Thurber is leading a team of 35 students and researchers from Scripps, UC Santa Barbara, Woods Hole Oceanographic Institution (WHOI), the University of Washington, and scientists and students from Chile. The Feb. 24 to March 17 cruise, called INSPIRE (International Southeast Pacific Investigation of Reducing Environments): Chile Margin 2010, includes Scripps scientists Lisa Levin and Donna Blackman.

The team is documenting the findings of the research cruise through a multimedia web page that includes daily dispatches from the voyage.

Working with the Census of Marine Life and the NOAA Office of Ocean Exploration and Research, the scientists are seeking new biological life forms and ecosystems adapted to various seafloor conditions. In addition to these biological and geological questions, the mission also will address the science of microbial ecology.

Thurber says the continental margin off Chile is home to incredibly biologically productive waters and stores roughly three percent of the world’s supply of methane within its sediments. Scientists have generally found evolutionarily related species living at hot vents and cold seeps, but rarely have they found the same species at both.

“There may be an area where hot fluid interacts with methane stored within the margin and forms a unique hybrid environment,” said Thurber. “This would be exciting and may provide an evolutionarily link between the hot and cold habitats.”

The scientists will probe the area with WHOI’s Autonomous Benthic Explorer (ABE), an autonomous underwater vehicle. ABE will aid the researchers’ search for hydrothermal and methane plumes, and their associated biological communities, while other instruments deployed from Melville will help to verify and sample biological organisms. A newly adapted camera system funded by the UC Academic Senate is helping the researchers select optimal sites to obtain samples for further study.

The team will spend the final days of the expedition focusing on extremely deep environments at 6,000 meters (nearly 20,000 feet), known as the “hadal” zone, and characterizing the microbes that have adapted to such an extreme setting.

In addition to UC Ship Funds, the voyage is supported by NOAA’s Office of Ocean Explorations and Research, the Census of Marine Life, and the Total Foundation.

Read more about Scripps’ deep-sea research in explorations magazine:

http://explorations.ucsd.edu/Features/2008/Deeply_Connected/

http://explorations.ucsd.edu/Research_Highlights/2009/Apr/Costa_Rica_Rocks/

—Mario C. Aguilera