MAR 17, 2015 8:08 PM PDT

Deepest, Deadest Part of Ocean Shows Signs of Life

WRITTEN BY: Will Hector
Scientists have discovered evidence of oxygen-breathing microbial life more than 200 feet below the ocean floor-or 12,000 feet below sea level in the Pacific Ocean.

The microbes were found all the way through the sediment from the seafloor to the igneous basement at seven sites in the South Pacific gyre, considered the "deadest" place in the ocean.
Microbial life was found 10,000 feet deeper than the usual depth of the cockatoo squid, shown here.
Published in the journal Nature Geoscience, the new findings contradict previous discoveries that oxygen was absent from all but the top few feet of sediment in biologically productive regions of the ocean.

NO LIMIT TO LIFE
"Our objective was to understand the microbial community and microbial habitability of sediment in the deadest part of the ocean," says Steven D'Hondt of University of Rhode Island, the lead researcher on the project.

"Our results overturn a 60-year-old conclusion that the depth limit to life is in the sediment just meters below the seafloor in such regions. We found that there is no limit to life within this sediment. Oxygen and aerobic microbes hang in there all the way to the igneous basement, to at least 220 feet below the seafloor."

Based on predictive model and core samples collected in 2010 with the International Ocean Discovery Program's (IODP) research ship, JOIDES Resolution, the researchers believe that oxygen and aerobic microbes occur throughout the sediment in up to 37 percent of the world's oceans and 44 percent of the Pacific.

ALIVE, BUT NOT ACTIVE
The best predictors of oxygen penetration to the igneous basement are a low sediment accumulation rate and a relatively thin sediment layer. Sediment accumulates at just a few inches to feet per million years in the regions where the core samples were collected.

In the remaining 63 percent of the ocean, most of the sediment beneath the seafloor is expected to lack dissolved oxygen and to contain anaerobic communities.

While there was evidence of life throughout the sediment, the researchers admit there wasn't a lot of it. They found extremely slow rates of respiration and quantities that were nearly undetectable by previous techniques.

"It's really hard to detect life when it's not very active and in extremely low concentrations," D'Hondt says.

"The findings show the lowest cell concentrations and lowest rates of microbial activity ever encountered in marine sediment," says Carlos Alvarez-Zarikian, expedition project manager and staff scientist with IODP at Texas A&M University.

"It shows that there is no limit within the sediment in these deep environments that can reach 18,000 feet or greater below the ocean surface. The research team used new instruments and techniques that have never been utilized before on drilling expeditions such as this one."

Source: Texas A&M University
About the Author
  • Will Hector practices psychotherapy at Heart in Balance Counseling Center in Oakland, California. He has substantial training in Attachment Theory, Hakomi Body-Centered Psychotherapy, Psycho-Physical Therapy, and Formative Psychology. To learn more about his practice, click here: http://www.heartinbalancetherapy.com/will-hector.html
You May Also Like
DEC 10, 2019
Immunology
DEC 10, 2019
T Cell Subset Uniquely Equipped to Target IBD
A specialized form of T cell emerges as a new focus for gastrointestinal health research, specifically in the context of inflammatory bowel disease (IBD) f...
JAN 20, 2020
Microbiology
JAN 20, 2020
Microbes Create a More Sustainable Building Material
Concrete is the second most widely consumed resource on the planet (after water), and it has a massive carbon footprint....
FEB 02, 2020
Microbiology
FEB 02, 2020
A Potential Treatment for MERS is Found
A coronavirus causes MERS, which currently has no treatment. This work may help change that....
FEB 10, 2020
Immunology
FEB 10, 2020
Measles infections can give the immune system amnesia
The immune system detects the presence of invading microbes that it recognizes from previous infections, and initiates a full-blown immune response. New re...
FEB 17, 2020
Immunology
FEB 17, 2020
Another HIV vaccine attempt fizzles out
Years of work and over $100 million in study costs have been abandoned after an HIV-vaccine tested in South Africa failed to protect treated individuals ag...
FEB 18, 2020
Microbiology
FEB 18, 2020
Newly Found Glycopeptide Antibiotics Kill Bacteria in a New Way
The overuse and misuse of antibiotics and the adaptability of microbes has created a problem that people must solve....
Loading Comments...