Featured Research

from universities, journals, and other organizations

Life underground: Microbes active far beneath seafloor

Date:
June 12, 2013
Source:
University of Delaware
Summary:
Genetic researchers have revealed active bacteria, fungi and other microbes living in 5 million-year-old ocean sediment.

Jennifer F. Biddle, assistant professor of marine biosciences in UD’s College of Earth, Ocean, and Environment.
Credit: Photo by Evan Krape

Microbes are living more than 500 feet beneath the seafloor in 5 million-year-old sediment, according to new findings by researchers at the University of Delaware and Woods Hole Oceanographic Institution (WHOI).

Related Articles


Genetic material in mud from the bottom of the ocean -- called the deep biosphere -- revealed an ecosystem of active bacteria, fungi and other microscopic organisms at depths deeper than a skyscraper is high. The findings were published in Nature on June 12.

"This type of examination shows active cells," said co-author Jennifer F. Biddle, assistant professor of marine biosciences in UD's College of Earth, Ocean, and Environment. "We knew that all of these cells were buried, but we didn't know if they were doing anything."

In fact, the microbes are reproducing, digesting food and even moving around despite the extreme conditions found there: little to no oxygen, heavy pressure and minimal nutrient sources. The organisms could shed light on how carbon and other elements circulate in the environment, the scientists reported.

Extracting the data

The researchers analyzed messenger RNA (mRNA) in sediment from different depths collected off the coast of Peru in 2002 during Leg 201 of the Ocean Drilling Program. This first glimpse into the workings of the heretofore hidden ecosystem was made possible by the first successful extraction of total mRNA, or the "metatranscriptome," from the deep biosphere.

Messenger RNA is highly sought-after by microbial ecologists because its presence indicates that the cells that made it are alive and because it carries the instructions for the proteins the cells are making. But because the metabolic rates in the deep biosphere are very low and mRNA is present in small amounts, extracting enough of it to analyze from deep sediments had been thought by many scientists to be impossible.

"It's not easy," said lead author William Orsi, a postdoctoral researcher advised by Biddle and WHOI's Virginia Edgcomb. "There's a certain amount of banging your head against the wall before it works."

The genetic sequencing was performed at the Delaware Biotechnology Institute, generating more than a billion bases of information. UD's Glenn Christman, who received a master's degree in marine biosciences and works in Biddle's lab as a bioinformatician, created new computer programs to help examine the immense amount of data.

Determining microbial activity

The team found evidence of cell division occurring in all three domains of life: bacteria; single-celled archaea, commonly found in oceans; and eukaryotes (organisms with nucleus-containing cells), specifically fungi.

Other researchers previously suggested that cells in the deep biosphere were buried many years ago and continued to survive by essentially repairing themselves. The new findings show, however, that these cells are able to divide and create new cells.

"It's the first time it's been seen," Biddle said, adding that researchers do not know how long it takes for a cell to divide, but it could be on a geologic timescale of thousands of years.

Messenger RNAs coding for enzymes involved in sulfate reduction and nitrate reduction, processes cells use to generate energy-storing molecules, also were found.

"It's been theorized that much of the energy that microbes get in this environment comes from sulfate reduction," said Orsi. "Basically, instead of breathing with oxygen, they 'breathe' with sulfate."

Until now, models of microbial activity in deep sediments have included sulfate reduction but have not included significant use of nitrate. The current research found comparable numbers of mRNAs involved in nitrate reduction and sulfate reduction, suggesting that both processes are important in the deep biosphere community.

The researchers also found evidence that cells in the deep biosphere are eating amino acids, which are a rich source of carbon and nitrogen and can only come from other living (or recently deceased) organisms.

They think those dead or dying cells are native to the deep biosphere rather than remnants that drifted down through the water because most of the dead material that reaches the seafloor from above is rapidly eaten. Deeper than a few centimeters down, most of the amino acids come from cells that lived and died there.

"By the time you get 100 meters down, the bacteria are eating the leftovers of the leftovers of the leftovers of the leftovers -- and they are still yummy for bacteria," Biddle said.

The study also showed that these deep biosphere microbes can move, which was previously in question. Genetic material indicated that some of the cells have flagella, or small tails that can propel them forward. Other cells produced mRNAs related to gliding and twitching. The ability to move was linked to how porous the sediment was.

"It's reminiscent of that line from Jurassic Park, 'Life finds a way,'" Biddle said. "If there's space to move, they move."

Broader implications

Finding life in the deep biosphere could refine understanding how carbon moves through the environment. Longtime global models show carbon sinking into ocean sediment, getting buried deeper and deeper and eventually getting released from within Earth's crust through a volcano.

"But there's something happening to it on the way down," Biddle said. "Models suggest that activity in the subsurface is not that important, but we'd like to revisit that with this new information."

Another reason could be to explore for new pharmaceutical ingredients. The researchers found antibiotic defense mechanisms showing in the RNA data, possibly representing a "seed bank" for medical advances in antibiotics, antifungals and immunosuppressants.

Now that a new approach to analyzing the mRNA has been developed, Biddle is interested in studying other sites beyond the Peru Margin, where the water depth is about 150 meters and there are high sedimentation rates. The activity and depth of the water above the seafloor may impact the microbial ecosystems that exist below.

"This is just this one site in one place, and there's still the rest of the world to go explore," Biddle said. "This kind of data is going to be possible to get from other areas, and this should hopefully be the groundwork for it."

The research was funded by grants from the National Science Foundation and the Center for Dark Energy Biosphere Investigations.

Article by Teresa Messmore, with material from Woods Hole Oceanographic Institution


Story Source:

The above story is based on materials provided by University of Delaware. The original article was written by Teresa Messmore. Note: Materials may be edited for content and length.


Journal Reference:

  1. William D. Orsi, Virginia P. Edgcomb, Glenn D. Christman, Jennifer F. Biddle. Gene expression in the deep biosphere. Nature, 2013; DOI: 10.1038/nature12230

Cite This Page:

University of Delaware. "Life underground: Microbes active far beneath seafloor." ScienceDaily. ScienceDaily, 12 June 2013. <www.sciencedaily.com/releases/2013/06/130612144738.htm>.
University of Delaware. (2013, June 12). Life underground: Microbes active far beneath seafloor. ScienceDaily. Retrieved December 22, 2014 from www.sciencedaily.com/releases/2013/06/130612144738.htm
University of Delaware. "Life underground: Microbes active far beneath seafloor." ScienceDaily. www.sciencedaily.com/releases/2013/06/130612144738.htm (accessed December 22, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Monday, December 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Earthworms Provide Cancer-Fighting Bacteria

Earthworms Provide Cancer-Fighting Bacteria

Reuters - Innovations Video Online (Dec. 21, 2014) Polish scientists isolate bacteria from earthworm intestines which they say may be used in antibiotics and cancer treatments. Suzannah Butcher reports. Video provided by Reuters
Powered by NewsLook.com
Existing Chemical Compounds Could Revive Failing Antibiotics, Says Danish Scientist

Existing Chemical Compounds Could Revive Failing Antibiotics, Says Danish Scientist

Reuters - Innovations Video Online (Dec. 21, 2014) A team of scientists led by Danish chemist Jorn Christensen says they have isolated two chemical compounds within an existing antipsychotic medication that could be used to help a range of failing antibiotics work against killer bacterial infections, such as Tuberculosis. Jim Drury went to meet him. Video provided by Reuters
Powered by NewsLook.com
Researchers Test Colombian Village With High Alzheimer's Rates

Researchers Test Colombian Village With High Alzheimer's Rates

AFP (Dec. 19, 2014) In Yarumal, a village in N. Colombia, Alzheimer's has ravaged a disproportionately large number of families. A genetic "curse" that may pave the way for research on how to treat the disease that claims a new victim every four seconds. Duration: 02:42 Video provided by AFP
Powered by NewsLook.com
Monarch Butterflies Descend Upon Mexican Forest During Annual Migration

Monarch Butterflies Descend Upon Mexican Forest During Annual Migration

Reuters - Light News Video Online (Dec. 19, 2014) Millions of monarch butterflies begin to descend onto Mexico as part of their annual migration south. Rough Cut (no reporter narration) Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

More Coverage


Deep Biosphere Harbors Active, Growing Communities of Microorganisms

June 12, 2013 The deep biosphere -- the realm of sediments far below the seafloor -- harbors a vast ecosystem of bacteria, archaea, and fungi that are actively metabolizing, proliferating, and moving, according a ... read more

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins