Microbes beneath sea floor genetically distinctJuly 22, 2008Tiny microbes beneath the sea floor, distinct from life on the Earth's surface, may account for one-tenth of the Earth's living biomass, according to an interdisciplinary team of researchers, but many of these minute creatures are living on a geologic timescale. "Our first study, back in 2006, made some estimates that the cells could double every 100 to 2,000 years," says Jennifer F. Biddle, PhD. recipient in biochemistry and former postdoctoral fellow in geosciences, Penn State. "Now we have the first comprehensive look at the genetic makeup of these microbes." Biddle is now a postdoctoral associate at the University of North Carolina, Chapel Hill. The researchers looked at sediment samples from a variety of depths taken off the coast of Peru at Ocean Drilling Site 1229. They report their findings in today's (July 22) online issue of the Proceedings of the National Academy of Sciences. "The Peruvian Margin is one of the most active surface waters in the world and lots of organic matter is continuously being deposited there," says Christopher H. House, associate professor of geoscience. "We are interested in how the microbial world differs in the subsea floor from that in the surface waters." The researchers used a metagenomic approach to determine the types of microbes residing in the sediment 3 feet, 53 feet, 105 feet and 164 feet beneath the ocean floor. The use of the metagenomics, where bulk samples of sediment are sequences without separation, allows recognition of unknown organism and determination of the composition of the ecosystem. "The results show that this subsurface environment is the most unique environment yet studied metagenomic approach known today," says House. "The world does look very different below the sediment surface." He notes that a small number of buried genetic fragments exist from the water above, but that a large portion of the microbes found are distinct and adapted to their dark and quiet world. The researchers, who included Biddle; House; Stephan C. Schuster, associate professor; and Jean E. Brenchley, professor, biochemistry and molecular biology, Penn State; and Sorel Fitz-Gibbon, assistant research molecular biologist at the Center for Astrobiology, UCLA, found that a large percentage of the microbes were Archaea, single-celled organisms that look like Bacteria but are different on the metabolic and genetic levels. The percentage of Archaea increases with depth so that at 164 feet below the sea floor, perhaps 90 percent of the microbes are Archaea. The total number of organisms decreases with depth, but there are lots of cells, perhaps as many as 1,600 million cells in each cubic inch. " These microbes influence the Earth's long-term carbon cycle and also these microbes may be quite ancient," says Biddle. If the rest of the world is like the Peruvian Margin, then at least one tenth and as much as a third of the Earth's biomass could be these tiny microbes living in the mud. However, this population lives at an unusual rate. Single-celled organisms usually consume food for energy and then rather than grow larger, simply divide and reproduce themselves. While the Bacteria Escherichia Coli, as an example, doubles its numbers every 20 minutes, these Archaea double on the order of hundreds or thousands of years and consume very little energy. "In essence, these microbes are almost, practically dead by our normal standards," says House. "They metabolize a little, but not much." According to House, organisms metabolizing at such slow rates is what we could expect to find in other areas of our solar system because such environments have much less energy available than on Earth. Perhaps, similar organisms may be in hydrothermal vents beneath the ice of Europa -- the second moon of Jupiter -- or in subsurface aquifers of Mars. "We do not expect the microbes in other places to be these microbes exactly," says House. "But, they could be living at a similar slow rate." Biddle notes that these microbes could survive major Earth impacts by asteroids, so the subsea floor could be a refuge for life during extinction events. Now this study shows they may be a reservoir of novel genetic material as well. Her future research will focus on understanding the lifestyle of the microbes. "For example, how do they die?" asks Biddle. "It is a simple question that we cannot answer." Penn State |
|||||||||||||||||||||
| Related Microbes Current Events and Microbes News Articles Cigarettes Harbor Many Bacteria Harmful to Human Health Cigarettes are "widely contaminated" with bacteria, including some known to cause disease in people, concludes a new international study conducted by a University of Maryland environmental health researcher and microbial ecologists at the Ecole Centrale de Lyon in France. Tiny bubbles clean oil from water Small amounts of oil leave a fluorescent sheen on polluted water. Oil sheen is hard to remove, even when the water is aerated with ozone or filtered through sand. MIT scientists pinpoint origin of dissolved arsenic in Bangladesh drinking water Researchers in MIT's Department of Civil and Environmental Engineering believe they have pinpointed a pathway by which arsenic may be contaminating the drinking water in Bangladesh, a phenomenon that has puzzled scientists, world health agencies and the Bangladeshi government for nearly 30 years. Earth's early ocean cooled more than a billion years earlier than thought: Stanford study The scalding-hot sea that supposedly covered the early Earth may in fact never have existed, according to a new study by Stanford University researchers who analyzed isotope ratios in 3.4 billion-year-old ocean floor rocks. Early life on Earth may have developed more quickly than thought The Earth's climate was far cooler - perhaps more than 50 degrees - billions of years ago, which could mean conditions for life all over the planet were more conducive than previously believed, according to a research team that includes a Texas A&M University expert who specializes in geobiology. Sweet as can be: how E. coli gets ahead Scientists at the University of York have discovered how certain bacteria such as Escherichia coli have evolved to capture rare sugars from their environment giving them an evolutionary advantage in naturally competitive environments like the human gut. Newly Discovered Fat Molecule: An Undersea Killer with an Upside A chemical culprit responsible for the rapid, mysterious death of phytoplankton in the North Atlantic Ocean has been found by collaborating scientists at Rutgers University and the Woods Hole Oceanographic Institution (WHOI). This same chemical may hold unexpected promise in cancer research. New imagining technique could lead to better antibiotics and cancer drugs A recently devised method of imaging the chemical communication and warfare between microorganisms could lead to new antibiotics, antifungal, antiviral and anti-cancer drugs, said a Texas AgriLife Research scientist. Nitrogen loss threatens desert plant life, study shows As the climate gets warmer, arid soils lose nitrogen as gas, reports a new Cornell study. That could lead to deserts with even less plant life than they sustain today, say the researchers. Scientists visualize how bacteria talk to one another Using imaging mass spectrometry, researchers at the University of California, San Diego have developed tools that will enable scientists to visualize how different cell populations of cells communicate. More Microbes Current Events and Microbes News Articles |
|||||||||||||||||||||
|
|||||||||||||||||||||
|
|||||||||||||||||||||