Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Microbes, by latitudes and altitudes, shed new light on life's diversity

13.08.2008
Oregon biologist Jessica Green is working in the new frontier of ecological and evolutionary research

Microbial biologists, including the University of Oregon's Jessica L. Green, may not have Jimmy Buffett's music from 1977 in mind, but they are changing attitudes about evolutionary diversity on Earth, from oceanic latitudes to mountainous altitudes.

In two recent National Science Foundation-funded papers in the Proceedings of the National Academy of Sciences, Green and colleagues show that temperature, not productivity, primarily drives the richness of bacterial diversity in the oceans, and that life, both plant and microbial, by altitude in the Rocky Mountains may be close, but not exactly, to what biologists have theorized for years.

Swedish naturalist and botanist Carl Linnaeus, the father of taxonomy who died in 1778, proposed that the planet once was covered by oceans, except for Paradise Island on the equator, and that all organisms emerged from the island and migrated as waters receded. More than a century later, microbiologist Lourens G.M. Bass Becking in the 1930s wrote that "everything is everywhere, but the environment selects."

"What's interesting to me," said Green, a professor of biology and member of the UO Center for Ecology and Evolutionary Biology, "is that the founders of these disciplines envisioned the same thing: That you have this broad dispersal of all of the organisms that each happened to be studying, and that they would colonize the surface of the Earth depending on whether the environment was suitable for them."

In the last decade, microbial biology, using molecular techniques, has changed everything, Green said in an interview about the two PNAS papers and an extensive review of microbial biogeography in the May 23 issue of the journal Science. She was lead author on the Science paper.

"Before now, all biologists could do was look at the biodiversity of microbes that could be cultured in a petri dish. We now know that the vast majority of microbial life cannot be kept in captivity. Now we have the ability to grab DNA from the environment and try to characterize different species or taxonomic groups using genetic material, allowing our field to blast off."

Yet, she added: "We are just beginning to scratch the surface of what these patterns look like."

Green was among several co-authors on a project led by biologist Jed A. Fuhrman of the University of Southern California and published in PNAS in May.

Using samples of ocean-dwelling bacteria collected over 15 years from 57 locations around the world and sorting them into species or taxonomic units, researchers found twice as many microbes at the equator than at the poles. In particular, they found that samples from colder waters still contained many bacterial species, suggesting that productivity as generated by light through photosynthesis has little influence on diversity.

Warmth dictated such diversity, the seven co-authors concluded, but they left open the possibility that the kinetics of metabolism related to temperature is still linked with photosynthesis. "What we found," Green said, "was that the diversity gradient more correlated with temperature than primary productivity."

As for the mountains, traditional wisdom, beginning with Linnaeus, has said that diversity of animal and plant life is highest at the bottom and decreases as you climb. While that scenario has been observed, a second one is emerging, that of a hump shape, with diversity at its height just above the foothills.

In a paper published Aug. 12 in a PNAS special publication (the "Sackler Colloquium: In the Light of Evolution--Biodiversity and Extinction") , Green, as principal investigator, and five colleagues documented diversity patterns of a combination of plant and microbial life, focusing on flowering plants and soil-abundant Acidobacteria, in the Rocky Mountains in Colorado. They found significant differences, using a combination of classical taxonomic and phylogenetic approaches.

Plant communities became less phylogenetically clustered than did microbial life as they drew samples from five sites rising over 24 miles, from 8,071 feet to 11,089 feet. As they went higher, plant life saw a decline in species richness, but for microbes, researchers saw a hump shape in species richness as they went up the slopes.

Their conclusion: "From our study, we saw that environmental selection seemed to play a larger role and was more important for microbes than the plants," Green said.

The trick to the research, she said, involved the scale from which the samples were drawn. Plants were gathered from one-meter-square quadrants, while microbes were taken from soil cores. "You have to be careful about the conclusions that you make," Green said. "So on a 2,000-meter elevation gradient, for example, the spatial scale relative to the body size of a plant is much, much larger when you consider what the universe looks like to a microbe."

That spatial consideration, she said, led her team to narrowly focus on the diversity of Acidobacteria rather than a wide range of microbes present in each area. This allowed the researchers to focus on patterns within one microbial phylum.

"Diversity patterns on mountainsides have been studied mostly on plants and animals for hundreds of years," Green said. "Yet microbes are the most diverse set of organisms on Earth, and they are really important for how ecosystems work. Our study establishes the first elevation-gradient pattern for microbes. We found that, yes, microbes do have a diversity pattern that is similar to what has been studied for plants and animals, but the pattern is different than what you see for plants in the Rockies, and there is much to be done to understand why microbes might have a different biodiversity pattern."

It could boil down to finding a good comparative technique, she said. "I don't think that microbes are fundamentally different from a biological standpoint from plants and animals. I think that we haven't figured out how to study them in an analogous way."

Jim Barlow | EurekAlert!
Further information:
http://www.uoregon.edu

More articles from Life Sciences:

nachricht Transport of molecular motors into cilia
28.03.2017 | Aarhus University

nachricht Asian dust providing key nutrients for California's giant sequoias
28.03.2017 | University of California - Riverside

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Transport of molecular motors into cilia

28.03.2017 | Life Sciences

A novel hybrid UAV that may change the way people operate drones

28.03.2017 | Information Technology

NASA spacecraft investigate clues in radiation belts

28.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>