Biologists Dig In The Dirt For Soil Microbes
January 3, 2013

Biologists Examine The Underground World Of Soil Microbes

Brett Smith for — Your Universe Online

Understanding biological diversity has been the key to learning how ecosystems around the world function in a sustainable manner. A team of American and Australian scientists has taken this philosophy and applied it to a section of the ecosystem that has largely been ignored, the microbial communities that lie just below our feet.

“We´ve been walking around on soil since the beginning of time and never really knew what was going on underneath us,” said research team member and Brigham Young University biologist Byron Adams.

“The organisms that live in soil do all kinds of important things for us — they decompose and decontaminate our waste and toxic chemicals, purify our water, prevent erosion, renew fertility,” he added.

Adams and his colleagues have taken the first steps in learning the unique differences among the microbial communities found in the different soils around the world, according to their report in the latest edition of the Proceedings of the National Academy of Sciences.

“People think you´re going to pick up a handful of dirt anywhere in the world and you´ll pretty much have the same bunch of microbes doing pretty much the same things,” Adams said. “That´s simply not true. They function very differently based on their environment. And when you have more species, you get more and different functions.”

Using metagenomic sequencing, the researchers compared the composition and functional traits of 16 soil microbial communities “collected from cold deserts, hot deserts, forests, grasslands, and tundra,” the report said.

The genetic information they collected on each soil microbe allowed the team to know which organisms do what and if some microbes are redundant in decomposition, fertilization, or other roles. If some soil communities have microbes that perform duplicate functions, a redundant species that goes extinct can quickly be replaced by another. Conversely, more desolate ecosystems might have a few specialized species and removing some could result in a catastrophic ecosystem event.

Their analysis showed that soils collected from “cold desert” environments have the lowest amount of diversity on their soil microbe communities. Meanwhile, most other soil samples showed similar levels of microbe diversity. The team also found a correlation between genomic diversity within the samples and functional diversity among microbes.

The study´s findings verified previous research that showed soil pH is a fairly decent predictor of diversity.

The research team noted that understanding the roles played by different soil microbes is essential to learning how to maintain the sustainability of these communities. They also said that their results are only a first step toward potentially harnessing these organisms in the pursuit of fertile soil and clean water.

“Now we will be able to make predictions of how ecosystems function, what causes them to collapse, and perhaps even predict, where collapses will take place and how we can prevent them,” Adams said. “The most obvious applications of this understanding will probably be in agricultural ecosystems.”

In their report, the researchers said future studies could examine soil microbial communities in these various ecosystems at different depths within the Earth.