Is It a Good Microbe or a Bad Microbe?by Bill Chameides | September 2nd, 2010
posted by Erica Rowell (Editor)
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In the news last week: Two microbes helping us out.
Welcome to Microbe Land or It’s a Small World After All
You may think that the world is all about humanity, our place on the evolutionary scale, our position at the top of the food web, and, for better or worse, our domination of the planet. Or, you may view such ideas as being oh-so-terribly retro and anthropomorphic. (For more on that subject, I commend Daniel Quinn’s Ishmael to your reading pleasure.)
Whatever you may think, I know of one class of organisms who, if I may assign anthropomorphic characteristics to them, would whole-heartedly disagree and with good reason. The organisms of which I speak are microbes — those microscopic creatures that include bacteria, fungi, protists, archaea, and plankton.
From the point of view of mass and metabolism, microbes rule the world.
It’s estimated that microbes make up 50 to 90 percent of all ocean biomass and more than 50 percent of the planet’s total biomass. They thrive in lots of environments where other things don’t do all that well, like, for instance, in our guts. Indeed, from many microbes’ points of view, the only reason we exist is to provide cozy nooks in our bellies for them to thrive. They feast off the food we ingest and, as a kind of microbial version of an afterthought, leave enough nutrition behind for us to survive on and continue to provide them their cozy, intestinal digs.
But let’s get back to our anthropomorphic view of the world and more specifically to a discussion of microbe-good and microbe-evil, for clearly, from our point of view, there are good microbes and bad microbes. Many of us humans worry about, even obsess over bad microbes, such as, for example, bacteria that make us sick. Prima facie evidence of that obsession: adding pesticides to our toothpaste.
But all that concern gives microbes a bad rap when in fact lots, perhaps even most microbes help us out. Take those bacteria in our guts for instance that help us digest our food, thereby sustaining us. And from the environment’s point of view, microbes play critical roles processing lots of stuff like the carbon in dead organic matter and cycling it back into the system for further use by green plants.
Two papers published last week highlight microbes that fall in the “good microbe” category.
Oil-Eating Microbes Cleaning Up the Gulf of Mexico
In a paper published in the journal Science, Terry Hazen of Lawrence Berkeley National Laboratory and colleagues found that a previously unknown species of cold-water, hydrocarbon-eating bacteria have been feasting on the underwater oil plume from the Deepwater Horizon blowout, degrading it at rates faster than anticipated.
What’s more, the tiny feeders have done so without creating low-oxygen or so-called dead zones that could harm marine life at depth. Hazen et al, who collected their data in late May and early June, found that oxygen saturation within the plume areas they measured averaged 59 percent while levels outside the plume were 67 percent.
Their study led the authors to suggest “the potential exists for intrinsic bioremediation of the oil plume in the deep-water column without substantial oxygen drawdown.” A definite plus.
Methane-Eating Microbes Battling Global Warming
If you’ve been paying any attention to the topic of climate change, you know that methane is a more powerful greenhouse gas than carbon dioxide (there just happens to be a lot more of the latter in the atmosphere). You might even have read (here or here, for instance) that scientists are concerned about methane releases from thawing permafrost in northern wetlands leading to a climate tipping point.
A new paper appearing in the journal Nature Geoscience by Nardy Kip of the Radboud University Nijmegen, the Netherlands, and colleagues finds that a special group of bacteria known as methanotrophs are working to limit methane emissions in peat bogs across the globe and may work even harder at warmer temperatures. Given that peatlands are thought to contain up to 30 percent of all land-based carbon, any process that slows the release of methane and does so at higher temperatures is an all-around good thing in a warming world.
Way to go, microbes. Could it be that we’ve been looking in the wrong places to solve our problems? Could it be that all our worries would be over if we only had some more microbes? Well, let’s limit that to the good ones. Tune in next week for a story on some microbes that have been up to some mischief.filed under: bacteria, carbon dioxide, climate change, faculty, global warming, methane, Planetary Watch
and: biomass, carbon, greenhouse gases, methanotrophs, microbes, peatlands, permafrost, pesticides, triclosan