10/7/2023 0 Comments Microcosm carl zimmer“We believe that as the polar ocean warms, the ecosystem will change to favor microbes,” says one researcher. Decomposing microbes can now feed on the dead plant matter and pump carbon into the atmosphere. The tundra has also become drier, so that oxygen can penetrate into the ground, allowing microbes to thrive. Scientists believe that the change has come as rising temperatures in the Arctic have reduced the stress experienced by the microbes. But as the Arctic has warmed in recent decades, the flow of carbon has reversed: The tundra has started releasing more carbon than it captures. The tundra of North America and Siberia has been storing away carbon for the past 11,000 years, since the glaciers retreated at the end of the last Ice Age. When tundra plants die, microbes can only break down a fraction of their biomass. Making life even harder for them is the lack of oxygen in the boggy ground. They are frozen for much of the year, and the stress of the cold makes them grow poorly even in warm months. The tundra is a tough place for microbes to make a living. To see the starkest evidence of the feedback between global warming and microbes, you need only travel to the Arctic. Or they may be stimulated to draw carbon dioxide out of the atmosphere, softening the blow of climate change. It’s possible that we will cause bacteria to churn out greenhouse gases far faster than they do today, adding to our own global warming.Ī microscopic view of oscillatoria, a bacteria found in freshwater. But scientists have only a rough sense of what those changes will turn out to be. And as we change the world’s microbes, we will also change their impact on the climate. They know just enough to recognize that as we raise the planet’s temperature, we will alter the planet’s microbes. Scientists are only just starting to figure out some of the rules that govern this feedback. As the climate changes, it can change the planet’s microbial menagerie. But the influence doesn’t just flow one way, from microbes to the climate. And in the process they’ve influenced the Earth’s climate. Microbes have been absorbing and releasing greenhouse gases ever since they first evolved in the ocean more than 3.5 billion years ago and spread on land about 2 billion years ago. “It’s eight times what humans are putting into the atmosphere through fossil fuel burning and deforestation,” says Allison. Meanwhile, the microbes that break plant matter into soil release 55 billion tons a year of carbon dioxide. The ocean is also rife with bacteria that feed on organic matter and release carbon dioxide as waste. On the surface of the ocean, photosynthetic bacteriasuck vast amounts of carbon dioxide dissolved in the water and turn it into organic molecules. Microbes have been absorbing and releasing greenhouse gases since they evolved 3.5 billion years agoĮven more impressive is the vast amount of carbon that microbes pump around the biosphere. “If you look at all the trees and the grass and the flowers and add all that up, there’s four times as much carbon in the soil,” says Steven Allison, a biologist at the University of California at Irvine. The world’s soils - the product of bacteria and fungi breaking down plant matter - contain more than 2.5 trillion tons of carbon. Together, microbes lock up - and release - a huge amount of carbon. Some scientists estimate that our planet is home to about 5 trillion trillion bacteria They pack the oceans and the soils they live just about everywhere they can find even a trace of liquid water. But taken together, microbes are a force to be reckoned with. But the giant scale of this picture hides some of the most important players in the global warming story, which are as crucial to the future of the planet as factories and forests: the planet’s vast swarms of microbes.Ī single bacterium, measuring a few millionths of an inch across, may not seem like much compared to a coal-fired power plant. Thanks to human activity, carbon dioxide is rising into the atmosphere faster than the planet can draw it down. This sort of diagram does a great job of illustrating the big picture. Some arrows rise up from cities and farmland, while other arrows plunge down to forests and oceans. When new reports about global warming come out, they typically include a picture of the land and sky, with arrows marking the movement of carbon dioxide around the planet.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |