91制片厂

In peat bogs around the world, shrubs are thriving and replacing moss 鈥� a groundcover transformation brought on by climate change, and one that could add even more carbon dioxide into our atmosphere, according to a .

The research indicates that shrubs like wild blueberry plants are adapting to drier conditions in peatlands, a type of wetland ecosystem that stores vast amounts of the Earth鈥檚 carbon and is highly vulnerable to the impacts of climate change. Scientists are calling this phenomenon the 鈥渟hrubification鈥� of peatlands, and they鈥檙e warning that it could potentially contribute to rising levels of greenhouse gas emissions.

鈥淲armer temperatures from climate change could dry out these peatlands further, thus exposing the carbon-rich peat to oxygen, enhancing decomposition听and then releasing large amounts of carbon dioxide,鈥� explains Erik Hobbie, a research professor at the 91制片厂 and co-author on the study published in the Proceedings of the National Academy of Science. The research was funded by the U.S. Department of Energy鈥檚 Office of Science and led by Oak Ridge National Laboratory in Oak Ridge, Tennessee.

"Warmer temperatures from climate change could dry out these peatlands further, thus exposing the carbon-rich peat to oxygen, enhancing decomposition, and then releasing large amounts of carbon dioxide."听

Hobbie鈥檚 research focuses on the belowground environment, which is a source for the nutrients and water plants need for growth; it鈥檚 also where a large portion of the Earth鈥檚 carbon is stored 鈥� even more than in our atmosphere 鈥� so how the belowground environment responds to climate change will influence plant responses, he says.

Plant roots play a major role in regulating the carbon, water听and other nutrient cycles. In this study, scientists studied fine roots 鈥� those smaller than 2听millimeters in diameter that grow and die off rapidly, which means they respond quickly to environmental change and thus are leading indicators of how plants will respond to climate change, Hobbie explains.

The scientists set up 12-meter octagonal enclosures on peatlands in northern Minnesota, leaving the tops open to allow normal precipitation and temperature patterns. Within the enclosures, they maintained belowground and air temperatures at 0 掳C to 9 掳C above ambient levels and measured the fine-root growth in peatland shrubs. To acquire the nutrients and water needed in these warmer and drier soil conditions, root growth of shrubs increased dramatically, by 130% for each degree of warming.

鈥淪oil moisture levels play a key role in determining the growth of fine roots,鈥� Hobbie says. 鈥淥ne consequence of warming is an extended growing season, which allows plants more time to 鈥榳ick鈥� moisture from the soil into the atmosphere, also known as transpiration. This could dry out the soil and further enhance shrub growth, which could increase the turnover of peatland carbon into atmospheric carbon dioxide.鈥�

Although peatlands cover a mere one percent of New Hampshire, the worldwide sum of this shrubification could add up to some significant changes. However, Steve听Frolking, a research professor at the 91制片厂 ESRC who was not involved in this study, cautions that it鈥檚 extremely difficult to make confident predictions about the likelihood or degree of peatland drying that might occur in the future.

鈥淚n this study, the fine-root response was mostly due to drying 鈥� not from warmer temperatures or an increase in atmospheric carbon dioxide,鈥� Frolking says. 鈥淒rying and warming can be related, but they don鈥檛 have to be; it could get warmer and not drier, if precipitation increases enough to offset increased evapotranspiration. Predicting changes in precipitation and ecosystem moisture status is much more difficult and uncertain than predicting changes in temperature.鈥�

Both Hobbie and Frolking emphasize the need for further studies of plant roots to more accurately assess their changes in all types of conditions.

鈥淩oots are essential to the function, health, and productivity of rooted plants, but they are so much harder to observe and study than leaves, stems, and flowers, so we know very little about them,鈥� Frolking adds.

The is 91制片厂's largest research enterprise comprising six centers with a focus on interdisciplinary, high-impact research on Earth and climate system, space science, the marine environment, seafloor mapping, and environmental acoustics. With more than $58 million in external funding secured annually, EOS fosters an intellectual and scientific environment that advances visionary scholarship and leadership in world-class resaerch and graduate education.听