Unprecedented drought in an artificial ecosystem may reveal how rainforests will cope with climate change.
https://www.sciencemag.org/news/2019/10/putting-artificial-ecosystem-drought-could-reveal-how-rainforests-will-cope-climate
Source: By Erik Stokstad, Science Magazine.
Excerpt: Earlier this month, the doors to the tropical rainforest, enclosed under a ziggurat of glass, were sealed shut. Christiane Werner turned a valve to release about $12,000 worth of carbon dioxide (CO2) spiked with carbon-13, an isotope that is normally scarce in the atmosphere. The luxuriant plants inside Biosphere 2, a 30-year-old set of greenhouses and artificial ecosystems in the Arizona desert, soaked up the isotopic tracer, enabling investigators to follow the flows of carbon through the healthy forest. Werner, an ecosystem physiologist at the University of Freiburg in Germany, and her team gathered these baseline data for the harsh test to come: the largest forest drought experiment ever monitored with isotopes. ...On 7 October, the researchers shut off the sprinklers that irrigate the rainforest, beginning a 6-week drought. ...A forest's consumption of CO2 slows during drought, but scientists haven't pinned down how thirsty rainforest plants—especially large trees—use and release their stored carbon. The answers are important for the global climate cycle, Klein says. Droughts, expected to become more severe as the climate warms, could turn tropical forests from sinks of greenhouse gases into sources that accelerate climate change. ...By tracking the carbon-13, the researchers will learn how quickly carbon is taken up during photosynthesis and then moves through the forest. ... Ultimately, results from the drought test will improve the way global climate models account for vegetation....
Source: By Erik Stokstad, Science Magazine.
Excerpt: Earlier this month, the doors to the tropical rainforest, enclosed under a ziggurat of glass, were sealed shut. Christiane Werner turned a valve to release about $12,000 worth of carbon dioxide (CO2) spiked with carbon-13, an isotope that is normally scarce in the atmosphere. The luxuriant plants inside Biosphere 2, a 30-year-old set of greenhouses and artificial ecosystems in the Arizona desert, soaked up the isotopic tracer, enabling investigators to follow the flows of carbon through the healthy forest. Werner, an ecosystem physiologist at the University of Freiburg in Germany, and her team gathered these baseline data for the harsh test to come: the largest forest drought experiment ever monitored with isotopes. ...On 7 October, the researchers shut off the sprinklers that irrigate the rainforest, beginning a 6-week drought. ...A forest's consumption of CO2 slows during drought, but scientists haven't pinned down how thirsty rainforest plants—especially large trees—use and release their stored carbon. The answers are important for the global climate cycle, Klein says. Droughts, expected to become more severe as the climate warms, could turn tropical forests from sinks of greenhouse gases into sources that accelerate climate change. ...By tracking the carbon-13, the researchers will learn how quickly carbon is taken up during photosynthesis and then moves through the forest. ... Ultimately, results from the drought test will improve the way global climate models account for vegetation....