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High CO2 Spurs Wetlands to Absorb More Carbon
http://newsdesk.si.edu/releases/high-co2-spurs-wetlands-absorb-more-carbon[font face=Serif][font size=5]High CO2 Spurs Wetlands to Absorb More Carbon[/font]
July 15, 2013
[font size=3]Under elevated carbon dioxide levels, wetland plants can absorb up to 32 percent more carbon than they do at current levels, according to a 19-year study published in Global Change Biology from the Smithsonian Environmental Research Center in Edgewater, Md. With atmospheric CO[font size="1"]2[/font] passing the 400 parts-per-million milestone this year, the findings offer hope that wetlands could help soften the blow of climate change.
Plant physiologist Bert Drake created the Smithsonian’s Global Change Ecological Research Wetland in 1987 at Edgewater. Back then, most scientists thought plants would gradually stop responding to rising CO[font size="1"]2[/font]. Whether or not terrestrial ecosystems could assimilate additional carbon—and act as powerful carbon sinks—was not known. This study tracked not only how much CO[font size="1"]2[/font] wetlands absorb, but also the impact of rising temperature and sea level, changing rainfall and plant type.
To simulate a high-CO[font size="1"]2[/font] world, Drake’s team surrounded marsh plots with open-top Mylar chambers. For this study they left half of the chambers exposed to today’s atmosphere. In the other half they added CO[font size="1"]2[/font] and raised the level to 700 ppm, roughly doubling the CO[font size="1"]2[/font] concentration as it was in 1987. Other plots of land were left without chambers. They compared the levels of CO[font size="1"]2[/font] going in and CO[font size="1"]2[/font] going out to determine the carbon exchange between the wetland and the atmosphere.
Two types of plants populate most of the world, and the experiment tested both. C3 plants—which include more than 95 percent of the plant species on earth, including trees—form molecules of three carbon atoms during photosynthesis, and they tend to photosynthesize more as atmospheric CO[font size="1"]2[/font] rises. C4 plants form molecules of four carbon atoms. But for C4 plants, photosynthesis is saturated with CO[font size="1"]2[/font] at present levels. For that reason the team expected photosynthesis to increase in the C3 plants but not the C4 plants as they raised CO[font size="1"]2[/font]. In this study, half the plots were dominated by the C3 sedge Scirpus olneyi and half by the C4 grass Spartina patens.
…[/font][/font]
July 15, 2013
[font size=3]Under elevated carbon dioxide levels, wetland plants can absorb up to 32 percent more carbon than they do at current levels, according to a 19-year study published in Global Change Biology from the Smithsonian Environmental Research Center in Edgewater, Md. With atmospheric CO[font size="1"]2[/font] passing the 400 parts-per-million milestone this year, the findings offer hope that wetlands could help soften the blow of climate change.
Plant physiologist Bert Drake created the Smithsonian’s Global Change Ecological Research Wetland in 1987 at Edgewater. Back then, most scientists thought plants would gradually stop responding to rising CO[font size="1"]2[/font]. Whether or not terrestrial ecosystems could assimilate additional carbon—and act as powerful carbon sinks—was not known. This study tracked not only how much CO[font size="1"]2[/font] wetlands absorb, but also the impact of rising temperature and sea level, changing rainfall and plant type.
To simulate a high-CO[font size="1"]2[/font] world, Drake’s team surrounded marsh plots with open-top Mylar chambers. For this study they left half of the chambers exposed to today’s atmosphere. In the other half they added CO[font size="1"]2[/font] and raised the level to 700 ppm, roughly doubling the CO[font size="1"]2[/font] concentration as it was in 1987. Other plots of land were left without chambers. They compared the levels of CO[font size="1"]2[/font] going in and CO[font size="1"]2[/font] going out to determine the carbon exchange between the wetland and the atmosphere.
Two types of plants populate most of the world, and the experiment tested both. C3 plants—which include more than 95 percent of the plant species on earth, including trees—form molecules of three carbon atoms during photosynthesis, and they tend to photosynthesize more as atmospheric CO[font size="1"]2[/font] rises. C4 plants form molecules of four carbon atoms. But for C4 plants, photosynthesis is saturated with CO[font size="1"]2[/font] at present levels. For that reason the team expected photosynthesis to increase in the C3 plants but not the C4 plants as they raised CO[font size="1"]2[/font]. In this study, half the plots were dominated by the C3 sedge Scirpus olneyi and half by the C4 grass Spartina patens.
…[/font][/font]
(See also: http://www.democraticunderground.com/112747829 )