Icy, not dicey: Even in the tundra way down under, CO2 helps plants thrive
With controversy surrounding recent statements—scientific and otherwise—about the purported status of the Arctic climate, we thought we would take a look toward the future of plants in the icy world.
Turning the issue on its head, as it were, we look southward to Antarctica for clues as to what an increase in atmospheric carbon dioxide (CO2) may mean for the tundra flora.
Although Antarctica may not be the center of the plant kingdom, there are any number of rugged grasses and other plants that grow in the coastal areas of that frozen continent.
Xiong and colleagues collected plants from the Antarctic Peninsula and transported them in chilled boxes to a laboratory here at Arizona State University.
Seeds from those plants were then grown in controlled environment chambers, where various preassigned temperature regimes were maintained for 90 days. Xiong and company found that “plants of both species grown at a daytime temperature of 20°C had greater relative growth rates and produced 2.2 to 3.3 times as much total biomass as plants grown at daytime temperatures of 12°(F) or 7°C.”
The team also found that plants grown in the warm chambers produced up to four times as many leaves and more than five times as much total leaf area as their cooler cousins.
They concluded that “warming along the Peninsula will lead to improved vegetative growth of these species.”
Even in the icy tundra, we arrive at the inevitable conclusion that a) increased atmospheric CO2 benefits plants, and b) increased temperature does not impede the ability of plants to benefit from CO2. In fact, increased temperature would likely increase the tremendous biological benefits of a world of higher levels of CO2.
Robert C. Balling Jr., Ph.D. is director of the Laboratory of Climatology at Arizona State University and coauthor of The Satanic Gases.
Xiong, F.S., E.C. Meuller, and T.A. Day, 2000. Photosynthetic and respiratory acclimation and growth response of Antarctic vascular plants to contrasting temperature regimes. American Journal of Botany, 87, 700-710.