California dreamin’
Budding botanists who want to do serious research without heading into the jungles might consider looking for work at Stanford University’s Jasper Ridge Global Change Experiment in balmy California. The main challenges for researchers there-who are studying the effects of changing environmental factors on the growth of plants-include mixing up “soil smoothies” and keeping out gophers, with mild Mediterranean climes to boot.
That was one of the messages at a Monday “ecolunch” seminar featuring Dr. Hugh Henry, a plant ecologist from the University of Western Ontario, who did a post-doctoral stint at Stanford.
The peculiar microclimate at the Jasper Ridge Biological Reserve makes for a November to May growing season. And during the summer, though temperatures are no hotter than Toronto’s, hardly any precipitation falls. As a result, the grasslands wither each year, allowing researchers to use the grasslands as a model system. On various experimental plots, they subject grasslands to increased carbon dioxide (CO2) levels, nitrates (they promote plant growth), and humidity, to gauge the potential impact of future changes in climate on grasslands. “You may see selection here-for plants that are selected for these environmental changes, or you might see changes in species composition across time,” Henry said.
Researchers knew that increasing nitrates, humidity and heating in a patch of soil can increase plant “output,” by up to 100 per cent. But they could not explain why plants didn’t grow even faster with all these factors present, when extra CO2 is pumped in. In fact, additional CO2 slightly dampened plant output.
Then, in July 2003, a freak fire swept through part of the experimental plot. But instead of ditching the lot and heading home, the researchers continued to monitor the burnt plots. To their surprise, they noticed that burning had caused the “suppressing effect” of additional CO2 to vanish-the scrubs in those plots grew greater than any other. After digging further, they found that the ash from the burnt plant litter, which contains phosphorus (another promoter of plant growth), is responsible for the plants’ growth spurt. So all went home happy, in the end?
Well, all except Henry’s field assistant perhaps, who, having spent the previous summer making smoothies at a place called Jumbo Juice, was rather unimpressed at having to blend up soil smoothies instead.
“She’s actually not in science anymore,” Henry quipped, drawing generous guffaws.
-Mike Ghenu
