Strange but True: Drought Helped Green Amazon Rainforest
In a new study that seemingly flies in the face of most previous research (not to mention common sense), a team of scientists from the University of Arizona has discovered that the Amazon rainforest responded to a drought in 2005 by becoming "greener", rather than brown. Scott Saleska, an assistant professor of ecology and evolutionary biology and the study's lead author, and his colleagues used images obtained from NASA's Terra Satellite to study changes occurring in the rainforest canopy. They found that the trees were able to thrive under the drier conditions - albeit temporarily - by taking advantage of the additional sunlight.
The trees used the added sunlight and water siphoned from their deep roots to increase their rate of photosynthesis - allowing them to greatly up their productivity in the short term. That's not to say that persistent drought-like conditions, brought on by further global climate change, would bear no effect on the rainforest trees: "You take away enough water for a long enough time, the trees are going to die," said Saleska.
"If you anthropomorphize a little bit, these trees are not dumb. They’ve been living here tens of millions of years. If you’re designing trees to live, make sure that they could survive. Make them take advantage of that sunlight," Saleska explained.
This new study is significant, explains UA climate modeler Joellen Russel, because it will force a rethink in modeling circles that had heretofore predicted droughts would kill off the Amazon jungle by mid-century - by forcing the trees to cut evaporation from their leaves and, thus, photosynthesis - and transform it into a savannah. For his part, Saleska plans on continuing his research by further investigating how the trees use the additional water and by monitoring the long-term effects of drier conditions and increased carbon dioxide.
Although more work needs to be done before conclusive evidence can be drawn from this study, it tentatively points to a somewhat brighter future for one of our largest rainforests (though, again, maybe only short-lived) and will likely prompt an important rethink in previous models.
See also: ::Dust In The Wind, ::IPCC on Latin America: Land Drought and Coastlines Floodings are on the MenuImage courtesy of markg6 via flickr