The Botanical Advantage to Climate Change

5 12 2009

According to a new research article published in the journal, Global Change Biology, researchers from the University of Wisconsin – Madison and the University of Minnesota – Morris conclude that evidence extracted from local Aspen and Birch trees suggest that the impact of inflated amounts of carbon dioxide in the atmosphere has increased the trees’ growth rates. This comes after researchers sampled the rings within the trees and compared it’s growth rates with the increase in carbon dioxide. The two seem to be in near perfect symmetry with one another. All plant-life absorb carbon from the atmosphere and convert it to energy for the plant to survive – a process known as photosynthesis.

A strand of Aspen.

“Trees are already responding to a relatively nominal increase in atmospheric carbon dioxide over the past 50 years,” says Rick Lindroth, a UW-Madison professor of ecology and an expert on plant responses to climate change.

It seems the two species of North American tree have taken the increase in carbon and in itself increased it’s rate of growth. Aspen and Birch trees, particularly in the American Midwest, are considered “foundation species”. These particular species impact every other plant around them. The concern that is impacting the researchers’ interests as well as the rest of the science world – is what effect will the increased growth of these species have on their symbiosis with other plants. Some plants which grow slowly may be overtaken and consumed by the rapid growth of these trees.

Ecological impacts involving the vitae of plant-life and the effects the plants themselves have on each other and their locale is a big question. Ecology is an ever-changing field and it’s very hard to predict what impacts factor A will have on factor B and vice versa.

“We can’t forecast ecological change. It’s a complicated business,” explains Waller, a UW-Madison professor of botany. “For all we know, this could have very serious effects on slower growing plants and their ability to persist.”

To the surprise to many, the growth rate of these particular species has increased phenomenally – as much as 50% faster growth than 100 years ago. The next question is, how much more carbon can the plants absorb? The plants can only handle so much carbon and can only grow to a certain point.

“Forests will continue to be important to soak up anthropogenic carbon dioxide,” says Waller. “But we can’t conclude that aspen forests are going to soak up excess carbon dioxide. This is going to plateau.”

“Aspens are already doing their best to mitigate our inputs,” agrees Cole. “The existing trees are going to max out in a couple of decades.”

The new study was funded by the National Science Foundation and the University of Minnesota – Morris.


Solar Chemistry a New Key to Finding Exoplanets

12 11 2009

For many years researchers have pondered why our Sun has a negligible amount of lithium compared to other stars in our galaxy. In comparison, our Sun actually has less than 1% of the lithium present in most other stars. Researchers using the ESO’s HARPS spectrograph analyzed over 500 different stars, 70 of which are planet-bearing star systems and compared each one’s lithium content, as well as other light chemicals (in comparison to the atomic weight of iron). It was revealed that star systems which bear planets contain far less lithium than those systems which bear no planets.

Artist's impression of a baby star still surrounded by proto-planetary material in which planets could form.
Artist’s impression of a baby star still surrounded by proto-planetary material in which planets could form.

Somehow, it seems that systems which host planets provide a way to destroy the lithium over the years. Lithium is thought to have been an abundant element since the big bang and is present in most every star. The anomaly of chemical amounts that vary from star to star has bewildered researchers for over 60 years. So can planets and other planetary bodies affect the star in a way enough to destroy and realign chemical composition within that star? It seems that way. Theoreticians have their work cut out for them trying to figure out what causes the anomaly.

Researchers have undergone this project of measuring and analyzing lithium content in hopes of finding a way to detect star systems which bear planets in a way easier and faster than the current method using the HARPS device. For reference, HARPS is a device attached to the La Silla 3.6″ ESO telescope and studies the “wobble” of gravity and light from stars to detect if the star hosts a planet. If the current research is right, researchers may now use the HARPS device to detect lithium content from a star to determine the likelihood of the said star hosting planets.

The team of astronomers and researchers primarily involved in the project are: Garik Israelian, Elisa Delgado Mena, Carolina Domínguez Cerdeña, and Rafael Rebolo (Instituto de Astrofisíca de Canarias, La Laguna, Tenerife, Spain), Nuno Santos and Sergio Sousa (Centro de Astrofisica, Universidade de Porto, Portugal), Michel Mayor and Stéphane Udry (Observatoire de Genève, Switzerland), and Sofia Randich (INAF, Osservatorio di Arcetri, Firenze, Italy).

Journal Reference: G. Israelian et al. Enhanced lithium depletion in Sun-like stars with orbiting planets. Nature, November 12, 2009. Adapted from materials provided by ESO.