Scientific American March 2010: On Newsstands Now

The Latest in Science News

Perspective: Start science sooner (p 28)
Scientists are carefully manipulating forests and grasslands to see how changes affect the biosphere, allowing them to forecast the future. The studies are discussed in a feature in this month’s Scientific American.

Much of the climate change news we read comes not from experiments but observations. In their article, Stan D. Wullschleger and Maya Strahl present key projects, some of which have been running for a decade, where researchers are altering temperature, carbon dioxide and rainfall to see how plant life responds. The work aims to imitate the effects of climate change on the environment and the results are not all negative, but show a range of interlinked responses. Future field experiments that can manipulate all three conditions at once will lead to better models of how long-term climate changes will affect ecosystems worldwide.

Climate: A controlled experiments (p 72)
What happens to the massive bodies of whales when they die?  Those that don’t end up beached, sink down to the deep seafloor providing a unique ecosystem for various communities of organisms.  As Crispin T.S. Little writes in this month’s Scientific American, a single whale carcass can support these specialized ecosystems for decades.

By studying whale-falls from offshore California, Japan and Sweden, researchers have documented over 400 species that live in and around the whale carcasses, feeding off the bubbler, meat, and exposed bones. These include bacteria that form symbiotic relationships with clams and the bizarre gutless worm called Osedax, also known as the ‘zombie’ worm.

There are an estimated 690,000 whale skeletons rotting in the world’s oceans at any time, though this is not a new phenomenon.  “In fact, ever since the discovery of whale-fall communities, researchers have suspected that similar communities may have existed even earlier than the first whales, on the sunken carcasses of ancient marine reptiles, among them plesiosaurs, ichthyosaurs, and mosasaurs,” writes Little.  The ecology and evolutionary history of whale-falls are crucial in understanding past oceanic reptile ecosystems as well as how present deep sea animals move between widely separated hydrothermal vents and methane seep environments.

News Scan: The deadliest catch (p 14)
Sushi fans lament: a favorite fish, the Northern bluefin tuna found in the Atlantic and Mediterranean, is being caught in such great numbers that it may soon become endangered.  This month at the Convention on International Trade in Endangered Species, delegates will discuss an international trade ban on this type of tuna. 

The Northern bluefin tuna is a commercially important fish, and one that appears almost identical to its genetic cousins. This means that enforcing any trade regulations will be difficult.  One option, as discussed by Michael Moyer in this month’s issue of Scientific American, is a new technological advance in DNA coding techniques—called DNA “barcoding.” 

Once the tuna has been caught and cut up, even taxonomist have trouble identifying the exact specie of tuna, such as Northern, Pacific, and Southern.  To ensure that the endangered specie of the bluefin is not being traded and sold to restaurants a method of identification is needed.  DNA “barcoding” will enable jumbled DNA collections of any tuna sample—even that sitting on the dinner plate—to be compared to a reference DNA collection.