Space-bound plankton aid global warming study

by Stephen Forgacs
Staff writer

UBC researchers are sending zooplankton, tiny animals near the bottom of the ocean food chain, into orbit in a quest to gain a better understanding of the world's oceans' ability to counter global warming.

Oceanographer Al Lewis and research technician Lara Chatters Fandrich will send zooplankton into space on a coming shuttle mission to study the role that gravity plays in guiding them from the oceans' depths to the surface. The zooplankton serve as tiny carbon couriers, ferrying carbon from the surface to the oceans' depths where it is stored.

"Oceans cover two-thirds of the globe and, because most of the world's vegetation is found in the ocean, are collectively responsible for consuming more carbon than all land plants combined," says Lewis, a professor in the Dept. of Earth and Ocean Sciences.

As couriers, zooplankton are an important component in the oceans' buffering ability for greenhouse gases. Through photosynthesis, phytoplankton -- tiny plants that live close to the surface in vast numbers -- take up carbon that has been absorbed at the ocean's surface from carbon dioxide in the atmosphere. Zooplankton venture to the surface from depths as great as 300 metres to feed on phytoplankton before returning to deeper water where the carbon is released.

Exactly how these tiny animals navigate on their migrations to the surface to feed is not clear, although the fact that they often migrate in darkness suggests sunlight is not solely responsible. Rather, Lewis believes zooplankton are guided by gravity. But many of these zooplankton lack anything resembling an inner ear, which gives most animals a sense of gravity.

"In designing an experiment to test the role of gravity it is important to remove or at least reduce gravitational forces for a period long enough to obtain meaningful results," Lewis says. "This is where the space shuttle comes in -- a microgravity laboratory that permits examination of the role of gravity in swimming and orientation."

Lewis and Fandrich will send zooplankton skyward in small transparent chambers where their swimming and orientation will be videotaped for study. Half of the plankton will spend the mission in low gravity, while the other half will be subject to gravitational forces similar to those on Earth.

A better understanding of how the world's oceans process carbon can help in determining the magnitude of the greenhouse effect and what can be done to minimize its impact, says Lewis.