VOLUME 20 #1

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Matt Oliver with gentoo penguins
Matt Oliver is tracking penguins, such as the Gentoos (above) that are moving to areas with less ice.

Follow the penguins

Birds provide clues to changing Antarctic climate

RESEARCH | What's the best way to study the Antarctic's ecosystem? Follow the penguins.

Scientists are tracking penguins on land, under the sea and even from space to unravel the environmental dynamics in the West Antarctic Peninsula as the region experiences climate change.

"We're not just down there bird watching," says Matthew Oliver, assistant professor of oceanography. "This is a concerted effort to put the whole ecosystem together."

Rising annual temperatures have had a trickle-down effect around the peninsula, which extends from Antarctica toward South America. Warmer conditions have decreased the amount of sea ice there, as well as potentially the numbers of krill that feed on phytoplankton nearby. Fewer krill means less food for Adélie penguins, and both populations have declined 70-80 percent in recent decades.

a colony of penguins on Antartica's Humble Island
A colony on Antarctica's Humble Island.

To better understand what is happening, researchers are studying this food web in relation to physical properties of the ocean. A team from the Polar Oceans Research Group has recently been in Antarctica attaching tracking devices to several penguins simultaneously. The penguins then go about their foraging routines, leaving their rookeries to swim out to sea and catch krill.

Each evening, their programmed tracking devices transmit information via satellite about where they have traveled during the previous 24 hours. Computers at UD receive emails from these penguins that describe their locations, and then they process that data and overlay the individual penguins' routes in colorful, zigzagged lines on a specialized map based on Google Earth.

Next, the researchers predict where the penguins' future scavenging patterns will be, taking into account additional information from NASA satellites.

Back in Antarctica, underwater robots called gliders are programmed and sent into the ocean to measure temperature, salinity, chlorophyll and other indicators along the birds' routes. By analyzing these different factors, the team is trying to figure out which elements influence the penguins' behavior.

"As we understand where these penguins are foraging, we want to know what that ocean substructure looks like," Oliver says.

The goal is to decipher what exactly the penguins are responding to in the water that leads them to forage in some areas but not others. Early results suggest that tides may be a key factor. Oliver hypothesizes that as the tidal phase shifts from one big tide per day to two, the flow of water changes in such a way that it impacts the krill distribution and penguin behavior.

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Other hypotheses involve ocean temperature and visual cues. The team will be examining at which depths the temperature is changing a lot, and whether there are certain optical parameters that are important because penguins are visual predators.

Penguins are a good indicator species for environmental change, Oliver says. Overall, the area is becoming less hospitable to Adélie penguins, which are either dying or need to move farther south where there is more ice. Meanwhile other species of penguins, the land-loving Gentoos and Chinstraps, are moving in.

"If you look where the animals are going, they are going there for a reason," says Travis Miles of Rutgers University, which is partnering with UD on the project that also involves the Virginia Institute of Marine Science. The study is funded by NASA in partnership with the National Science Foundation.

The experiments combine computer science, engineering, oceanography and biology, with researchers and graduate students constantly troubleshooting how to write code and analyze data in meaningful ways.

"We've got animals, robots, people, satellites," Oliver says. "It's been a really neat confluence of technology."

Article by Teresa Messmore

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