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News - May 2002

NSF PR 02-36

Media contact:

 Peter West

 (703) 292-8070

Dispatch 5, The coastal waters of Charcot Island

a large tabular iceberg
A large tabular iceberg.
Credit: Kristin Cobb

Deb Glasgow observes whales
Deb Glasgow observes whales.
Credit: Andrew Girard, Woods Hole Oceanographic Institution

the sun, low on the horizon
The sun, low on the horizon, reflected from the ice.
Credit: Kristin Cobb

Nathaniel B. Palmer steams through the ice
The Nathaniel B. Palmer steams through the ice in the gathering darkness.
Credit: Kristin Cobb

an elephant seal
An elephant seal.
Credit: Kristin Cobb

May 8, 2002 / the coastal waters of Charcot Island -- A sense of accomplishment and anticipation pervaded the Nathaniel B. Palmer as she steamed toward the end of the SO GLOBEC survey grid this week, creeping south below the 69th parallel.

With cold temperatures and good visibility, voyagers got a lesson in the life cycle of ice. Moving from open ocean toward Charcot Island, the Palmer passed through several stages of new ice -- grease ice, nilas, and pancake ice, then year-old pack ice, then finally, today, into a garden of ice floes, icebergs, and scrappy brash ice. The rapidly changing scenery told the story of sea ice like time-lapse photography.

The sun peeked out at 10:20am this morning, revealing a clear, beautiful day. Snow-covered ice in all shapes and sizes, separated by rivers and pools of water, glistened to the horizon, swathed in the sky's soft pink.

"This is great for people like me who like to sleep in," said Ana Sirovic, a graduate student from Scripps Institution of Oceanography in La Jolla, Calif. "I don't get to see so many sunrises when I'm home."

As the Palmer got closer to Charcot Island, the landscape grew more and more spectacular. Passengers on the bridge felt like they were on a museum tour or an iceberg safari as they stared out the glass at a changing wonderland of giant, chiseled ice sculptures. An iceberg taller and thicker than the ship passed close by her starboard side, looming over onlookers.

Even Palmer Captain Joe Borkowski, on his 56th voyage to the Antarctic, said the scenery was unlike any he'd ever seen. "Ice is a complex subject. You could read all the books you want to learn about ice, but every trip seems different."

By 2pm, the sun was already retreating from its short journey, repainting the view with a new pattern of striking shadows. By 4:30pm, the sky was just a low wash of orange as the sun sped away and the moon appeared.

A view from the top of the food web

Deb Glasgow enjoyed the day's views from the ship's ice tower, where she is observing marine mammals for the International Whaling Commission (IWC).

"The bird boys think they've got the best spot on the ship, but I think I've topped it," quipped Glasgow, who climbs three ladders every morning to her tiny, unheated room above the bridge. From her vantage point, she can see the heads of seabird researchers Matt Becker and Erik Chapman's in the "bird box," their observation station, below her.

Glasgow is mapping the distribution of whales and seals along the Palmer's survey grid. At the top of the Antarctic food web, whales and seals are important indicators of what's happening with animals lower down, including krill.

"Where I am seeing large groups of whales, they're also seeing krill on the BIOMAPER," Glasgow said. "The information is tying up really well."

Glasgow spends a lot of time scraping ice and frost off the ice tower windows. Visibility is critical as she scans the ocean for whale blows.

"It's like a little puff of air coming from the ocean, and from that I need to identify what kind of species it is," she said. Whales have distinguishing blows; for example, southern right whales make a V-shaped blow and sperm whales blow along a 45-degree diagonal.

Glasgow is also an artist and photographer. Her visual training allows her to pick out these tiny events from the vast ocean. Artists and scientists share the same keen powers of observation, she noted.

Glasgow is also trying to get photo ID's of individual whales when they surface.

"Humpbacks have a white coloring on the underside of the flukes that's quite individual, almost like the fingerprints we have," Glasgow said. Southern right whales can be identified by the unique pattern of callosities -- rough, large, wart-like growths -- that they have on their heads.

By matching a photo ID taken in Antarctica with one taken, for example, in Costa Rica, scientists can track whale migration routes. During Antarctic summers, whales migrate to the productive Southern Ocean to feed. During the winter, they head north to warmer climates to breed and raise their calves. Few whale surveys have been done in Antarctica this late in the year, Glasgow said. Sightings may be infrequent, making for slow days in the observation tower.

"It takes an enormous amount of patience and commitment, or you've got to be an extremely stubborn person," Glasgow said.

The singular sounds of cetaceans

Accustomed to working in a team of at least four observers during busy summer cruises, Glasgow is still adjusting to being the lone marine mammal observer on the Palmer. "It's a bit like solitary confinement up here. That's why I talk so much when I go downstairs," said Glasgow with her marked Australian accent. Glasgow offers her rare visitors tea from a thermos. "It's quite civilized up here," she said.

Glasgow also gets help from a Palmer scientist who is listening for whales. Down in the dry lab, where the only views are through small portholes, Scripps graduate student Ana Sirovic scans the ocean with her ears. Sirovic uses "sonobuoys," single-use instruments with a hydrophone, radiotransmitter, and antenna, that she throws into the water periodically. Sonobuoys capture underwater sounds which they relay to a receiver on the Palmer and finally to a computer where Sirovic is listening through headphones. She often hears the elaborate songs of humpback whales.

At the same time, Sirovic can "watch" the sound on her computer screen. Colorful pictures called spectrograms display the frequency and intensity of the ocean sounds. Different sounds have distinctive patterns. Sirovic can visually distinguish earthquakes -- which she picks up from all over the world -- from ship noises from ice cracking from biological noises like seals and whales. Moreover, she can tell what types of whales are out there.

"Every species has a different type of call," Sirovic said. "The frequency characteristics and the duration of the call will tell you what species it is. You can tell a blue whale from a fin whale from a humpback from a killer whale." Many whale calls are too low in frequency or too short to be heard by the human ear, but can still be seen on the spectrogram.

"Then within each species' language there are also dialects," Sirovic continued. Antarctic blue whales sound differently than Pacific blue whales, for example. Sirovic's goal is to learn enough about specific Antarctic calls to make sense of two years worth of sound data that she's been collecting from the bottom of the Southern Ocean.

Sirovic took part in an earlier SO GLOBEC cruise that deployed eight "bottom instruments," more sophisticated sonobuoys that record all the ocean's sounds for a year.

"Basically, we get to location, drop them in, and 11 months later it's got 27 gigabytes of data," Sirovic said. The long-term sound data will help scientists estimate the distribution, seasonality, and even population sizes of Antarctic-going whales. Scientists are particularly interested in how whale populations have changed since Antarctic whaling moratoriums were established in the Southern Ocean in the 1960's and 70's.

Working together to capture 'the big picture'

While Palmer scientists anxiously scanned the horizon and listened to the seas for signs of life, scientists on the Laurence M. Gould were in the thick of the marine mammal action deep in Marguerite Bay.

"There was a conveyor belt of whales the whole day," said Ari Friedlaender of the IWC, describing one day during which he saw more than 60 whales. Friedlaender, like Glasgow, is counting whales, but along the Gould's variable path instead of on a formal grid.

"We've seen more seals on a single floe this year than we saw the whole time last year. We're very happy," said Mark Hindell of the University of Tasmania, Australia, who is working with the Gould's seal group tagging crabeater seals and collecting blood and scat samples. Gould scientists hope to learn about the winter-feeding strategies of crabeaters, which -- despite their name -- feed chiefly on krill.

Data from last year's satellite tags showed the seals to be diving unexpectedly deep in the winter. This may mean they're supplementing their krill diet with fish, said Jen Burns of the University of Alaska, Anchorage. One tagged seal also gave birth to a pup, allowing scientists to record a mother seal's foraging behaviors.

The seal biologists climb right up on ice floes to tag seals. "It's a lot of fun. You get to sit on the ice floe, look around, and pet minke whales that swim up next to the floe," Burns said.

The Gould scientists proudly show off close-up videos of playing seals and breaching whales that they've taken in the field.

Only slightly envious of their colleagues' exploits on the Gould, scientists on the Palmer will leave the cruise with a different, but complementary, account of the Southern Ocean. While the Gould has captured a dynamic and eye-catching excerpt of the Antarctic ecosystem, the Palmer has methodically and patiently pieced together an intricate and wide-ranging portrait.

"I think it's amazing that, in a few days, we'll have a whole picture of what the area looks like," Sirovic remarked. "Not just in whale distribution, but in current structure, phytoplankton, nutrients, and everything."




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