Natural sound recording artist Kathy Turco usually comes to us with stories about Alaska's wildlife, but recently she visited the frozen continent, Antarctica, where troubling changes are coming to light. The linkage between climate warming and declining Adelie penguin populations is now compelling. Listen to her story here...(3.9MB)

ABOUT KATHY TURCO
Kathy Turco is the founder and sole owner of Alaska's Spirit Speaks: Sound and Science. She has been recording natural sounds in Alaska since 1988, and has owned a state of the art digital audio studio since 1995. Originally trained in zoology, she earned a M.S. degree in marine biology with subsequent training as a natural sound recording artist and radio producer. In addition to recording natural sounds in the field, she is the writer, voice talent, sound designer, and producer of her own science audio productions for national and international radio, and for science education web sites. As part of her business, she also provides natural sound effects and consultation, as well as works as a sound designer.

Email Kathy at alaskaspirit@mosquitonet.com

JOURNEY TO THE ICE. National Science Foundation icebreaker Nathaniel B. Palmer cruises along the Antarctic Peninsula at dusk. Geologist Eugene Domack of Hamilton College and his colleagues are attempting to build a continuous record of ice shelf changes during the last 15,000 years by looking at sediment core samples. One of their major goals is to interpret a 2.5 (degree) C rise in annual average surface air temperature of the peninsula over the past 54 years.

DISINTEGRATING ICE SHELF. Ice cave remnant Marr Glacier at Norsel Point. This small shelf, fed by glaciers from the Loubet Coast, has been receding recently; previously, it had been growing during a 400-year cooling period. Like other receding ice shelves, it may be a sensitive monitor of rising regional temperatures. Evidence from sediment and glacial core samples indicates that other periods of warmth have occurred in Antarctica, but the present temperature is the warmest in 500 years and is increasing rapidly.

GLACIER GIVES WAY. This mile-long ice cliff of Marr Ice Piedmont has been calving into Arthur Harbor, Anvers Island, Antarctica, for at least 30 years. Over this period, the glacier cliffs have receded about 500 meters - the cliff's previous position was to the left of the line of ice floating in the harbor and extended to the headland at the extreme upper left. The regional temperature increase is highest in winter - average June temperatures have increased 5 (degrees) C - which not only affects glaciers but also reduces winter sea ice.

ICY MYSTERIES REVEALED. Palmer Station personnel explore the face of Marr Ice Piedmont, where this channel opened during the last two years, revealing the rocky island in the foreground. Previously this location was covered by glacier ice and thought to be a peninsula. Probably more significant is the fact that, since 1973, sea ice has decreased by more than 20 percent. Heavy winter ice occurs only in one out of five years now; 50 years ago, it occurred in four out of five years. Scientists have discovered that the advance and retreat of sea ice can disrupt crucial relationships among sea birds, sea mammals, krill, and ocean plankton.

TINY PLANTS ON THE MOVE. Hairgrass (Deschampsia antarctica) surrounding a clump of pearlwort (Colobanthus quitensis). Here on Stepping Stone Island near the U.S. Palmer Station, botanist Tad Day has found that global warming increases the number and viability of seeds produced; it also encourages more vegetative growth of pearlwort than hairgrass. Both species, which are the continent's only two vascular plants, have spread beyond previous locations over the last 30 years.

MISSING PENGUINS. Bill Fraser stands on the smooth pebbly surface of a former large colony of Adelie penguins on Torgersen Island. He believes the missing penguins are due to less ice and more snow. Rising winter temperatures and less sea ice mean there is more water vapor and more snow, which accumulates in deep drifts on the lee of these islands. Adelies, strongly loyal to habitual nesting grounds, lay eggs on the snow anyway, only to have the nests fail because of cold and wetness. On the windward side, most colonies are declining more slowly than those on the lee side.

FOOD HUNTING. Adelie penguin male feeding young on Humble Island. This bird searches for its prime food, krill, along the sea ice edge. The tiny radio transmitter this penguin wears has allowed researchers to infer that foraging takes longer during years that have less sea ice.

CENTER OF THE FOOD CHAIN. Krill (Euphasia superba), which has perhaps the greatest biomass of any creature on Earth, is the staple food for the entire range of Southern Ocean predators, from fish to whales, including Adelie penguins. Growing to no more than 2.5 inches long individually, the genus has the staggering reproducing capability to create swarms of as much as 60,000 krill per cubic meter of seawater. Krill appear to prefer feeding on algae and diatom blooms under the sea ice edge, and years of low sea ice also may be a time of low krill reproduction, another problem for penguins.

KASTEN CORE ON DECK. On the rear deck of Nathaniel B. Palmer, technicians for the National Science Foundation prepare a kasten core device to lower into sediment near the Müller Ice Shelf, Antarctica. This 3-meter-long square tube can collect sediment dating back some 8,000 years. During this April 1999 cruise, technicians also deployed longer cylindrical cores in waters nearly 1,000 meters deep, including a core that retrieved 20 meters of sediment. It was the longest core ever pulled from the Antarctic shelf.

MAPPING THE DEPTHS. Multibeam sonar topographic map of the Palmer deep region of the Bellingshausen Sea, near Anvers Island, Antarctic Peninsula, along with traditional navigation tools. The National Science Foundation's Nathaniel B. Palmer research ship is able to map the ocean bottom continuously, providing geologists with new visions of geology and past climate. Within this 1,440-meter depression, Eugene Domack was able to find small basins containing sediment records dating back to the last glacial period; these indicate extremely rapid climate changes over the last 3,700 years.

SEARCHING FOR ANSWERS. Searchlights from above the bridge pick out icebergs as the icebreaker Nathaniel B. Palmer maneuvers through Antarctic Peninsula waters. This 300-foot ship is a prime tool for National Science Foundation studies of biology, geology, and climate change in Antarctica.