Mother Nature comes through at the South Pole
- but at what price? The International Herald Tribune explains
ROSS ISLAND, Antarctica — Cape Royds, home to the southernmost colony of penguins in the world, is a rocky promontory overlaid with dirty ice and the stench of pinkish guano. Beyond the croaking din of chicks pestering parents for regurgitated krill lies the Ross Sea, a southern extension of the Pacific Ocean that harbors more than one-third of the world’s Adélie penguin population and a quarter of all emperor penguins, and which may be the last remaining intact marine ecosystem on Earth.
Andy Isaacson for The New York Times
Summer melt on the Ross Sea ice.More Photos »
The penguin colony is one of the longest-studied in the world. Data on its resident Adélie penguins was first acquired during the 1907-9 expedition of Ernest Shackleton, the eminent British explorer, whose wooden hut stands preserved nearby.
“This is penguin nirvana,” David Ainley, an ecologist with the consulting firm H. T. Harvey and Associates who has been studying Ross Sea penguins for 40 years, said on a morning in January. “This is where you want to be if you’re a pack ice penguin.”
Of the species that stand to be most affected by global warming, the most obvious are the ones that rely on ice to live. Adélie penguins are a bellwether of climate change, and at the northern fringe of Antarctica, in the Antarctic Peninsula, their colonies have collapsed as an intrusion of warmer seawater shortens the annual winter sea ice season.
In the past three decades, the Adélie population on the peninsula, northeast of the Ross Sea, has fallen by almost 90 percent. The peninsula’s only emperor colony is now extinct. The mean winter air temperature of the Western Antarctic Peninsula, one of the most rapidly warming areas on the planet, has risen 10.8 degrees Fahrenheit in the past half-century, delivering more snowfall that buries the rocks the Adélie penguins return to each spring to nest — and favoring penguins that can survive without ice and breed later, like gentoos, whose numbers have surged by 14,000 percent.
The warmer climate on the Antarctic Peninsula has also upended the food chain, killing off the phytoplankton that grow under ice floes and the krill, a staple of the penguin diet, that eat them, by as much as 80 percent, according to a new study published this month in The Proceedings of the National Academy of Sciences.
But in the Ross Sea a reverse trend is occurring: Winter sea ice cover is growing, and Adélie populations are actually thriving. The Cape Royds colony grew more than 10 percent every year, until 2001, when an iceberg roughly the size of Jamaica calved off the Ross Sea ice shelf and forced residents to move 70 kilometers north to find open water. (The iceberg broke up in 2006, and the colony of 1,400 breeding pairs is now recovering robustly.) Across Ross Island, the Adélie colony at Cape Crozier — one of the largest known, with an estimated 230,000 breeding pairs — has increased by about 20 percent.
Climate change has created a paradise for some pack ice penguin colonies and a purgatory for others, but the long-term fate of all Adélie and emperor penguins seems sealed, as relentless warming eventually pulls their rug of sea ice out from under them. Some scientists attribute the recent sea ice growth in the Ross Sea to the persistent ozone hole, a legacy of the human use of chlorofluorocarbons that cools the upper atmosphere over the continent, increasing the temperature difference with the lower atmosphere and equator, and over the last 30 years has delivered significantly brisker westerly winds in the summer and autumn. The warming of Earth’s middle latitudes is having a similar effect, increasing that temperature difference and sending stronger winds that push sea ice off the coast and expose pockets of open water, called polynyas, that give nesting Adélie penguins easier access to food.
Meanwhile, consumers’ appetite for Chilean sea bass (Antarctic and Patagonian toothfish) may also be benefiting Ross Sea penguins, as fishing fleets from southern nations converge on one of the last remaining refuges of the fish (Dissostichus mawsoni). A fishery in the Ross Sea that opened in 1996 and was certified sustainable in December by the Marine Stewardship Council, could ultimately serve Adélie penguins by reducing competition for Antarctic silverfish (Pleuragramma antarcticum), a sardine-size fish that the penguins and toothfish enjoy. Dr. Ainley and colleagues have reported seeing fewer killer whales in the southern Ross Sea since 2002. The whales feed on toothfish, and fewer sightings suggest that the fishery is already altering the ecosystem.
Researchers witnessed Ross Sea penguin colonies thrive during the 1970s when commercial whaling removed 20,000 Antarctic minke whales, also a food competitor of Adélies, from the penguins’ wintering area. Adélie populations eventually leveled off after 1986, after an international moratorium on whaling began (and remained static until the more recent influences of climate change). Japanese whaling of minkes resumed right after the moratorium was instituted, purportedly for science, a claim that conservation groups dispute and that has incited a confrontation in the Ross Sea between the Japanese fleet and the Sea Shepherd Conservation Society, an antiwhaling vigilante group.
A major spill of heavy crude oil from a wrecked freighter has coated an estimated 20,000 endangered penguins on a remote South Atlantic island chain, the local authorities and environmental groups said Tuesday.
More than 800 tons of fuel oil has leaked from the Maltese-registered ship, which ran aground on Nightingale Island, part of the Tristan da Cunha archipelago, a British territory, early in the morning of March 16, local officials said. All 22 crew members of the M.S. Oliva were rescued.
“The scene at Nightingale is dreadful, as there is an oil slick encircling the island,” Trevor Glass, a local conservation officer, said in a statement.
The ship has broken in half and an additional 800 tons of fuel oil is believed to be leaking from the front section of the hull, said a spokeswoman with the Royal Society for the Protection of Birds, a British-based conservation group monitoring the situation.
So far, only one salvage vessel has arrived from South Africa, and its spill response and bird rescue capabilities were described as limited. A second, better-equipped response ship is expected to depart for the area from South Africa on Thursday.
Conservation groups said the wreck could pose a different ecological threat to the chain as rats could have come ashore from the vessel, which was carrying 66,000 tons of soybeans from Brazil to Singapore. Several islands in the archipelago are rodent-free, and a rat infestation could potentially do more harm to bird life than any oiling, experts said.
The Tristan Da Cunha archipelago lies about 1,700 miles from the nearest land, in South Africa, making it the most remote inhabited island group in the world. The islands are rich in life and are home to about 200,000 penguins, including nearly half of the world’s population of northern rockhopper penguins, an endangered species whose population has plunged in recent decades for unknown reasons.
Jay Holcomb, the director emeritus of the International Bird Rescue Research Center, a bird conservation group that responds to oil spills, said in a posting on the group’s Web site that about 20,000 rockhopper penguins had been “confirmed oiled.” Images from the island showed large groups of penguins, which have distinctive spiky crests, coated in oil. “Many of the birds have been oiled for over a week, which limits their chances of survival,” Mr. Holcomb wrote.
The estimate of 20,000 was based on an early visual survey of the archipelago’s penguin habitat and may be adjusted, the center said. The extreme remoteness of the island chain poses a serious challenge for responders as there is no airport and oiled birds cannot be removed because of concern about transmission of diseases to which the birds have no resistance, Mr. Holcomb said.
The owner of the wrecked vessel could not be immediately identified. The authorities in Malta, where the ship is registered, did not respond to a request for information on Tuesday.
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