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Seabirds The Decline and Fall of the Emperor ? CLIMATE CHANGE AND SHRINKING THREATEN POLAR by David Levin

Few things go together as naturally as ice and . But in is threatened, and therefore so are emperor penguins.

t nearly four feet tall, the Emperor penguin is Antarc- Antarctica where French scientists from French Polar Institute tica’s largest seabird—and thanks to films like “March Paul Émile Victor have conducted penguin observations for of the Penguins” and “,” it’s also one of the more than 50 years. continent’s most iconic. If global temperatures continue “Long-term data are required, if you really want to study to rise, however, the large colony of emperor penguins in the impact of climate variability on populations,” she said. Terre Adélie in may eventually disappear, “Antarctica is, on average, the windiest, driest, and coldest accordingA to a study led by researchers from the Woods Hole place on Earth. For this reason, it’s very hard to study emperor Oceanographic Institution (WHOI). penguin colonies. The only place we can study an entire colony The decline of those penguins is likely connected to a si- over their entire year’s cycle is in Terre Adélie, because there, the multaneous decline in Antarctic sea ice resulting from warming scientific base is not far from the penguin colony.” temperatures in the region, said Stephanie Jenouvrier, WHOI “If you want to study the effects of climate on a par- biologist and lead author of the study. ticular , there are three pieces that you have to put Unlike other seabirds, emperor penguins breed and raise together,” said Hal Caswell, a mathematical biologist at their young almost exclusively on sea ice. WHOI and collaborator on the paper. If that ice breaks up and disappears early “The first is a description of the entire in the breeding season, massive breeding Our best life cycle of the organism, and how in- failure may occur, she said. “As it is, dividuals move through that life cycle. there’s a huge mortality rate just at the projections The second piece is how the cycle is breeding stages of penguins’ life cycle, affected by climate variables. And the because only 50 percent of chicks survive show only 500 crucial third piece is a prediction of to the end of the breeding season, and what those variables may look like in then only half of those fledglings survive to 600 breading the future, which involves collabora- until the next year.” tion with climate scientists.” Disappearing sea ice may also affect pairs by 2100. Jenouvrier used results from various the penguins’ food source. The climate models to determine how chang- feed primarily on , , and , a —Stephanie Jenouvrier es in sea ice might affect the emperor shrimplike , which in turn feeds penguin population at Terre Adélie. She on tiny zooplankton, phytoplankton, and algae that grows on found that if greenhouse gas emissions continue to rise at levels the underside of the ice. If the ice goes, Jenouvrier said, so too similar to today—causing temperatures to rise and Antarctic will the plankton, causing a ripple effect through the food web sea ice to shrink—penguin population numbers will diminish that may starve the various species that penguins rely on as prey. slowly until about 2040, after which they would decline at To project how penguin populations may fare in the future, a much steeper rate as sea ice coverage drops below a usable Jenouvrier’s team used data from climate models, sea ice fore- threshold. casts, and a demographic model that Jenouvrier created of the “Our best projections show roughly 500 to 600 breeding emperor penguin population at Terre Adélie, a coastal region of pairs remaining by the year 2100. Today, the population size is

16 Oceanus Magazine Vol. 50, No. 2, Summer 2013 | www.whoi.edu/oceanus ANTARCTIC REGION

30 30 0 Port Elizabeth SOUTH 30 Year-round research station AFRICA Scale 1:68,000,000 S o u t h A t l a n t i c Azimuthal Equal-Area Projection O c e a n 0 500 1000 Kilometers 40 Anta 0 500 1000 Miles rctic Co nve Twenty-one of 28 Antarctic consultative nations have rg enc made no claims to Antarctic territory (although Russia e and the United States have reserved the right to do so) Bouvet Island and they do not recognize the claims of the other (NORWAY) PRINCE EDWARD ISLANDS nations. (SOUTH AFRICA) 50 South Georgia and the South Sandwich Islands BRITISH (administered by U.K., claimed by ARGENTINA) CLAIM ÎLES Southern CROZET Ocean NORWEGIAN CLAIM ARGENTINE undefined limit 60 Falkland Islands CLAIM 60 (Islas Malvinas) (administered by U.K., Scotia Sea Orcadas SANAE IV French Southern claimed by ARGENTINA) (ARGENTINA) Neumayer (SOUTH Novolazarevskaya and Antarctic Lands SOUTH ORKNEY (GERMANY) AFRICA) (RUSSIA) ISLANDS (FRANCE) Maitri Syowa (JAPAN) SOUTH (INDIA) 70 SHETLAND area of Molodezhnaya ARGENTINA ÎLES Ushuaia ISLANDS enlargement (RUSSIA) Enderby KERGUELEN Drake Halley(U.K.) Land Passage Belgrano II (ARGENTINA) Mawson Heard Island and CHILE Mac. Robertson (AUSTRALIA) 80 Land McDonald Islands Palmer (AUSTRALIA) Land Ronne Ice Shelf Amery Ice Shelf Zhong Shan(CHINA) Davis(AUSTRALIA) CHILEAN Progress(RUSSIA) CLAIM Bellingshausen Stephanie Jenouvrier/WHOI Sea Ellsworth I n d i a n 90 W 90 E Peter I Island South Pole Peter Kimball/WHOI 2800 m. O c e a n Few things go together as naturally as ice and penguins. But sea ice in Antarctica is threatened, and therefore so are emperor penguins. around 3,000 breeding pairs,”S o u Jenouvrier t h said. The study was published in June 2012 in the journal Global Change Biology. Ross Jenouvrier is continuing P a cthe i researchf i c on penguins. At TerreAmund sen Ice Shelf Adélie, scientists are institutingO c e aan n easier method of monitoringS ea 80 the penguin population. “We putting what’s called a PIT (Pas- sive Inductive Transponder) tag under the skin of the birds,” she said. “It’s like what we put in cats and dogs. We’ll be able average minimum to record the identity of each bird, so we will be able to know if extent of sea ice

they are survivingArgentina, and B returningrazil, Chile, China, to the Poland, colony.” Terre Adélie At the sameRussia, time, South Jenouvrier Korea, Urugu hasay eachexpanded have her research64 to 70 a station on King George Island. Anta explore climate change impacts on penguin colonies through- rctic Esperanza Circle out Antarctica. (ARGENTINA) e 120 c n e “Over the last60 century, we have already observedMar ambiothe disap- g 66 Southern r (ARGENTINA) ve pearance of the ArtuDionro Islets Prat penguinBerna colony,rdo close to the West U.S. Library of Congress on (CHILE) Ocean C O'Higgins 55 ic ,” Jenouvrier said. “In 1948 and the 1970s, ct Z ar (CHILE) Peter Kimball/WHOIEA 60 nt scientists recorded more than 150 breeding pairs there. By LAN A D CL S o u t h 1999, the population was down to just 20 pairs, and in 2009,Circle it AIM 62 Macquarie Island had vanished entirely.” p (AUSTRALIA) P a c i f i c rctic Campbell Graham Anta Island O c e a n (NEW ZEALAND) AUCKLAND ISLANDS Also collaborating65 on the study werePalmer ChristopheLand Barbraud and Henri (NEW ZEALAND) Tasmania Weimerskirch of the Centre d’Etudes(U.S.) Biologiques de Chizé in France and Vernadsky 60 50 Hobart Julienne Stroeve and Mark Serreze of the National(UKRAINE) Snow and Ice Data SNARES ISLANDS Center; and Marika Holland Antafrom ther Nationalctic Center of AtmosphericLarsen (NEW ZEALAND) Adelaide Ice Shelf Melbourne Research in the United30 States.P Fundingeninsula for the study was provided by the NEW 30 WHOI Ocean Life Institute, the WHOI Arctic Research Initiative, and the ZEALAND South Island CHATHAM ISLANDS Canberra WHOI Access to the Sea program; the National Science Foundation, Agence (NEW ZEALAND) Christchurch Southern San Martin Wellington A U S T R A L I A National de la Recherche70 Biodiversité, the Institut Paul Émile Victor, the 40 Ocean (ARGENTINA) 180 Sydney Alexander von Humboldt Foundation, Marie-Curie150 Rothe Europeanra fellowship, (U.K.) North Island and the Cooperative Institute for Research in Environmental Sciences vis- 803121AI (R02207) 3-05 iting fellowship. 64 68

At top, WHOI biologist Stephanie Jenouvrier readies a five-month-old emperor penguin chick for tagging in Terre Adélie (center). Tags help identify birds and track whether they return to the colony to breed.

Woods Hole Oceanographic Institution 17