All eyes on the ice: like a giant white scoresheet, the Antarctic Peninsula is daily recording changes in the environment. And change is occurring more rapidly there than almost anywhere else on Earth.
No. There's a new gang in town--a bigger, bolder bunch called the gentoos. They've been steadily taking over this patch: they had just 56 nests here 99 years ago, but today, they have 2,200. Over the same period, Adelie nests have declined from 925 to fewer than 400. It's now difficult to spot a black-hood in the crowd.
But it's wrong to say that the Adelie gang are moving out, because Adelies are site-specific nesters, according to Ron Naveen, founder of Oceanites, a US-based science and educational foundation. Founded in 1987, it runs the only publicly funded ongoing monitoring in Antarctica. 'Young birds return to their natal colonies to breed,' Naveen says. 'Given their site-specific proclivities, the alternative explanation is that the Adelies are dying off.'
This dramatic changing of the guard is happening elsewhere on the peninsula, too. Last year, 21 gentoo nests were found at Vernadsky Station on Galindez Island, where there were none a couple of years before. At Arthur Harbour, the breeding population of Adelies has plummeted from about 15,000 some 30 years ago to fewer than 5,000 now.
It's almost too easy to point the ,finger at the dark shadow of climate change, which has affected the Antarctic Peninsula much more rapidly than the rest of the continent, with average mid-winter air temperatures rising 4-5[degrees]C and sea temperatures rising more than 1.2[degrees]C over the past 50 years. Adelies are believed to be one of the penguin species that prefer colder and icier environments: in years in which there's more sea ice, larger numbers of Adelies return to their breeding grounds. So the link with climate change seems clear. But strangely, chinstrap penguin numbers have also declined nearly everywhere on the peninsula, and their populations have traditionally increased in seasons with less sea ice.
Resembling a short tail on a fat, white stingray, the peninsula stretches north into Drake Passage towards South America, west of the Weddell Sea. Unlike East Antarctica, its coast is rugged, with high mountains plunging sharply to the water. Its milder temperatures, prolific wildlife and relatively easy accessibility--just two days' sailing from South America have made it the primary Antarctic tourist destination, hosting more than 90 per cent of the continent's visitors. 'The peninsula is where the action is best in terms of easily observable wildlife in Antarctica; Jacques Sirois, Peregrine Adventures onboard polar biologist, tells another shipload of eager passengers. 'There are lots of shallows and islands--there is a lot of good habitat.'
It's also the wettest part of the continent, receiving some 700 millimetres of precipitation annually--predominantly wet snow, but long-term tourism operators are reporting more rain and hail. In stark contrast, the Antarctic Plateau receives less than ten millimetres of dry snow each year.
Earlier this year, the disintegration of the 13,680-square-kilometre Wilkins Ice Shelf, in the peninsula's southwest, highlighted once again the changes being wrought on one of the fastest-warming regions on Earth. Temperatures have gone up and down here in the past--we know from ice-core samples that there have been ice ages about every 100,000 years, interspersed with warmer periods of 10,000-20,000 years--but the present rate and extent of change are what's sounding the alarm. This warming era has reached ice that previous fluctuations haven't, and the rate of change is accelerating. British Antarctic Survey (BAS) researcher Alison Cook's 2005 study of 244 Antarctic Peninsula glaciers found that 87 per cent of them have retreated during the past 40 years, whereas 62 per cent were advancing just 50 years ago. Sjogren Glacier, at the northern tip of the peninsula, has retreated eight kilometres since 1993.
But Sirois, a French-Canadian veteran of 36 voyages to the Antarctic Peninsula and a similar number to the Arctic, says he's seeing more obvious effects of climate change in the latter. 'There is so much thermal inertia [the tendency of a material to remain at the same temperature] in Antarctica--there is so much more ice here" he says. With 90 per cent of the world's ice bound up in Antarctica, it's like defrosting a whole frozen chicken, whereas the Arctic is like a flat minute steak in comparison.
Some of those seeing the changes firsthand don't hold overly pessimistic views about global warming. 'I don't necessarily see the changes as catastrophic,' Sirois says. 'In the Arctic, we are losing habitat for the polar bear, but many more species are coming in, so it may make Arctic waters richer.'
Many animal populations can adapt to changing conditions. In a University of North Carolina study of old Adelie penguin colonies on Anvers Island, on the Antarctica Peninsula's western flank, sediment samples indicated that Adelies living 500 years ago ate a lot of squid. During a cold snap between 1500 and 1850 (sometimes called the Little Ice Age), their diet changed to include more silverfish (any of various fishes having silvery scales). Fifty years ago, studies showed that Adelies ate mainly krill, but Naveen says Oceanites' observations suggest that in the past few years, they've begun eating more fish again. 'We observe more and more white Adelie guano rather than krill-stained pink,' he says.
Whale populations are increasing: southern right numbers are still growing at an average of seven per cent a year. Fur seal numbers are way up in some areas. 'The population of Antarctic fur seals has bounced back to perhaps its original size [pre-sealing], or beyond" Sirois says. 'We're talking about three to four million fur seals coming back from almost nothing.'
Blue-eyed shags, which had declined throughout the peninsula during the 1990s, seem to have stabilised, and on Cuverville, Paulet and Pleneau islands, shag populations have doubled in the past seven years. Antarctica's two native species of flowering plant, the Antarctic pearlwort and Antarctic hair grass, are both rapidly increasing in the warmer temperatures, with BAS scientists reporting a huge 25-fold increase in hair grass on Galindez Island.
Other populations aren't doing so well, however. For example, King George Island provides a prime example of Adelie and chinstrap penguins in decline. 'There is less sea ice there in the winter, and as a result, there are probably fewer krill there now 'Sirois says.' The krill use the sea ice as a nursery, and in the winter, seek shelter under the ice, where they feed on algae'
Krill is the motor that drives nearly everything in Antarctic waters. Birds, fish, whales and seals live directly on it, and other animals depend on them in turn. 'It's rare to have one species so dominant in an ecosystem,' says Steve Nicol, leader of the Southern Ocean Ecosystem Program at the Australian Antarctic Division. 'For the past 20 years, we've been trying to estimate how much krill there is, and its distribution. The consensus is about 200-500 million tonnes and somewhere around there seems about right. Much of the krill population lives in the South Atlantic area [immediately to the east of the peninsula].'
Nicol says there are often dramatic cycles in the abundance of krill in a region. This could explain changing populations of other animals, such as penguins, but studies have yet to explain why these fluctuations occur. 'When you're seeing only a small amount of krill off South Georgia [Island], what's happening elsewhere? Have they just moved somewhere else? We don't know.'
Although Nicol doesn't believe that climate change will increase sea temperatures beyond the 5[degrees]C in which krill can survive, it will continue to reduce the limited amount of sea ice there, and that could dramatically affect the huge krill populations in the South Atlantic.' lf you lose 20 kilometres of sea ice there, it would have a huge effect" he says. 'If you lost the same amount in East Antarctica, you would barely notice it.'
There are five main krill species and one, Antarctic krill, which grows to a length of about five centimetres, is by far the most abundant. Krill fisheries, operating since 1977, have taken up to 500,000 tonnes a year--generally considered by most scientists as an insignificant amount when compared with total stocks and the amount of krill eaten by creatures higher up the food chain. 'If you do some rough, back-of-the-envelope calculations, you get 100-300 million tonnes consumed by those animals,' Nicol says.
Last year, krill fishers from the USA, Japan, Korea, Norway, Poland and Ukraine took 104,586 tonnes of krill, but the current catch limit, set by international group the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), is four million tonnes a year. 'It's probably the only fishery in the world where the allowable limit is so much larger than what's currently being taken,' Nicol says.
With limited markets and huge infrastructure requirements to catch and process krill in remote waters, krill trawling simply hasn't been economically viable. But with the appearance of new markets in the health and food industry--with 'krill oil' the latest source of omega-3--and a growing need for fish meal (for use in fish farming, pet foods and rose fertiliser) as other sources run out, that economic balance may soon change. In addition, Nicol says, a changing climate on the Antarctic Peninsula may open it up to fishing all year round, where it has traditionally had a break over winter.
CCAMLR sets what it believes are sustainable catch limits for species such as krill, mackerel, icefish and Patagonian toothfish, but says that illegal, unregulated and unreported fishing in the vast Southern Ocean is extremely difficult to control. It estimates that fishing for toothfish is well in excess of allowable limits. For example, estimates for the 2005-06 season included 16,843 tonnes of legally caught toothfish, and 3,420 tonnes of illegal and unreported fishing. This figure has dropped considerably from a decade before, when an estimated 32,673 tonnes were plundered.
One of the major problems with fishing in Antarctic waters is the toll on seabirds such as albatross and petrels, which are attracted to the baited hooks put out by longline fishing vessels. 'We are talking about global numbers in the order of 300,000-500,000, probably more, seabirds a year,' Sirois says.' In the Southern Ocean, perhaps 100,000 birds a year. There are 24 species of albatross in the world [depending how you classify them] and we know that 22 are declining, and the other two probably so. The black-browed albatross is the world's most common albatross and 80 per cent breed in the Falklands. We're losing about 15,000 of them every year.'
This large-scale impact on wildlife has accompanied human activity on the peninsula. In fact, there's been so much large-scale slaughter, it's amazing that you can still see wildlife there at all. The volcanic Deception Island was just one of many southern blackspots for whales. Around South Georgia, there were nine whaling stations; 175,250 whales were taken there between 1904 and 1966, including more than 41,000 blues.
Although today's tourists can'ooh' and'aah' at the many humpbacks, minkes and dwarf minkes that surface and leap around the cruise ships and Zodiac boats, it's a poor facsimile of what once was. 'If we had come here 200 years ago, we would have seen thousands of whales by now', Sirois says.
It's the peninsula's stunning beauty and prolific wildlife that fuel its latest change, Sirois says. 'The biggest change by far that I've seen is the tourist invasion of Antarctica--the human tsunami: An estimated 47,000 tourists travelled to the frozen continent last summer, 10,000 more than the year before and five times more than a decade ago.
There are more and larger cruise boats making the journey across Drake Passage, some with more than 500 aboard. The number of cruise-only passengers (those who don't step off the ship) has doubled in the past year, and according to Sirois, Antarctica is no longer a destination just for the serious naturalist, as it was only five or so years ago/It used to be that everyone who came on board had their own binoculars" he says. 'Now hardly anyone does. They even rent them out on the ship, but still people don't take them:
Of course, in terms of raw numbers, 47,000 is a tiny figure for such a large continent. 'Compared to other places, it's almost negligible; Sirois says. But favourite and convenient landing and anchorage sites are relatively few and frequently visited, and questions are being asked about whether there should be a cap on tourist numbers. 'It's a difficult area,' says Phillip Tracey, policy adviser at the Australian Antarctic Division. 'Most [Antarctic] treaty parties watch the industry carefully, but there's no firm discussion on capping numbers at this stage. While tourism is growing in terms of absolute numbers, there isn't a great deal of environmental impact on the ground. In general, tourism is recognised as having very low impact, because people are living aboard the ships.
'One feature of Antarctic tourism is [that it's] very responsible. Over 20-30, years we've seen the very orderly development of a very responsible industry'
The Antarctic Treaty parties and International Association of Antarctic Tour Operators follow site-management plans for 20 of the most visited sites, including restrictions on how many people can go ashore at a time and the number of vessels that can be there. For example, at Petermann Island--where more than 12,000 people walked through the penguin breeding grounds last year--no more than 100 can be on shore at a time, and some areas are of-limits altogether.
There may be no recorded scientific evidence that this tide of humanity is affecting animal behaviour, but little things have changed. Peregrine Adventures guide Graham Charles has noticed a difference in the behaviour of the inquisitive leopard seal. 'They used to puncture about 30 Zodiacs a year--they don't anymore,' he says. Older gentoos that have encountered humans before are less likely to be inquisitive than the younger birds.
'Tourism has to reach a critical mass very soon" Charles continues. 'It's a giant continent, but we're running out of space--there aren't enough safe hidey holes, particularly for yachts. Most of the moorings can only take three yachts at a pinch. If you're the fourth, and there's a storm ...'
Sirois believes the waves of visitation might be slowed by the reality of the dark carbon footprints we leave just by coming to this special place. The mid-sized Peregrine cruise ship Akademik Ioffe, with 110 passengers aboard, burns through some 16-18 tonnes of fuel a day when on the move. Preliminary assessments suggest that this gives each passenger a carbon debt of about five to eight tonnes. Add to this the at least eight tonnes of emissions each Australian creates by flying to the tip of South America and back, then the carbon footprint for an Antarctic Peninsula trip is more than the average Australian household emits in an entire year. 'This is where the crunch will eventually come" Sirois says. 'We are probably the last generation to travel in this way.'
Just as white symbolises purity, for many of us, Antarctica and its unique wildlife symbolise all that is right with the natural world. Black marks on our universal environmental record stand out clearly here. Nearly everyone who comes has 'always wanted to travel to Antarctica', and when they leave, many can only describe their experience in spiritual terms. As one of the growing numbers of people blessed to have visited, I know it's our generation's imperative to pass on a place that's as white as possible.
Antarctic Peninsula land and sea temperatures are on the rise. The annual influx of visitors won't help
Waves of Antarctic visitors might be slowed by the reality of the dark carbon footprints they generate. The 117-metre, 110-passenger ice-strengthened vessel Akodemik Ioffe, on which writer Ken Eastwood travelled, burns 16-18 tonnes of fuel a day when on the move, which is estimated to give each passenger a carbon debt of about five to eight tonnes. Add the eight tonnes of emissions each Australian creates through return flights to the tip of South America and back, and ...
the carbon footprint for an Antarctic Peninsula trip is more than the average Australian household emits in an entire year
Hanging by a thread
Stable for most of the past century, the Wilkins Ice Shelf covered about 16,000 square kilometres before it began to retreat during the 7990s.
It's now estimated to have shrunk to about 11,0(30 square kilometres
In February, a 100-square kilometre chunk fell away from the shelf's south-western front Recent images show that the shelf is now joined to Charcot Island by a bridge of ice about 27 kilometres wide. When this breaks--possibly in the next year--the ice mass will be destabilised and is expected to break up rapidly
|Printer friendly Cite/link Email Feedback|
|Comment:||All eyes on the ice: like a giant white scoresheet, the Antarctic Peninsula is daily recording changes in the environment.|
|Date:||Oct 1, 2008|
|Previous Article:||The spoils of Kilimanjaro.|
|Next Article:||That moment.|