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A Visitor's Introduction to Antarctica and its Environment


Contents


Reprinted with kind permission of Scientific Committee on Antarctic Research by New Zealand Antarctic Programme (now Antarctica New Zealand), A Programme of the Ministry of Foreign Affairs and Trade

Text prepared in 1980 by: SCAR Working Group on Biology Conservation Subcommittee

W N Bonner (Chairman), United Kingdom; W S Benninghoff (Secretary), USA; V A Gallardo, Chile; K R Kerry, Australia; B C Parker, USA; J Prevost, France.

The subcommittee acknowledges the valuable help of J P Croxall, G E Hemmen, R B Heywood, M W Holdgate, R I Lewis Smith, Sayed Z El Sayed and Mrs J Whiting in preparing this information.

Copyright New Zealand Antarctic Programme (now Antarctica New Zealand), P O Box 14 091, Christchurch, New Zealand

ISBN 0-477-02556-0

Introduction Top

Antarctica, the last continent to be explored and exploited - the continent about which still least is known - has many unusual, interesting and beautiful features. This booklet has been prepared as an introduction to Antarctica, its environment, and the various forms of life which have found ways to survive the hostile conditions of the continent, its associated islands and surrounding oceans.

Geographic and physical features

The continent of Antarctica lies almost entirely within the Antarctic Circle (at 66 33 S). It is covered by 90 per cent of the world's ice which has an average thickness of about 2,000 metres. Scarcely five per cent of this land mass is without permanent ice or snow, and only the coastal rock outcrops and highest mountain peaks project through the ice sheet.

The climate for most of Antarctica is that of a cold desert. In the region of the South Pole about seven centimetres of snow accumulates annually and it has an annual mean temperature of -49C. As the ice sheet reflects most of the sun's heat back into the atmosphere, it collects almost no heat and significantly influences world weather patterns.

From a supercontinent, Gondwanaland

Two hundred million years ago Antarctica was joined to Africa, Australia, India, New Zealand and South America forming the supercontinent, Gondwanaland. Forces within the Earth affecting the crust caused these continents to separate and drift apart. Thirty million years ago the continents, as we know them today, reached their approximate present positions.

Antarctica, having drifted into the area of the Earth's southern pole, then experienced four or more months of winter darkness, was surrounded by an ocean, and was almost totally ice-covered. Those processes which produced the early and gradual separation of the continents, with concurrent climatic changes, were responsible for the extinction of a number of plants and animals.

Today, for example, ferns, freshwater fishes, amphibians and reptiles are found in Antarctica only as fossils. The geographical separation, and cold-dry climate which developed, prevented many groups of plants and animals on other continents from invading and colonizing Antarctica: for example, trees, flowering plants, land-based reptiles and mammals. Indeed, Antarctica is the only continent where man is not indigenous and where civilizations have never developed.

Antarctic forms of life today

The forms of life found on and around this frozen continent today possess unusual adaptations for surviving the rigours of cold temperatures, low humidity, ice sheets or salty soils characteristic of the region. Birds and seals in Antarctica (and to a lesser extent in the sub-Antarctic) breed and raise their young on ice or land, but depend on the rich resources of the ocean for their food. The marine ecosystem is rich with life. Whales, fishes, cephalopods and krill have provided, and will continue to provide, resources for mankind.

The terrestrial life in Antarctica is simpler than that of the ocean. The appearance and the roles played by the organisms within their ecosystems, and the adaptations they show to the rigourous conditions are, however, of interest. Also on land, there are a variety of freshwater and saline lakes and ponds which contain a limited selection of aquatic forms.

The world must learn to use Antarctica's living resources wisely, to respect the delicate balance which these organisms occupy in Antarctic eco-systems, and to preserve or protect them from irreversible harm or damage. Unfortunately, there were periods in our history when respect for the balance of ecosystems was lacking, and costly lessons were learned through trial and error.

Antarctica's role in human history has been recent, so that, apart from the marine ecosystem, it remains relatively pristine. Today we are facing a challenge to manage resources, living and non-living, and to keep Antarctica unspoiled. Success in this undertaking will benefit both present and future generations.

Science in the Antarctic

Exploration of Antarctica dates from 200 years ago when in 1773 Captain James Cook first crossed the Antarctic Circle. Early voyages combined exploration with exploitation, or the hope of it. Many valuable cargoes of seal skins and blubber oil were obtained, mostly from the sub-Antarctic islands. Later expeditions had a stronger scientific element in them, but science often had to take second place to national or personal interests. Antarctic science therefore suffered from a lack of continuity and coordination.

It was clear to many scientists that a thorough investigation of the Antarctic could only be accomplished by planned international cooperation. This was first achieved during the International Geophysical Year (IGY) of 1957-58, a world-wide programme based on research into the earth sciences. Antarctica occupied a key position in the programme and 12 nations set up research stations on and around the Antarctic continent, including for the first time ever, a research station at one of the Earth's poles. The IGY was successful, both in the quality of its scientific results, and in the extent and nature of the cooperation between nations, largely brought about by the scientific community.

Encouraged by this, and to ensure that the valuable activities initiated during the IGY did not cease at the end of the set period, the International Council of Scientific Unions (ICSU) in September 1958, set up a body known as the Special (now Scientific) Committee on Antarctic Research (SCAR), which was to organize and coordinate future international scientific research. SCAR membership originally consisted of the 12 nations actively pursuing scientific research in Antarctica at the time of IGY, but in 1978 two other nations were added.

The present SCAR membership is: Argentina, Australia, Belgium, Chile, Federal Republic of Germany, France, Japan, New Zealand, Norway, Poland, South Africa, UK, USA and USSR.

SCAR has established a number of permanent working groups which coordinate scientific and logistic programmes, organize symposia, and plan Antarctic contributions to global research programmes. There are also groups of specialists which deal with topics of particular importance or immediate interest. Scientific results are freely exchanged between the SCAR nations, and the committee ensures that details of future scientific programmes are made available to its members.

The Antarctic Treaty

In order to facilitate the pursuit of research in the Antarctic, and to ensure that it remained open to all nations to conduct scientific or peaceful activities there, the governments of the 12 nations who were then active in the Antarctic signed the Antarctic Treaty in Washington on 1 December 1959. It has since been acceded to by many other nations. The 14 Articles of the Treaty may be summarized as follows:


I - Antarctica shall be used for peaceful purposes only; any
military measures are prohibited.

II - Freedom of scientific investigation in Antarctica and
cooperation as applied during IGY shall continue.

III - Plans for scientific programmes and the observations and
results thereof shall be freely exchanged; scientists may be
exchanged between expeditions.

IV - All national claims are frozen from the date of signature. No
future activity of any country during the life of the Treaty
can affect the status quo on any rights or claims to
territorial sovereignty.

V - Nuclear explosions and disposal of radioactive waste are
prohibited in Antarctica.

VI - The provisions of the Treaty apply to the area south of 600S.

VII-VIII - Any contracting party may appoint observers. They
shall have complete freedom of access at any time to any area
of Antarctica, with the right to inspect any other nation's
buildings, installations, equipment, ships or aircraft or to
carry out aerial observations.

IX - Regular consultative meetings of the active signatory nations
shall be held.

X - Contracting parties shall ensure that no activity contrary to
the Treaty is carried out.

XI - Any disputes between contracting parties shall be resolved by
peaceful negotiation, in the last resort by the International
Court of Justice.

XII - The Treaty shall remain in force for a minimum of 30 years.

XIII-XIV - Provides the legal details of ratification and deposit.

In the years since the signing of the Treaty, consultative meetings have reached agreement on more detailed measures, including the protection of wildlife and special areas of biological interest. Other subjects on which unanimous agreement can be reached are constantly under review. The inspections by national observers have been carried out in a spirit of friendly cooperation, and the flow of data and publications between all nations has been continuous and unrestricted.

The Treaty does not apply to the high seas, nor to the sub-Antarctic islands north of 600S, though the latter are subject to national legislation which, amongst other things, lays down regulations for the conservation of wildlife. This booklet deals with the flora and fauna, and their ecosystems, from a biological, rather than a strictly geographical, basis. All visitors to the Antarctic can play an important role by being advocators of the Treaty's purposes, and by spreading the words, concepts and ideas contained in this guide.

The Antarctic marine ecosystem

In contrast to the sparsely vegetated, barren and ice-covered continent, the nutrient-rich waters surrounding Antarctica support a wealth of plant and invertebrate animal life on which large populations of fishes, penguins, sea birds, seals and whales feed. These Antarctic organisms have a number of features that set them apart from those of tropical and temperate waters, such as large body size, slow growth and few species. They are also remarkably well adapted to the severe environmental conditions in which they live. Some of the fish, for example, have special blood proteins which act as anti-freeze.

The marked seasonal changes in these high latitudes accompanied by the shortened period of light for plant growth, have brought about species acclimated not only to low temperatures but also to seasonal feeding and overwinter energy storage in fats and related substances. These are among the environmental factors which have helped shape the character of Antarctic life with its high degree of specialisation.

The Southern Ocean isolates the Antarctic continent from the rest of the world. Surrounding the continent are two concentric water masses. The more northerly tends to move in a westerly direction under the influence of the prevailing winds (the West Wind Drift), while the water nearest the continent circulates in the opposite direction (the East Wind Drift). Superimposed on these circumpolar movements is a tendency for the surface water to drift to the north.

At its northern limit, the cold Antarctic surface water sinks beneath the less dense sub-Antarctic surface water. The region where this sinking occurs is referred to as the Antarctic Convergence, or Polar Front. At the Convergence there is a sudden change in temperature. An increase in nutrient salts occurs south of the Convergence, contributing to the richer, more productive marine ecosystem there compared with the sub-Antarctic surface waters north of the Convergence.

The Antarctic Convergence influences the distribution of phytoplankton, zooplankton, fish and birds.

At the edge of the Antarctic continent cold water sinks, forming the bottom water, which moves northwards over the sea floor and fans out into the Atlantic, Pacific and Indian oceans. Above the bottom water lies the relatively warmer, more saline, and nutrient-rich south-flowing circumpolar deep water.

The upward movement of this water creates a zone of upwelling, supplying to the surface water large amounts of nutrients that contribute to the luxuriant growth of phytoplankton and other marine life close to the coasts of Antarctica.

The development of fast ice close to the continent and pack ice south of the Antarctic Convergence also profoundly influences the Antarctic marine ecosystem. The area covered with pack ice undergoes seasonal fluctuations. It is reduced from 24 million km2 in September to 18 million km2 in February.

Throughout its cycle of waxing and waning, the circum-Antarctic ice belt moves from east to west, and with it follow the multitudes of marine organisms that inhibit the pack ice zone. On the basis of ice distribution, we can recognize three concentric zonations: the fast ice zone, the pack ice zone, and the open waters.

Phytoplankton

Phytoplankton are free-floating and drifting plants and comprise the first link in the food chain. Diatoms are an important component of Antarctic marine phytoplankton and number about 100 species; other groups, the dino-flagellates with about 70 species, and the silico-flagellates are present also.

These phytoplankton, usually single-celled and microscopic, play the key photosynthetic role by converting solar energy into chemical energy. Concentrations of diatoms are seen as a greenish discolouration of surface waters. Phytoplankton-laden waters provide food for krill and countless other tiny floating animals (the zooplankton), themselves consumed by carnivores.

Seasonal and geographical variations in the amount of phytoplankton are conspicuous in the Southern Ocean. Large standing crops are found in the Scotia Sea, west of the Antarctic Peninsula and in the Ross Sea. Small standing crops are more typical of the oceanic regions, i.e. away from the coast.

Zooplankton

Zooplankton are those animals which are unable to swim effectively against the horizontal currents of the ocean; they drift in the ocean, some species browsing phytoplankton, others consuming the browsers. Although most zooplankton species are circumpolar in distribution, they frequently show centres of concentration at different depths or in different latitudes.

The circumpolar distribution of many plankton species seems to be lop-sided, with large populations in the Scotia/Weddell Sea region and thinner bands around the rest of the continent. As with the phytoplankton stocks, waters south of the Antarctic Convergence are richer in zooplankton than sub-Antarctic waters to the north.

Antarctic zooplankton also exhibit seasonal variations. In summer, they are more plentiful in coastal than in open ocean waters, while in winter they are found at greater depths. The dominant organisms in Antarctic zooplankton are the copepods and the euphausiids such as krill. In the past krill supported enormous stocks of whales.

The swarming habit of the krill greatly assist the baleen whales which feed on them, Blue Whales preferring adolescent krill and Fin Whales favouring the adults. These swarms often extend over some hundreds of square metres; the maximum dimension recorded for a swarm is several kilometres. Krill can be dense enough to discolour sea water, and therefore at times can be easily spotted from the deck of a ship.

In recent years, Antarctic krill has been the focus of much international attention and is already the object of commercial exploitation by many countries. Over-exploitation of such a living resource, upon which so much of the Antarctic marine ecosystem depends, could bring about a major ecological disaster.

Fish

Nearly 75 of the 80-100 species of Antarctic benthic fish belong to the group Nototheniiformes, most of which are sluggish bottom dwellers, with large heads and tapering bodies. As a group, they are highly diversified in structure, habit and distribution. Although Antarctic bottom fish can be locally important in coastal regions, such as Iles Kerguelen and South Georgia they are usually insignificant in the Southern Ocean as a whole, because the narrow continental shelf surrounding the continent limits the abundance of spawning sites of these bottom dwellers.

There are no reliable estimates of the stocks, biomass or productivity of Antarctic fish. Although the USSR is now marketing Notothenia rossi in Moscow and other cities, it is difficult even to guess the magnitude of this or any other fish stock in the Antarctic. Their remarkable adaptation to temperatures below the natural freezing points of their body fluids has recently begun to attract considerable attention.

The anti-freeze (a glyco-protein) isolated from an Antarctic fish may be useful as a refrigerant for red blood cells, sperm and tissue. The ice fish of the Antarctic are the only vertebrates which entirely lack the red oxygen-carrying pigment, haemoglobin, in their blood. This condition is another adaptation to cold conditions - by reducing the number of red blood cells the viscosity of the blood at low temperatures is decreased and the energy expenditure of circulating the blood reduced.

The study of adaptation to extreme polar conditions in fish and other animals is among the most fascinating and promising in Antarctic biology.

Cephalopods (squid and octopus)

Squid and octopus are known to be extremely important organisms in the Antarctic ecosystem. They are prey for sperm whales, seals, penguins, sea birds and fishes. The Southern Hemisphere population of sperm whales consumes, for example, about 50 million tonnes of squid each year, an amount approximating to 75 per cent of the world's current annual fisheries catch.

As predators, the cephalopods could perhaps consume about 100 million tonnes of Antarctic krill per year. It is difficult to assess the resource potential of cephalopods, which are strong swimmers with net-avoidance capabilities that have prevented adequate sampling for biological study. Special sampling efforts will be required to fill in the gap of knowledge that exists for these organisms.

At present no commercial fishery for cephalopods exists in the Southern Ocean, but an active Japanese fishery has harvested about 20,000 tonnes per year in New Zealand waters.

Birds, seals and whales are discussed in another section. It is important here to mention that they derive their food either directly from the sea or at one step removed from it. Hence, they are an important part of the marine ecosystem.

Human influence on the marine ecosystem

The short and simple marine food chain in the Antarctic, diatoms-krill-whales, is well known. The simplicity of the system makes it more vulnerable to outside disturbances than the more complex and stable ecosytems encountered in tropical and subtropical waters. Its vulnerability is now being tested under the strain of two man-made factors: the commercial exploitation of the mammalian populations, and the influence of toxic chemicals introduced from the industrial regions to the north.

There can be no doubt that the Antarctic marine ecosystem has been significantly influenced by man's exploitation of baleen whales. The disastrous decline in these stocks is well documented and has had profound effects on other parts of the ecosystem. The detection of DDT and other chlorinated hydrocarbon pesticides in Antarctic organisms furnished the first evidence of the global dispersal of this class of persistent pollutants.

Pollutants recognize no national boundaries or territorial seas, and are transported from their place of origin to the marine environment via the atmosphere, water movements and migrating organisms. Pesticides have not been found in Emperor Penguins, which may suggest that birds and seals that are more or less confined to higher latitudes are likely to be less contaminated than those spending part of their life away from the continent.

The existence of large amounts of krill in the Antarctic has been known for many years, but interest in commercial exploitation arose only in the mid 1960s, at a time when the baleen whale stocks had greatly declined due to over-harvesting. Pressure to exploit krill is increasing, since in recent years the stocks of fish taken in traditional waters have declined or become less accessible to many nations. This has sharpened peoples' focus on the virtually untouched krill stocks.

Because of the reduction of Antarctic whale populations, the consumption of krill has fallen from an estimated 190 million tonnes per year to only 40 million tonnes per year. However, this decline in whales has been matched to some extent by increases in other krill consumers, for example, seals and penguins. If a substantial fishery for krill develops, as seems likely, humans will be another major consumer in the system, and the effects on the other components of the system are unknown, and could be undesired.

So there is a need for careful control of krill exploitation, which will involve not only the collection of statistics about krill catches but also observations on the biology of krill and its consumers. A start has already been made: SCAR, in association with other international scientific bodies, has launched a major international long-term scientific study of the marine ecosystem, entitled Biological Investigations of Marine Antarctic Systems and Stocks (BIOMASS); the Antarctic Treaty governments have also recently concluded the Convention for the Conservation of Antarctic Marine Living Resources.

Marine mammals

Seals

Together with penguins, seals are probably the most characteristic, and certainly the most engaging, animals that a visitor to the Antarctic will encounter. Seals are mammals which have adopted an aquatic mode of life but which, unlike the whales, retain the need to return to land (or in the case of most polar seals, to ice) to breed.

The Antarctic supports a much larger number of seals than does the Arctic; indeed, one species alone, the Crabeater Seal, accounts for about half the world's seals. The greater abundance of Antarctic seals is due to much larger, often more productive feeding areas within the vast expanses of the Southern Oceans; the seals have also exploited the drifting pack ice as a breeding ground, and there are no native terrestrial predators, such as polar bears or man.

Antarctic seals therefore behave very differently from the northern seals and show little fear of man. Often seals in the Antarctic can be approached closely without their apparently showing obvious signs of disturbance. However, careful observation of this behaviour will reveal that groups of breeding seals, or females accompanied by pups, can exhibit signs of stress, which may lead to the abandonment of young, when confronted by a human visitor. Therefore, it is best not to approach seals too closely, and to endeavour to observe or photograph from a distance.

Seals, including pups, should never be handled. Not only can this molestation of seals be harmful to them but, as Antarctic seals are capable of surprisingly swift responses, severe injuries to the molester can also result.

The Antarctic seals have developed different ways of exploiting their marine food supply. These involve differences in both feeding habits and geo-graphical distribution.

The most abundant of the true Antarctic seals is the Crabeater Seal, Lobodon carcinophagus, which has an estimated population of about 15 million. As soon as a ship enters a belt of loose pack ice, one can expect to see these seals lying on the floes. Crabeater Seals feed directly on krill, and have specially modified teeth and palates for straining them.

The seals are most abundant on the fringes on the pack ice and are generally solitary, though in the spring during the breeding season they are found in family groups of a cow and her pup together with an attendant male.

The bodies of Crabeater Seals often bear patterns of parallel scars. In adult seals these are usually healed, fresh scars being found more often in juveniles. It was once believed that these scars were caused by Killer Whales, but it now appears more likely that they are inflicted by Leopard Seals.

The Leopard Seal, Hydrurga leptonyx, is another familiar seal of the pack ice. However, it may be most conspicuous when hunting penguins near a rookery. It is the largest of the true Antarctic seals. The females measure up to 3.4m with an easily recognizable outline - a somewhat reptilian head, a sinuous neck and a highly-arched thorax. Its very long fore-flippers are also characteristic.

The Leopard Seal, like the Crabeater, has very complicated teeth, equally well adapted to straining krill or catching active prey such as fish or penguins. However, about two-fifths of their diet consists of the flesh of warm-blooded animals, birds (mostly penguins), other seals (usually young Crabeaters), and occasional carrion; about the same proportion is krill. Smaller quantities of fish, squid, and other invertebrates are also taken.

The remaining pack ice seal of the Antarctic is the Ross Seal, Ommatophoca rossii. This is much less often seen by the ordinary visitor as not only is it far less abundant than Crabeater or Leopard seals, but it is characteristically a seal of heavy consolidated pack ice, where few ships can penetrate. The Ross Seal is another large seal, females measuring up to 3.3m and averaging 2.1m in nose to tail length. As in other true Antarctic seals, the female is a little larger than the male.

The Ross Seal is easily recognized by its short head, large eyes and its tendency to lift its head, inflate its throat, and adopt a characteristic "singing position". Often there are dark stripes running from the chin to the chest and along the sides of the neck. These feed mainly on squid, but take significant quantities of fish and other invertebrates.

Because of its remote habitat, its biology is little known; there seems to be some evidence of a clumped distribution, for it is much more frequently seen in some areas than in others. The comparative rarity and lack of scientific information on the Ross Seal has led to its protection under the Antarctic Treaty.

The Weddell Seal, Leptonychotes weddellii, inhabits the fast ice and the area near the shore around the whole of Antarctica. It is the seal most likely to be encountered at close quarters by a visitor. Weddell Seals are usually found in groups, sometimes up to many hundreds in size, though breeding and non-breeding groups are usually distinct. These seals show a distinct preference for lying on snow or ice, even when rock or shingle beaches are available. Birth and rearing of young occurs from September to November, depending on latitude, and at this season there is considerable territorial fighting between the males.

The food of the Weddell Seal consists mainly of fish, though some squid and other invertebrates are taken. These seals are capable of deep diving to seek their food, and have specially adapted eyes for seeing underwater in low levels of light intensity.

The remaining two species of seals likely to be encountered in the Antarctica are not strictly Antarctic species, although they overlap from the sub-Antarctic zone. The most impressive is the Southern Elephant Seal, Mirounga leonina. It is the largest of all seals, adult males reaching a length of up to 4.5m and a maximum weight of about 4 tonnes. The males are much larger than the females, and during the breeding season in September to November they maintain harems of up to 70 females.

Elephant Seals breed mostly on the sub-Antarctic islands, particularly South Georgia, Iles Kerguelen, Heard Island and Macquarie Island, but during the moulting season, in December to March, they appear on land farther south. Large numbers are now to be seen in the South Orkney and South Shetland islands. Elephant seals feed mainly on squid and fish and probably catch some of their food in deep water.

The Antarctic Fur Seal, Arctocephalus gazella, is the remaining seal species to be found in the Antarctic. Unlike the species described earlier, this is not a true seal, but a member of the group of eared seals, which includes sea lions.

The Antarctic Fur Seal was very heavily exploited by fur hunters in the 19th century; the total population was reduced to a few thousand, and in some places such as the South Shetland Islands, probably totally exterminated. With protection since the early years of this century, it has shown a remarkable recovery from a population centre at South Georgia. Here the seals have been increasing at approximately 17 per cent per year, so that the whole population doubles in about five breeding seasons.

As a result of this population explosion, Fur Seals are now commonly encountered on many islands groups in western Antarctica, including the South Sandwich, South Orkney and South Shetland islands. Away from the breeding grounds, the animals most likely to be seen are young male or non-breeding adults.

Fur Seals produce their pups in December in dense colonies. The male holds a territory and actively defends a group of females. Their food consists mainly of krill, although smaller quantities of fish and squid may also be taken.

Whales

The former abundance of the great whales in the Antarctic is now a feature of the past. Although most are greatly reduced in numbers, no species has become extinct, and the chance still exists to see occasionally the greatest whales of all, the Blue Whale (Balaenoptera musculus) and the Fin Whale (B. physalus). It is not easy to distinguish the various members of the genus Balaenoptera from each other when seen from a ship.

The smallest of them, the Minke Whale (B. acutorostrata) is usually unmistakable on account of its small size (less than 7.6m long) and its habit of approaching ships), but the Sei Whale (B. borealis) is readily taken for a Fin or even a Blue Whale by an unskilled observer.

The slow-moving Humpback Whale (Megaptera novaengliae), with its long knobbed flippers and hunched back, is occasionally to be seen close in to shore around the coasts, while the Southern Right Whale (Eubalaena glacialis) is occasionally sighted around South Georgia, though it rarely enters polar waters.

All of these whales feed by filtering out plankton from the surface waters of the sea, using horny plates - baleen - hanging from the upper jaws as a filter bed, and by far the most important organism in their diet is krill.

However, they do not all feed indiscriminately: Sei Whales, which have very fine baleen, take significant quantities of copepods, particularly in the more northerly part of their Antarctic distribution; Blue Whales concentrate

on first year krill with a length of 20-30mm; Fin Whales take mostly second year krill 30-40mm long; Right Whales have very long baleen plates and tend not to gulp at concentrations of plankton, as do the others, but feed continuously, skimming the surface waters and catching the dispersed organisms such as copepods.

None of the large whales breed in the Antarctic. Instead they use the productive waters of the Southern Oceans as a feeding ground, where they lay down vast reserves of blubber to sustain them during their stay in the less productive but warmer waters where they produce their young.

The toothed whales of the Antarctic, with one exception, are much less well known. The exception is the Sperm Whale (Physeter catodon). Sperm Whales seen in the Antarctic are invariably adult males. Because of their polygamous nature, there is a surplus of males in the breeding areas and some move to Antarctic waters where they feed on squid.

Probably the most conspicuous of the toothed whales in the Southern Ocean is the Killer Whale (Orcinus orca). It is generally seen in small groups, where the adult males can be recognized by their very tall dorsal fins. Killer Whales are generalized carnivores, taking a variety of food organisms; they are important predators of seals.

Two species of Beaked Whales, Hyperoodon planifrons and Beradius arnuxii, are also commonly seen, but almost nothing is known of their biology. Several other species of small toothed whales have been seen in Antarctic waters, and one or two specimens have been collected, but there is a great gap in our knowledge here.

Birds

Each spring the coast of Antarctica awakens with the return of millions of seabirds to breed. Their arrival is a dramatic end to the long dark polar winter. First to arrive are the Adelie Penguins, who have walked, often up to 50km, across the sea ice to reach their nesting grounds. The petrels and skuas arrive soon after, flying in from the open sea. Most of the established breeding birds return to the same nest site and to the same mate. When necessary, the site is cleared of snow and the pair bond re-established before the new breeding season begins.

The numbers of birds breeding around the rocky coastline and the offshore islands are enormous, 100 million or more individuals. Most of these are Adelie Penguins. Other birds include three more species of penguins, several species of petrels, a skua, a gull and a tern. The sub-Antarctic islands to the north also are invaded in spring by seabirds. Although the species are generally different from those breeding on the Antarctic continent, they are very closely related and include penguins, petrels and skuas. These islands are also the home of the albatrosses, the largest, most spectacular and perhaps the most beautiful of all sea birds.

While large congregations of birds are found ashore in the summer, large numbers of young, adolescent and non-breeding birds may also be observed throughout the Southern Ocean at any time, ranging widely in their search for food. Watching these birds at sea is one of the genuine pleasures of long sea voyages under strong winds and rough seas.

Compared with other continents, Antarctica has very few species of breeding birds. Even when the sub-Antarctic species are included, the total is just over 40 as compared with several thousand found collectively in Africa, South America and Australia. Although few species breed in the Antarctic region, the numbers of individuals are very large.

True terrestrial birds are not found on the Antarctic continent and only a few, including two species of duck, two sheathbills and a pipit, have successfully colonized some of the southern sub-Antarctic islands.

Sea-birds have been more successful than land birds in colonizing the Antarctic region because they have evolved over long periods of time adaptations for life bound to a marine environment. Particular features such as those which help conserve body heat (e.g. special waterproof plumage, an insulating layer of subcutaneous fat, large body size, compact form and a lack of bare skin), have enabled them to extend their range south to exploit the Southern Ocean and establish breeding colonies on the sub-Antarctic islands and the Antarctic continent.

Food in the form of marine zooplankton, cephalopods and fish is readily available to them. Little, if any, food is available on the Antarctic continent to support terrestrial species, even if they were physiologically equipped to withstand the rigours of an Antarctic winter. Thus, most of these birds depend entirely on the sea for food and spend most of their life at sea in search of it. Some, notably the albatrosses and petrels, spend the first few years without ever visiting land, while others visit occasionally.

Because of the very large numbers of sea birds and the amount of food they eat, they are important components of the marine ecosystem, like seals and whales.

Antarctic species can be divided into four major groups or orders. Of these the Petrels (order Procellariformes) comprise the greatest number of species and include the albatrosses, petrels, shearwaters, prions, storm petrels and the diving petrels. Petrels are a diverse group of birds linked by the common characteristics of tube-like nostrils on the upper beak. They range in size from the Wandering Albatross, which has a wing span of about 3m, down to the tiny Wilson's Storm Petrel, which weighs 35g and has a wing span of 40cm.

All are marine species adapted for a life at sea. On land most have difficulty in walking and generally visit it only in the breeding season. All species feed at sea. The smaller birds feed on zooplankton including krill, and the larger species (albatrosses and some petrels) consume large squid, fish and crustaceans. The Giant Petrels also feed ashore on carrion, and these and many other species (Albatrosses, Cape Petrels, Storm Petrels) feed at sea on the organic wastes discharged by ships.

Most Antarctic bird species breed annually and lay a single egg which is very much larger in relation to their body weight than most other birds. King Penguins and some albatrosses breed less frequently and have the lowest reproductive rate of any birds.

The Penguins (order Sphenisciformes) are the best known, and most numerous of all Antarctica's birds. Their combined biomass accounts for about 85 per cent of the biomass of all the Antarctic birds, of which over half is Adelie Penguins. Penguins are stocky, flightless birds with wings reduced to flippers with which they propel themselves through the water. On land they walk upright with a waddling gait or in short hops.

Most penguins stand 60 to 70cm high but the largest, the Emperor Penguin, stands waist high (about 1m) and weighs up to 41kg. They nest in large dense colonies with some containing 80,000 or more birds. The sight, smell and noise of any colony is unforgettable. Most build nests of stones and in them incubate one or two eggs.

The Emperor Penguin is unique among Antarctica's birds. It breeds in winter, on the ice along the coast of the continent and at one colony at the base of the Antarctic Peninsula, when weather conditions are at their worst and in almost continuous darkness. These penguins do not build a nest or defend a fixed territory. Instead the male incubates the egg on its feet and can shuffle around as required. During very cold periods the incubating birds form dense huddles to conserve heat. The chicks leave the colonies in spring, while still moulting their down, and are rafted out to sea on broken pieces of pack ice. Like the larger petrels, penguins do not breed until several years old and may live 30 to 40 years.

The remaining groups of birds feed close to land or on marine organisms scavenged along the shore. Two species of Cormorants (order Pelecaniformes), Blue-eyed Shag and Kerguelen Shag, are fish-eating birds that pursue their prey underwater. They are not strong flyers and mostly stay close to shore. The chicks, usually 2-4 in number, are naked when newly hatched and are carefully brooded until the dark down appears.

The Gulls, Terns, Skuas and Sheathbills all belong to the (order Charadriiformes).

The South Polar Skua breeds all around the Antarctic continent and its more northern counterpart, the Brown Skua, on sub-Antarctic islands. Both feed on marine life and also on carrion, when available. The Dominican Gull and the Antarctic Tern breed along the coast or on the offshore islands at the northern end of the Antarctic Peninsula, and the sub-Antarctic islands. All these species feed around the shores in summer, but most range widely during the winter. The Arctic Tern migrates annually to the Antarctic.

The Sheathbills, however, remain mostly on land during the austral winter. These curious all-white birds, although, unrelated, bear a superficial resemblance to pigeons, both walking and when in flight. Their feet, unlike other Antarctic sea birds, have only rudimentary webs. They are mostly scavengers along the shore line feeding on marine organisms and carrion. They also prey on penguins by taking eggs and small chicks.

Conservation and Antarctica's Birds

Antarctica and the sub-Antarctic islands have been isolated for a long time, and those birds which colonised the areas have done so in the absence of terrestrial predators. Most exhibit a remarkable tameness which permits close observation and study. Communal nesting habits, and in the case of penguins and petrels, extreme adaptation to a pelagic life have left the birds highly vulnerable to the activities of man.

Nesting birds, even penguins in the dense rookeries, are easily disturbed and will desert their nest. This causes a disruption in the orderliness of the colony, fighting and exposing the eggs and chicks to increased predation from skuas and other natural enemies. Giant Petrels, gulls and terns are birds that are easily disturbed.

Already man has caused considerable damage to populations of birds on the sub-Antarctic islands. At about the turn of the century penguins were slaughtered in millions for their oil and other birds exploited for their feathers. At the same time alien animals were introduced, some of which became feral.

Although the harvest of penguins has ceased, feral cats and rats remain and prey on these ground nesting birds. Grazing animals destroy or modify the vegetation, allowing soil erosion and the loss of cover for the burrowing birds. Fortunately, no introduced predators have become established on the Antarctic continent.

Terrestrial life Top

Terrestrial life in the Antarctica is unlike that in all other major regions of the world: the vegetation is composed almost entirely of low lying mosses and lichens, and there are no vertebrate animals (besides birds and seals which depend on the marine environment for food). Even the climatically less severe sub-Antarctic islands possess a very limited tundra-like vegetation of short flowering plants and ferns with very few shrubby species and no trees; apart from a few land birds, only invertebrate animals are native to the region.

The terrestrial environment

Two principal factors have brought about the impoverished flora and fauna. The isolation of the Antarctic and sub-Antarctic regions from other continental land masses has created a sea barrier to immigration by plants and animals, and only ten thousand years ago the region was even more heavily ice-capped and inhospitable.

The second factor is the harsh weather, particularly the cold summer, which prevents the establishment and growth of all but the hardiest plants. If vertebrate animals could find their way here, the short slow-growing vegetation would be insufficient to support most herbivores, and consequently no carnivores could survive; seabirds and seals would be available as food for only part of the year, because of their patterns of migration.

Antarctic terrestrial life, excluding a few species of snow dwelling bacteria and algae, is restricted to areas which become snow-free for a few months in summer. Such land is mostly in coastal areas and offshore islands where the warming influence of the adjacent ocean creates a slightly more hospitable environment; this applies also to the more alpine sub-Antarctic islands. In many potentially suitable areas vegetation is excluded by dense colonies of penguins or seals.

Vegetation requires a regular supply of water during the summer. This, together with the nutrients dissolved in it, permits limited growth for a few months, rarely longer even in the more northerly regions. Because of warming by the sun's radiation, temperatures at plant level often exceed 20C even when the air temperature is well below the freezing point, thereby creating a relatively favourable environment for plants and invertebrate animals.

While both plants and invertebrates can often tolerate long periods of drought and snow cover, many plants are capable of carrying out respiration and photosynthesis below 0C as long as solid freezing has not occurred. Unstable ground, due to the frost heaving and down-hill movement of soil over the permafrost, limits the distribution and continuity of plant communities, while ground exposed to wind and dessication is also sparsely colonized.

Wherever there is vegetation, there is usually invertebrate life, albeit inconspicuous, with the wetter habitats having the greatest diversity and highest numbers. High densities of some invertebrates also occur in the relative warmth and shelter beneath stones and rock crevices.

Terrestrial plants

Despite their wide separation, the sub-Antarctic islands have vegetation that is broadly similar in appearance. Typically there is a coastal fringe of tall Tussock grass (Poa spp.) which is often frequented by birds and seals; on South Georgia these plants reach 2m in height. Wet marshes and bogs are dominated by short rushes, mosses and liverworts which have accumulated deposits of peat several metres in depth over the past 10,000 years. Drier, shallower soils are often covered by short grassland which, in the more exposed situations, has a high proportion of mosses and lichens.

Sheltered hillsides have swards of burnet, a woody shrub-like plant, whose ripe fruits are covered by barbed burrs which readily attach to clothing. Windswept ridges, plateaux and high altitude areas have sparse "fellfield" vegetation of mosses, lichens and scattered tufts of wind-dwarfed grasses and compact ground-hugging cushion-like plants. Ledges, crevices and wet rock support a variety of mosses, liverworts, lichens and occasional ferns. On the sub-Antarctic Indian Ocean islands the large-leafed Kerguelen cabbage (Pringlea antiscorbutica) grows amongst small plants on sheltered "herbfield" slopes, and other unusually large-leaved herbs, including the MacQuarie Island cabbage (Stilbocarpa polaris) occur in similar communities on MacQuarie Island.

Farther south, in the maritime Antarctic region of the South Sandwich, South Orkney and South Shetland islands, and west coast of the Antarctic Peninsula to 680S, only two flowering plants occur in a few scattered localities, the Antarctic hair grass (Deschampsia antarctica) and Antarctic pearlwort (Colobanthus quitensis). They often grow together on moist sunny, sheltered slopes near the shore.

However, the predominant Antarctic vegetation consists of mosses and lichens. Wetter areas are dominated by shallow mats and carpets of moss, while well drained hillsides may have tall turf-forming mosses which accumulate banks of frozen peat up to 2m in depth. A few species of liverworts and toadstools also inhabit the wetter moss communities.

Drier habitats have a discontinuous colourful mosaic of small cushion-like mosses and bushy and encrusting lichens, the latter predominating wherever exposure to wind is high.

In and near penguin rookeries where the ground is continually trampled, and concentrations of phosphate and nitrogenous matter reach high levels that little exists but a leafy green alga (Prasiola crispa) forming extensive sheets.

Coastal rocks receiving constant deluges of sea spray or the excrement of cliff-breeding sea birds, are typically covered by expanses of vivid red, orange and yellow lichens which contrast with the drab colours of other species on rocks away from such enrichment.

Coastal areas of continental Antarctica are more sparsely vegetated due to the much drier atmosphere, infrequent availability of melt water or rain, and strong winds. However, wherever shelter is afforded, small aggregations of moss cushions and turfs or encrustations of lichen may be found. A few species are found several hundred kilometres inland, particularly near breeding colonies of Snow Petrels and Antarctic Petrels.

Terrestrial animals

In regions of extreme living conditions, the fauna comprises few species although these often occur in vast numbers. On the sub-Antarctic islands there are a few native land birds - two duck species and a small pipit at South Georgia and one duck on Iles Kerguelen. The mammals, such as reindeer, rabbits, cats, rats and mice have all been introduced by man.

A variety of large invertebrates are conspicuous on these islands, especially amongst the vegetation which provides a source of food, moisture, shelter and warmth. Flies and midges are commonly seen in the air, and some islands also have small moths. Beetles, the largest of all indigenous southern polar land invertebrates, spiders, mites and springtails also occur commonly.

In the soil, earthworms are sometimes seen and there are a few snail species. Many forms of microscopic animals live in the film of water adhering to plants, especially mosses, and in the damper soils.

At more southerly latitudes the terrestrial fauna is much less diverse. Springtails, no more than 2mm in length, and mites occur in great quantities amongst mosses, lichens and beneath stones, especially near penguin and petrel colonies.

One species of mite has been found only a few hundred kilometres from the South Pole. A very few species of wingless midge occur on the Antarctic Peninsula and one winged species inhabits some of the South Shetland Islands.

The remaining animal populations comprise microscopic protozoa and slightly larger groups, such as nematode worms, rotifers and tardigrades, which occupy the moister mosses and soils.

The three species of duck which inhabit some of the sub-Antarctic islands feed mainly on freshwater algae; they also graze mosses and flowering plants at pool margins and take small freshwater and marine crustaceans. The diet of the South Georgia Pipit is mainly insects, spiders and seeds, although in winter they feed in small flocks along the shoreline, presumably on marine invertebrates. In sub-Antarctic and Antarctic coastal areas, the omnivorous sheathbill scavenges the shoreline and penguin colonies.

Human influence on the terrestrial environment

For over 200 years the sub-Antarctic islands have been important commercially. Land-based sealing and whaling activities, which ceased by 1965, resulted in settlements and processing stations on several islands. Such human impact led to widespread destruction of the vegetation around these areas, while the introduction of domestic animals (sheep, goats, cattle, horses, pigs, poultry, cats, dogs) and the accidentally introduced rats and mice have caused significant changes to both the vegetation and the native wildlife.

Many of the domestic animals were fed on imported fodder containing seeds of temperate climate plants. Thus, on most islands numerous introduced weed species occur around the existing and ruined settlements. However, few of those have adapted to their new environment and encroached into the native vegetation or spread any distance from their source.

The most destructive introduced animals are the reindeer of South Georgia and Iles Kerguelen, and the rabbits of MacQuarie Island and Iles Kerguelen, both of which have devastated large areas of vegetation, causing the virtual extermination of some species and erosion of soil on hillsides.

In Antarctica, the building of several large research stations and the use of vehicles and aircraft have produced a serious local effect on the meagre flora and fauna, while unknown damage may have been done by exhaust fumes, chemicals and oil waste disposal, etc.

Most of the problems relating to the human invasion of these southern lands took place before any consideration was given to the need for careful control of the environment. The Antarctic and sub-Antarctic tundra, whether richly vegetated or apparently barren, is a very fragile system.

Establishment and growth of plants and their associated fauna is extremely slow, and once an area of vegetation or soil is destroyed or disturbed, it will take many years for it to recover and return to its original state; even boot marks in a moss bank may persist at least 10 years. Decay is very slow and much litter remains for decades defiling the landscape.

The inter-relationship between plants, animals and their environment in these simple systems are being monitored and studied in detail. Scientific investigations over many years may help us to understand the more complex systems elsewhere in the world. Because it is one of the few remaining regions in the world relatively uninfluenced by man, except in the immediate vicinity of the research stations, the current generation has become fully aware of the need to respect and care for its fauna and flora.

Lakes, ponds and pools

Antarctica contains a surprising number and variety of lakes, ponds and pools. However, even the warmest lakes are frozen to depths of one or two metres for 8 to 12 months of the year, and some are always covered with ice. The ice cover limits the amount of light that can enter the lakes, thus restricting plant growth; where floating algae (phytoplankton) do occur, they are adapted to low light levels and have a peak of activity in early spring when the lakes are still ice-covered.

Nearly all Antarctic lakes have arisen as a result of glacial retreat, though a few have been formed by earth movements. The most recent freshwater bodies are found as short-lived pools in depressions on glaciers and ice fields. They contain no life.

As deglaciation uncovers bedrock, more conventional lakes can form. These contain pure water, with the addition of only small amounts of mineral salts from sea spray and leaching from the surrounding rock. There may be a sparse vegetation of blue-green algae and diatoms forming a felt on the bottom, and occasionally small water-fleas (for example, the Copepod (Pseudoboeckella poppei) are present.

Lakes that have been established longer are characterized by increased levels of nutrient salts in their water, though these are still very low. These oligotropihic lakes can support a crop of plants and hence animals, which feed on the plants or on detritus. When not kept clean by ice scour, the bottoms of such lakes are often partially or totally covered with a dense felt of blue-green algae and diatoms, and there may be rich growths of aquatic mosses.

Around the edges of the lake one may see the Fairy shrimp (Branchinecta gaini), the largest of the freshwater invertebrates in the Antarctic. Tiny rotifers, tardigrades and nematode worms are also to be found. Bacteria are important, particularly in the lake sediments, where they are involved in decomposition and recycling of nutrients.

Lakes and pools near penguin rookeries or the hauling out grounds of Elephant or Fur Seals rapidly become enriched by the excreta of these animals and are then termed eutrophic. The activities of the animals make the water turbid, and the bottom vegetation is reduced or absent though there may be a rich growth of phytoplankton.

When the amount of organic material in the pool is very high, the available oxygen is used during decomposition for oxidising the organic compounds; the deep waters and sediment may then become anoxic, producing conditions toxic to plant life. The smell of hydrogen sulphide when the water or mud is disturbed indicates the presence of rotting organic material.

Few animals can live in these pools, and none at all in the worst of the seal wallows which support a population of bacteria and flagellates only.

Interesting lakes are found in continental inland ice-free areas, often called "dry valleys" or "oases". Because of the general aridity of the Antarctic, these lakes are often drying up and completely dry lake beds may be found. Dry valley lakes often receive small amounts of melt water carrying salts leached from the rocks, but if the annual input of water only equals or is less than the loss by evaporation or sublimation of ice, the lake will gradually become more saline. Some lakes have water over 13 times more saline than sea water, and freezing points as low as -48C.

Saline lakes may also arise by the evaporation of sea water, trapped in arms of the sea cut off by the rising of the land, as the deglaciation reduced the load of the ice sheet. Even in very salty water there may be some life in the form of algae, flagellates and bacteria. In some saline lakes a layer of freshwater floats on top of the denser saline layer beneath. If there is a thick ice cover on top, this will insulate the liquid layers from the cold air above and some of these lakes are warmed by solar radiation or geothermal heat to reach temperatures near the bottom as high as 35C.

In a lake of this type, for example Lake Bonney in south Victoria Land, extensive algal mats occur attached to the gravel bottom. These mats grow and produce gases which render them buoyant. They detach in pieces and rise through the water to positions underneath the ice. Here the algal mats slowly collect solar heat and melt their way upwards through the ice which is 3-4 metres thick on Lake Bonney. When they reach the surface the mat pieces dry and blow away, sometimes colonizing other locations.

Lake Bonney was among the first lakes discovered on the Antarctic continent. Scott in 1903 first observed this lake and described two nearly separate small basins. In 1912, Scott's second expedition discovered that the two lobes had joined more completely and the lake had apparently enlarged. Today, Lake Bonney continues to grow, as do other lakes in this dry valley region.

A strange type of lake occurs on land adjacent to ice shelves. In these lakes the outflow has been dammed by the ice of the shelf, so that the lower layers of the lake on the seaward side are in contact with the sea under the ice shelf and the lake surface rises and falls with the tide. Permanent ice cover prevents wind-generated turbulence from mixing the layers. In such a lake a freshwater community in the upper layer may overlie a marine community beneath.

Kroner Lake, on Deception Island, was a well known volcanic lake in the Antarctic, but it disappeared in the 1969 eruption, though new lakes have been formed since. Kroner Lake was heated by volcanic activity and never froze completely in winter, maximum temperatures of 10C being recorded. It contained a community of bacteria, fungi and algae.

Lakes and pools in sub-Antarctic regions freeze over only for a few weeks each year. Ice scour is minimal and the water is fringed by an emergent vegetation of reeds, grasses and the Antarctic buttercup. Fully aquatic vascular plants, such as starworts, colonize shallow water, and mosses and algae extend into deep water. Algae form a phytoplankton.

The freshwater fauna of the sub-Antarctic is richer in species and contains, in addition to the Antarctic forms, beetles and fly larvae. There are, however, no native freshwater fish or amphibia.

Conservation in the Antarctic

The need for conservation is probably be better understood today than ever before. The pressure of increasing human populations on the environment has produced a general awareness of the value of unspoilt nature or wilderness. The last remaining extensive wilderness is the Antarctic.

The continent used to be protected by its remoteness and inaccessibility but now, technological advances have enabled increasing numbers of visitors to penetrate it. Some come as members of scientific expeditions, some as tourists wishing to visit an area unique both in its scenery and wildlife. Most, if not all, will value their stay in the Antarctic for the way in which it brought them in contact with nature at its simplest and most imposing.

But life in the Antarctic has to contend with some of the world's harshest environments, and is pressed to its limits without the added stress that can be imposed by man. If those who seek the wilderness are not to destroy what they search for, some controls based on an understanding of the system and a respect for its components are essential.

The Antarctic is not totally unspoiled and pristine, though it is more nearly so than any other equivalent area of the world's surface. Man's influence is most apparent at the scattered scientific stations and sites of intensive research. The construction and operation of stations, with the associated problems of waste disposal, energy generation, transport and resupply, present an obvious threat to the nature and the aesthetic value of the environment.

The influence is localized and small in proportion to the Antarctic continent as a whole. However, it is of greater significance than might be expected by comparing it with the entire area, because most stations are established on rocky sites in coastal areas where conditions are most favourable for the wildlife and vegetation.

Less obvious are the changes caused by past exploitation. The search for Fur Seals in the 19th century stripped the beaches of the South Shetland Islands, and a century later the whaling industry devastated the stocks of the larger whales.

There are other hidden or, as yet, only suspected changes which cannot be appreciated by simple inspection or comparison with earlier accounts. The change in the age of sexual maturity of the Crabeater Seal may affect the population dynamics, and hence the total numbers, of this most abundant of all the world's seals. The change may be associated with a complex readjustment of the many food chains based on krill, as a consequence of the reduction of the Antarctic baleen whales.

Pollution of the environment is another scarcely detectable and recent change which may have far-reaching consequences. The snow that falls over Antarctica and its oceans now contains minute traces of man-made chemicals which become concentrated in the bodies of marine organisms such as penguins and seals.

Many visitors are surprised to find vegetation on areas of land around the Antarctic coasts. The deep luxuriant moss banks and the bright orange and yellow rock lichens stand out in a land of rock and snow. What is often not appreciated is that these plants grow extremely slowly and the scars of human footprints or the collection of souvenirs can endure for decades.

The tameness of penguins and other sea birds is another great attraction of the region. But not all individuals will tolerate close approach. In any colony some desert their eggs or chicks, and the skuas which prey upon them are quick to pounce. Excited penguins often step on their own eggs as well. Even apparently impassive members of a colony may be subtly disturbed, resulting in an unnecessary drain on their energy reserves which can be restored only by long feeding trips at sea. Too much disturbance can mean reproductive failure and shrinking populations.

Although this booklet is concerned mainly with living organisms and systems, there are other features of the Antarctic that are potentially subject to disturbance. In some parts of the Antarctic, in that tiny fraction of the land which is free of snow and ice at some time of the year, there are rocks which contain fossils, agates, geodes or other attractive specimens.

A visitor may feel tempted to collect such material and take it home as a momento of their trip to the Antarctic. However, this sort of collecting can have very serious consequences for scientific research. The supply of these specimens is always limited, and even where they appear abundant, once those that are present have been taken, there can be no replacement.

Fossils in particular can be of great importance in interpreting the history of the Antarctic and the other southern continents and the evolution of plants and animals. A fossil taken home is lost forever to the scientific community.

Similar considerations apply to the strangely-shaped rocks sculpted by the Antarctic winds for many thousands of years, and known as ventifacts, and the patterned ground that is the result of freeze-thaw activity. When a ventifact is removed, or patterned ground disturbed, many thousands of years may need to elapse before the feature is restored, if indeed this ever happens.

The first organized attempt to provide a coordinated system for conservation in the Antarctic was the Antarctic Treaty's Agreed Measures for the Conservation of Antarctic Fauna and Flora. These measures provide, in conservationist terms, a management plan for the Antarctic. They lay down rules for conduct that will help to preserve Antarctic ecosystems, and provide for the designation of specially protected species and areas where activities are specifically limited. The Agreed Measures also prohibit the importation of non-indigenous animals and plants, except under special licence.

Citizens of governments which have ratified the Antarctic Treaty may be legally bound by the Agreed Measures, while others are free to ignore them. The information and advice in this booklet is intended for all groups. By using common sense, visitors to Antarctica can make an important contribution to its conservation, and thus avoid damaging the environment and its wildlife and vegetation.

The following points may be helpful:

  1. Remember that the vegetation is fragile and very slow growing. Avoid walking over moss-banks or lichen-covered scree slopes.
  2. Do not collect conspicuous lichens or moss-tufts. The best souvenirs to bring back from the Antarctic are memories and photographs.
  3. Do not collect fossils, other interesting mineral specimens,or disturb patterned ground. Remember these features are irreplaceable on a human time scale.
  4. Do not disturb nesting bird colonies. Stay outside the margins of a colony and observe from a distance.
  5. Do not disturb sleeping seals and never attempt to handle seal pups.
  6. Avoid marked sites where scientific experiments are going on. A close examination of a microclimate recorder for example could result in some very misleading data. Remember that these experiments represent somebody's professional work - and have cost some government (perhaps yours) a great deal of money. Respect the scientists' interests and careers.
  7. Take all litter back with you. It takes decades for it to break down in the Antarctic environment.
  8. Encourage your associates and comrades to follow your efforts at keeping Antarctica's wilderness conserved and unspoiled for future generations.