land-based vertebrate animals inhabit Antarctica. Invertebrates which can
tolerate the lower temperatures, exist in the Antarctic Peninsula but are
still considered rare. They range from protozoa (single-celled creatures),
rotifers, tardigrades and nematodes to arthropods (mainly mites and
springtails). The largest invertebrate is the wingless midge (Belgica
antarctica), which grows to 12 mm long. Only 67 species of insects have
been recorded, and most are less than 2 mm long. Most of them are
parasites, like lice which live in the feathers and fur of birds and
seals, where they are protected from the harsh climate for much of the
time. Collemola (springtails) are the only free-living insects. They feed
on algae and fungi, and remain dormant in winter.
the severe climate, many plants thrive in the Antarctic. There are more
than 200 species of lichen and over 50 species of bryophytes, such as
mosses. A wide of variety of fungi are also survive the harsh Antarctic
conditions. Over 700 species of algae are found in the Antarctic, the
majority of which are single-celled plants called phytoplankton.
Phytoplankton, protozoa (single celled animals) and bacteria are all
important food sources within the Antarctic marine environment. In
addition, these microscopic organisms play a crucial role in removing
carbon dioxide from the atmosphere.
surrounding ocean, however, abounds in living creatures. Large numbers of
whales feed on the rich marine life, especially krill. Six species of
seals (including the crabeater, elephant, and leopard) and about 12
species of birds live and breed in the Antarctic. The most prominent
inhabitant of the Antarctic is the penguin. A flightless bird, it lives on
the pack ice and in the oceans around Antarctica and breeds on the land or
ice surfaces along the coast. Most typical are the Adélie and Emperor
from the Greek words phyto (plant) and plankton (made to wander or drift),
phytoplankton are microscopic organisms that live in watery environments,
both salty and fresh. Some phytoplankton are bacteria, some are protists,
and most are single-celled plants. Among the common kinds are
cyanobacteria, silica-encased diatoms, dinoflagellates, green algae, and
are extremely diverse, varying from photosynthesizing bacteria (cyanobacteria),
to plant-like diatoms, to armor-plated coccolithophores (drawings not to
scale). (Collage adapted from drawings and micrographs by Sally Bensusen,
NASA EOS Project Science Office.)
Like land plants,
phytoplankton have chlorophyll to capture sunlight, and they use
photosynthesis to turn it into chemical energy. They consume carbon
dioxide, and release oxygen. All phytoplankton photosynthesize, but some
get additional energy by consuming other organisms.
depends on the availability of carbon dioxide, sunlight, and nutrients.
Phytoplankton, like land plants, require nutrients such as nitrate,
phosphate, silicate, and calcium at various levels depending on the
species. Some phytoplankton can fix nitrogen and can grow in areas where
nitrate concentrations are low. They also require trace amounts of iron
which limits phytoplankton growth in large areas of the ocean because iron
concentrations are very low. Other factors influence phytoplankton growth
rates, including water temperature and salinity, water depth, wind, and
what kinds of predators are grazing on them.
food chain is based on phytoplankton, a varied group of tiny free floating
plants. In spring and early summer their numbers increase rapidly,
producing "blooms" like a think pea soup which can cover
thousand of square kilometers of the ocean. These blooms provide a food
source which is 300-400 times more concentrated than normal for a variety
of zooplankton (tiny animals, especially copepods and krill, which in turn
provide food for fish, seals, whales and penguins.
Norwegian whaling term meaning "small fry", Krill are one of the most
important elements in the Antarctic food chain. They feed on microscopic plants
(phytoplankton) that float around the Southern Ocean. The krill, in turn, then
become the basic food for baleen whales, seals, penguins and many seabirds.
are two families of krill: the Bentheuphausiidae family, which consists
exclusively of a deep-water species called Bentheuphausia amblyops, and the
Euphausiidae family, which consists of 89 known krill species, including --
perhaps most commonly -- Euphausia superba, or Antarctic krill. Unlike
Bentheuphausiidae krill, the Euphausiidae family is bioluminescent.
that Antarctic krill emit a yellow-green light that is thought to either
camouflage the krill's shadow or aid the krill in mating or schooling at night.
Krill are invertebrates that grow to about two inches in length and live in
large schools, or swarms, as dense as 10,000 krill per cubic meter of water.
live in the surface waters of the Southern Ocean, which extends north from the
Antarctic continent to the polar front -- an area where the cold water of the
Antarctic submerges beneath the warmer waters of the Atlantic, Indian, and
Pacific Oceans. As this deep, cold water rises to the surface of the Southern
Ocean, it brings nutrients from all the world's oceans into the sunlight, making
this area home to what is possibly the earth's largest assemblage of
phytoplankton. It is this massive gathering of phytoplankton that allows for
such tremendous swarms of krill, which harvest the miniscule phytoplankton
particles with a specially developed feeding basket that filters them out of the
water. The krill also find nourishment by scraping ice algae off the underside
of pack ice, particularly in spring. These are successful techniques,
apparently, since the total biomass, or weight, of Antarctic krill -- which is
estimated to be between 100 and 800 million tons -- may be the largest of any
multi-cellular animal on the planet.
spring, over 100 million birds breed around the rocky Antarctic coastline and
offshore islands. Around
35 species visit the subantarctic Islands. They range from the magnificent
wandering albatross, which flies thousands of kilometres to feed, to gulls,
skuas, cormorants and terns, which hunt closer inshore. The wandering albatross
has the longest - up to 3.5 meters - wingspan of any bird. The name of this
magnificent creature is truly deserved as wandering albatross can travel up to
10,000km of a single feeding trip.
the Antarctic, there are more species of petrels than of any other bird family.
Petrels are birds which are characterized by their tube-like nostrils on the
Most return to the same sites
each year. Some, like the albatross, mate for life. In addition five species of
land birds live all year round on South Georgia, Kerguelen and Marion
are about 200 different kinds of fish which live in Antarctic waters,90 per cent
of the total number of individual fish belong to the well studied group, the
This sub-order is divided into four families: Antarctic cod,
plunder fish, Dragonfish and ice fish.
Other bottom-dwelling fish include
eel-pouts, sea snails, rat-tailed fish, hagfish, barracuda, lantern fish and
skates are also found in these cold waters. Some species of Antarctic Cod can
produce a compound similar to 'anti freeze' in their blood which stops their
body fluids from freezing, even when temperatures drop below freezing. It lowers
their freezing point to about -2°C.
are flightless birds found in the Southern Hemisphere from the Antarctic
to the equator. There are 18 species of penguins in the southern water,
seven of them live around Antarctica.
The Adelie and emperor breed on the Antarctic shores and are
the only two species found in the Ross Sea area.
Chinstraps breed on
islands around Antarctica and gentoos are found from the Antarctic islands
to the sub-Antarctic.
Another three species (the King, rockhopper and
macaroni) live on the sub-Antarctic islands.
Because ice covers almost all
of Antarctica, penguins have to get all their food from the sea, where
they spend about half their time. They are able to dive very deeply
(emperors can dive to 250 meters) and all are excellent swimmers. The feet
and tail act as a rudder and the flippers as propellers. They feed mostly
on small fish and krill, each one captured individually. The penguins are
also food for other ocean predators: leopard seals and killer whales. On
land their main predator is the skua, a bird which takes both eggs and
seals that live in the cold waters near the Antarctic are called 'pinnepeds'.
Six types live in Antarctica: Antarctic Fur Seals, Crabeater Seals,
Leopard Seals, Ross Seals, and Weddell Seals.
The Southern Elephant Seal is the largest of all the pinnepeds and one of
the largest mammals other than whales. Fully grown males may reach a
length of 4.5 meters and weigh about 4,000 kilograms. They are of course well
adapted to the cold climate, with their big round bodies, layers of
blubber and small extremities.
Seals catch most of their prey under water, but spend some time on
land or ice floes giving birth, raising their young and basking in the
On land they are quite ungainly but in the water they are very
graceful and are excellent swimmers. Much larger numbers of seals are found
in the Antarctic compared to the Arctic, which reflects the much greater
abundance of food resources in the Southern Ocean.
Southern Ocean whales are migratory, heading to tropical waters during the
Antarctic winter. They are found there in the
summer, feeding on krill and other marine resources. Fourteen species of cetaceans (the name given to whales,
dolphins and porpoises) are found in Antarctica. Of these, twelve are
whales. There are two groups, the baleen whales and the toothed whales.
is a huge hairy-edged plate in the whale’s mouth, which acts as a sieve.
The whale sieves out krill, small fish and crustaceans.
Six species of
baleen whales are found in Antarctica, including the huge blue whale,
which is the largest animal that has ever lived. It grows up to 24 meters
and can weigh 84 tons. Other baleen species are the fin, southern right
whale, sei, minke and humpback. Four species of toothed whales are found
in Antarctica. Except for the sperm whale, they are much smaller than the
baleen whales and weren’t widely hunted. The other species are the
southern bottlenose whale, the orca whale and the southern fourtooth
whale. They all have teeth and feed on fish and squid.