Antarctica has marked seasonal differences. In the winter there is total darkness all day long and in the summer there 24h daylight. And it is accompanied by changes in the extent of sea-ice cover. All the physical conditions has a major influence on the marine and land ecosystem.
Antarctica has the most coastal marine organisms in the world, so there is a great wildlife.
All the organisms which live in Antarctica have to deal with very harsh living
conditions. The living conditions are better in the water because the water remains at a constant temperature and there is no wind. But special adaptation with the cold and the variation of light is needed.
The ocean ecosystem contains few species but a lot of other animals
depend on these species. The primary producers (phytoplankton) are located in the ocean. The nutrients in the cold water are used directly by the phytoplankton; phytoplankton grows only in the summer due to the energy input from sunlight being converted to carbon dioxide and then to biological compounds. This energy is transmitted to the next member of the food chain, like the krill. Phytoplankton is microscopic but their concentration is visible on the water surface, so the other animals can see it. Phytoplankton is the main source of primary production in Antarctica. So in the winter, when there’s total darkness, phytoplankton can’t grow because there’s no sunlight. Sometimes it could be carried under the ice from distant open water. So the secondary producers aren’t able to eat it and many of them could die because they can’t found any food.
The krill is the most important animal in the Southern Ocean, in the marine
ecosystem. There source of food is phytoplankton and they are the source of food for the other species from higher trophic levels. They have trouble to survive in the winter, when the phytoplankton isn’t produced. So they shrink and use up their own body’s reserves. If the krill disappears then the other animal species would be forced to disappear because they won’t have their main source of food anymore. The krill plays a major role in the marine ecosystem.
In Antarctica, the land ecosystem must endure harsh temperature
variations, so they have to be able to adapt. Some of the birds migrate north during the winter and most of the birds breed on the islands, because the temperature is higher there. The major group of birds in Antarctica is the penguins, who are the most aquatic of the seabirds. They are located on fringes of ice and on the Antarctic islands. They feed at sea but breed on the land. To resist the cold they are able to store a layer of fat under their skin for insulation. So if there’s a quick change in the temperature, the penguins won’t able to resist the cold and could die. The penguins feed mostly on krill and on squid. So if the food chain is broken, the penguins won’t be able to eat.
The whales, are mammals who have many of the same adaptations as the
penguins which reduce the effect of the cold. They migrate to the north to escape the harsh winter, in the summer they return southwards. They spend the winter in the sea; they come out of the water only to get air. So we can see that their lives are affected by the cold weather and the disparition of the phytoplankton in the during the winter season.
Here we can see a food chain of the ecosystem of Antarctica. So we can understand now if the chain is broken, then all the wildlife of Antarctica is in danger:
The physical conditions that affect life in Antarctica are the low air
temperatures all year long, the strong winds that increase the cold, the light that varies from months of total darkness to total sunlight and the fact that all but 2% of the continent is covered with ice. But the life in Antarctica is also affected by the fishing, the tourism and the climate change. These physical factors affect the primary production and the supply of food.
In my opinion, the wildlife in Antarctica is mainly affected by humans (Scientifics), and by the pollution. There is a lot of rubbish that had begun to accumulate around the scientific stations and the sewage is disposed into the sea and due to the cold water, it doesn’t really decompose. In 1990, a pipe supplying fuel to one base fractured, so there was oil spilled in the sea. This accident affected the growing of the phytoplankton. So if an accident like this could occur once again, the consequences could be greater and all the food chain would be broken and the wildlife in Antarctica destroyed.
So I think that the humans affect a lot more the life in Antarctica then the physical environment does.
