Earlier breakup of the Arctic sea ice, caused by global warming, shortens the spring hunting season for female polar bars in Western Hudson Bay. It is also believed to be responsible for the fall in the average weight of these bears. As female polar bears become lighter, their ability to reproduce and the survival of their cubs decline. As the bears grow thinner, they are more likely to wander into human territory for food, increasing the chances of them having collisions with man. The reduction in sea ice cover in areas where there are known polar bear populations and the early breakup of the ice in these areas are a cause for concern.
Global warming is having a negative and significant effect on these majestic creatures. Polar bears spend most of their lives on the sea ice, which is vital for their survival, at least in terms of their lifestyles. The sea ice surface is the platform that provides them with a place to hunt seals and other marine animals from. Sea ice is the most scarce during the summer months, causing the polar bears to retreat to land and survive on their storage of fat reserves until the sea ice comes back in the autumn. If the length of the sea ice season continues to decrease, then polar bears will have lesser time on the ice to feed. Their stored fat from life on the ice will not provide enough nourishment for their time on land, posing a danger to their health, and to their species in the long run.
If the climate continues to warm as projected by the Intergovernmental Panel on Climate Change, and the ice continues to break up earlier, it is likely that in 20 to 30 years, polar bear reproduction in western Hudson Bay will be significantly limited.
Sources:
NASA/Goddard Space Flight Center (2006, September 14). Warming Climate May Put Chill On Arctic Polar Bear Population. ScienceDaily. Retrieved June 29, 2008, from http://www.sciencedaily.com /releases/2006/09/060913191415.htm
Saturday, June 28, 2008
Entry 2: 29/6/08
I shall continue on my last post.
The four species of penguin that breed on Antarctica, mainly the Adélie, Emperor, Chinstrap and Gentoo penguins, are under increasing pressure. Global warming is causing the ground which the penguins raise their young to melt and disappear. Food has also become scarcer because of global warming and the problem of overfishing.
The Antarctic Peninsula is warming five times faster than the average rate of global warming in the rest of the world. The Antarctic Ocean has warmed down to a depth of 3000m. Sea ice that is formed from seawater is significantly lesser off the West Antarctic Peninsula, with 40% less ice than 26 years before. This decrease of ice has led to the decrease in the population of krill, which is the main source of food for the Chinstrap penguins. With the decrease in krill, the Chinstrap penguins have decreased by 30% to 66% in some colonies. The Emperor penguins have halved in size over the last 100 years. Warmer winter temperatures and stronger winds forces the Emperors to raise their chicks on thinner ice, and chicks and eggs sometimes get blown away.
Warmer temperatures mean that the atmosphere can hold more moisture, which brings more snow. The Adélie penguin, which needs land that is free of snow and ice to raise their young, are in jeopardy. The food chain of Antarctica and the survival of many other species all depend on the sea ice.
The four species of penguin that breed on Antarctica, mainly the Adélie, Emperor, Chinstrap and Gentoo penguins, are under increasing pressure. Global warming is causing the ground which the penguins raise their young to melt and disappear. Food has also become scarcer because of global warming and the problem of overfishing.
The Antarctic Peninsula is warming five times faster than the average rate of global warming in the rest of the world. The Antarctic Ocean has warmed down to a depth of 3000m. Sea ice that is formed from seawater is significantly lesser off the West Antarctic Peninsula, with 40% less ice than 26 years before. This decrease of ice has led to the decrease in the population of krill, which is the main source of food for the Chinstrap penguins. With the decrease in krill, the Chinstrap penguins have decreased by 30% to 66% in some colonies. The Emperor penguins have halved in size over the last 100 years. Warmer winter temperatures and stronger winds forces the Emperors to raise their chicks on thinner ice, and chicks and eggs sometimes get blown away.
Warmer temperatures mean that the atmosphere can hold more moisture, which brings more snow. The Adélie penguin, which needs land that is free of snow and ice to raise their young, are in jeopardy. The food chain of Antarctica and the survival of many other species all depend on the sea ice.
Credits: WWF(World Wildlife Fund)
Sources:
World Wildlife Fund (2007, December 15). Penguins In Peril As Climate Warms. ScienceDaily. Retrieved June 29, 2008, from http://www.sciencedaily.com /releases/2007/12/071213203604.htm
Glossary:
Peninsula:a large mass of land projecting into a body of water .
Krill: The collection of small marine crustaceans of the order Euphausiacea that are the principal food of baleen whales.
Thursday, June 26, 2008
Entry 1:26/6/08
I will be doing on the topics Ecology and Nutrient Cycles in the Ecosystem and Issues on Sex. I shall now begin my first post with a question related to Ecology and Nutrient Cycles, which I will resolve within the next few entries. The question is as follows: What are the effects of global warming on the ecosystem in the north and south poles?
Already, with the depleting ice-shelves caused by global warming, cetaceans such as whales, dolphins and porpoises are being affected by the rising temperatures. Beluga whales, narwhales and bow head whales are among those in Antarctica that are being affected. The decline of krill, tiny marine shrimp-like animals that are the whales' source of food, may in turn affect the population of whales. The decline is because of the lessening sea ice. As sea ice cover decreases, human activities such commercial shipping, oil and gas mining explorations and military activities will increase. This will result in greater risks from oil and chemical spills and more collisions between whales and ships. Changes in the sea temperate may also kills some whales that are unable to survive in warmer waters.
All these effects as a result of global warming will ultimately drive whales to extinction if they are allowed to continue. If this happens, there may be a unbalance in the ecosystem as predators which hunt the whales may also decline as a result, releasing a chain effect of events that are devastating.
I shall stop here for now...
Sources
http://www.sciencedaily.com/releases/2007/05/070522125023.htm
http://dictionary.reference.com/browse/cetaceans
Glossary
Cetaceans: Any of various aquatic, chiefly marine mammals of the order Cetacea, including the whales, dolphins, and porpoises, characterized by a nearly hairless body, anterior limbs modified into broad flippers, vestigial posterior limbs, and a flat notched tail.
Already, with the depleting ice-shelves caused by global warming, cetaceans such as whales, dolphins and porpoises are being affected by the rising temperatures. Beluga whales, narwhales and bow head whales are among those in Antarctica that are being affected. The decline of krill, tiny marine shrimp-like animals that are the whales' source of food, may in turn affect the population of whales. The decline is because of the lessening sea ice. As sea ice cover decreases, human activities such commercial shipping, oil and gas mining explorations and military activities will increase. This will result in greater risks from oil and chemical spills and more collisions between whales and ships. Changes in the sea temperate may also kills some whales that are unable to survive in warmer waters.
All these effects as a result of global warming will ultimately drive whales to extinction if they are allowed to continue. If this happens, there may be a unbalance in the ecosystem as predators which hunt the whales may also decline as a result, releasing a chain effect of events that are devastating.
I shall stop here for now...
Sources
http://www.sciencedaily.com/releases/2007/05/070522125023.htm
http://dictionary.reference.com/browse/cetaceans
Glossary
Cetaceans: Any of various aquatic, chiefly marine mammals of the order Cetacea, including the whales, dolphins, and porpoises, characterized by a nearly hairless body, anterior limbs modified into broad flippers, vestigial posterior limbs, and a flat notched tail.
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