Penguins are aquatic, flightless birds that strictly inhabit the Southern Hemisphere. Though popularly associated with Antarctica, penguins inhabit all southern continents, extending as far north as the Galapagos Islands off the coast of Ecuador. In fact, only a few penguin species live in the southernmost regions, and at least ten species live in the temperate zone. Most penguins spend half of their lives on land and half in the oceans. They feed on small marine creatures such as krill, fish, and squid while swimming underwater.

Cold-species penguins are dependent on Antarctic ice, so temperature increases that thin ice shelves, which are important breeding and feeding sites for penguins, can adversely affect penguin populations (Botterill, 2003).

Antarctic warming led to the collapse of portions of the Antarctic Larsen Ice Shelf in 2002, reducing important penguin breeding and feeding areas and drowning thousands of emperor penguin chicks, who were forced to take to the water before they learned to swim. Some scientists believe that cold-species penguins are indicators of the health of Antarctic ecosystems and the consequences of Antarctic climate change.

Global climate changes can perturb the distribution of penguin food sources and harm the health of cold-species penguin populations (Axelrod, 2004). During the winter, marine algae freeze into the ice pack. Ice melts during the spring release algae, which are eaten by krill. This increased food source expands the krill population in time for the penguin's spring breeding time. Warming decreases winter ice, which in turn decreases the release of algae and, consequently, the surge in krill population. Less food available for breeding penguins reduces penguin fertility.

global climate change. Populations of Adelie penguins--the most southerly distributed penguin species, which inhabits the area from South Africa's Prince Edward Islands to the Antarctic Peninsula-- are declining. Penguin populations in the Indian Ocean and more southerly regions of Antarctica are thriving. In some cases, penguin populations thrive because they have access to their primary food source earlier in the breeding season. In other cases, shifts in the location of the primary food source forces penguins to forage further to feed, reducing their fertility.

These changes in food availability are due to the Antarctic Circumpolar Current (ACC), which mixes 140 million cubic meters of water from the Indian, Pacific, and Atlantic Oceans and flows from west to east around Antarctica. The ACC is filled with krill and other penguin food sources. Climate change can alter wind patterns and drive the ACC away from or closer to penguin nesting sites, affecting their populations both directly (by increasing or decreasing food supply) and indirectly (because food supply affects fertility).

References

1. Axelrod, Regina S., David Leonard Downie, and Norman J. Vig, eds. The Global Environment: Institutions, Law, and Policy. 2d ed. Washington, D.C.: CQ Press, 2004.

2. Botterill, Linda C., and Melanie Fisher, eds. Beyond Drought: People, Policy, and Perspectives. Collingwood, Vic.: CSIRO, 2003.

Free term papers are not written to satisfy your specific instructions. You can use our professional writing services to buy a custom written research paper, term paper, or essay on Global Warming at affordable price. CustomTermPapers is the best solution for those who seek help in writing term papers, essays, and research papers related to Global Warming and other relevant topics.