How Pollution Is Affecting Polar Bear Populations

As mentioned in a previous post, air, water, and thermal pollution do not affect the polar bear separately, but rather, play into each other. The air pollution leads to thermal pollution. As mentioned previously, thermal pollution is caused by greenhouse gas emissions, leading to global warming. The increase in CO2 in the atmosphere is bringing about the increase in temperature, leading to the melting of polar ice caps. The polar ice caps melting is destroying habitats, polluting the water, and interrupting food chains. The ice caps are the primary sources for hunting, mating, and denning for the polar bear. If you take the polar bear completely out of the food chain, there would be chaos.

Polar bears play a huge role in their ecosystem. In the Arctic, they are at the top of their food chain. This means that the effects of pollutants are intensified with each step in the food chain. For example, in an extremely simplified food chain, the water pollution may kill off the smaller fish, which will cause the seals to move locations to find a new food source, leaving the polar bears with nothing to eat. This will cause the polar bears to move inland to attempt to find alternate food sources on land. Alternatively, if the ice caps melting causes polar bears to either move or their populations to eventually go extinct, we will begin to see a problem with overpopulation in other species. A polar bear’s diet consists primarily of seal because of the high fat content needed to fuel the bear. Polar bears are the main predators of ringed and bearded seals in the arctic. The loss of a primary predator will mean the seal populations can grow rapidly, leading to an increase in the hunting of smaller fish. The hunting of smaller fish will either lead to less fish being available to other creatures or not enough fish for the seals to sustain their population, again greatly affecting the food chain. Fish are a main food source for multiple animals in the ocean and in the arctic. Having an increase in fish hunting by seals will leave less fish for other organisms, causing a decrease in their populations, with will cause ripples in their food chains.

Ripples in food chains may seem insignificant. After all, food chains are more like food webs and are absolutely massive. How can the removal of one species, such as the bearded seal, really be that big of a deal? As mentioned in “What to Know About Polar Bears”, the males are the primary hunters of the bearded seal, so we’ll focus on them. If the bearded seal were suddenly gone, either from extinction or relocation due to lack of food, the polar bear would be forced to find another source of food. Often, in times of great stress, the polar bear will move inland to find food. This is where the trash pollution comes into play. Being moved inland means more exposure to the trash that litters the shores of the polar basin. These polar bears, desperate to find food, will eat almost anything in an attempt to find nourishment. Obviously, eating trash provides none of the nutrients necessary and either choking on the material or the harsh chemicals in the trash will lead to the polar bear’s eventual death, causing a decline in their population. Also, I previously mentioned how, in rare cases, polar bears will turn to cannibalism. This is another situation that is brought about by periods of high stress and desperation. These polar bears eating their own kind is only damaging to their own populations and, again, will lead to a decline in their numbers.