Plastic bags have long been used for many purposes, but people do not always consider the effects that plastic bags have on our seas when they go to use one.
According to a 2007 survey by Marine Conservation Society's Beachwatch survey, the equivalent of 45 plastic bags was found for each kilometre of beach. Many of these washed ashore after being on the water for years, and are only a small portion of the amount that are still out there. The problem is that, once they are in the sea, they will just float around and cause much damage to other aspects of the environment.
The effects that plastic bags have on our seas are often a second thought, because not many people intend their bags to end up there. The problem lies in the fact that every continent in the world is surrounded by coastline, and sea covers 70% of the globe. Plastic bags are not easily biodegradable, and will often end up being whipped up by the wind and carried off to the water that surrounds everyone.
Because they will not rot down for hundreds of years once they are in the ocean, the effects that plastic bags have on our seas are long lasting. The main problem, of course, is the effect on marine wildlife. Many animals are endangered by plastic bags invading their natural habitats for a variety of reasons.
The first and foremost is the flexibility of polyethylene bags, and the shape of them. These bags can easily trap a creature inside, or get stuck around a body part, effectively disabling it. If a plastic bags gets stuck over a creatures head then it may suffocate, or it will be prevented from being able to eat, forcing it to starve to death. Of course, a tangled plastic bag will not always have such a debilitating affect, but it certainly causes a great deal of unneeded distress and will negatively impact a creature's life.
The worst circumstance by far has to be when a plastic bag is swallowed. Predators of jellyfish in particular, for example, may mistake a plastic bag for their common prey. They will then eat the bag and end up choking, or having the bag block their digestive transit and causing extreme and fatal problems. This is happening all over the world and is becoming more common as the amount of bags at sea increases.
The effects that plastic bags have on our seas do not just end with the fact they harm animals directly. The nature of the plastic also means that when even small fragments are ingested they can make any sea creature toxic, and this can even end up affecting humans who may later eat them. When the bags finally do rot down, they release these chemicals into the sea and so have a widespread effect.