While scanning a couple of scientific news sites today I came across a story about sea otter and dolphin deaths. The story, which you can read here, talked about how new diseases and toxins are affecting marine mammals. These diseases are the result of humans, and although the pollution is often unintended it is still a major problem.
Now, I hope that if you are reading this you happen to actually like and care about animals and just the fact the the pollution is harming and killing these animals is enough to upset you. However, you shouldn't just worry about the animals health, you should worry about everyone else's as well. Remember DDT and Bald Eagles? Well, the same thing happens all over the world in every ecosystem. It's called biomagnification, and it means that a compound increases as it moves up the food chain.
Think of it like this, a pesticide gets spread over some plants. The grasshopper eats the plants and when he does he happens to ingest some of the pesticide. Since the grasshopper is immune to the pesticide he survives, but now those chemicals are in him. Next the songbird eats the grasshopper. Since the bird has to eat lots of grasshoppers to survive it now has lots of the toxins in it's system. And it's not just the songbird who eats the grasshopper, small mammals and reptiles do too. However, for this example let's say that the toxin is still not really present enough to harm these secondary consumers. Now, let's think of the hawk that eats reptiles, songbirds, and small mammals. All of the toxin, in all of these animals, is now built up in the hawk. Now when the hawk lays its eggs the toxin causes the shells to be thin and the chicks develop with defects or are squashed before the can be born. This leads to a decreasing population of hawks.
It's simple math. You start with the grasshopper equaling 1. The bird, small mammals, and reptiles each eat 20 grasshoppers, so they eat now equal 20. The hawk eats 20 of them, so the hawk now equals 400.
Now take the examples above and apply it to dolphins or sea otters. Both of these species eat the same things out of the ocean as we do. If a bunch of fish or oysters are putting so much mercury, bacteria and other toxins into the marine mammals that their immune systems have dropped to the point where they can now get rare diseases, think of what that means for us.
As if it isn't bad enough, those compromised immune systems allow the animals to get diseases that they normally wouldn't. The diseases can then mutate and jump back into land animals and then into humans. Have you heard of drug resistant strands of bacteria and viruses? This is caused by evolution and mutation of theses diseases.
So, how did it get there and how do we stop it? Well, the sewage and dumping into rivers and other water systems is one way, but did you know that any road, sidewalk, parking lot, or other paved or compacted soil area will do the same thing? Think about it, if we leave the hose running out over the lawn most of the water is eventually either absorbed by the ground or evaporates up into the atmosphere. If we do the same thing to the driveway the water either goes down the drain or evaporates out. That water that goes down the drain ends up in a river or stream that then goes to the ocean. Here you can see biomagnification again where a little bit of toxin and pollutant in one stream joins thousands of streams.
To help with this we need to be more aware of where we are building and what we are destroying. One way is buffer strips, which are areas of trees and other vegetation that line a water way. This vegetation will slow down and stop erosion and water pollutants if we leave them there. Another is by making sure to leave soil undamaged and uncompacted near waterways. This will decrease surface run off.
The last way I want to highlight is through natural filter systems. Wetlands, marshes, and bogs, things most farmers and developers dislike, work as natural kidney systems that filter out the toxins that are in the water. Instead of draining them they need to be left in peace to work as they need to. If you remove one of your kidneys you can survive, but you are limited by what you can do. If you remove both kidneys you are dead.
So, I'm sorry this one was long but I just wanted to highlight the fact that even though we may not think that we are damaging the environment, we still are. And the next time you look at the amount of money we have to spend cleaning up a polluted area just remember that the environment used to do that for free.
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