Wednesday, December 03, 2008

H2O Pollution Causes "Wonky Babies"

It is a known fact that ships used for the military and for economic purposes pollute the ocean. What is not as well known however, are the specific negative effects this pollution can have on organisms living in the sea. Ceri Lewis, an ecotoxicologist, conducted an experiment to find out exactly how certain pollutants effect the sperm and reproduction of two species of worms and one species of mussel. These, and many other marine species, send their sperm out into the water hoping it will come in contact with an egg and fertilize it successfully. This is risky because the sperm can be easily damaged by the polluted water.
Lewis and her colleagues looked at the lug worm, green rag worm, and a mussel in the lab under conditions that mimic those in the marine-environments these organisms are found. They exposed their sperm to water contaminated with a carcinogenic byproduct of fossil-fuel combustion and to water contaminated by toxic heavy metals such as copper and cadmium. The scientists' results showed that the pollution caused significant impairments to the sperm. In some cases, such as in the rag worm, the sperm swam at about half the speed they would have in clean water. In other cases, the sperm made it to the egg on time but exhibited high levels of DNA damage, such as in the mussel. An example of the damage the pollution was causing is problems in DNA-repair enzymes. This meant that even though the embryo's were being fertilized, they had DNA damage and were creating abnormal offspring. During embryonic development, the cells were dividing in an asymmetrical fashion resulting in unequal amounts of developing tissues. This made it unlikely that the offspring would survive or reproduce.
A strange observation Lewis made is that many animals can reproduce successfully in highly polluted environments. She found this interesting and understanding the mechanisms by which this occurs could be useful. For now, we should try to keep our oceans as clean as we can to protect the vast diversity of wildlife and to give them a fighting chance for survival.
Edit (Dec 8):
Most of the comments asked about species that can successfully reproduce in polluted environments or those that are not affected by the pollution. I did some more research and found an experiment done in 2007 called "Is selenium affecting body condition and reproduction in boreal breeding scaup, scoters, and ring-necked ducks? " by Jean-Michel A. DeVink, Robert G. Clark, Stuart M. Slattery, and Mark Wayland. Although this isn't necessarily related to the mussells, it is a similar topic. Of course, pollution negatively affects most animals and other organisms but in this experiment, they looked at levels of Selenium (Se) and Mercury (Hg) in different birds. "Overall, we found no support for a relationship between selenium and boreal scaup and scoter declines, and discuss current Se threshold concentrations." They found no relationship between the levels of metals and the breeding of the birds which shows that they are not affected in this way by these toxins.
Of course there are many more instances of pollution having a huge impact on animals in nature. One interesting negative affect pollution has is increasing the level of noise in the ocean which makes it hard for whales and dolphins to communicate. They send signals through the water to each other and the noise in the ocean is increasing at a regular level, making it hard for them to understand one another. This leads to problems in reproduction, mating, and everything else that requires communication between individuals. The article can be found here. There are many interesting articles about pollution in the ocean and its affects and I think this is a very important issue that should be addressed and taken seriously.
Posted by Julie K. Riley (11)


At 10:32 AM, Anonymous Jen Kodela said...

Why are some species able to reproduce in highly polluted environments? Is it because they have developed some resistance?

At 1:01 PM, Anonymous Anonymous said...

Are the species that can successfully reproduce related to the worms and mussels? Could this lead to the worms and mussels dieing off?

-Cecelia Hunt

At 1:28 PM, Anonymous Anonymous said...

What species are able to reproduce normally? I would imagine theses species are ones that dont have the sperm swimming freely to the eggs but have less contact with the pollluted water. Interesting article.

Erica Damon

At 7:01 PM, Anonymous Anonymous said...

Interesting blog. I wonder if the species that can reproduce normally in highly polluted environments are ones who have been around longer, and therefore seen more pollution, and have built up a level of resistance against it. I know pollution in the ocean now is most likely higher than it has been, but the oceans and rivers have been polluted for a long time. Maybe some were able to build a resitance a lot faster than others, so maybe that someone in the population had a mutation that got passed on. Interesting. Did they mention anything about other factors affecting the situation? ie. temperature, weather conditions, etc?

Katie Cole

At 1:42 PM, Anonymous Anonymous said...

Very interesting, I was wondering if any other resistance that has been developed to be able to live relatively normally in the polluted waters?

Amanda Joyce

At 11:21 PM, Anonymous Anonymous said...

This is very important, and I agree that we should try and keep our Oceans clean. Those that can successfully reproduce in polluted water do they reproduce better or about the same as they would in normal conditions?

Ada Marie Flores


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