An oyster, the species, which has existed since time immemorial, has now become extinct. In fact, we have to admit that it has practically died out, being unable to survive the twentieth century. Our native oyster, Crassostrea virginicus, seems to have entirely disappeared. The question arises what the reason for this ecological catastrophe is and what is more important if it could have been averted.
Just one hundred years ago, oysters were practically thriving near the Easter coasts of the United States but due to such factors as global warming, overfishing, the rise in water temperature, and naturally increased pollution (it is probably the key factor), the total amount of the oyster population reduced by ninety-five percent.
As far as the reasons are concerned, we can single out the following ones. First, oysters natural habitat is continuously destroyed; perhaps this issue requires further explanation. According to the research “Temperature tolerance in the oyster, Crassostrea Virginia, is affected by cadmium,” conducted by Marine Research Center, the species is extremely vulnerable to the rise in water temperature, and cadmium of the heavy metals makes it perfectly intolerable for them.
A marine researcher Gisela Lannig says that almost half of the oysters, which were exposed to the cadmium pollution, died within the period of twenty days, just because they could not obtain enough oxygen (Lannig, 3).
An oyster is a cold-blooded organism, so its temperature depends upon the temperature of the environment. It is believed by many researchers that this species can stand heavy metals and rising temperature but not the combination of these two factors. Such an assault on their organisms is practically fatal to them.
According to marine researcher Sokolova, the combination of temperature rise and heavy metal pollution on metabolic chemistry cause trouble not only for oysters but also for other cold-blooded species. In spite of the fact that the pollution level has been determined as tolerable for the species, and seemingly oysters have developed natural equilibrium. At first glance, they seemed to handle water temperature rise for a period of a few months, nevertheless, the combined long-term effects make their survival highly improbable (Sokolova, 2).
The consequences of this disaster cannot be overestimated because oysters are, to a certain degree, a natural water filter. Earlier, the water in the Chesapeake Bay could be filtered by the oyster population in three days, but now this process can take almost a year. According to recent studies, there are approximately three hundred species, which are entirely dependant on the oyster reefs, such as for instance croaker, sheepshead, or stone crab. Moreover, we can say that oyster beds serve as food for a wide variety of larger fish.
Thus, the question of how to help the oysters comes down to the problem of water pollution, which undoubtedly requires a great deal of further research and action because we cannot predict the ending of this story.
Bibliography
University of North Carolina at Charlotte. “Oysters Can Take Heat And Heavy Metals, But Not Both.” ScienceDaily. 2008. Web.
American Physiological Society. “Rising Ocean Temperatures, Pollution Have Oysters In Hot Water.” ScienceDaily. 2008. Web.