I recently read an article that was mentioned in bioremediation presentation last week, building off of the clean up of the 2010 Deepwater Horizon disaster in the Gulf of Mexico; this article discusses its affect on marine life in the area. Researchers have found from samples of the area that the crude oil prolonged the action potential (up to 90%) of isolated cardiomyocytes in juvenile tuna neurons, thus blocking potassium reabsorption during the repolarization period following synapse. This was also found to decrease the calcium current that in turn disrupted excitation-contraction coupling in cardiomyocytes.
During early fish development, embryos are significantly vulnerable to high PAH (hydrocarbon constitute in crude oil) toxicity levels resulting from such disasters, and ultimately lead to long term acute and chronic side effects. Although the exact mechanisms leading to such cardiac functions are unknown, there is plenty of evidence validating the toxicity effects on marine life; following the Exxon Valdez spill, exposed fish embryos characterized significant heart failure, bradycardia, arrhythmias, reduction of contractibility, and edema surrounding the heart.
To explore these mechanisms, researchers assessed juvenile bluefin and yellowfin tuna captured in the area and held at the Tuna Research Conservation Center for observation. The cardiotoxic effects of four crude oil samples were assessed. The cardiac depolarization disorder is suggested to lead to cardiac arrhythmias, as the human homolog for the disorder causes such conditions and can lead to death. With PAHs interfering with EC coupling, lowered Ca2+ output levels during shortened depolarization (blockage of K+ pores in ion channels) periods result in the deficiency in producing contractile movements in cardiomyocytes.
With these findings, it is critical to understand the devastating effects of such disasters, and the need to control and properly clean up such events.