The effects of ultraviolet radiation on the larvae of marine invertebrates and the enhanced effects due to coastal pollution (Crassostrea virginica).

摘要

Stratospheric ozone depletion has increased ultraviolet (UV) radiation levels worldwide and the effects of UV radiation on marine organisms has become an area of focus for marine scientists due to the harmful nature of short wavelength UV radiation to aquatic organisms. Coastal pollution also is increasing because two-thirds of the world's urban centers are now located near estuaries. As a result, benthic organisms from many coastal environments have elevated levels of organic contaminants in their tissues. Because some organic pollutants are known to have phototoxic effects (toxicity enhanced by light), the effects of UV radiation on larvae of marine invertebrates with complex life history strategies (oysters and crabs), and the enhanced effects due to coastal pollution, were investigated.; This research addressed the sublethal effects of transplantation of Crassostrea virginica to a polluted boat dock area and subsequent exposure of larvae from the transplanted oysters to UV radiation. In the presence of UV radiation, growth rates of larvae from dock site oysters were significantly reduced within twenty four hours. This is the first report of phototoxicity in organisms collected directly from the marine environment and the first to address the effects of different stressors sequentially applied to the parent and offspring of a marine species.; Polycyclic aromatic hydrocarbons (PAHs) are known to be phototoxic to marine organisms and their larvae and were the most likely cause of the phototoxic response of oyster larvae. A review of the concentrations of PAHs in tissues and sediments of Mobile Bay, Alabama, indicated that PAHs are present in both and that concentrations decrease as distance from the port increases. Two of the three PAHs that were found in the highest concentrations in sediments and oysters are phototoxic and were used in experiments to examine phototoxicity in larval crabs. The crab experiments showed that phototoxicity occurs at UV radiation levels and PAH concentrations that independently have no detectable effect on larval mortality rates. Mortality rates were pronounced in larvae exposed to PAHs and UV radiation and there were differential abilities among the larvae of the crab species examined to resist phototoxic effects.