What effect does oil have on marine life when a spill occurs?

When an oil spill occurs, it can have devastating effects on marine life, primarily due to the physical and chemical properties of oil. The correct response highlights that oil smothers marine life. When oil spreads over the surface of the water, it creates a slick that reduces the amount of light that penetrates the water column. This can inhibit photosynthesis for phytoplankton, which are the foundation of the marine food web.

In addition to blocking sunlight, oil can coat the bodies of marine organisms like fish, birds, and sea turtles. This coating can impair their ability to breathe (in the case of gills in fish), insulate (in the case of birds losing the waterproofing of their feathers), and navigate or hunt for food. Furthermore, the toxic compounds in oil can be harmful if ingested or absorbed by marine organisms, leading to long-term health issues.

The other answer choices do not accurately represent the effects of an oil spill. Oil spills do not create breeding grounds, clean the water, or reduce competition for resources; rather, they disrupt ecosystems, lead to habitat destruction, and can cause significant mortality and chronic health effects in affected species.