What is a common threat to ocean ecosystems?

The chosen answer highlights pollution from runoff, waste, and fertilizers as a significant threat to ocean ecosystems. This is a pressing issue in environmental science because it directly impacts water quality and the health of marine life. Runoff from agricultural fields often carries fertilizers that contain nutrients, particularly nitrogen and phosphorus. When these substances enter the ocean, they can lead to eutrophication, a process that causes excessive growth of algal blooms.

These algal blooms can deplete oxygen in the water, creating dead zones where marine life cannot survive. Additionally, runoff can introduce harmful substances like pesticides and heavy metals, which can have toxic effects on marine organisms and disrupt entire food webs. The shift in water chemistry not only affects individual species but can also threaten biodiversity and the overall functioning of marine ecosystems.

While waste from household products can contribute to ocean pollution, the impact of agricultural runoff is particularly pronounced due to its volume and the concentrated nutrients it delivers to coastal waters. Excessive sunlight exposure does not pose a direct threat to ocean ecosystems in the way pollution does, as marine environments are adapted to a range of light conditions. The natural increase of marine populations can potentially lead to overpopulation in certain habitats, but it is not a pervasive threat like pollution, which has widespread and detrimental