Agriculture, Food, Natural Resources, and the Environment Practice Exam

Nutrient enrichment drives eutrophication, which triggers algal blooms in water bodies. When these blooms die and decompose, bacteria break down the organic matter and consume large amounts of dissolved oxygen. This leads to oxygen depletion, creating hypoxic or even anoxic conditions that stress or kill many aquatic organisms and reduce overall biodiversity. That drop in dissolved oxygen is the most direct and recognizable consequence in aquatic ecosystems, making it the best description of eutrophication’s effect. The other outcomes don’t fit as well: while nutrient input can alter which species are present, it typically reduces biodiversity rather than increases it; soil fertility relates to terrestrial soils, not aquatic systems; and climate stability isn’t a direct result of nutrient enrichment in water.