With reference to Eutrophication, which of the following statements is/are correct? 1) It is a phenomenon of nutrient enrichment of a water body. 2) It depletes dissolved oxygen of the water. Select the correct answer using the codes given below:

Both statements are correct, so the answer is C. Eutrophication is the enrichment of a water body with nutrients, mainly nitrogen and phosphorus, which usually enter through sewage, detergents and agricultural runoff from fertilisers. This excess nutrient load triggers algal blooms. When these algae die, decomposing bacteria consume large amounts of dissolved oxygen, and the resulting hypoxia kills fish and other aquatic life.

Statement 1 is correct: nutrient enrichment is the defining feature of eutrophication itself.

Statement 2 is correct: oxygen depletion is the usual consequence, especially at night and during decomposition of dead algal biomass. Dead zones in the Gulf of Mexico and the Baltic Sea are the classic examples.

Core concept: nutrient loading, algal bloom and hypoxia form a chain, and aspirants should know both the cause and the effect. Mains angle: GS-III on water pollution, sewage treatment, and the role of fertiliser use and nutrient management in river basins such as the Ganga.

Trap: candidates sometimes treat eutrophication as only nutrient enrichment or only oxygen loss and mark a single statement. Both are parts of the same process, so both are correct.