Question

Addition of phosphate fertilizers to water bodies causes:
A) Enhanced growth of algae
B) Increase in amount of dissolved oxygen in water
C) Deposition of calcium phosphate
D) Increase in fish population

Answer 1

Hint: Phosphate fertilizers are essential for growth of plant life and their nourishment but the overabundance of it in water can cause adverse ecological effects. When there is too much phosphate fertilizer, it can speed up the eutrophication process in the rivers and lakes.

Complete step by step solution:
Phosphorus is a common constituent of agricultural fertilizers, manures, and organic waste in industrial effluent and sewage. It is essential for plant life but when there is too much phosphate in the water bodies, it can negatively affect water quality and biological condition. Excess amounts of phosphate fertilizer can cause increased growth of algae and large aquatic plants in water bodies, which in result speed up or lead to eutrophication. Eutrophication is the reduction in the amount of dissolved oxygen in water bodies caused by an increase of mineral and organic nutrients. Bank erosion occurring during floods can transport a lot of phosphorus from the rivers banks into streams, lakes or other water bodies. Soil erosion is a major contributor of phosphate fertilizer to streams.
Thus, addition of phosphate fertilizers to water bodies causes enhanced growth of algae.
Thus, option A is the correct answer.

Additional information:
Phosphorus gets attached to the soil particles and thus, moves into the water bodies via runoff during rainfalls. The algae caused by the excessive phosphate fertilizer is not good for marine life

Note: Phosphorus is generally considered the “limiting nutrient” in aquatic ecosystems. In appropriate quantities, phosphorus can be used by vegetation and soil microbes for their growth. However, in excess quantity, it can lead to water quality problems such as eutrophication and harmful algae growth.