Question

Which of the following threats to freshwater is posed by the excessive use of fertilizers on

afarmland?

(a) Fertilizers may be eroded from the soil upon rainfall.

(b) Fertilizers can permeate into the soil and enter aquifers.

(c) Fertilizers can lead to excessive plant growth and water uptake.

(d)Fertilizers can lower the soil moisture and make the farm barren​

Answer 1

When manure or commercial fertilizers enter surface water, the nutrients they release stimulate microorganism growth. The growth and reproduction of microorganisms reduce the dissolved oxygen content of the water body. Without sufficient dissolved oxygen in surface water, fish and other aquatic species suffocate.