Question

Which of the following is characteristic of eutrophic lakes?

a) Eutrophic lakes have hypoxic conditions
b) Eutrophic lakes are overfertilized
c) Eutrophic lakes have anoxic conditions
d) Both b and c

Answer 1

Characteristic of eutrophic lakes includes being overfertilized and having hypoxic conditions due to excessive nutrient input leading to extensive algal blooms and subsequent oxygen depletion.

Step-by-step explanation:

The characteristics of eutrophic lakes include being overfertilized and suffering from low oxygen concentrations. During the process of eutrophication, there is a large input of nutrients, particularly nitrogen and phosphorus, which can come from sources such as agricultural and urban runoff, including fertilizer and sewage. This nutrient overload leads to the excessive growth of algae, known as algal blooms, which reduce light penetration and cause aquatic plants to die when they can no longer photosynthesize (aphotic conditions). The decomposition of these algae consumes a significant amount of oxygen, leading to hypoxic conditions, where oxygen levels fall below 2 ppm, creating dead zones where aquatic life struggles to survive due to lack of oxygen.