Problem 9 - Biology: The Dynamic Science

Question

During the spring overturn in a temperate zone lake: a. oxygen is carried from the surface to the bottom, and nutrients are carried from the bottom to the surface.b. nutrients are carried from the surface to the bottom, and oxygen is carried from the bottom to the surface. c. nutrients and oxygen are carried from the bottom waters to the surface waters. d. nutrients and oxygen are carried from the surface waters to the bottom waters. e. oxygen concentration remains constant at all depths, and nutrients sink to the bottom.

Step-by-Step Solution

Answer

The correct answer is option a. oxygen is carried from the surface to the bottom, and nutrients are carried from the bottom to the surface.

Step 1: Understanding the Spring Overturn

In the spring, when the temperature of the lake's surface water increases and becomes as much as the bottom water, the water in the temperate zone lake begins to mix. This process is known as spring overturn.

Step 2: Movement of Oxygen and Nutrients

During the spring overturn, oxygen, which is in the cooler and denser upper layer of the water, is carried down to the bottom. Simultaneously, nutrient-rich water from the bottom is carried up to the surface of the lake.

Step 3: Identifying the Correct Answer

Considering the movement of oxygen and nutrients during the spring overturn, the correct answer is a. oxygen is carried from the surface to the bottom, and nutrients are carried from the bottom to the surface.