[Campbell Biology P.1237] What is a thermocline, as described in the text? | Practice Question

What is a thermocline, as described in the text?

  • A: A zone in temperate lakes where mixing of water occurs in spring and fall.
  • B: An abrupt temperature change in the ocean and most lakes, separating warmer upper layers from colder deeper waters.
  • C: The primary factor distinguishing marine biomes from freshwater biomes.
  • D: A region in aquatic biomes characterized by the absence of light.

Explanation

The text states: 'In the ocean and in most lakes, an abrupt temperature change called a thermocline separates a more uniformly warm upper layer from more uniformly cold deeper waters.' Option A describes 'turnover', Option C refers to salt concentration, and Option D describes an 'aphotic zone'.