34.6-34.7

Question 1

What defines the boundary between the photic and aphotic zones?

Answer 1

The boundary is determined by the distance that light penetrates (200 m).

Question 2

The transition from an aquatic biome to a terrestrial biome is known as a(n) _____________.

Answer 2

intertidal zone

Question 3

People often confuse estuaries with intertidal zones. Briefly explain the difference between
them.

Answer 3

An intertidal zone is where the ocean meets land. An estuary is where a river or stream merges
with the ocean.

Question 4

The two broad types of freshwater biomes include _____________ and _____________.

Answer 4

Standing water, flowing water
lake, river

Question 5

Compare the characteristics of a river at its source (headwaters) with the characteristics far
downstream.

Answer 5

At its source, a river has low levels of nutrients, is fast flowing, and is clear and cold. Downstream,
a river usually widens out, slows down, and has much more silt that makes it murky and warm