What ecosystem services from U.S. national forests had the ...

[tichca]

What ecosystem services from U.S. national forests had the greatest demands placed on them following World War II and the country's rapid population growth?
 
  A) soil formation and agriculture
  B) grazing and agriculture
  C) food, fiber, and plant growth
  D) grazing, recreation, and timber resources
  E) soil formation and wilderness protection

Question 2

Describe the biological pump.
 
  What will be an ideal response?

[Brummell1998]

Answer to Question 1

D

Answer to Question 2

The overall effect of photosynthesis in shallow waters, of the settling of organic matter, and of decomposition in deep waters is the transfer of CO2 and nutrients from the surface waters to the deep ocean. This process is known as the biological pump. It is balanced by upwelling (see Chapter 5), which brings nutrients and carbon-rich waters back to the surface, replenishing the nutrients and carbon removed by the biological pump. The biological pump has a profound effect on ocean chemistry. As a result of its operation, surface waters are measurably depleted in carbon and severely depleted in phosphate and nitrate (the major nutrient elements) relative to deep waters. If the biological pump were to ceasefor example, as the result of a mass extinctionthe ocean would assume a more uniform composition in a few thousand years, as the thermohaline circulation homogenized the ocean.