Biogeochemical Cycles

Guano from fish-eating birds is a commercial source of this element.

• carbon

• sulfur

• sodium

• phosphorous

• potassium

How does the burning of fossil fuels contribute to the net increase in atmospheric carbon?

• Photosynthesis is reduced by virtue of increased smoke and haze

• Carbon released by the burning is not in a form that can be readily absorbed by plants, leaving residual carbon in the atmosphere.

• Carbon that has been sequestered underground is added to the carbon cycling between the atmosphere and the biosphere.

• Carbon released by the burning is more easily absorbed in the atmosphere than that produced by natural means.

• Carbon released by the burning increases plant growth, producing more carbon for the atmosphere.

Which of the following pathways indicate how nitrogen is added to the largest nitrogen reservoir?

• Nitrifying bacteria and lightning

• Decomposing plant and animal material

• Denitrifying bacteria and volcanic activity

• Nitrates taken up by plant roots

The net annual primary productivity of a particular wetland ecosystem is found to be 8,000 kcal/m2 per year. If respiration by the aquatic producers is 12,000 kcal/m2 per year, what is the gross annual primary productivity for this ecosystem, in kcal/m2 per year?

• 4,000

• 8,000

• 12,000

• 20,000

• 96,000

The process by which a soil nutrient is reduced and released to the atmosphere as N2 gas

• photosynthesis

• eutrophication

• nitrogen fixation

• denitrification

Which of the following major storage reservoirs of carbon, stored in the form of carbon dioxide, is NOT represented in this diagram?

• algae

• soil bacteria

• the moon

• the ocean

The diagrams above show an area that was once a pasture that has since undergone changes to the vegetation over time. Which of the following changes in the hydrologic cycle is most likely to occur as a result of the change in vegetation in the area?

• increased infiltration

• increased runoff

• decreased transpiration

• decreased precipitation

The greatest amount of fresh water is found in which of the following?

• the atmosphere

• estuaries

• lakes

• rivers and streams

• polar ice caps and glaciers

What is it called when plants give off water vapor as a waste product?

• condensation
• evaporation
• sublimation
• transpiration

Formation of clouds.

• evaporation

• condensation

• sublimation

• deposition