Chapter 25

Which of the following statements is TRUE about photosynthesis and chemical weathering?

Both processes use CO2 as a reactant (i.e., decrease atmospheric CO2 levels).

Which of the following equations is the chemical reaction for cellular respiration?

C6H12O6 + 6O2 → 6CO2 + 6H2O

What can Antarctic ice core samples tell us about atmospheric CO2 levels? (Select all that apply.)

CO2 ice core data confirm CO2 measurements taken directly from the atmosphere. Ice cores can help scientists estimate atmospheric CO2 levels from centuries ago.

If a forester treats his soil with a broad-spectrum fungicide, how would this affect the rate of CO2 released from the system?

CO2 released from the system will decrease because this would decrease the number of decomposers in the system.

Which of the following represents an accurate description of the movement of carbon through a food web?

Carbon is removed by the producers, and added by the consumers.

The _____ cycle deals with geological processes and carbon reservoirs, some of which have been built up (or take place) over a period of millennia. In contrast, the _____ cycle involves biological processes that are carried out on a daily and/or seasonal basis.

Long-term carbon; short-term carbon

Recall that in the northern hemisphere, atmospheric CO2 levels are highest in early spring and lowest in early fall. What accounts for this seasonal fluctuation in atmospheric CO2 levels? respiration plate tectonics biomineralization photosynthesis human activities

Photosynthesis

The rate of respiration _____ throughout the year.

Remains more or less constant

Photosynthesis _____ the atmosphere, whereas respiration _____ the atmosphere.

Removes CO2 from; introduces CO2 to

Recall that sedimentary rocks, living organisms, oceans, and soil are all carbon reservoirs. If the carbon in each of these reservoirs was instantly transformed into atmospheric CO2, which reservoir would contribute the MOST CO2 to the atmosphere?

Sedimentary Rocks

Photosynthesis and respiration both play a major role in the _____ carbon cycle, and can affect atmospheric CO2 levels on a seasonal or annual basis.

Short-term

Which of the following processes is responsible for the changes scientists observed in atmospheric concentrations of 12C, 13C, and 14C over the last 200 years? subduction chemical weathering the clearing of forests the burning of fossil fuels volcanism

The burning of fossil fuels

Over the last several decades, what have researchers discovered about atmospheric CO2 levels?

They have increased.

There is evidence that increased levels of CO2 in the atmosphere may increase Earth's surface temperature. How might this affect the spread of mosquitoes and malaria? (Select all that apply.)

Warmer temperatures may increase the habitat range of mosquitoes. Warmer temperatures may result in malaria cases in new regions.

Which of the following processes INCREASES the amount of CO2 in the atmosphere? (Select all that apply.) subduction photosynthesis chemical weathering volcanic eruptions respiration

volcanic eruptions respiration

Photosynthesis and respiration affect atmospheric CO2 levels on a _____ timescale, whereas volcanic eruptions affect atmospheric CO2 levels on a _____ timescale.

yearly; century