Chapter 3 Problems
1. True or false: The carbon stable isotope value of CO2 in the atmosphere is
currently about -8o/oo.
2. True or false: Some plants have 15N values of 0o/oo, signifying that they are
composed of N2 gas, the nitrogen isotope standard that also has a 0o/oo value.
3. True or false: The sulfur isotope value of sulfate in seawater is -21o/oo.
4. True or false: When you dry plant samples, all the hydrogen isotopes disappear
from the sample as water evaporates.
5. True or false: Oxygen isotopes are rare in humans.
6. True or false: Stable isotope records of past ecologies are present in many
historical materials, including forest soils.
7. True or false: In species invasions in lakes, newly arrived fish rapidly acquire the
same isotope values as the older, resident fish.
8. True or false: When animals move and migrate, they can retain their old isotope
values in tissues such as hair and feathers.
9. True or false: The isotope values of CO2 in the atmosphere are often inversely
related to CO2 concentrations.
10. True or false: Human diet planning needs to include a consideration of stable
isotopes for a healthy balanced diet.