1. Carbon Cycle Carbon Pools: 1. Atmosphere, 0.035% CO2
2. Ocean, a carbon
sink
3. Earth’s crust,
300 Ma deposits
4. Soils, can be a
sink, e.g.,
MgSiO3 + CO MgCO3 + SiO2
also, peat bogs
Fig. 22.1

2. Chlorinated Hydrocarbons
--synthetic compounds containing chlorine and carbon,
first synthesized in 1874
--used for pesticides after WWII, 1940s to 1970s
--DDT most infamous, used for mosquito control to stop
malaria in Sri Lanka in early 1950s
--malaria dropped from 2 million cases per year to zero!

3. Problems with DDT --long-lived compound, lasts for decades in soil or
water without breaking down
--soluble in fat, but does not metabolize so builds up
in tissues when consumed
--concentrations will increase in long-lived species,
perhaps to toxic or harmful levels
--in birds, high concentrations block calcium production in
eggshell formation, resulting in thin eggs being laid
and breaking when incubated
--nearly caused the extinction of top predators such as
bald eagles, peregrine falcons, and brown pelicans

4. Biomagnification

5. Rachel Carson (1907 – 1964)
Author of ‘Silent Spring’
(1962)
First to draw attention of
dangers of pesticides to the
public