2. Earth’s Atmosphere: Not Much of It
Mass Atmosphere = 5.2 x 1018 kg
Mass Oceans = 1.4 x 1021 kg
Mass Earth = 6.0 x 1024 kg
Live Biomass = 1 x 1015kg
Carbon Dioxide = 3 x 1015 kg
Trunover Time for carbon dioxide =
5 years in atmosphere, centuries
in oceans
3. Carbon dioxide cycles between low values in summer and
higher values in winter in the Northern Hemisphere due to
seasonal differences in photosynthesis.
Annual input from fossil fuels and deforestation: 3 x 1013 kg
carbon dioxide. Half accumulates in the atmosphere, rest is
absorbed in oceans, leading to acidification.
Pre-industrial carbon dioxide level was 280 ppm, now 380 ppm.
7. Modern Stromatolites Fossil Stromatolite (2.5
Billion Years Old)
Banded Iron Formation
Oxygen Was A Poison to Early
Life Forms on Earth. Took about 1
billion years before oceans and
atmosphere were fully oxygenated
8. Oxygen in the air allowed the evolution of eucaryotes and aerobic
respiration, finally leading to the world’s life forms present today.
9. Ozone in the upper atmosphere (derived from O2) protects against the splitting
H2O to H and OH, with H escaping to space.
Earth has lost about 25% of its water while water is nearly all gone on Venus and
Mars.
Oxygen also produced the ozone shield which protects water in the upper
atmosphere from boiling away as hydrogen
17. In this course we emphasize the ecology and biology of the
algae rather than the taxonomy. Main groups we will cover:
Cyanobacteria (blue-green algae)
Green Algae
Red Algae
Brown algae – brown seaweeds, kelps, diatoms
Dinoflagellates
Coccolithophores
Others
