Life from the Sea (Miracle Planet)

Ø Stromatolites from Shark Bay Australia.

- Cyanobacteria form limestone

- Analogy for early life form: cyanobacteria

- Cyanobacteria produce oxygen, and therefore changed the atmosphere

Ø North Pole, Australia – oldest known fossils 3.5 billion years old. Primitive bacteria, but still advanced. Also Stromatolites in same strata: so even at this point in Earth’s history, there must have been a long time for forms to have evolved.

Ø Juan de Fuca Ridge (WA) has “Black Smokers” with bacteria who live on minerals in water (hot). Analogy for early life?

Ø Geothermal display at Yellowstone. 200 geysers and many hot springs. “Grand Prismatic Spring” colorful with bacteria. Ph = 1, No O₂ in some mud pools and these have anerobic bacteria.

Ø Early life clearly had two things: absence of oxygen and high temp. Changed when oxygen was released as by product of respiration.

Ø Great Slave Lake (NWT) –rocks show that the atmosphere had loads of O₂ but more way more CO2 as compared to today.

Ø Tower Karst of China – Carbon dioxide is tied up in limestone, and being liberated.

Ø Carbon dioxide measurements at Mauna Loa: shows that levels have been increasing over the last few years.

Ø Venus, has 200,000 times the Co₂ as ours, high surface temperature. No limestone, so all Carbon dioxide is still in the atmosphere.

Ø Great Barrier Reef Australia – largest Coral “structure” in the world. Coral makes limestone and limestone is partly made of carbon dioxide. So, when coral grows, it removes carbon dioxide from the atmosphere.