Geobiology

1. Carbon-the basis of life Microbes Life in extreme environments Origin of life on earth Origin of the atmosphere Astrobiology... Geobiology

3. Where do we find Carbon? • Present in all living things • Diamonds and graphite • Calcium carbonate (limestone) • Oil • Coal • Atmosphere (CO2) • Meteorites • Volcanic eruptions

4. Carbon

5. Carbon Sea creatures get C from the ocean water to make CaCO3 (carbonate)

6. Ooze fun facts Sediment with >30% organic matter Carbonate ooze: 48% of the ocean floor Accumulates: 5 cm/1000 years 50 meters per million years Dissolves at depths > 4.5 km

7. Foraminifera-carbonate shell (this guy is < 1 mm wide) Ocean Thermometers!

8. Carbon Shells and coral and carbonate ooze forms limestone

9. Siliceous ooze Plankton with silica shells Covers 15% of the ocean floor Makes chert

10. Carbon Diatoms are algae with a silica shell... 45% of the total production of biomass from CO2 in the ocean water

11. Carbon Radiolaria are another algae with a silica shell... Chewy carbon center with a silica coating

12. Chert Made from radiolaria

13. Ooze Summary • Ooze is plankton with shells of: -Carbonate: Foraminifera -Silica: Diatoms and Radiolaria • Ooze pulls carbon out of the water. • When buried and heated, it can form PETROLEUM

16. Microbes • Used to make bread and beer • Yogurt and cheese • Antibiotics • Minerals such as pyrite or magnetite

17. Microbes are everywhere Single-celled organisms: Bacteria, fungi, algae, protozoa

18. Intracellular production of iron minerals is an example of direct precipitation. Enzyme Bacteria Microbe cell wall

19. Extracellular precipitation of calcium carbonate is an example of indirect precipitation. Bacteria Microbe cell wall

20. Modern stromatolites grow in the intertidal zone. Ancient stromatolites form columns.

21. Modern stromatolites grow in the intertidal zone. Ancient stromatolites form columns. A cross section reveals layering similar to that seen in ancient stromatolites.

22. Modern stromatolites grow in the intertidal zone. Ancient stromatolites form columns. A cross section reveals layering similar to that seen in ancient stromatolites. Microbes live on the surface of the stromatolite. Sediment is deposited on the microbes,... ...which grow upward through the sediment, forming a new layer.

23. Life in Extreme Environments • High Temperature • High Acidity (low pH) • High Salinity • Low Temperature

24. Thermophiles like it hot

25. Acidophiles like acidicwater • pH can be as low as 1 • They turn mine drainage into sulfuric acid

26. Halophiles like it salty

27. Iceworms like it chillyThese live in frozen methane

28. Origin of Life • The Life in a Flask experiment • The Murchison Meteorite • Early earth had minimal oxygen-mostly CO2

29. Origin of Life • Oldest microbes are 3.5 Ga • Only microbes for 1 billion years!

30. Earth’s Atmosphere #1 • Earth’s first atmosphere was H and He • Heat from sun and magma drove it away

31. Earth’s Atmosphere #2 • 4.4 Ga • Volcano erupts gases • Gases = CO2, some N, some H2O • After cooling, CO2 went into oceans • Carbonate deposition

32. Atmosphere #3 • Cyanobacteria (3.3 Ga to 2.7 Ga) • Photosynthesis produces Oxygen (O) • Early O reacts with Fe in oceans to form Iron oxide minerals • When Fe is gone, excess O goes into atmosphere

33. Cambrian Explosion • At 540 Ma there was an explosion of life • Related to rise in oxygen in atmosphere?

34. Early animals: Hallucigenia

37. 800 429 Ma Mass extinction End-Permian mass extinction 364 Ma Mass extinction 600 Diversity of organisms 400 End-Cretaceous mass extinction Cambrian radiation 200 208 Ma Mass extinction 0 600 400 200 0 Age (Ma)

38. Geologic Time Scale • Boundaries of Geologic Time are related to extinction events

39. 4560 Ma Earth and planets form 4510 Ma Moon forms 4000 Ma Oldest continental rocks 4000 3500 Ma Record of magnetic field Fossils of primitive bacteria 3000 2000 1500 1000 Mass extinctions 500 200 Ma Present 359 Ma 251 Ma 65 Ma

40. Geologic Time Scale • Precambrian (4.6 Ga to 540 Ma) • Paleozoic (540-250 Ma) • Mesozoic (250-65 Ma) • Triassic • Jurassic • Cretaceous • Cenozoic (65 Ma to the present)

41. Extraterrestrial Life? To have life, we need water Drainages on Mars:

42. Mars Earth

43. Martian Meteorite

44. Martian bacteria?

45. ET life? The Drake equation states that: N = R* X fp X ne X fℓ X fi X fc X L where: N is the number of civilizations in our galaxy with which we might hope to be able to communicate; and R* is the average rate of star formation in our galaxy fp is the fraction of those stars that have planets ne is the average number of planets that can potentially support life per star that has planets fℓ is the fraction of the above that actually go on to develop life at some point fi is the fraction of the above that actually go on to develop intelligent life fc is the fraction of civilizations that develop a technology that releases detectable signs of their existence into space L is the length of time such civilizations release detectable signals into space.