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

Where do we find Carbon? Present in all living things Diamonds and graphite Calcium carbonate (limestone) Oil Coal Atmosphere (CO 2 ) Meteorites Volcanic eruptions

Carbon

Sea creatures get C from the ocean water to make CaCO 3 (carbonate)

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

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

Carbon Shells and coral and carbonate ooze forms limestone

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

Carbon Diatoms are algae with a silica shell... 45% of the total production of biomass from CO 2 in the ocean water

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

Chert Made from radiolaria

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

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

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

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

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

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

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

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

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

Thermophiles like it hot

Acidophiles like acidic water pH can be as low as 1 They turn mine drainage into sulfuric acid

Halophiles like it salty

Iceworms like it chilly These live in frozen methane

Origin of Life The Life in a Flask experiment The Murchison Meteorite Early earth had minimal oxygen- mostly CO 2

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

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

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

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

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

Early animals: Hallucigenia

Diversity of organisms Age (Ma) Cambrian radiation 429 Ma Mass extinction 364 Ma Mass extinction End-Permian mass extinction 208 Ma Mass extinction End-Cretaceous mass extinction

Geologic Time Scale Boundaries of Geologic Time are related to extinction events

4560 Ma Earth and planets form 4510 Ma Moon forms 4000 Ma Oldest continental rocks 3500 Ma Record of magnetic field Fossils of primitive bacteria Mass extinctions 359 Ma251 Ma 200 Ma 65 Ma Present

Geologic Time Scale Precambrian (4.6 Ga to 540 Ma) Paleozoic ( Ma) Mesozoic ( Ma) –Triassic –Jurassic –Cretaceous Cenozoic (65 Ma to the present)

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

MarsEarth

Martian Meteorite

Martian bacteria?

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.