geobiology carbon-the basis of life microbes life in extreme environments origin of life on earth...
TRANSCRIPT
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 (CO2)• Meteorites• Volcanic eruptions
Carbon
Carbon
Sea creatures get C from the ocean water to make CaCO3
(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 CO2 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 stromatolitesform columns.
Modern stromatolitesgrow in the intertidal zone.
Ancient stromatolitesform columns.
Modern stromatolitesgrow in the intertidal zone.
A cross section reveals layering similar to that seenin ancient stromatolites.
Ancient stromatolitesform columns.
Modern stromatolitesgrow in the intertidal zone.
A cross section reveals layering similar to that seenin ancient stromatolites.
Microbes live on thesurface of the stromatolite.
Sediment is depositedon 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 acidicwater
• pH can be as low as 1• They turn mine drainage
into sulfuric acid
Halophiles like it salty
Iceworms like it chillyThese live in frozen
methane
Origin of Life
• The Life in a Flask experiment
• The Murchison Meteorite
• Early earth had minimal oxygen-mostly CO2
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
Div
ers
ity o
f org
an
ism
s
Age (Ma)
0200400600
800
0
200
400
600
Cambrianradiation
429 MaMass
extinction
364 MaMass
extinction
End-Permianmass extinction
208 MaMass extinction
End-Cretaceousmass extinction
Geologic Time Scale
• Boundaries of Geologic Time are related to extinction events
4560 MaEarth and planets form
4510 MaMoonforms
4000 MaOldestcontinentalrocks
3500 MaRecord of magnetic field Fossils of primitive bacteria
Mass extinctions
359 Ma 251 Ma 200 Ma 65 Ma Present
1500
1000
2000
3000
4000
500
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)
To have life, we need water
Drainages on Mars:
Extraterrestrial Life?
Mars Earth
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.