Hydrothermal%20Vent%20Communities

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Hydrothermal Vent Communities

• How Life Originated?

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Hydrothermal vent discovery-1977
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• Cold seawater sinks down through the crust.
• O2 and K are removed from the seawater.
• Ca, SO4, and Mg are removed from the fluid.
• Na, Ca, and K from the crust enter the fluid.
• Highest temperatures (350-400 oC), Cu, Zn, Fe,
  and H2S from the crust dissolve in the fluids.
• Hot acidic fluids with dissolved metals rise up
  through crust.
• The hydrothermal fluids mix with cold, O2-rich
  seawater. Metals and sulfur combine to form
  metal-sulfide minerals MnO2, FeO(OH),

• Sea Water sinks through the crust and is filtered

• Basically cold seawater is converted to a very
  hot fluid rich in dissolved metals. Promotes
  robust chemistry ? initial phase of life?

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• Robust and complex chemistry

www.pmel.noaa.gov/vents
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Black White smokers

• 2. As the water heats up, it reacts with the
  rocks in the ocean crust
• All oxygen is removed. It becomes acidic. It
  picks up dissolved metals, including iron, copper
  and zinc. It picks up hydrogen sulfide.
• 3.The hot rising fluids carry the dissolved
  metals and hydrogen sulfide with them.
• 4. The hydrothermal fluids exit the chimney and
  mix with the cold seawater. The metals carried up
  in the fluids combine with sulfur to form black
  minerals called metal sulfides. These tiny
  mineral particles give the hydrothermal fluid the
  appearance of smoke. Many factors trigger this
  reaction. One factor is the cold temperature of
  the seawater. A second equally important factor
  is the presence of oxygen in the seawater.
  Without oxygen, the minerals would never form.

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• The beginning chemistry of life?

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Hydrothermal Vent Distribution
Pink, western Pacific green, northeast Pacific
blue, East Pacific Rise yellow, Azores red,
Mid-Atlantic Ridge orange, Indian Ocean
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Hydrothermal energy source

• H2S O2 ? SO4 H ATP
• Chemosynthetic (sulfur oxidizing)
• Thermophilic Bacteria (up to 120oC)
• Hot, anoxic, sulfide rich water mixes with Cold
  oxygenated water
• Hydrothermal Vents as origin of Life?

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Bacteria from 120oC
http//mollie.berkeley.edu/volkman/
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Vent biological communities

• BACTERIA (Bacteria and Archea)
• 400 morphological invertebrate species
• New species every 2 weeks during 25 years!
• Evolutionary Origin
• Derived from surrounding Deep Sea
• Derived from Shallow Water species
• Many evolutionary radiations at species level
• Many vent taxa originated at other organically
  enriched environments (cold seeps and whale
  bones)
• Vents as stable refugia from Global extinctions

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Cold Seeps

• CH4 O2 ? CO2 H20 ATP
• CH4 ? CH3- H ATP
• H2S O2 ? SO4 H ATP
• Hydrocarbon reservoirs
• methane bubbling
• Continental shelves and Trenches
• 200 invertebrate species

• ATP is used as an energy carrier for cells
  natural synthesis

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Invertebrate food sources

• Food chain based on sulfur-oxidizing bacteria
• Symbiosis with Bacteria
• tube worms
• Vent Mussels and vent clams
• Ingestion of Bacteria
• Grazers (gastropod limpets and snails)
• Filter Feeders (vent shrimp, polychaete worms,
  amphipods, anemones)
• Predators
• Ventfish, octopus
• Scavengers
• Crabs

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Tube worms
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http//web.uvic.ca/7Everenat/364-13.jpg
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Vent Mussels (Bathymodiolus )
www.divediscover.whoi.edu/i
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www.divediscover.whoi.edu/i
Vent Clams (Calyptogena)
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Vent Shrimp (Bresiliidae)
www.ifremer.fr/
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Alvinellid worms
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Vent limpets
http//web.uvic.ca/abates/
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www.divediscover.whoi.edu/i
www.senckenberg.uni-frankfurt.de/
Vent Crabs
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Ventfish (Thermarces cerberus)
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Light organs in vent organisms
www.deepsea.com/
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Periferic filter feeders
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Sea floor Spreading opens new vent areas over
geological time
www.pmel.noaa.gov/vents/PlumeStudies
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Chemical Reactions

• Depends on ambient temperature

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Hydrothermal Vent Communites

• 25 years of exploration have revealed
• A new phylum
• At least 20 new families
• Over 90 new genera
• Over 300 new species
• Over 250 new strains of
• free-living bacteria
• Biomass
• Up to 30 kg/m2
• 1000 x greater than
• typical biomass
• observed on
• deep-sea floor

Geol 104/BioES 154
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Hydrothermal Vent Macrofauna Environmental
Constraints on Life Cycles and Reproduction

• Suitable vent environments for these organisms
  are rare.
• Individual vents have short life-spans.
• Volcanic eruptions and earthquakes pose further
  hazards.
• These conditions favor rapid growth rates,
  continuous reproduction, and high fecundity.

Geol 104/BioES 154