Transcript Chemosynthetic Environment

Chemosynthetic
Environment
A Fossil Analogy
By Natalie Quintana
What are chemosynthetic
environments?
• Hydrothermal vents
– Located at mid-ocean ridges
– Discovered in 1977 on the Galapagos Rift, in
the Pacific
• Cold seeps
– located continental margins extending from
the coast to abyssal plains
How do hydrothermal vents form?
• Tectonic plates separate
• Hot, melting rock from earth’s mantle rises to the
surface, causing lava to erupt onto ocean floor
– temperatures exceeding 350C
• The lava forms a underwater mountain, sea
mount
– Chain of these sea mounts forms the mid-ocean ridge
– Black smokers appear at hydrothermal vents
Black smokers and midocean ridge
http://ve.ou.edu/weaver/mor/black
_smoker.mov
What about cold seeps?
• Discovered in the Florida Escarpments, in
the Gulf of Mexico
• Occur when cold fluids with high methane
concentration seep from a trench and
quickly transform organic matter when
reacts with high temperature
Modern fauna!
• Hydrothermal vents
– Giant tubeworms
– Chemoautotrophic
bacteria
– White clams
– mussels
• Cold Seeps
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–
Tubeworms
Mussels
Clams
Various shrimp
Chemoautotrophic
bacteria (methane &
sulfide reducing
bacteria)
Fossil Record
• Gastropods represented seep communities for 100my
• Fossil mytilids common in Jurassic-Cretaceous seeps in
California & Eocene-Oligocene seeps in Washington
State
• Many modern groups of organisms originate in the later
Mesozoic or early Cenozoic
• Ancient seep carbonates represent an archive of
chemosynthetic processes
– Negative carbon isotope
– Methane and sulfide reducing bacteria