55319991 hydrothermal vents diagenesis and chemical balance

7/29/2019 55319991 Hydrothermal Vents Diagenesis and Chemical Balance

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Ocean VentsyAlso known as hydrothermic vents, these areas provide

energy for extremely unique ecosystems

y The ecosystem is based around the bacteria that dochemosynthesis where the bacteria oxidize sulfides inorder to obtain energy

yVarious other animals feed on the bacteria or have

them in their body like the tube wormsy These vents leak water with hydrogen sulfide dissolved

in, a highly toxic chemical that would normally killthese organisms if not for specialized enzymes


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Hydrothermal vents: Black smokersy A black smoker or sea vent is a type of hydrothermal vent

found on the seabed, typically in the abyssal and hadalzones. They appear as black chimney-like structures that

emit a cloud of black material.y The black smokers typically emit particles with high levels

of sulfur-bearing minerals, or sulfides.

y Black smokers are formed in fields hundreds of meterswide when superheated water from below Earth's crustcomes through the ocean floor. When it comes in contactwith cold ocean water, many minerals precipitate, forminga black chimney-like structure around each vent.

y Can exceed 1000 degrees C


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Hydrothermal Vents: White smokers

yWhite smokers refer to vents that emit lighter-hued

minerals, such as those containing barium, calcium,and silicon.

y These vents also tend to have lower temperatureplumes of around 150-200 degrees C.

y These alkaline hydrothermal vents also continuouslygenerate acetyl thioesters, providing both the startingpoint for more complex organic molecules and theenergy needed to produce them.


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Cold Seepsy Sometimes called cold

vents or underwater lakes,these areas usually have abrine pool where the highsalinity brine does not mixwith the water above

y Methane comes up

through the sediment andprovides energy for theecosystem around thebrine pool

http://www.zmescience.com/research/underwater-lakes/


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Chemical Balancey There is a slightly lower average pH of marine water

compared to pure water ranging from 6.7 to 7 asopposed to the usual 6.76 to 7.47 at 25C

y Salinity is the measure of dissolved salt in seawater

y The main difference between fresh water and oceanwater is the salinity: ocean water has 30-50 parts perthousand of salt (sodium chloride, magnesium,

calcium sulfates and bicarbonates are some of them)y The major elemental components of sea water are

oxygen, hydrogen, chloride, sodium, magnesium,sulfur, calcium, potassium, bromine and carbon


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Hydrothermal Circulationy Occurs around the Earths

crust around areas of hightemperature, usually near

volcanic activityy Newly formed basalt

creates the effect whencold dense water sinks intoit and then rises to thesurface after adsorbing the

heaty These basalts may take

millions of years to cooland the effect to stop inthat area

http://www.geol.ucsb.edu/faculty/hacker/geo102C/lectures/part1.html


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Hydrothermal Circulationy This creates a convection current where the cooling

and heating waters are constantly moving

yAnother area that causes this effect is hydrothermalvents

y Non-oceanic hydrothermal circulation also creates hotsprings and geysers


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Diagenesisy Diagenesis the physical, chemical or biological change of

sediment after its initial deposition and throughlithification

y Lithification is when sediments compact under pressure tobecome solid rock

y Diagenesis is similar to metamorphism, however does notrequire high pressures or temperatures to occur

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As nitrate, phosphate and silicate are released fromdecaying organic matter through diagenesis they diffuseback into the water column and can be reused

y Diagenesis increases pressure on decaying organic matter,changing dead organisms tissues into hydrocarbons


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ReferencesyAn introduction to the WorldsOceans fifth edition by

AlynDuxbury and AlisonDuxbury

yhttp://www.zmescience.com/research/underwater-lakes/

yAn Introduction to the Chemistry of the Sea byMichael E. Q. Pilson

y Introduction toOcean Sciences byDouglas A. Segar

55319991 hydrothermal vents diagenesis and chemical balance

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