Hydrothermal Vents

The diagram (click for full size) represents a hydrothermal vent system as scientists might encounter along the Juan de Fuca Ridge. Look over the diagram and follow the movement of sea water through the venting system. After you have completed your journey, answer the following questions:

1. What rock type did you first encounter?
What is its rock classification? Igneous, Sedimentary or Metamorphic
Is this rock most likely to be found on continents or ocean floors?

Check out this site:
http://www.dc.peachnet.edu/~pgore/geology/geo101/igneous.htm

2. What enabled the sea water to pass through the rock?

3. What happens to the temperature of sea water as it passes down through the rock?

4. What causes the sea water to change temperature?

5. Could the sea water become steam at this depth? Explain!

6. As the water passes down through the rock, it picks up elements. What elements might be added to the sea water?

Check out these sites:
http://www.pmel.noaa.gov/eoi/chemistry/fluid.html
http://www.pmel.noaa.gov/eoi/chemocean.html

7. Why do you think that some chimneys are inactive?

8. Why do you think that some vents have no chimneys?

9. The chimney in the diagram indicates that it produces black "smoke", other chimneys can produce "white" smoke. What could cause the difference?

Check out this site:
http://rho.pmel.noaa.gov/oerd/randall/web/monolith_91.html

10. What chemical process produces the chimney?

Check out this site:
http://www.amnh.org/exhibitions/permanent-exhibitions/rose-center-for-earth-and-space/david-s.-and-ruth-l.-gottesman-hall-of-planet-earth/why-is-the-earth-habitable/life-that-lives-off-the-earth-s-energy/life-at-the-hydrothermal-vents/ancient-black-smokers/black-smokerhome.html

11. Would it be dangerous for a submersible to get too close to a Black Smoker? Explain!

12. The abyssal depths had always been regarded as a desert, incapable of supporting life. There is no sunlight down there to support photosynthesis. Much to everyone's surprise there was abundant life on the seafloor especially around the hydrothermal vents. Clams, crabs, tube worms and even fish lived in this chilly deep-sea denizen. Describe briefly what you perceive as some of the environmental conditions in which these organisms live.

13. The Microbial Biosphere referred to in the diagram, is bacteria. What role do they play in this hydrothermal environment?

Check out this site:
http://www.pmel.noaa.gov/eoi/chemocean.html

14. If you couldn't study the bacteria around hydrothermal vents, where could you go to study bacteria under superheated conditions?

15. Ore deposits are thought to occur in pockets beneath the vents. How do you think these minerals accumulated? What time frame would you imagine for the mineral formation?
Suggestion: Ask a scientist at our web site

16. Note the Plume in the diagram. What is the difference in temperature between the plume and the ambient temperature of the seawater around it?

17. Do you think the plume would last a long time given its temperature and its location? Explain!

This question could be asked of the scientists onboard the Brown. Just ask a scientist at our web site

18. What contributed to the formation of the "valley" in which the smoker is located?

Check out this site:
http://pubs.usgs.gov/publications/text/understanding.html#anchor48