What are some answers to the following questions about hydrothermal vents?
- Pressure at a hydrothermal vent vs. pressure on the ocean surface
- Temperatures of water at ocean depths vs. temperature at vents
- List of chemicals emmitted from vents, pH of vent fluids vs. pH of normal ocean water.
---> Also, vents are continually forming and then become extinguished. What is the average 'life span' of a vent'?