The white lines represent the ocean ridges.

Your journey across the abyssal plain was long and flat — and pretty boring. As you near the middle of the Atlantic Ocean, the landscape starts to change dramatically.

Rising up from the bottom of the ocean is the Mid-Ocean Ridge — a chain of mountains running between the North and South Poles, a distance of nearly sixty-nine thousand kilometers (thirty-nine thousand miles)! Mountain ridges like this are found in all of the Earth's oceans as shown in the map on the right.

These ridges are formed as the center of the ocean spreads apart and new ocean floor forms. Get ready for an exciting trip as you investigate how the ridges were discovered and look at the forces that are pushing the ridges apart and causing the spreading to take place.

These ridges are important for another reason. Isolated along these ridges are places where life on Earth may have originated. These vents, called hydrothermal vents, and the communities that surround them, are truly amazing places!

Essential Questions

• What is a mid-ocean ridge?
• Describe the process of chemosynthesis?
• What are hydrothermal vents?
• What organisms live around hydrothermal vents?