The Microsoft data center is completely underwater.
With the data center underwater there may be some things that could cause this to be more beneficial than not so. It's easier to keep the computers free from changing it's location. It's less prone to damage or human hands. In most cases data and RAM that is being used on these data centers in most cases doesn't need to be upgraded and doesn't need to be changed. It can sit for years and years and perform it's taskes at a cheaper cost than in many other locations like paying rent or a building.
Is there any risk of damaging the comuters?
No. since the computers are completely underwater and recieving electrical current under water. There is no chance that the water will change the computers.
Can it harm the surroundings?
No. It won't since it's in a confined tube with steel and protected.