Devil's Hole is a part of the Ash Meadows National Wildlife Refuge. It is a pit in the earth near the side of a mountain. The bottom of the pit is filled with warm water. Ground water is everywhere here. What makes this special is the pre-historic fish still surviving near its surface. The Hole is fenced in to prevent aquarium people from harvesting the tiny pupfish as they once did.
Being an avid scuba diver, I have scaled the fence several times to dive. Shame on me! But I have always been very careful not to disturb the tiny blind pupfish or anything else.
One time I came across an unexpected thing. Someone had built a short pier at the shallow end of the pool. On the end of the pier was a strip-chart recorder dangling a float in the water. My curiosity caused me to open the cover to the recorder and look in.
The ink on the paper traced out what were obviously lunar and solar tide patterns. I conclude that as a solar body passes overhead, the compressed earth's crust get ever so slightly lighter. This leaves more room in the hole. Water is sucked in. The reverse occurs as the bodies are off to one side.