OT: why the spewing water

[Doug]

I was looking at this link and right now it shows each boat slip with spewing water rising out of the water. Is this to try to prevent the water from freezing up and possibly hurting the floating docks?

[trader4]

I can't see it in the link, but for boat owners that choose to leave their boats in the water during hard freezing winters, they use air bubblers to prevent ice from freezing directly around the boat.