Pond Boss Forums INTRO Questions & Observations Strange 'phenomenon' in aquatic vegetation

Before I get into it, I want to thank the moderators and creators of this forum for letting me join. I hope this post is in the right place and within the forums acceptable guidelines. If it's not, I apologize.

So, I need help identifying what these things are in a lake I fish almost daily. They are large cylindrical openings in the weeds, one being over four feet across, and the other about 3 feet wide. They come almost to the surface of the water, and go down to just above the substrate, where the seem to continue under the vegetation, much like a burrow or tunnel made by wildlife. But they appeared overnight. They almost resemble barrels or huge pipes but are 100% vegetation and not made by people. I saw a large snapping turtle float up from one and he swam straight back down into it when he saw me, but I've never seen a turtle make a structure like this in water. My dad said it could possibly be a spring of some sort, but there is no current or flow from it, and you can see the bottom substrate when looking down into it. I've got a couple photos but they aren't of great quality. Any information is much appreciated. I'm having trouble adding the photos but will continue to work on it
Edit** photos are in the reply below

Here's the images

Underwater crop circles?

I'm beginning to think so

Never seen that before

Closest I've seen to that was holes made in vegetation (FA) over SMB nests. I assumed the male was keeping access to his nest open.