Obviously its the work of aliens.

Its November, its cold. The marsh has freezed up then melted refreezed partially etc. The ice is not thick enough for anything bigger than a gull to be standing on it without breaking.

I just was outside and noticed a weird pattern of ice melting.

Sorry for quality i took them on an iphone. But the pattern looks similar to when someone shovels snow on ice. They are pretty straight lines. To my knowledge there are no pipes in the marsh in that area. My second thought is muskrat underwater tunnels. These were not there yesterday. The big area when the ice is melted was more open yesterday as well. It seems to have partially frozen over night.  And the far side of the marsh was completely open water yesterday and has frozen over night. My parents tell me that the marsh or "lake Martha" is fed by springs so that could be a cause for this as well.
Any better explanation would be welcomed.