Slow whirl

Well yes, it's been a long time, too long I admit, since my last post here. You know, sometimes life simply requires full attention: a boy child, very big efforts everyday for building up a new carrier with photography, etc.
However I kept coming here every now and then to see what was going on, and I must say the quality of the works posted to NPN is always at the top, this is really The Place to go on the web to see stunning pictures and meet very talented photographers.

I took this picture a day of the last week about 10 minutes after sunset, while I was leading a private workshop in the Alps. The still element in the fg is simply a log almost completely submerged in the very calm waters of the Lake of Avigliana, a small glacial lake lying at the feet of the Western Alps and not far from my hometown of Torino. Initially, I considered the bubbles of foam a disturbing element and so I tried to get rid of them by moving the water with my hands, but the only result was bringing more bubbles in, instead of pushing them out.
Then, I realised that those bubbles were moving in circles, very slowly. I tried a few shutter speeds and at the end 6 seconds turned out to be the perfect exposure to record the motion and draw a path with the bubbles.

I hope you like it and please feel free to comment, any thought and suggestion is highly appreciate.

Thanks,
Paolo