Weird algae stripes

The other day I was waiting for my friend and her daughter and noticed a weird stripe-y pattern in the distribution of algae. As I kept watching, the pattern started to change.At first I thought that maybe the algae were collecting in nodes of standing waves that were reflected from the sea wall (ok, lake wall) I was sitting on, but this really does not fit with how the pattern developed later, and I have no clue what was going on.

Watch the movie and tell me what you think, please?

Seriously, though. What is going on? I don’t think the pattern is formed by advective processes – you see bubbles and the occasional leave and they don’t move a lot. I noticed that whenever the wind changed, the pattern in the algae also changed, but I didn’t notice a clear rule. And the wave theory only works for the waves coming in in parallel to the wall, I think. Any ideas?