However, this weekend I noticed patches of tiny bubbles forming on the surface. Some of these bubbles seem to be coming off the jellyfish but their presence next to the patches may be unrelated other than the floating blobs happened to be in the right place. Most of the swarms of bubbles are independent of the blobs. I suspect these bubbles might be caught under a translucent film. I'm not sure at this point whether the bubbles are merely offgassing CO2 as the temperature rises in the house with the progression of summer or something biological.
You can see the edge of a blob on the left and some of the clumps of small bubbles in the middle. If you look at the surface as a whole you can tell there is some kind of oily film on the surface.