I just found this (linked below) and it leads me to believe that I may have a couple things going on...
1.) Protozoan Scums (page 15)
"Whitish-grey scums appear often in still waters. They form a shiny, almost oily film on the surface of the water (A, B, C). Sometimes they will also appear as a “foam” (D). "
2.) Diatom Blooms (page 11)
"Floating diatom blooms (A, B) form a brown scum or film, often glistening, on the bottom or the surface of the water, coloring the water. Rarely is this scum evenly distributed. Most
commonly diatoms are found attached to rocks or other surfaces where they appear as a
glistening brown or golden brown gelatinous mass (C). "
There does not seem to be any real concern so life goes on.