A friend and I were driving through the Southern tier of Western New
York the other evening a little before sunset.

Dave noticed that there were odd patches and streaks of calm, bright
water on the surface of two ponds that we passed.

The calm, bright kind of surface also seemed to be near the shore of
the pond at one end at least (I didn't get out of the car and take a
good look all around the pond).

We argued about what might cause the effect. Unfortunately, we didn't
take any pictures to help with the argument.

My theory is that there could be any number of sources of oil (from
the road; from decaying vegetation in or near the pond; from geese
swimming in the pond). From our vantage point, we didn't see
irridescence and many of the odd patches were long streaks or bands
rather than circular.

I've googled around and haven't been able to come up with a search
term that would tell me whether others have noticed and explained this
little oddity.

I did see that aquariums can develop natural "oil slicks" and I wonder
whether you ponders have seen anything like that yourselves.

Marty