Normally iron oxide percipitate does not float and it accumulates on underwater surfaces. If your pond does not have underground seepages flowing into it I doubt you have iron bacteria and iron oxide. Although anything is possible. See this link for an example.
http://en.wikipedia.org/wiki/File:Iron_hydroxide_precipitate_in_stream.jpg

Last edited by Bill Cody; 04/26/11 04:20 PM.

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