stats analysis

[Ron Devine Vave]

hi there,   A friend is doing a field study, looking at six naturally occurring sponge colonies (all of the same species) on a small reef section (each at different depths). In each sampling time (4 in total, to determine seasonal effect), he took out a small piece of each sponge and extracted chemicals from it. in total, their were about 9 chemicals.   Will it be okay to do a repeated measures anova with the six sponge colonies as subjects and using time as within-subjects factor, and the different chemicals as measurements? This is, despite the fact, that the 6 sponge colonies were at different depths and could have had an effect on the amount of chemical produced.   looking forward to your replies. ron