strains (Fig 5). Within the Micromonospora isolates, 10 different phylotypes were identified (Fig 11). The dominant Micromonospora phylotype observed among our isolates belonged to Micromonospora aquatica totaling 70 isolates. These results seemed unusual at first, since the actinomycetes clearly displayed different growing morphologies yet were grouped together according to the phylogenetic analysis of their partial 16S rRNA gene sequence (Fig.27, Fig. 28). Since these different growing morphologies were only associated with those actinomycetes isolated from sponges (Fig. 28), the chemical profile of their extracts were analyzed and compared. These data revealed that sponge-associated Micromonospora aquatica strains were found to produce a variety of diffusible pigments that were not observed from the sediment associated M. aquatica strains (Fig.27). Bioassay-guided fractionation revealed that these pigments consisted of compounds that were not only different from sediment associated M. aquatica strains, they were also bioactive against gram positive-bacteria (Fig. 29; Appendix A, B). In fact, all of the diffusible pigment-producing sponge associated Micromonospora aquatica isolates show bioactive fractions against gram-positive bacteria while those associated to sediments are inactive. Since the bioactive fractions were from those that produced diffusible pigments, it is reasonable to assume that these pigments are responsible for the bioactivity.