Abstract
Glass and metal substrates exposed to subtropical seawater exhibit a characteristic succession of periphytic microorganisms. Substrates which are biologically and physically inert (glass and stainless steel) fouled rapidly and produced a complex, two-tier microfouling layer. Characteristic microorganisms were bacteria, fungi, choanoflagellates, diatoms, ciliates, and microalgae. Active substrates (brass and copper-nickel alloys) were selective for bacteria which secrete extracellular mucoid material, fouled at a slower rate, and were characterized by a less diverse microfouling community. Substrate appears to influence microfouling at all stages of development, especially in the early stages of substrate conditioning, and primary film formation. Primary films may insulate periphytic microorganisms from toxic substrates.