Effects of biofilms on zebra mussel postveliger attachment to artificial surfaces

Abstract. The zebra mussel is an introduced fouling organism in North American inland waters. This field study tested whether natural biofilms, formed by covering substrata with a 100-μm mesh that allows microorganisms to attach and films to develop in the absence of postveligers, influenced the attachment of zebra mussel postveligers to artificial surfaces. Low-wettable polycarbonate and wettable glass surfaces were used in the experiments over four field seasons to study biofilm formation (1997–1998) and mussel attachment (1998–2000). The presence of the mesh did not quantitatively affect biofilm development on either substratum as determined by microscopic direct counts and colony-forming units on R2A agar. Natural biofilms on polycarbonate surfaces positively influenced postveliger attachment compared to substrata that initially had no film (ANOVA, p-values ranged from ≤.05 to ≤.001). Biofilms did not influence postveliger attachment to glass surfaces (ANOVA, p>.05). Attachment to both substrata was similar on surfaces with and without previously settled postveligers. Based on these results, we conclude that biofilms can enhance postveliger attachment to some but not all artificial surfaces.