Differential microbial fouling on the marine bryozoan Pentapora fascialis

Marine fouling is a commercially important problem affecting abiotic and biotic surfaces. In this study we investigated the surface fouling on a colonial reef-building invertebrate, the bryozoan Pentapora fascialis, from the Welsh coast. We captured 300 scanning electron microscope (SEM) images of 5 colonies of the bryozoan P. fascialis in order to quantify the level of fouling on the exterior surfaces. Evidence for differential fouling was found to occur at several spatial scales, including between older and newer zooids, between proximal and distal regions of the same zooids and between colonies. The current year's growing zooids were found to have a higher level of fouling than older zooids. The difference in the mean level of fouling of proximal regions of zooids compared to distal regions was found to be significant in P. fascialis. In agreement with the differential fouling previously observed by other authors in the laminar bryozoan Flustra foliacea where the proximal region of a zooid was observed to have a higher level of fouling, the fouling coverage in P. fascialis was higher in the proximal region of zooids. A reduction of fouling on some bryozoan surfaces may be caused by production of antimicrobial compounds. Further studies of microbial fouling of a similar quantitative scale in other bryozoans could aid in the identification of novel antimicrobial agents useful for preventing microbial fouling on abiotic surfaces in the marine environment.

Distribution and morphological variation of colonies of the bryozoan Pentapora fascialis (Bryozoa: Cheilostomata) along the western coast of Italy

Bathymetric range, substrate, colony density, colony size, and some zoarial features (form of the colony and branches) of the carbonate reef building cheilostome bryozoan Pentapora fascialis (Pallas) were recorded from 15 localities along the western coast of Italy. A wide range in the depth distribution of colonies was observed (11 to 60 m). Colonies occurred on several different types of substrate including gorgonians, sponges, bedrock and rock boulders, in current swept areas. Density was approximately 1 colony/m2. The most frequent colony size-class was 10 to 20 cm in diameter and was typically found growing epizoically on gorgonians. Ellipsoidal colony forms with expanded, foliaceous laminae were characteristic of larger colonies; these frequently grew on rock substrates. Subspherical colonies with a diameter less than 20 cm grew as epizoans and had a narrow branches structure. This information will help to inform decisions on taxonomic discrepancies within the Pentaporidae. In addition the data provide a useful baseline for the future estimation of a carbonate budget in the region.