The fouling community is a community of organisms that cover underwater structures of anthropogenic origin, and is a form of marine hard bottom epibenthic community. Its temporal patterns are determined by its seasonal and successional dynamics. One of the most important ecosystem services provided by the fouling community is its filtration capacity (FE), which improves the quality of seawater. The aim of this research was to describe the temporal patterns of the fouling community in the Slovenian coastal sea, to estimate experimentally the clearance rates (CR) for some common filter feeders of this community and to estimate the overall FE of the fouling community on small underwater structures. At the Morgan locality near Piran, structures carrying terracotta plates were placed monthly over the course of a year, and the assemblage on the plates was analysed using laboratory and photographic methods, first monthly and then at less frequent intervals. Experiments to evaluate CR were conducted with the ascidian Styela plicata and two bryozoan species, Schizoporella errata and Bugula neritina, measuring the decrease in the number of particles in suspension when the animals were fed under controlled laboratory conditions. The FE of the fouling community was evaluated in the case of biofilters, overgrown cylinders made of plastic mesh. Colonization of sessile invertebrates was influenced by the timing of placement of the structures, with sea temperature playing an important role. The most diverse and abundant invertebrate groups were bryozoans (Bryozoa), tubeworms (Serpulidae), and bivalves (Bivalvia). We have shown, that, due to its abundance and high CR, S. errata is an important filter feeder in the Slovenian coastal sea. We have as well demonstrated that fouled biofilters filter large amounts of seawater and we anticipate that, if strategically placed, similar structures could alleviate problems associated with eutrophication in degraded areas of the Slovenian coast.
|
