Deformities in larval Prodiamesa olivacea (Meigen, 1818) (Diptera,Chironomidae) and their use as bioindicators of toxic sediment stress

The early development of epibenthic communities on stabilised coal-waste material from Poole Bay Artificial Reef (PBAR) was studied by deployment of arrays of slabs (each slab, 20 × 20 × 5 cm), suspended 1 m off a sandy seabed, on the PBAR site (50 ° 39′ 72″ N, 01 54′ 79″ W; depth 12 m) in May 1991. Effects of season, substratum orientation and period of exposure on recruitment and community development of epibenthos, as determined from percentage cover and biomass (ash-free dry weight) measurements, were evaluated over the following 14 months. The initial barnacle- and serpulid polychaete-dominated community developed into an ascidian-polyzoan turf on the slab bases and into an algal-hydroid turf on the tops. The number of colonisers reached maxima of about 21 and 12 sessile taxa, on the bases and tops, respectively. Epibenthic biomass was greater on the slab bases than on the tops throughout the study. The main recruitment season was from February to August. Encrusting bryozoans, ascidians and hydroids were generally better competitors for space than were serpulids and barnacles. The small (< 5 cm) mobile invertebrate community was dominated by porcelain crabs (Porcellanidae) and scale worms (Polynoinae). This revised version was published online in July 2006 with corrections to the Cover Date.