Epifaunal development on an artificial reef

The Poole Bay Artificial Reef Project (PBAR) monitored the development of the first stabilized coal-waste artificial reef in the U. K. This study documented epifaunal colonization using percentage cover techniques and biomass in terms of ash-free dry weight, for three years following development in June 1989. The colonization pattern of the major functional taxa on the coal-waste was similar to that found on the concrete control blocks and on other power station waste artificial reefs. Coal-waste material immersed for 7 months to 3 years supported epifaunal communities common to nearby natural reefs, irrespective of location
or depth. The initial "hard" encrusting community on PBAR progressed to a "softer" turf and sponge dominated assemblage, and comparison of PBAR with local natural reefs and the Florida Institute of Technology older oil ash reef, suggests that the PBAR epifaunal community has not yet reached a mature stable state. Sessile epifaunal biomass (AFDW) on PBAR and a local natural reef were similar. Several methods were devised for the estimation of surface area available for colonization, which gave a maximum area ratio of the sand (reef footprint) lo a reef unit of 1:3; colonization of these areas produced a biomass (AFDW) ratio of between I:I and I:3. Biomass correlated well with percentage cover for erect organisms (red algae, coelenterates and erect bryozoans) and ascidians, but not for encrusting organisms (barnacles; serpulids and encrusting bryozoans). Production (per unit area) of the sessile reef epifauna and sand macrobenthos were similar, whilst the bases of freestanding slabs were at least twice as productive as any face of the reef blocks.