Epifaunal Settlement, the Processes of Community Development and Succession over Two Years on an Artificial Reef in the New York Bight

An experimental reef of 16,000 solid blocks (500 tons) of synthetic, cementitious materials was established, at depth of 20 m in the New York Bight in 1980. The reef covers an area of 1,230 m² and has a profile of 70 to 130 cm. Measurements of epifaunal settlement and growth on test bricks retrieved from the reef site allowed the processes of community development and seasonal succession to be followed in detail over 2 years.

Test bricks were made from a concrete, and from two coal waste materials (fixated mixtures of fly ash and FGD scrubber sludge) from two modern power stations. The bricks were compared for their suitability as substrates for colonization by organisms characteristic of reefs. Comparative settlement and growth of communities on the different bricks are described in terms of species richness, abundance and the surface area of brick covered. Altogether 36 species of attached epibenthic organisms were recorded colonizing the bricks. About the same number of species occurred on all bricks, and although several dominant species settled year-round, seasonality played a role in structuring colonization patterns; a few animals (Balanus crenatus, Zirfaea crispata, Polydora socialis) had associations with a particular type of material.

There were differences in settlement and in the rate of community development between the two coal wastes and the concrete. Concrete tended to be overgrown more quickly than either coal waste. Differences between communities persisted after 2 years in the sea; nevertheless, coal waste bricks appeared suitable substrates for development and growth of epifaunal communities.