Effects of an artificial reef on the surrounding soft-bottom community (central Adriatic Sea)

Abstract

The benthic communities of the soft seabed inside and outside the Cesano-Senigallia artificial reef (central Adriatic Sea) were investigated seasonally for 2 years (spring 1997 to winter 1999) to evaluate the effects of the reef on the surrounding bottom. The community living close to the reef is typical for the coastal area. Mean species richness and densities over the entire sampling period were comparable inside and outside the reef, while higher values were recorded at the control site. However, the ShannonWiener diversity index was higher close to the reef than at the control. Physical factors associated with the presence of the artificial structures appear to affect composition and abundance of the infauna community more than biological factors do (predation). The area inside the reef was characterized by fine mud favouring the settlement of deposit and suspension feeders, mainly polychaetes. Outside the reef, molluscs were numerically dominant, with an increasing proportion of sandy-bottom species with increasing distance from the structures. These differences were more marked in spring and autumn, while in the other seasons the reef effect appeared to be reduced to a narrow area close to the structures.

Trophic relationships among scorpaeniform fishes associated with gas platforms

“…As artificial substrates deployed on soft bottoms alter biodiversity, favouring either the settlement of hard bottom species on the structures themselves or the development of deposit and suspension feeders in the surrounding sediment (Fabi et al 2002), it might be expected that the type of prey differs when predators live near or far from the structures. In our study, the similarity between the diet of tub gurnards caught near the platforms and of those caught at control sites suggests that artificial structures do not affect this predator's prey choice, since it consistently feeds on soft-bottom organisms whose occurrence in the study area does not depend on the presence of hard substrates.…”

Subtidal littering: Indirect effects on soft substratum macrofauna?

“…These, along with the activities and deaths of reef-associated organisms, can result in organic enrichment (WILDING, 2006) and modification of granulometry caused by the introduction of shell fragments that derive from fouling biota (DAVIS et al, 1982;AMBROSE & ANDERSON, 1990;BAROS et al, 2001). Finally, predators attracted by the structures may forage on plants and animals that live in adjacent sediments (DAVIS et al, 1982;BAROS et al, 2001, FABI et al, 2002.…”

Artificial reefs: from ecological processes to fishing enhancement tools

“…The presence of these man-made reef structures will affect: i) nearby sandy areas and also ii) water column processes in the vicinity of ARs. Habitat linkages among distinct reef compartments are driven by hydrological processes (changes in water flow patterns), sediment type, geomorphological, chemicalphysical and biological processes (FABI et al, 2002;KIRKE, 2003;DEDIEU et al, 2007;FALCÃO et al, 2007FALCÃO et al, , 2009) and also biotic processes (YANAGI;NAKAJIMA, 1991;LINDQUIST et al, 1994;PEPE et al, 1998;SHENG, 2000;DALE;PREGO, 2002;POLUNIN, 2001;FABI et al 2006;EINBINDER et al, 2006). AR structures can affect biological processes differently within different reef compartments.…”

“…This process contributes to the organic enrichment of sediments due to entrapped drift algae and other organic materials driven from reef biological activities and deaths of reef associated organisms. Deposition of biomass in the lee of the reefs favours benthic remineralization, promoting nutrient regeneration in pore water (FABI et al, 2002;DEDIEU et al, 2007). Sediment nutrient enhancement from deposited organic material can be incorporated into the reef food web, enhancing sandy benthic production which contributes to the rehabilitation of sandy coastal areas via sediment chemical trophic chain pull-out (FALCÃO et al, 2007(FALCÃO et al, , 2009).…”

“…biomass or abundance (SOYER, 1985;DANOVARO, 1996;FABI et al, 2002). Nevertheless, sandy benthic communities have an important role in coastal food webs since they are an important food/energy source and a crucial link between lower and higher trophic levels (DALE; PREGO, 2002), such as commercial fish feeding on benthic ARs resources (LINDQUIST et al, 1994;PEPE et al, 1998;FABI et al, 2006).…”