Trophic organization of the macro-zoobenthic assemblages within coastal areas subjected to anthropogenic activities

Abstract

Coastal areas, in general, are affected more and more by anthropogenic activities. Benthic macrofauna assemblages react to this disturbance and constitute, then, an effective biological tool to study the degree of contamination of the biotope. For this study three coastal sites, more or less exposed to anthropogenic activities but differing according to their opening to the sea, were studied. Sediments were sampled aboard a research vessel and using a 0.1 m2 Van Veen grab. Results show that Tunis bay and Dkhila coast, which are more open to the sea, appear more balanced on the trophic plan, and the biodiversity state is more satisfactory. However, Bizerte lagoon is closed, except for a limited communication with the sea via a narrow ship canal. So, the ecosystem presents some eutrophication signs and a great trophic imbalance in which carnivores largely dominate the benthic assemblages. In this situation, the herbivore chain is substituted by a microbial chain and only some opportunistic species can survive in these anoxic sediments related to the strong fluctuations of the environment factors during the year.

Spatial and Temporal Structures of the Macrozoobenthos from the Intertidal Zone of the Kneiss Islands (Central Mediterranean Sea)

“…Identified species are classified here into trophic groups according to [38] and later modified by [1] [39]- [42]. Three currently available univariate Biotic Indices (BIs) are tested, namely AMBI.…”

“…Owing to their position at the interface of land and sea, shallow waters and coastal areas are generally highly productive and ecologically important [1] [2]. However, coastal ecosystems often form a mosaic of interlinked habitats that should not be considered in isolation.…”

Functional diversity of the macro‑invertebrate community in the port area of Kerkennah Islands (Tunisia)

“…These factors create a pressure leading benthic communities to several reactions; some species are disturbed and cannot develop naturally, and others, more resistant, impose their opportunistic strategy of life and exclude more sensitive and less competitive species (Glémarec, 1993). In general, cases where only one or just a few factors govern marine life are rare; this prevents from discriminating the effect of each factor (Anonymous, 2004;Afli et al, 2008a).…”

Does increased connectivity with the Mediterranean Sea improve the ecological status of the macroinvertebrates in the lagoon of Boughrara (SW Mediterranean)?

“…Calculations were performed using PRIMER v6 package (Clarke and Gorley 2006). Identified species were classified into trophic groups according to Fauchald and Jumars (1979) and notably modified by Grall and Glémarec (1997), Hily and Bouteille (1999), Afli and Glémarec (2000), Pranovi et al (2000) and Afli et al (2008a) as follows:…”

“…Indeed, in 2013 the stations are not scattered as in 2010, which means that there is a general homogenization of the ecosystem conditions and the benthic community. Nevertheless, the lagoon of Boughrara seems to be more balanced trophically, especially in 2013, compared with the other Mediterranean lagoons, as the lagoon of Bizerte dominated widely by carnivores (Afli et al 2008a), the southern lagoon of Tunis dominated by micrograzers, the lagoon of Ghar El-Melh dominated by selective deposit feeders (Afli et al 2009b) and the lagoon of Smir dominated by detritus feeders (Chaouti and Bayed 2011).…”