| Title | Trophodynamics of suprabenthic fauna on coastal muddy bottoms of Southern Tyrrhenian sea (Western Mediterranean) |
| Abstract | The trophodynamics of suprabenthic fauna were analyzed in the Gulf of Castellammare (North-western Sicily, Italy) at depths ranging between 40 and 80 m. Variations in species abundance and biomass together with changes in nitrogen and carbon stable isotope composition were explored at a seasonal scale, from November 2004 to June 2005. Suprabenthos showed maximum biomass and abundance from late winter to summer, while minimum values were found in autumn. The highest abundances of mysids and copepods occurred in March, 1 month after the peak of primary production. Amphipod abundance was higher in summer, likely due to a relative increase in organic matter in the sediments. Statistical analysis provided evidence for separation of sample abundances as a function of season. The best match between suprabenthos abundance and environmental variables was found with Chlorophyll a recorded 3 months before the sampling.
Stable isotope analyses suggest a relatively complex food web in the Gulf of Castellammare with several potential food sources. Some suprabenthic species (i.e. mysids and copepods) exhibited depleted values of ´13C, indicating a planktonic source of nutrition. Cumaceans and amphipods displayed more enriched ´13C values, pointing to more detritivorous behaviour. A third group with intermediate ´13C values comprised species with a mixed diet (e.g. Ampelisca spp., Apherusa vexatrix and Harpinia spp.). Assuming a 15N- enrichment of ca. 2.54 between consumers and their diet, at least two trophic levels can be distinctly identified: (1) filter feeders/grazers (mysids, copepods), suspension/deposit feeders (Ampelisca spp., A. vexatrix, small Goneplax rhomboides) and omnivores, alternatively feeding on detritus and small invertebrates such as meiobenthos (the cumacean Leucon mediterraneus or the amphipod Westwoodilla rectirostris); (2) carnivores on small crustaceans and zooplankton (the amphipod Harpinia spp., the gobiid fish Lesuerigobius suerii and the decapod Philocheras bispinosus).
Seasonal changes in isotopic composition occurred for the dominant suprabenthic species. This may result from diet shifts associated with changes in the availability of different food sources and/or from change in the primary sources of organic matter that are particularly variable in coastal environments. |
| Source | Journal of sea research (Den Burg. Print) 61, pp. 174–187 |
| Keywords | Suprabenthos (Hyperbenthos)Assemblage DynamicsStable IsotopesSeasonal VariationsEnvironmental Factors |
| Journal | Journal of sea research (Den Burg. Print) |
| Editor | Elsevier Science, Den Burg, Paesi Bassi |
| Year | 2010 |
| Type | Articolo in rivista |
| Authors | E. Fanelli, J.E. Cartes, F. Badalamenti., P.Rumolo, M. Sprovieri |
| Text | 6838 2010 Suprabenthos Hyperbenthos Assemblage Dynamics Stable Isotopes Seasonal Variations Environmental Factors Trophodynamics of suprabenthic fauna on coastal muddy bottoms of Southern Tyrrhenian sea Western Mediterranean E. Fanelli, J.E. Cartes, F. Badalamenti., P.Rumolo, M. Sprovieri The trophodynamics of suprabenthic fauna were analyzed in the Gulf of Castellammare North western Sicily, Italy at depths ranging between 40 and 80 m. Variations in species abundance and biomass together with changes in nitrogen and carbon stable isotope composition were explored at a seasonal scale, from November 2004 to June 2005. Suprabenthos showed maximum biomass and abundance from late winter to summer, while minimum values were found in autumn. The highest abundances of mysids and copepods occurred in March, 1 month after the peak of primary production. Amphipod abundance was higher in summer, likely due to a relative increase in organic matter in the sediments. Statistical analysis provided evidence for separation of sample abundances as a function of season. The best match between suprabenthos abundance and environmental variables was found with Chlorophyll a recorded 3 months before the sampling. Stable isotope analyses suggest a relatively complex food web in the Gulf of Castellammare with several potential food sources. Some suprabenthic species i.e. mysids and copepods exhibited depleted values of ´13C, indicating a planktonic source of nutrition. Cumaceans and amphipods displayed more enriched ´13C values, pointing to more detritivorous behaviour. A third group with intermediate ´13C values comprised species with a mixed diet e.g. Ampelisca spp., Apherusa vexatrix and Harpinia spp. . Assuming a 15N enrichment of ca. 2.54 between consumers and their diet, at least two trophic levels can be distinctly identified 1 filter feeders/grazers mysids, copepods , suspension/deposit feeders Ampelisca spp., A. vexatrix, small Goneplax rhomboides and omnivores, alternatively feeding on detritus and small invertebrates such as meiobenthos the cumacean Leucon mediterraneus or the amphipod Westwoodilla rectirostris ; 2 carnivores on small crustaceans and zooplankton the amphipod Harpinia spp., the gobiid fish Lesuerigobius suerii and the decapod Philocheras bispinosus . Seasonal changes in isotopic composition occurred for the dominant suprabenthic species. This may result from diet shifts associated with changes in the availability of different food sources and/or from change in the primary sources of organic matter that are particularly variable in coastal environments. 61 Articolo in rivista Elsevier Science 1385 1101 Journal of sea research Den Burg. Print Journal of sea research Den Burg. Print J. sea res. Den Burg. Print Journal of sea research. Den Burg. Print JSR Den Burg. Print paola.rumolo RUMOLO PAOLA giovanni.fanelli FANELLI GIOVANNI mario.sprovieri SPROVIERI MARIO fabio.badalamenti BADALAMENTI FABIO TA.P04.028.001 Biogeochimica dell ambiente marino |
