Influence of Allochthonous Plant Detritus on Gammarus insensibilis Stock (Amphipoda) Occurrence in the Soft-bottom Epifauna of the Northern Adriatic Sea
Sediments and benthic epifauna were examined at a coastal station (ca.26 m water depth) located in the northwestern Adriatic Sea. Sediment cores were taken every 90 days from April 1995 to January 1996. Epifauna was further investigated by means of trophic traps deployed on the sea bottom. Sediments were characterized by the occurrence of coarse plant detritus derived from aquatic angiosperms (Zostera sp., Cymodocea nodosa) commonly distributed in lagoons and salt marshes of the Po delta area. The epifauna was dominated by the brackish amphipod Gammarus insensibilis Stock, whereas other taxa occurred in negligible densities (< 2% quantitative dominance). A positive relationship was found between coarse organic matter in sediments and G. insensibilis spatial abundance. Analyses of population parameters from core samples and of size-frequency distributions from trophic traps permitted to exclude passive dispersal as the causative factor for the constant, even though seasonally variable, presence of the amphipod in the benthic system. Our results provide clear evidence of an “outwelling” flux of particulate plant detritus linking brackish coastal areas to adjacent marine environments in the northwestern Adriatic Sea. Moreover, they give support to the hypothesis that advection of allochthonous particulate detritus in marine environments may determine an “estuarine” characterization of epifaunal soft-bottom assemblages.
KeywordsSalt Marsh Venice Lagoon Plant Detritus Total Organic Content Particulate Detritus
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- Brun B (1975) Quelques aspects des cycles biologiques de deux Gammares (Crustacés Asnphipods) des eaux saumâtres du littoral méditerranée français. Arch Zool Exp Gen 116: 343–358Google Scholar
- den Hartog C, Vergeer LHT, Rismondo AF (1996) Occurrence of Labyrinthula zosterae in Zostera marina from Venice Lagoon. Rot Mar 39: 23–26Google Scholar
- Fava G, Zangaglia A, Cervelli M (1992) Ecology of Idotea baltica (Pallas) populations in the lagoon of Venice. Oceanol Acta 15: 651–660Google Scholar
- Franca P, Michelato A (1992) Northern Adriatic Sea, oceanography of the basin proper and of the western coastal zone. Sci Total Environ Suppl. 1992: 35–62Google Scholar
- Kevrekidis T, Lazsnidou-Dimitriadou M (1988) Relative growth and secondary production of the Amphipod Gammarus aequicauda (Martynov, 1931) in the Evroa Delta (N. Aegerian sea). Cah Biol Mar 29: 463–495Google Scholar
- Nixon SW (1980) Between coastal marshes and coastal waters — a review of twenty years of speculation and research on the role of salt marshes in estuarine productivity and water chemistry. In: Hamilton R, MacDonald KB (eds) Estuarine and wetland processes. Plenum Press, New York, pp 437–525Google Scholar
- Odum EP (1980) The status of three ecosystem-level hypotheses regarding salt marsh estuaries: tidal subsidy, outwelling and detritus-based food chains. In Kennedy V (ed) Estuarine Perspectives. Academic Press, New York, pp 437–525Google Scholar
- Patarnello T, Battaglia B, Bisol PM (1992) Genetic differentiation among geographic populations of two species of the genus Gammarus: G. insensibilis and G. aequicauda (Crustacea, Amphipoda) Vie Milieu 42:263–268Google Scholar
- Scarton F, Curiel D, Rismondo A (1995) Aspetti della dinamica temporale di praterie a fanerogame marine in Laguna di Venezia. Lay Soc Venice Sci Nat 20: 95–102Google Scholar
- Stock JH (1967) A revision of the European species of the Gammarus locusta-group. Zool Vehr Leiden 90: 1–56Google Scholar
- Tenore R, Hanson RB, McClain J, MacCubbin AE, Hodson RE (1984) Changes in composition and nutritional value to a benthic deposit feeder of decomposing detritus pools. Bull Mar Sci 35: 299–311Google Scholar