Structure and production of the benthic macroinvertebrate community in a shallow lagoon in the Bay of Cadiz

Abstract

The composition and distribution of the benthic macroinvertebrate community in a lagoon fish-pond system in the Bay of Cadiz. Spain, were studied by taking monthly samples at 4 sites during 1991. A total of 29 macroinvertebrate species, representing 16 orders. were identified. Gastropods, amphipods and chironomid larvae dominated the macrofauna in term of numbers of individuals, while in biomass terms gastropods, bivalves and polychaetes were dominant. The diversity (H') and evenness (J') indices of this community were low, ranging from 0.58 to 1.85 and 0.30 to 0.75 respectively (natural log base). Monthly total invertebrate density showed considerable seasonal variation, with a main peak in winter. Taking the most abundant species only, the densities of Hydrobja minoricensis, H. ventrosa, Microdeutopus gryllotalpa and Chironomus salinarius were positively related, and the density of Nereis diversicolor negatively related, to the biomass of benthic macroalgae (Ulva lactuca and Cladophora sp.). The density of C. salinarius was also positively related to the silt content in the sediment. Mean annual production varied between 13.3 g m-' yr-' ash-free dry weight (50.7 g m-2 yrr' dry weight) and 27.3 g m-' yr-' AFDW (122.0 g m-'yr-' DW) depending on the sampling site, yielding production/biomass (P/B) ratios between 1.08 and 1.37 yr-l. The annual production estimate for the whole system was 19.5 g m-' yr-' AFDW (66.6 g yr-' DW).

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“…The results of the number and density of species and diversity indices revealed the same seasonal distribution pattern of the molluscan community, ranging from rich community in the summer to an poorer one in winter, apparently due to a "dystrophic crisis" episode occurring during summer. Similar seasonal patterns have also been observed in other studies (Amanieu et al, 1977;Gravina et al, 1989;Arias and Drake, 1994;Dounas and Koutsoubas, 1996;Lardicci et al, 1997). This study gives for the first time a list of mollusc species hosted by the peculiar habitat of Hammamet Marina, which can be considered as far from definitively complete.…”

Population dynamics and reproductive strategy of Scolelepis goodbodyi (Polychaeta: Spionidae) in a subtropical atlantic beach

“…In general, temperature increases can be a stimulus for spawning in polychaetes, though temperature decreases may have a similar effect (ARIAS & DRAKE 1995). The continuous reproduction observed in this study was also reported in a population of Scolelepis goodbodyi from Barequeçaba Beach, in São Paulo (MACCORD & AMARAL 2007).…”

Macrozoobenthic community structure in a poikilohaline Mediterranean lagoon (Laki Lagoon, northern Aegean)

“…Muus 1967;Scalera Liaci et al 1982;Cottiglia et al 1983aCottiglia et al , 1983bKhoury 1984;Mauge´1986;Kevrekidis et al 1990). The increased number of macroalgae during summer and autumn, when both epibenthic predators are most abundant and their feeding activity, especially in summer, is probably high, may offer macrobenthic invertebrates a refuge from predation (Arias and Drake 1994).…”