Polychaete assemblages of rocky shore along the South Adriatic coast (Mediterranean Sea) (original) (raw)
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Marine Biology, 2003
This study reports on the distribution of polychaete assemblages along a depth gradient from 5 to 25 m, along a stretch of rocky coast near Otranto (South Adriatic sea, Italy). Three depths were sampled in May and November 2000. At each depth three sites (about 100 m apart) were sampled by scraping off three replicate quadrats of 20·20 cm. The experimental design enabled identification of across-and along-shore spatial patterns of variation of polychaete assemblages. A total of 4,168 specimens, belonging to 152 taxa were collected. Multivariate analysis showed that the polychaete assemblages differed significantly among depths with the clearest differences between the shallowest sites (5 m) and the deeper ones (15-25 m). A considerable source of variation among sites at each level of the shore was also exhibited by the analyses, with the greatest differences among sites within depths recorded at 5 m. The species most contributing to the differentiation of assemblages among depths and sites within each depth were identified. Some potential causes of the observed differences are hypothesized and discussed. The importance of quantitative observation to provide the context for studying the underlying ecological processes is also stressed.
Diversity, 2020
The knowledge on the hard bottom polychaete assemblages in the Northern Adriatic Sea, a Mediterranean region strongly affected by environmental pressures, is scarce and outdated. The objective of this paper was to update the information on polychaete diversity and depict their patterns of natural spatial variation, in relation to changes in algal coverage at increasing depth. Hard bottom benthos was quantitatively sampled by scraping off the substrate from three stations at Sveti Ivan Island (North Adriatic) at three depths (1.5 m, 5 m and 25 m). Polychaete fauna comprised 107 taxa (the majority of them identified at species level) belonging to 22 families, with the family Syllidae ranking first in terms of number of species, followed by Sabellidae, Nereididae, Eunicidae and Serpulidae. Considering the number of polychaete species and their identity, the present data differed considerably from previous studies carried out in the area. Two alien species, Lepidonotus tenuisetosus, whi...
2011
Changes in benthic community structure are strongly related to environmental factors, and we need to determine how these natural changes occur in order to interpret the possible changes associated with anthropogenic impacts. The aim of this survey was to characterize and classify the polychaete assemblages inhabiting unpolluted soft bottoms in the Spanish Mediterranean in relation to environmental factors. Thirteen localities were sampled at depths between 9 and 31 m, from 2004 to 2006. Multivariate techniques showed that the structure of polychaete assemblages detected in 2004 was consistent over time and correlations between polychaetes and environmental factors were detected. The study area comprises four kinds of communities mainly characterized by polychaete assemblages, sediment types, and depth.
Polychaete distribution pattern on the Valencian Community coast, Spanish Mediterranean
Ciencias Marinas, 2011
Changes in benthic community structure are strongly related to environmental factors, and we need to determine how these natural changes occur in order to interpret the possible changes associated with anthropogenic impacts. The aim of this survey was to characterize and classify the polychaete assemblages inhabiting unpolluted soft bottoms in the Spanish Mediterranean in relation to environmental factors. Thirteen localities were sampled at depths between 9 and 31 m, from 2004 to 2006. Multivariate techniques showed that the structure of polychaete assemblages detected in 2004 was consistent over time and correlations between polychaetes and environmental factors were detected. The study area comprises four kinds of communities mainly characterized by polychaete assemblages, sediment types, and depth.
Deep Sea Research Part I: Oceanographic Research Papers, 2019
Knowledge of the diversity of deep-sea polychaetes in the Mediterranean Sea is still scarce and fragmentary, due to the absence of comprehensive taxonomic revisions of several families, with the majority of recent works relying on higher level taxonomy. In the present work samples were collected with a box-corer along the Sardinian Slope, a bathyal escarpment area located in the western Mediterranean Sea, at seven depth levels separated from each other by a 300 m interval, ranging from 600 to 2400 m. Samples were sifted with a 0.3 mm mesh, and polychaetes were identified at the lowest taxonomic level and characterised from the biogeographic and tropho-functional point of view. Ninety-seven taxa were recorded, 60 of which identified at the species level; eight taxa are likely to be undescribed species, possibly endemic to the Mediterranean Sea, whereas another seven are reported for the first time for the Mediterranean Sea. The majority of taxa shows an Atlantic-Mediterranean or strictly Mediterranean distribution, thus confirming the similarity between Atlantic and Mediterranean deep-sea assemblages, but also the unicity of the latter. Conversely, cosmopolitan taxa, usually considered common in deep-sea assemblages, represented a minor component. The trophic guild composition of the assemblage varied along the slope, with shallower assemblages (600-900 m) including a relatively high percentage of predators and microphagous omnivores, while deeper assemblages (1500-1800 m) showed a > 90% percentage of deposit-and filter-feeders, with the 1200 m assemblage characterised by intermediate features. This outcome suggests that in the presently investigated area, the environmental conditions of shallower samples allow the stable occurrence of at least two trophic levels, whereas deeper assemblages depend mainly on organic matter coming from shallower levels and from the water column. The examined polychaete assemblages are characterised by low density and a complete absence of dominance, with the evenness index J' ranging from 0.72 to 1; the wide ranges of the H' index (0.50-2.67) and of Hill's N1 (1.65-14.65) suggest a high variability at low spatial scale. If compared to Atlantic deep-sea polychaete assemblages the assemblage studied shows an almost tenfold lower organism abundance, but species diversity is only two-to four-fold lower, suggesting that biodiversity in Mediterranean deep-sea environments is possibly underestimated. Diversity of polychaete assemblages in the deep Mediterranean Sea is likely to be underestimated due to their low density, and adequate sampling strategies should be planned to have a better insight into the functioning and diversity of these communities.
Acta Oecologica, 1999
Spatial changes in species composition and structure of sublittoral soft-bottom polychaete assemblages along a transect parallel to the shoreline off the Barcelonès and Maresme regions on the Spanish Catalan coast (NW Mediterranean sea) are described. The transect (20 m mean depth) covers 30 km through an area affected by both water sewage discharges and river outflow. These effluents generate a spatial gradient of both silt and organic enrichment, according to the prevailing southerly currents in the zone. South of the effluents, eutrophized sediments supported a macrofaunal assemblage which was typical of polluted bottoms, characterized by the massive presence of Capitella capitata and Malacoceros fuliginosus, high abundance and biomass, low values of species richness, and a simplified trophic structure dominated by surface and subsurface-deposit feeders. North of the effluents, both the mud and organic matter content in sediment decreased drastically and the polychaete assemblages described were progressively less affected with distance. Thus, a clear change in species composition, as well as low values of abundance and biomass, increases in species richness, and a more complex trophic structure on the polychaete assemblages was observed north rather than south of the effluents. © 1999 Éditions scientifiques et médicales Elsevier SAS
1991
The exislence of i.\ boundary between midlittor<l.l and infraJittof<l.l polychaete assembl.ages was investigated at four stations exposed 10 different degrees of wave action around the coasts of Capraia Island (Tuscan Archipelago -'ryrrhenian Sea). Three samples were taken from each station: above, below and passing across the zero level. Filly-onc species ofpolychaetes were found, and lour polychaete assemblages were recognized: 1) exposed infra!iuorai and midlittoraJ, 2) semi-exposed infralittoral, 3) sheltered midlittora!, and 4) ~hellered infra!ittora!. The main factors inl1uencing their composition and structure were considered to be physical disturbances (emersion and wave action) and predation pressure; also alga! cover turned out to play an important role. A discontinuity between midlittora! and infra!ittora! zones was not clearly demonstrable at all the stations and the existence of a polychaete midlitwr!,1 assemblage is likely to be a local event rather than a genera! fea· ture.
Estuarine Coastal and Shelf Science, 2007
and 50 m depth) located on 21 inshoreeoffshore transects between the FrencheSpanish border and the mouth of the Rhône River were sampled during the 1998 Fall. Their polychaete fauna was analyzed to: (1) describe the distribution pattern of polychaete assemblages at the scale of the whole Gulf of Lions, (2) identify the relationships between these assemblages and the main environmental parameters, (3) establish a link between these assemblages and the benthic communities already described for Northwestern Mediterranean, and (4) assess recent historical changes in trends in densities and a diversity between assemblages. Three polychaete assemblages were identified using cluster analysis and associated procedures. These assemblages were tightly associated with depth and sediment granulometry as indicated by the concordance between their spatial distributions and the sedimentary map of the Gulf of Lions. Assemblage I contained most of the 10 and 20 m deep stations and was associated with littoral fine sands. Assemblage I was found all over the Gulf of Lions and was characterized by high abundance and high biomass due to the presence of large numbers of the serpulid Ditrupa arietina. Assemblage II was mostly composed of 30 m deep stations and was associated with littoral sandy mud. Assemblage II was dominated by the lumbrinerid Lumbrineris latreilli. It was composed of two sub-assemblages (IIa and IIb) in relation with sediment granulometry. Sub-assemblage IIb was associated with finer sediment than sub-assemblage IIa. Sub-assemblage IIa was only found in the Southern part of the Gulf of Lions, whereas sub-assemblage IIb was mostly found in the Northern part of the Gulf of Lions. This pattern is probably indicative of the sedimentation of fine particles originating from the Rhône River at intermediate depth as suggested by: (1) the sedimentary map of the Gulf of Lions, and (2) the outputs of recent models of sediment transport in the Gulf of Lions. Assemblage III was composed of 40 and 50 m deep stations; it was associated with terrigeneous coastal mud and found all over Gulf of Lions. Assemblage III was dominated by the sternaspid Sternaspis scutata. These three assemblages were tightly related with the benthic communities already described independently by Picard . Recherches qualitatives sur les biocénoses marines des substrats meubles dragables de la région marseillaise. Recueil des Travaux de la Station Marine d'Endoume 52, 1e160] and Guille . Bionomie benthique du plateau continental de la côte catalane française. II e Les communautés de la macrofaune. Vie et Milieu 21, 149e280] based on samples collected along the Provençal and the French Catalan rocky coasts, respectively. Unfortunately, no quantitative data were available to compare the a-diversity of the three newly defined assemblages with historical data collected by these two authors. We therefore compared our diversity measurements with the data collected by Desbruyères et al. [Desbruyères, D., Guille, A., Ramos, J.M., 1972/73. Bionomie du plateau continental de la côte catalane espagnole. Vie et Milieu 23, 335e363] in the Bay of Rosas (Spanish Catalan coast). Due to differences in the sampling effort between the two studies, this comparison was restricted to trends between assemblages. Our results show maximal densities and minimal a-diversity in the Littoral Fine Sand assemblage, which was not the case in Desbruyères et al. [Desbruyères, D., Guille, A., Ramos, J. M., 1972/73. Bionomie du plateau continental de la côte catalane espagnole. Vie et Milieu 23, 335e363]. Major temporal changes obviously reflect the increases of Ditrupa arietina (in the Littoral Fine Sands assemblage), and to a lesser extent Lumbrineris latreilli (in the Littoral Sandy Mud assemblage).
Diversity, 2021
In the different mesophotic bioconstructions recently found along the Southeastern Italian coast, polychaetes have been proved to show high species richness and diversity, hitherto never investigated. In the present study, the species composition and functional role of polychaete assemblages were analysed; the updated key to identification of the Mediterranean species of genus Eunice was presented and some taxonomic issues were also discussed. On the total of 70 species Serpulidae and Eunicida were the dominant polychaetes. Facing similar levels of α-diversity, the polychaete assemblages showed a high turnover of species along the north-south gradient, clearly according to the current circulation pattern, as well as to the different bioconstructors as biological determinants. Indeed, Serpulidae were dominant on the mesophotic bioconstructions primarily formed by the deep-sea oyster Neopycnodonte cochlear, while the Eunicida prevailed on the mesophotic bioconstructions mainly built b...