Benthic communities form an important component of the marine food chain. Their occurrence also provides information on the health of the ecosystem. A study was carried out to understand the distribution and abundance of macrobenthos along with sediment characteristics and physicochemical parameters in Visakhapatnam Harbour, a major port along the east coast of India. In all 84 macrobenthic taxa were reported from the port area of which 60 were polychaetes and 24 were other invertebrate taxa. Our observations revealed an increase in the number of polychaete species observed over the last 20 years from this region. An earlier study reported 38 polychaete species in 1975 and a year later the number of polychaete species reported was 12, indicating an increase in the number of polychaete species in the present study by about 150%. The macrobenthic abundance and dominance of species varied with the seasons. Pre-monsoon was dominated by Cirratulus sp., during monsoon tanaids were dominant indicating a seasonal shift in the occurrence and dominance of macrobenthos. During post-monsoon, Cossura coasta was dominant followed by Nephtys dibranchis and amphipods. Sediment characteristics (sand, silt and clay), organic carbon and dissolved oxygen were the important factors influencing the abundance and species diversity. The abundance of macrobenthic forms also varied with inner and outer harbour region. Higher species diversity was observed in the outer harbour suggesting the outer harbour has semi-polluted conditions such as higher dissolved oxygen (DO) and salinity, low nutrients (nitrite, nitrate and silicate) and low organic carbon in the sediment.

The Scotia Arc and Amundsen Sea are contrasting regions within West Antarctica. The Scotia Sea shelf is well studied and central to the origin and diversity of the Southern Ocean benthic fauna, whilst the shelf of Amundsen Sea is one of the least studied shelf areas in the world; a ‘white spot’ on the map of benthic research. Here we report on the tanaidaceans collected using an epibenthic sledge on two expeditions, BIOPEARL 1 and 2, of the RRS James Clark Ross in 2006 and 2008, respectively. This study represents the first analysis of the tanaidacean fauna of those two basins. Thirty-seven species were found in the Amundsen Sea from 500–1500 m depth and 51 species were found at depths ranging from 200–1600 m in the Scotia Sea. In the Scotia Sea, many species were unique to each of the study sites which may be evidence of allopatric speciation episodes. Site specificity was especially evident for Typhlotanais and Pseudotanais. Only three species were common to both basins. Around 90% of the species were previously undescribed. Our findings increase the number of the tanaidaceans known in the Southern Ocean by 50%.

Shade plots, simple visual representations of abundance matrices from multivariate species assemblage studies, are shown to be an effective aid in choosing an overall transformation (or other pre-treatment) of quantitative data for long-term use, striking an appropriate balance between dominant and less abundant taxa in ensuing resemblance-based multivariate analyses. Though the exposition is entirely general and applicable to all community studies, detailed illustrations of the comparative power and interpretative possibilities of shade plots are given in the case of two estuarine assemblage studies in south-western Australia: (a) macrobenthos in the upper Swan Estuary over a two-year period covering a highly significant precipitation event for the Perth area; and (b) a wide-scale spatial study of the nearshore fish fauna from five divergent estuaries. The utility of transformations of intermediate severity is again demonstrated and, with greater novelty, the potential importance seen of further mild transformation of all data after differential down-weighting (dispersion weighting) of spatially ‘clumped’ or ‘schooled’ species. Among the new techniques utilized is a two-way form of the RELATE test, which demonstrates linking of assemblage structure (fish) to continuous environmental variables (water quality), having removed a categorical factor (estuary differences). Re-orderings of sample and species axes in the associated shade plots are seen to provide transparent explanations at the species level for such continuous multivariate patterns.

Macrofaunal community structure is determined by a number of environmental variables. The riverine run-off during the monsoon brings about drastic changes in the physico-chemical parameters of a tropical estuary. The aim of the present study was to investigate the influence of rainfall in structuring the benthic macrofaunal community of a tropical estuary. The temporal dynamics of the macrobenthic community in the monsoon dominated Mandovi estuary (central west coast of India) was studied fortnightly from June 2007 to June 2009. A fixed location, downstream of the Madovi river, was sampled for benthic and water parameters. Ten replicates were collected during each sampling date using a Van Veen grab (0.04 m2). The macrofaunal abundance showed temporal fluctuation. The multivariate analysis showed the clustering of the samples linked to the environmental parameters (CCA and LINKTREE). The temporal variation observed in the macrofaunal abundance was basically due to changes in abundance of the dominant species. The variation in macrofaunal abundance was brought about by the recruitment and settling of re-suspended adults. It can be concluded that the macrofaunal structuring is influenced by temporal changes in the environment associated with the annual monsoon rainfall. Hence climate induced changes in the monsoonal pattern may affect the macrobenthic assemblages of tropical estuaries.

Macrobenthic data from estuaries along the Pernambuco coast in north-eastern Brazil were analysed to evaluate the effect of sieve mesh size (1.0 mm × 0.5 mm) and sampling depth (0–10 cm × 0–20 cm) on the description of infaunal communities, in an attempt to discuss standardized sampling procedures for different ecological studies objectives in these ecosystems. In general, the difference in sieve retention was less evident for biomass but was important for abundance: the 1.0 mm sieve retained only 27% of total individuals but 77% of total biomass. Regarding sampling depth, the 0–10 cm layer contained most individuals (94%) but contributed just 64% of the overall biomass. Although no strong differences in community structure were observed at most sites with the use of different sieves, the correlations among community dissimilarity using different meshes with environmental parameters (organic matter, total-N and microphytobenthos) indicated that the use of the 0.5 mm sieve will allow a better evaluation of the status of these estuaries. The results also highlight the importance of taking the vertical distribution of tropical macrofauna into account for quantitative estimates: for taxa composition and abundance the top layer is clearly essential, whereas for biomass the deeper layers should also be considered.

Spatial variations on the macrobenthic composition and structure associated with artificial reefs (ARs) on the south-eastern Brazil coast were related to particle size and geochemical characteristics of the sediment and to bottom currents velocity in the vicinity of ARs and two control areas (CAs). The sampling periods were related to Paraiba do Sul River (PSR) flow, highest in summer months. The sediment was more heterogeneous near the ARs, composed mainly of mud and gravel and with greater abundance of shellfish compared to the CAs predominated by mud. The influence of the artificial structures on the hydrodynamics of the site was evident with significantly lower current velocity. Macrobenthos richness, abundance and diversity varied spatially, with higher mean values near the ARs in both sampling periods, reinforcing the influence of artificial structures on the associated infauna. Significant temporal differences in the concentrations of phosphorus, nitrogen and dissolved organic carbon only on the CAs suggest that the effect of the artificial structures surpasses the environmental seasonality related to the PSR flow. The artificial modules created a more heterogeneous grain size of the sediment that contributed to the enrichment of associated macrobenthos, with higher species richness and abundance due to a higher niche availability.

Although taxonomic sufficiency (TS) was developed for rapid environmental assessments, it has recently been adopted to study the spatial patterns of macrobenthos in relation to natural environmental gradients. To accept TS as a routine approach in wider benthic studies, it needs to be valid for various taxa and geographically different water masses. This study examined the effects of taxonomic resolution on depth-related multivariate patterns of macrobenthic polychaetes on the western Indian continental shelf. An extensive data set based on samples collected from a wide geographical area (7°–22°N latitudes) covering a large depth gradient (30–200 m) has been analysed. Species level polychaete community data had shown a significant variation between shallow and deeper waters. Our results indicated that generic and family level data also can detect community shifts along a depth gradient in a similar way to species level data. The entire western continental margin (200 m depth) is lying in the oxygen minimum zone (dissolved oxygen <0.5 ml l−1). This study indicated that family level results were sufficient to document the correlations of low oxygen on macrobenthic polychaetes. This study also tested the effects of transformations on depth-related patterns of polychaetes. In multivariate analyses, transformations play a role in defining the balance between contributions from common and rare species in the measure of similarity of two samples. Our results showed that the type of transformations did not make any prominent differences in the multivariate analyses.

Although thalassinidean shrimps exert considerable influence over the structure of benthic communities no ecological studies have been conducted on the larvae and adults of Lepidophthalmus siriboia and Upogebia vasquezi in the equatorial region. The aim of the present study was to identify the reproductive period of these species in an Amazonian estuary. Monthly collections were performed in the estuary of the Marapanim River (northern coast of Brazil) over the course of one year (August 2006 to July 2007) and adults were obtained from bare sandy substrate and between boulders in the intertidal zone of the estuary at four sites. Thalassinidean larvae were also sorted from plankton samples (200 μm mesh) collected monthly at six sites. Larvae of the species Callichirus major, Lepidophthalmus siriboia and Upogebia vasquezi were collected, whereas adults of only the latter two species were found. Upogebia vasquezi was the most abundant species. There was no correlation between larval density and abiotic factors (water temperature, salinity and pH); however, the density of U. vasquezi adults was negatively correlated with salinity in the burrows. Lepidophthalmus siriboia and U. vasquezi reproduce throughout the year in the Marapanim River estuary, with peaks of greater intensity in some reproductive periods of the year, mainly correlated with changes in salinity.

In early 2004 the Victoria Land Transect project sampled coastal north-western Ross Sea shelf benthos at Cape Adare, Cape Hallett, Cape Russell and Coulman Island from 100–500 m deep. We describe the benthic macrofaunal assemblages at these locations and, to assess the use of seafloor sediment characteristics and/or depth measures in bioregionalizations, determine the extent to which assemblage compositions are related to measured differences in these factors. Percentages of fine sand and silt, the ratio of sediment chlorophyll a to phaeophytin, and depth were identified as important explanatory variables, but in combination they explained only 17.3% of between-location differences in assemblages. Consequently, these variables are clearly not strong determinants of macrofaunal assemblage structure. Latitude per se was not a useful measure of community variability and change. A significant correlation between both number of individuals and number of taxa and sediment phaeophytin concentration across locations suggests that the distribution of the benthos reflects their response to seafloor productivity. A number of factors not measured in this study have probably influenced the structure and function of assemblages and habitats. We discuss the implications of the results to marine classifications, and stress the need to incorporate biogenic habitat complexity into protection strategies.

The aim of this study is to characterize the different macrozoobenthos communities in Mar del Plata waters (south-western Atlantic) on the basis of their abundance and habitat, and to determine how sediment characteristics, like the grain-size composition, affect macrobenthic community structure. Multivariate techniques indicated that benthic communities and sediments in the surveyed area were included into the following five well-defined groups: (1) a medium sand assemblage dominated by the bivalve Crassinella marplatensis and Diplodonta patagonica, the echinoderm Encope emarginata, the tanaidacean Bacescapseudes sp. and the polychaete Armandia loboi; (2) a medium to very fine sand assemblage dominated by ostracods, the tanaidacean Bacescapseudes sp., amphipods and polychaetes of the family Nephtyidae; (3) a fine to very fine sand assemblage dominated by the tanaidacean Bacescapseudes sp.; (4) a silt and fine sand assemblage dominated by polychaetes particularly Scolelepis sp. and individuals of the family Nephtyidae; and (5) a fine sand assemblage dominated by amphipods and the tanaidacean Bacescapseudes sp. These results revealed the patchy distribution of macrobenthic assemblages as a result of sediment characteristics and serve as baseline information for this area strongly subjected to trawling perturbations.

An extremely dynamic chain of archipelagos links South America and the Antarctic Peninsula. It includes islands, which are large and small, old and young, near continental margins and isolated, and well sampled and poorly known. The current study sampled the macrobenthos of all the major archipelagos of this arc at shelf and slope depths using an Agassiz trawl. At least four samples (200 m, 500 m, 1000 m and 1500 m) were taken down-slope at Falkland Trough, Shag Rocks, South Georgia, South Thule, Powell Basin, Elephant Island, and Livingston Island sites and one sample was collected in the caldera of Deception Island. Despite the biogeographical and biodiversity importance of this region, this is the first time (by definition) entire standardized trawl samples have been analysed from all its archipelagos and at any consistent taxonomic level. We found 15 phyla and 29 classes of macro- and megafauna in total across the samples, many of which occurred at all sites. Even at remote and geologically young sites richness was high. Richness increased with abundance and wet mass and was highest in the shallow shelf samples and lowest at 1500 m. Abundance and wet mass varied more than two orders of magnitude, even within classes or study areas. There were strong similarities between the ascidian dominated shallow faunas of the two active volcanic sites, Southern Thule and Deception Island despite huge differences in isolation. There were also strong faunal similarities between Falkland Trough and Shag Rocks despite being on opposing sides of the Polar Front. In contrast two near neighbours with similarly soft substrata, Elephant and Livingston islands were amongst the most dissimilar.

The necessity to move from a traditional fishery management to an ecosystem approach is now acknowledged. Indicators are required to support the development of this approach. For example, community indicators have been proposed to assess the impact of fishing. We tested here the applicability of one such community indicator, the abundance-biomass comparison (ABC method), as a measure of the impact of bottom trawling (years of sampling: 2001 and 2003) on the benthic invertebrates – typically starfishes, crabs, squat lobsters, shrimps and large hard-shelled molluscs- of “Grande Vasière”, a major French fishing zone, in the Bay of Biscay. The ABC method is generally used as an impact indicator for different types of physical, biological and anthropogenic disturbances on benthic communities. This method is based on the assumption that increasing disturbance shifts communities from dominance by large-bodied species with low turnover rates toward dominance by small-bodied species with high turnover rates. At less disturbed areas the average biomass of individuals is greater than at more heavily disturbed areas. The ABC method measures this effect by comparing the ranked distributions of abundance and biomass within a given community. We applied the ABC method and compared the size structure and the species diversity at two areas exposed to moderate and high bottom trawl effort. Species diversity was lower in the most exploited area. The highly trawled area was dominated by opportunistic organisms, mainly one species of swimming crab Liocarcinus depurator, one species of squat lobster Munida rugosa and Norway lobsters Nephrops norvegicus, which are large-bodied species. Consequently, the results of the ABC method were inconsistent with the theoretical expectation for these particular macrofaunal communities and the measured levels of fishing intensity. 


Le régime alimentaire des larves de Chaoborus flavicans a été étudié dans le troisième bassin (profondeur = 0,8 m) de la lagune d'épuration des eaux usées d'un village de l'Aveyron. Sur un cycle annuel, l'eau a été constamment saturée en oxygène à la surface ; sur le fond, le pourcentage de saturation a varié entre 62,8 et 141,4%. La température de l'eau a varié de 4,6 à 25,7%C. La concentration moyenne annuelle en chlorophylle a a été de 99,3 µg/l, et la biomasse annuelle moyenne de zooplancton de 4,4g/m2 en poids sec, incluant en particulier Brachionus calyciflorus et Polyarthra remata (Rotifères), et Daphnia pulex (Cladocères). La population de C. flavicans réalise cinq générations par an et sa densité a varié entre 1931 et 21586 individus/m2.Le pourcentage d'estomacs vides n'est pas signifïcativement différent pour les quatre stades larvaires. La caractérisation du régime alimentaire des larves a fait appel aux indices : de Fréquence, de Contribution Numérique, de Contribution Pondérale, et tout particulièrement d'Importance Relative — déjà utilisé en ichthyologie (Pinkas et al. 1971). Aux trois premiers stades, les larves se nourrissent exclusivement de B. calyciflorus. Au contraire, les larves de stade IV présentent une grande euryphagie, pas signifïcativement différente sur le fond et en pleine eau. L'Indice d'Importance Relative et l'Indice de Sélectivité (Vanderploeg & Scavia 1979) indiquent que ces dernières exploitent les ressources trophiques de la lagune selon un gradient de vulnérabilité décroissante des proies.

L'examen des relations entre les données biologiques (macrofaune benthique) et les variables du milieu, recueillies conjointement dans 9 lacs jurassiens, est effectué à l'aide d'une analyse de co-inertie. La forte corrélation entre les deux séries de variables valide la classification biologique proposée antérieurement et permet de préciser la signification des deux indices utilisés.L'indice biologique littoral (Bo) est associé au potentiel trophique du système et l'indice de déficit faunistique (Bz) traduit l'évolution de la qualité chimique de l'eau et des sédiments selon la profondeur. Les lacs les plus biogènes, définis par les indices les plus élevés, sont corrélés positivement avec la minéralisation (conductivité, bicarbonates, Ca/Si des sédiments) et avec l'oxygénation hypolimnétique (saturation en O2 dissous, potentiel redox) et correlés négativement d'une part, avec la teneur du sédiment en matière organique et les paramètres associés (COT, NT, Fe, Si) et d'autre part, avec la concentration en orthophosphates, en sels ammoniacaux et la biomasse algale (Chl a).L'analyse de co-structure, en accord avec la tendance corrélative de Bo et Bz , étaye une combinaison des deux critères dans un indice global de valeur biogène. Toutefois, la corrélation entre Bo et Bz n'est pas généralisable et les deux indices sont utiliséspour définir le type biologique d'un lac et interpréter la note globale.La discussion des résultats suggère une révision du classement des lacs par une recherche des conditions de transformation et de transfert de la matière assimilable aux organismes consommateurs.

Une étude quantitative des peuplements d'invertébrés benthiques en relation avec certains substrats naturels et artificiels, utilisés pour la consolidation des berges, a été réalisée dans 9 stations du bief de Waulsort lors de la mise en chômage technique de la Meuse (Belgique). Les stations à grande hétérogénéité physique sont caractérisées par une richesse et une diversité faunistique importante (33 familles, 15 790 nd./m2, H' = 2,08) de même qu'une colonisation optimale de substrat. Les stations à substrats artificiels, fortement homogènes, restent peu accueillantes pour la faune benthique (17 familles, 1 352 ind./m2, H' = 0,52). Dans la perspective de l'aménagement futur des berges du barrage de Waulsort, la construction de perrés non cimentés à faible pente doit être privilégiée.

Le présent article constitue la deuxième partie d'un triptyque consacré à la classification biologique (parties I et II) de 9 lacs de la Franche-Comté jurassienne en relation avec les facteurs écologiques (partie III). Cinquante-quatre taxons ont été répertoriés par l'application d'un protocole original d'analyse comparative de la macrofaune des sédiments (Verneaux et al. 1993a). Appliquées à quarante-deux taxons déterminés au genre, des analyses factorielles des correspondances permettent de sélectionner vingt-trois taxons (taxons repères) hiérarchisés par analyse de la distribution bathymétrique de leur densité relative et de leur fréquence. Utilisés pour caractériser les peuplements benthiques à 4 profondeurs (Z0 : 2 m, Z1 : 0,25 Zmax, Z2 : 0,50 Zmax, Z3 : 0,75 Zmax) ils permettent d'établir une classification des systèmes lacustres qui est alors comparée à une précédente classification obtenue par analyse de la biodiversité en zone littorale (B0 = v0 √d0) et de l'évolution de la variété avec la profondeur relative exprimée par un indice de déficit taxonomique fi = kvi/v0 (Verneaux et al. 1993a). Cette étude de la nature de la faune montre : — qu'en zone littorale, où les conditions mésologiques sont optimales, les systèmes étudiés, non pollués globalement, possèdent tous des taxons repères sensibles et se différencient essentiellement par le critère adéquat quantitatif B0, — que la modification de la nature de la faune avec la profondeur constitue un critère d'appréciation du mode de fonctionnement des systèmes susceptible de compléter utilement l'indice de déficit taxonomique fi. Ce travail souligne la nécessité d'associer, en matière de typologie, une analyse des 3 critères fondamentaux que sont la variété, la densité et la nature de la faune.

Les auteurs proposent une nouvelle méthode de classification biologique des lacs fondée sur une analyse comparative de la macrofaune des sédiments. Cette recherche inclut la définition préalable d'un protocole d'échantillonnage permettant la comparaison de systèmes lacustres de profondeur maximale très différente. Ce protocole original est caractérisé par : — des prélèvements de sédiments meubles effectués à une profondeur en zone littorale (Z0 : 1-2 m) et à trois profondeurs, relatives à la profondeur maximale des systèmes étudiés, en zone limnétique (Z1 = 0,25 Zmax, Z2 = 0,50 Zmax, Z3 = 0,75 Zmax) ; — un nombre d'échantillons par profondeur prospectée (ni) proportionnel à la longueur (L en km) de chaque isobathe (n0 = 1,8√10 L et n1, n2, n3 = 1,4√10 L). 325 stations ont été réparties, suivant un protocole standard, dans 9 lacs du Jura et 104 taxons, dont 98 genres ont été recensés. Une analyse factorielle des correspondances, appliquée aux stations et aux genres, montre que les stations se distribuent le long de l'axe F1, dans un ordre de variété faunistique décroissante et de profondeur croissante, exprimant l'évolution de la variété et de la densité en fonction des modifications des conditions écologiques avec la profondeur. Une première différenciation des lacs a été obtenue en fonction de la variété totale et de la densité globale des 9 systèmes étudiés. Ces deux critères permettent de distinguer des lacs très biogènes et des lacs peu biogènes (variété totale et densité globale faibles). Cette deuxième catégorie de lacs regroupant toutefois des systèmes dont les caractéristiques écologiques différaient nettement, une seconde classification biologique a été établie par la prise en compte : — d'un critère quantitatif : le couple variété-densité en zone littorale exprimant le potentiel biogénique des systèmes (Bo = vo √do) ; — d'un critère qualitatif : la régression de la variété générique en fonction de la profondeur relative. Une hypothèse de linéarité de la distribution bathymétrique relative de la variété faunistique permet le calcul d'indices de distribution faunistique (f¡ = kiv¡/vo) qui traduisent l'évolution des conditions écologiques avec la profondeur. Ces deux critères (Bo et f) constituent les coordonnées d'un système d'axes comportant 4 niveaux (2 niveaux quantitatifs et 2 niveaux qualitatifs) qui permettent de classer les lacs en fonction de leur aptitude biogénique.

Une série de dragages effectués dans la Saône au niveau de 13 stations réparties sur 377 km de rivière montre que le macrobenthos du chenal de cette rivière est, dans les stations les moins dégradées, largement dominé par les Ephéméroptères fouisseurs (Ephoron virgo et Ephemera lineata). La comparaison avec le macrobenthos du Haut-Rhône indique que ce dernier, qui présente des caractéristiques mésologiques et hydrologiques similaires, se situe typologiquement plus à l'amont que la Saône. La durée et l'importance de l'étiage combinées avec les différences de pente, cette dernière influençant la vitesse du courant et la granulométrie, sont probablement les facteurs essentiels qui structurent les peuplements macrobenthiques de ces deux cours d'eau.