The number of non-indigenous aquatic species (NIS) has rapidly increased globally. The majority of published evidence on the effects of NIS on local communities is from single species studies in which the interactive effects of NIS are not considered. Here we present experimental evidence of separate and interactive effects of two widespread non-indigenous benthic predators, the round goby (Neogobius melanostomus) and the North American mud crab (Rhithropanopeus harrisii) on benthic invertebrate communities in a shallow coastal ecosystem of the Gulf of Riga, the Baltic Sea. The two species have recently colonized multiple sub-basins of the Baltic Sea and due to their rapid range expansion, increasing densities and local functional novelty, they are expected to have strong separate or interactive effects on native communities. Our laboratory experiment demonstrated that round goby and mud crab exerted a significant predation pressure on different benthic invertebrate species and the effects of the studied predators were largely independent. Predation was stronger at higher temperature compared with low temperature treatment. Among the studied invertebrate species gammarid amphipods were consumed the most. Interestingly, round goby did not prey on the mud crabs despite a large size difference of the studied predators.

Coastal ecosystems are highly complex and driven by multiple environmental factors. To date we lack scientific evidence for the relative contribution of natural and anthropogenic drivers for the majority of marine habitats in order to adequately assess the role of different stressors across the European seas. Such relationship can be investigated by analysing the correlation between environmental variables and biotic patterns in multivariate space and taking into account non-linearities. Within the framework of the EMBOS (European Marine Biodiversity Observatory System) programme, hard bottom intertidal communities were sampled in a standardized way across European seas. Links between key natural and anthropogenic drivers and hard bottom communities were analysed using Boosted Regression Trees modelling. The study identified strong interregional variability and showed that patterns of hard bottom macroalgal and invertebrate communities were primarily a function of tidal regime, nutrient loading and water temperature (anomalies). The strength and shape of functional form relationships varied widely however among types of organisms (understorey algae composing mostly filamentous species, canopy-forming algae or sessile invertebrates) and aggregated community variables (cover or richness). Tidal regime significantly modulated the effect of nutrient load on the cover and richness of understorey algae and sessile invertebrates. In contrast, hydroclimate was more important for canopy algae and temperature anomalies and hydroclimate separately or interactively contributed to the observed patterns. The analyses also suggested that climate-induced shifts in weather patterns may result in the loss of algal richness and thereby in the loss of functional diversity in European hard bottom intertidal areas.

We examined the benthic fauna in four areas along a mangrove tidal channel in south-eastern Brazil, between October 2008 and August 2009. The tested hypothesis is that the most abundant groups avoid competition as they occupy different types of substrata and that the longitudinal distance from the sea also affects the occurrence of benthic fauna along the channel. We also examined the prop root epibiont fauna to describe this different community. Polychaeta was the dominant group in the sediment whereas Isopoda and Tanaidacea were the dominant groups on the prop roots. We found a tendency for higher infauna species richness and diversity in the innermost channel area during the summer. Higher abundance of epibiont fauna was also found in summer with tidal movements allowing the colonization of the prop roots of the mangrove forest by some taxa. The polychaetes Ceratocephale sp. and Laeonereis acuta had indication of habitat partitioning, with the first occurring mainly in very fine sand sediment whereas the latter preferred medium sand sediment. The microcrustaceans Chelorchestia darwini and Tanaidacea sp. 1 occurred in high abundance colonizing the prop roots. Exosphaeroma sp. was found in high abundance in infauna and epibiont fauna. The tested hypothesis of spatial partitioning of the mangrove channel by the benthic fauna was confirmed with the most abundant species occupying the substrata with different grain fractions and prop roots in different stations.

The main objectives of this study are the establishment of a detailed description of five semi-submerged and shallow-water marine caves from the Tarkhankut Peninsula (Crimea), their biological characteristics with particular attention to species composition, and the distribution of sponge assemblages in these caves. Three semi-submerged and two submerged caves with lengths of 9–131 m and volumes of 61–3060 m3 have been investigated. All of them are karst-abrasive or karst in origin. In the investigated caves, we inventoried seven sponge species. All were recorded species of Porifera belong to the class Demospongiae and have previously been recorded also in adjacent open sea waters. These species are tolerant to different hydrological conditions, mostly temperature and salinity. Some of them have wide geographic distribution. The species composition of sponges from the shallow water caves of Crimea is quite different from the sponge composition in Mediterranean caves. This could be due to the geographic isolation of the Black Sea and the differences in the hydro-chemical parameters of the milieu (water salinity in Tarkhankut is 18–21‰).

We examined the benthic macroinfauna at three strata during two seasons (winter and summer) on two sandy beaches (dissipative and reflective) in south-eastern Brazil. The hypothesis raised is that effects of morphodynamics and zonation determine the structure of macroinfauna, with dissipative beaches having comparatively higher species richness and density than the reflective beaches. Flamengo beach (dissipative) had higher species richness but lower density compared to Grumari beach (reflective). A high dissimilarity in assemblage structure (91.75%) was detected between the two beaches. Zonation in the occurrence of macroinfauna was detected for the two beaches in the two examined seasons. At Grumari beach, Emerita brasiliensis occurred mainly in stratum 1 (intertidal swept zone) while Saccocirus sp. occurred in stratum 2 (infralittoral at 0.5 m depth), whereas at Flamengo beach E. brasiliensis and Enoploides sp. had the highest density in stratum 1 (intertidal swept zone) whereas Scolelepis goodbodyi and Donax uncinata dominated in stratum 3 (infralittoral at 1.0 m depth). Scolelepis goodbodyi, Dispio uncinata, Enoploides sp., Nematoda and Trileptium sp. were associated with higher a Dean parameter and content of organic matter at Flamengo beach. In contrast, Hastula sp., Donax sp., Pisionidens indica, Hemipodus californiensis, Saccocirus sp. and Phyllodocidae were associated with the higher wave period and grain size of Grumari beach. The hypothesis that macroinfauna structure differs between the beaches and strata was confirmed, with the dissipative beaches having comparatively higher richness but lower density than the reflective beaches.

Larval survival during planktonic dispersal is crucial to the connectivity among benthic populations. Although predation has been suggested as an important cause of larval mortality, this process has rarely been quantified in the field. We measured the abundance of various larval species in the water column in St George’s Bay, Nova Scotia, Canada, on 3 different occasions in summer (August 2008, July and August 2009), the period of high larval abundance in our region. We sampled four numerically dominant predators (scyphozoans: Cyanea capillata and Aurelia aurita; fishes: Gasterosteus aculeatus and Merluccius bilinearis) and lobster larvae near the water surface with a neuston net and other larval species in the water column (3 m depth) with a ring net. Larvae found in the gut contents of the predators included various species of gastropods, crustaceans and bivalves, and these were more abundant in the scyphozoans than the fishes. We attribute these differences to variation in predation method. For certain larval taxa, we found significant differences between the proportional abundance in the guts of C. capillata and in the water column, indicating prey selectivity. This study evaluates the potential impact of predation on larval survival and indicates that the presence of predators can cause changes in abundance and consequent taxonomic shifts in species dominance of larvae, influencing their successful subsequent recruitment to the benthos.

We studied the effect of point-source and non-point-source pollution on the retention capacity of the stream and its link with the metabolic state (primary production and respiration) and invertebrates assemblages in a third order Mediterranean stream. Two experimental sites were chosen: one in the upper part of the catchment (Montégut site) characterized by low concentrations in nitrate and phosphate and one in the lower part of the catchment (Lézat site) characterized by high nitrate and phosphorus concentrations. Both experimental sites were located on reaches that included a Waste Water Treatment Plant (WWTP) point nutrient source allowing discussion of the relative effects of point-source and non-point-source nutrients loads on ecosystem function (respiration and uptake rates) and aquatic organism assemblages. NH4 +-N, and PO4 3 −-P uptake rates were determined using solute additions conducted at constant rates (short-term nutrient addition procedure) and NO3 −-N uptake rates were determined using instantaneous solute addition (slug addition procedure). Rates of gross primary production (GPP) and ecosystem respiration were determined using the open system, two-stations diurnal oxygen change method. Benthic invertebrate communities were investigated for species and functional feeding groups diversities measurements. Results show that autotrophy in the river results from nutrients of two distinct origins: point sources for phosphorus (urban area and WWTP) and non-point sources for nitrogen (agricultural zones) with local additions from WWTP inputs. Comparison between the two sites shows that the WWTP did not affect uptake rates, respiration or primary production of the ecosystem in the low-nutrient Montégut reach despite increase of invertebrates communities biomass density. Inputs from the WWTP, in the high nitrate and phosphate Lézat reach, increased respiration, lower benthic biomass and led to changes in the species composition and did not affect uptake rates.

Sterechinus antarcticus inhabits the shelf and the slope of the Weddell Sea and is the predominant echinoid between 450 and 1200 m. Growth lines visible in the half pyramids of the Aristotle's lantern were interpreted as annual growth marks. A Von Bertalanffy growth function was fitted to age-diameter data of 217 specimens (D∞ = 82.4 mm, K = 0.017 y−1, t0 = 1.633 y). Based on 92 trawl samples, a representative size-frequency distriution of S. antarcticus was established. From the growth curve, the size-frequency sample and diameter - weight regressions, mortality and somatic productivity of S. antarcticus were calculated by a size-converted catch curve and the weight specific growth rate method. Gonadal productivity was estimated by an average value for reproductive output of cold water echinoderms. Mortality rate Z as'well as somatic P/B ratio amounted to 0.07 y−1. Annual somatic production was estimated as 0.3 mg m−2y−1, and annual gonadal production as 0.25 mg m−2 y−1 between 100 and 1200 m (0.6 and 0.5 mg m−2 y−1 between 450 and 1200 m).

Data on the growth (20 species) and productivity (19 species) of Antarctic and subantarctic macrobenthos were compiled from published and unpublished sources. Differences in the production/biomass (P/B) ratio between Antarctic, Arctic and non-polar populations were examined using a set of 363 data arrays (327 non-polar, 26 Antarctic, 10 Arctic). Each array contained annual P/B ratio, mean individual body mass, geographical latitude, water depth, bottom water temperature and the nominal variables TAXON (Mollusca, Crustacea, Polychaeta, Echinodermata) and REGION (Antarctic, Arctic, non-polar). The P/B ratio was found to vary with body mass, taxon, temperature and water depth. P/B ratios of Antarctic and Arctic populations were significantly lower than those of non-polar populations. For Antarctic populations this difference could be explained completely by the effects of temperature and water depth. The strikingly high biomass of many Antarctic benthic communities is probably related to adaptations to low and oscillating food levels, and particularly to the low maintenance energy requirement associated with the low ambient temperature.

The geographical distribution and depth zonation of Eusirus perdentatus Chevreux, 1912 in the eastern Weddell Sea and adjacent Lazarev Sea (Antarctica) is described. A total of 963 individuals of this carnivorous predator caught during six successive cruises at 71 stations between 176 and 799 metres water depths were used. Individuals of E. perdentatus have been kept alive for nearly five months in the laboratory. During this period females released 53 juveniles in April. Oocytes and embryos of females have been counted and measured. The duration of embryonic development in E. perdentatus was estimated at c. 12 months, using an empirical relationship based on the mean diameter of 4390 fertilized eggs. There is strong evidence that this species is semelparous with hatching of juveniles at the end of austral summer. Two methods, herein termed as Year Class Model and Moult Class Model, have been applied in order to describe the growth of females by means of cumulative length-frequency data.

Depth distribution data were compared for 172 European and 157 Antarctic benthic invertebrate species occurring in the respective shelf areas. Antarctic species showed significantly wider depth ranges in selected families of the groups Bivalvia, Gastropoda, Amphipoda and Decapoda. No differences were found in Polychaeta, Asteroidea and Ophiuroidea, where European species also showed comparatively wide bathymetric ranges. These extended levels of eurybathy in the Antarctic benthos may be interpreted either as an evolutionary adaptation or pre-adaptation to the oscillation of shelf ice extension during the Antarctic glacial-interglacial cycle.

African clawed frogs (Xenopus laevis) in a South Wales pond ate a wide variety and size range of prey. Zoobenthos and zooplankton made the greatest contribution to diets, both numerically and by weight. Terrestrial invertebrates made up a small proportion of the diet numerically but a large proportion of the diet mass during the spring and summer. Nektonic prey were present throughout the year but made up a very small proportion of diet. Cannibalism was important when eggs and larvae were present in the pond. Electivity values were consistently positive for chironomids (larvae and pupae) and daphnids but were consistently negative for tubificids. In addition, electivity increased for larger sizes and pupae of Chironomus plumosus, but was low for the largest size class (> 12 mm). Electivity of other taxa showed an increase when densities of chironomids and daphnids were reduced. Mean sizes of daphnids and cyclopods were consistently larger in frog stomach contents than in the water column, indicating that predation on zooplankton by Xenopus laevis is size-selective.

Le réseau hydrographique de la rivière Arc s'étend dans une région fortement urbanisée et industrialisée où l'agriculture joue un rôle encore important. Ce travail présente un compte rendu global sur la situation chimique des eaux et sur les peuplements de la rivière, réalisé au cours d'un cycle annuel à partir d'analyses multivariées (18 paramètres physicochimiques, 17 stations d'étude : 9 sur le cours principal, 8 sur les affluents). Les situations hydrochimiques ainsi mises en évidence sont ordonnées selon un gradient d'eutrophie représenté par la première composante principale. Les éléments allogènes, qui jouent un rôle prépondérant dans le fonctionnement de cet hydrosystème, déterminent une eutrophication qui masque l'eutrophisation naturelle de la rivière. Seuls quelques affluents exempts de pollution sont encore proches de leur situation originelle.Les peuplements benthiques (151 taxons) du réseau hydrographique de l'Arc (15 points d'échantillonnage pris sur le cours d'eau axial et les affluents) ont été étudiés au moyen d'une analyse factorielle des correspondances. Les stations du cours supérieur se caractérisent par la présence d'espèces lénitophiles adaptées au régime temporaire des milieux aquatiques. Dans la majeure partie du cours principal, la forte pollution organique et chimique est favorable à la prolifération d'espèces saprobiontes. Les affluents, peu ou pas perturbés, hébergent un peuplement se rattachant globalement au biocénotype du rhithron et constituent un réservoir d'espèces susceptibles de recoloniser le cours axial de la rivière.

Des récoltes d'invertébrés benthiques ont été effectuées dans le Gave d'Ossau, rivière des Pyrénées-Atlantiques, et dans ses principaux tributaires, entre 450 et 2 150 m d'altitude. Après une présentation détaillée du milieu, un bilan des espèces les plus intéressantes est donné : 7 sont nouvelles pour la Science, 16 pour la France et 26 pour la zone 2 de la Limnofauna Europaea.La succession longitudinale des biocénoses et leur déterminisme sont ensuite analysés. Sur le Gave d'Ossau, on observe un remplacement progressif des espèces d'amont par des espèces d'aval plutôt qu'une succession de communautés nettement individualisées ; le schéma de zonation des cours d'eau proposé par Illies et Botosaneanu (1963) apparaît difficile à appliquer à ces rivières de montagne.