On the continental shelf of the Antarctic the major disturbance to benthic ecosystems is from iceberg scouring; however, this is based on observations from the Peninsula region. We combine observation and experimentation in the McMurdo Sound region of the Ross Sea to determine if community recovery patterns there are similar to those in better-studied Antarctic regions, and if local immigration is an important factor in recovery dynamics. We found that regardless of habitat differences in depth, substrate, and oceanographic setting, iceberg disturbance strongly impacted benthic communities in McMurdo Sound. Notably, in shallow water (<30 m) where anchor ice is an annual disturbance, both the benthic communities and recovery processes were more variable than at deeper locations. A manipulative experiment performed in a shallow area indicated that recruitment might be more important than immigration to infaunal community recovery. We conclude that whilst disturbance frequency influences dominant epifauna, recovery from iceberg disturbance is a slow ecological progression that is dependent on the extremely inconsistent recruitment processes of the high Antarctic benthic ecosystem.

Edwardsiidae is one of the most speciose families within order Actiniaria with ~75 valid species of burrowing sea anemones. Five edwardsiids have been recorded in South Atlantic waters with only two species known for Brazil: Nematostella vectensis and Edwardsia migottoi. Such low diversity is probably the result of a historical small number of specialists in the region combined with difficulties in collecting and identifying these small burrowing animals. Although edwardsiids have been reported from Brazil since at least the 1960s, these reports did not include proper descriptions or specific identification, making comparison to other valid species impossible. Here we describe a new genus, Isoscolanthus gen. nov., and two new species: Isoscolanthus iemanjae sp. nov., Isoscolanthus janainae sp. nov. and we also describe Scolanthus crypticus sp. nov., the first species of the genus for Brazil. Isoscolanthus gen. nov. is easily distinguished from other edwardsiid genera by a combination of external (i.e. presence of periderm and nemathybomes in proximal end and 12 tentacles), microanatomical (i.e. four microcnemes) and cnidom features (i.e. pterotrichs in nemathybomes). In addition to the description of the new genus and species, we expand the range distribution of Nematostella vectensis and Edwardsia migottoi in the South-western Atlantic. The number of edwardsiids known from Brazil is raised from two to five species, substantially increasing the diversity of soft-bottom sea anemones for South Atlantic waters.

Brazilian mangroves have ecological and economic importance, with molluscs, crustaceans and polychaetes being diverse and common faunal groups. The present study characterizes the macrofauna associated with logs from two mangrove forests in Pará State, northern Brazil, sampled in September, January and April, between 2008 and 2010, at three different distances from a tidal channel (2, 10, 20 m). In each forest, five logs (diameter/length: 10/40 cm) were randomly selected at each distance, totalling 15 logs per sampling date. The macrofauna was removed, counted and identified. Three-way analysis of variance was used to compare mean numbers of individuals, numbers of taxa and Berger–Parker dominance per log, between forests and among sampling dates and distances from the tidal channel. Non-metric multidimensional scaling and permutational multivariate analyses of variance were used to investigate macrofaunal structure in relation to the three factors. A total of 5437 individuals from both estuarine and terrestrial faunas was found in both forests, with 85 taxa distributed among Mollusca, Annelida, Arthropoda and Nemertea. Abundance increased from September through January to April in both mangrove forests. The most dominant species was Neoteredo reynei, representing 48% of total abundance. No significant difference in any variable was found among the two forests and between the three distances. Logs may represent a stable microhabitat for the macrofauna, with little variation in humidity, salinity or temperature, despite different distances from the tidal channel. However, macrofaunal structure varied significantly between forests and among sampling dates, probably due to seasonal differences in precipitation and salinity between both locations.

Meiofauna, macro-infauna and epifauna were sampled at two offshore sandbanks in the southern North Sea in 2006. The epifaunal and infaunal communities in the dynamic environment of the sandbank crests were species poor, with lesser weever, solenette, Crangon crangon, amphipods and deposit-feeding polychaetes the predominant benthic taxa. Abundant early life-history stages (24–39 mm) of the lesser weever Echiichthys vipera on the sandbank crests indicated that these habitats may be important nursery grounds for this species. Species diversity of infauna and epifauna was greater in the deeper waters parallel to the sandbanks. Contrasting patterns were evident for meiofaunal nematodes, where communities collected on the sandbank crests were more diverse than those recorded in the deeper off-bank sites. The fauna of sandbank crests is composed of a restricted range of the fauna typically associated with sandy habitats, particularly taxa adapted to live in this dynamic environment.

Ecological information on the polychaete community may improve habitat descriptions and distribution models of commercially important species that are polychaete-feeders. This study reports on the first new observations in nearly three decades on the polychaete assemblages in the south-eastern Bering Sea. This information was used in an exploratory assessment of the association between polychaete assemblages and environmental variables that define the benthic habitat. The spatial association between polychaete assemblages and groundfish predators was also explored for insight into whether prey assemblages influence predator distribution. Canonical correspondence analysis indicates that surficial sediment is the most important factor in organizing polychaete assemblages, over other common environmental variables such as depth and temperature. Co-correspondence analysis of the distributions of groundfish species and polychaete families does not indicate that predators are associated with specific prey families. Families that are most frequent in stomach contents of some of the fish in the analysis, mainly Maldanidae and Nephtyidae, are widely distributed across the Bering Sea shelf in diverse sediment types, as are the principal polychaete-feeders in the eastern Bering Sea such as Alaska plaice (Pleuronectes quadrituberculatus) and northern rock sole (Lepidopsetta polyxystra).

Beds of Modiolus modiolus, in areas of moderate to strong tidal currents, develop into reefs with a relief of wave like undulations 0.09–0.45 m in amplitude and length scales of 6–18 m. Cores taken by diver operated suction sampler were targeted at positions on the ridges and troughs of a reef, in the Irish Sea off north-west Wales, allowing the fauna to be compared between adjoining ridges and troughs. Sessile epifauna was mostly attached to the larger mussels clumped together on the ridges. The crevice fauna and infauna were also nearly three times more abundant on the ridges, but the lists of species were similar from the two sub-habitats. Species richness was higher on the ridges, however, diversity and evenness measures were similar for ridges and trough samples. The Modiolus sub-habitats were found to be distinct from other macrofaunal assemblages in the wider southern Irish Sea. Deposition of faecal pellets in the spatially complex habitat amongst the mussels provided conditions suitable for an infauna more typical of inshore muddy sands enriched by organic matter. The scale of the ridge and trough morphology may increase variability between replicates when grabs are used remotely to sample this type of biogenic feature.