This study reports on the seasonal variations of the community structure of a coastal ecosystem, off the central coast of Brazil. Samples were collected on a monthly basis on board a bottom otter trawl vessel from October 2003 to September 2004. A total of 57 species belonging to 26 families and 10 orders were collected. Resident species, which presented a high proportion of juveniles throughout the year, were the most abundant. Among these, benthonic fish of the Sciaenidae family were the dominant species, followed by Tetraodontiformes, nektonic Sciaenidae and Clupeiformes. Benthonic fish were more abundant during the spring/summer months (October to February) and pelagic species dominated the autumn/winter months (May to September). However, these differences were not statistically significant. The spring/summer months were also characterized by reproduction activity, while the autumn/winter months saw high proportions of juveniles. Indicator species analyses showed that 5 species presented significant differences in their occurrence and abundance throughout the seasons of the year. This study shows that the coastal area is an important place for reproduction and a nursing ground of many species. It also shows evidence of community-level reproductive patterns for a tropical ecosystem. Future studies are necessary to identify the likely ecosystem forcings underlying these patterns.

Since 1971 the macro-benthic infauna at Station P, 18.5 km off the Northumberland coast (central western North Sea), have been sampled by grabbing each January/February. The data series now includes over 260 taxa from 173 genera. The most abundant taxa are Heteromastus, Levinsinia and Priospio which between them account for nearly 45% of the individuals recorded while the top 10 ranked taxa between them include almost 70% of the individuals recorded. Both total abundance and genera richness have varied through the 36 year series, particularly during the late 1980s–early 1990s but there was no trend and values in the 2000s are similar to those at the start of the series. However, MDS ordination of the entire genera abundance series shows a trend in composition of the macrobenthos through time. There is evidence that the changes in composition were driven by fishing impacts, but also influenced by the trend in climate warming and altered fluxes of phytoplankton to the benthos. Given that the dominant taxa have not changed and the total abundance and richness are similar this implies a turnover and redistribution of individuals across many taxa and raises the possibility of shifts in the ecological functioning of the system.

Benthic nematode and macrofaunal communities are regularly utilized in impact studies. However, very few studies are carried out utilizing both communities. A literature search using the search engine Scopus (www.Scopus.com) covering the last twenty years, using the keywords ‘Macrofauna’ and ‘Disturbance’ then ‘Meiofauna’ and ‘Disturbance’ and finally ‘Macrofauna and Meiofauna’ and ‘Disturbance’, gave 210, 115 and 36 hits respectively. To assess the differential response of meio- and macrofauna to in situ burial a replicated random block designed field experiment was carried out over a 9-month period on an intertidal mud flat. In situ burial was achieved by spreading 4 cm of anoxic mud on top of each treatment plot at two different intensities. Differences in the response of the two faunal communities over time were assessed using both univariate and multivariate techniques. Clear differences in community behaviour over time and in response to the different intensities of disturbance were observed. Overall macrofauna were found to be more sensitive to physical disturbance than meiofaunal nematodes, although, attributes of meiofaunal nematode communities were more sensitive to the initial impacts of disturbance. The observed community-specific responses and sensitivities of meiofauna and macrofauna to the physical disturbance associated with in situ burial highlights the importance of using both faunal types in the assessment of the effects of seabed disturbance in the marine environment.

Differences in the reef biota between the Point Labatt Marine Reserve and adjacent unprotected reference areas were examined following an 18-year period of protection from fishing. Quantitative measures of fish, invertebrates and algae were obtained by divers at 16 depth-stratified locations inside and outside the reserve, and the significance of differences examined using a combination of univariate (ANOVA) and multivariate (MDS) analyses. Strong depth-related differences in the composition and abundance of algae and invertebrates were observed, both inside and outside the reserve. These community differences were most pronounced in shallow near-shore waters (<10 m depth), and were largely due to variations in the abundance of a small group of species with widespread distributions. Spatial patterns in fish were not closely related to depth, and it appears that trophic linkages between fish and the underlying algal and invertebrate assemblages at Point Labatt are either weak or occur at spatial scales larger than that covered in this study. No significant reserve-related differences were detected in the abundance, diversity or community structures of algae, invertebrates and fish examined in this study. In many cases this is because the biological attributes measured were highly variable in space, and required more intensive sampling regimes to improve statistical precision. This study emphasizes the need for more robust survey designs and their timely implementation in marine conservation planning processes.

Sampling data on abiotic parameters and benthic communities in the northern lagoon of Tunis were obtained seasonally from November 1999 to November 2000. Abiotic parameters studied revealed evident improvement of water quality compared with previous. Indeed, management has re-established a tidal marine influence (Gulf of Tunis), induced a remarkable change in physico-chemical parameters and as a consequence, a regulation of the lagoon environmental quality. A total of 90 species of benthic macroinvertebrates, belonging to seven different taxa were collected in the northern lagoon of Tunis. A comparison of ecological indices indicate significant variations in the spatial and seasonal distribution and structure of the benthic community and reflect changes that might be related to open marine water and climatic influences as well as effects of discharge of the neighbouring city. Generally, the lagoon macrobenthic community appeared to be better structured, richer and more diverse than the one described before sanitation works began. However, significant disturbance of the benthic communities is detected in the south-eastern lagoon zone (C) and is dominated by disturbance indicator species. In contrast, the Station A2 which is sufficiently influenced by marine currents, is dominated by species of marine affinity and indicates an undisturbed zone. Multivariate analysis indicates heterogeneity in the benthic community structure between stations and suggests that the most significant variations of abundance occur in the groups: Anthozoa, Placophora, Cephalopoda, Ascidia and Echinodermata. The results of correspondence analysis also testify to a gradational distribution of benthic species in relation to hydrological and edaphic (organic matter) factors.

Distribution and structure of intertidal macrobenthic communities in the Zwin nature reserve, a lagoonal inlet consisting of marsh and tidal flat habitats, was investigated using univariate and multivariate analyses. Macrobenthos community structure was related to environmental characteristics and discussed in the framework of the implemented extension of the nature reserve.

Based on explorative multivariate techniques, five different sample groups (SGs) were distinguished, which were, in general, located in different habitats of the Zwin nature reserve. The ecologically most important SGs consisted of the highest macrobenthic density, diversity and highest densities of Nereis diversicolor and Scrobicularia plana; these important prey species for wading birds and fish occurred in the deep tidal inlet channels. This habitat was characterized by fine to medium sand sediment and strong tidal currents, guaranteeing water renewal at each high tide. Other SGs were found in less and erratically submersed and thus stressed areas (i.e. tidal pond, salt pans and shallow flats). These assemblages were characterized by typical r-strategists (i.e. Capitella capitata and Polydora cornuta) and typical supralittoral, mobile species (i.e. Orchestia gammarellus and Collembola spp.). Being ecologically most important, the extension of wide, tidal creeks should be a prime target within the future development and management of the nature reserve.

The Aleutian margin is a dynamic environment underlying a productive coastal ocean and subject to frequent tectonic disturbance. In July 2004, we used over 500 individual bottom images from towed camera transects to investigate patterns of epibenthic megafaunal density and community composition on the contiguous Aleutian margin (53°N 163°W) at depths of 2000 m, 3200 m and 4200 m. We also examined the influence of vertical isolation on the megafaunal assemblage across a topographic rise at 3200 m, located 30 km from the main margin and elevated 800 m above the surrounding seafloor. In comparison to previous reports from bathyal and abyssal depths, megafaunal densities along the Aleutian margin were remarkably high, averaging 5.38±0.43 (mean±1 standard error), 0.32±0.02 to 0.43±0.03 and 0.27±0.01 individuals m−2 at 2000 m, 3200 m and 4200 m, respectively. Diversity at 2000 m was elevated by 15–30% over the deeper sites (3200–4200 m) depending on the metric, while evenness was depressed by ~10%. Levels of richness and evenness were similar among the three deeper sites. Echinoderms were the most abundant phylum at each depth; ophiuroids accounted for 89% of individuals in photographs at 2000 m, echinoids were dominant at 3200 m (39%), and holothurians dominated at 4200 m (47%). We observed a 26% reduction in megafaunal density across the summit of the topographic rise relative to that documented on the continental slope at the same depth. However, the two communities at 3200 m were very similar in composition. Together, these data support the modified ‘archibenthal zone of transition’ framework for slope community patterns with distinct communities along the middle and lower slope (the upper slope was not evaluated here). This study fills a geographical gap by providing baseline information for a relatively pristine, high-latitude, deep-sea benthic ecosystem. As pressures grow for drilling, fishing and mining on high-latitude margins, such data can serve as a reference point for much-needed studies on the ecology, long-term dynamics, and anthropogenically induced change of these habitats.

Population dynamics of the planktonic diatom Pseudo-nitzschia pungens was investigated at the Zhelin Bay, China, between May 2000 and December 2004. Monthly or seasonal plankton samples were collected from nine stations along the inner to outer bay gradient. Among the 1045 samples collected, P. pungens on average accounted for 2.9% of the total phytoplankton cells, with densities ranging from 0 to 50.94 × 104 cells l−1 and a grand mean of 1.43 × 104 cells l−1. Two hundred and fourteen samples (20.5%) had densities of P. pungens above 104 cells l−1 and 40 samples (3.8%) had densities that were above 105 cells l−1. Results of the grey incidence–regression analysis show that water temperature, zooplankton and salinity were the most important among the 13 environmental factors influencing population density of P. pungens. Water temperature has a highly significant linear relationship with the population density, with 23.8°C or higher being an essential condition for the algal bloom. Grazing by zooplankton was probably the most important factor controlling the algal bloom. With continued decreasing of richness and organism size of the zooplankton community at the Zhelin Bay, P. pungens blooms may become more frequent. The bay has a large-scale mariculture operation, therefore it is important to carefully examine and monitor the potential impacts of toxin-producing P. pungens on human health as well as ecosystem health of the bay.

The spatial variation in abundance and composition of subtidal meiobenthos communities was studied in two Portuguese estuaries under distinct degrees of anthropogenic pressure. Samples were collected from 20 sampling stations along both estuarine gradients from freshwater (<0.5) to euhaline areas (>30). Of these stations 11 were located in the Mondego estuary, a system exposed to high anthropogenic stress, and 9 in the Mira estuary, a naturally stressed system located inside the Natural Park ‘Costa Vicentina’ (south-western coast of Portugal).

Total meiobenthos density was higher in the Mira estuary and in both estuaries the community was dominated by nematodes. Among the twelve taxa identified in the Mira estuary, Harpacticoid copepods and Polychaeta were the second and the third most abundant groups respectively. In the Mondego estuary, Polychaeta was the second while Harpacticoid copepods was the third most abundant group in the thirteen total taxa recorded.

Estuarine gradients of salinity, particles size and water nutrients were clearly detected in both estuaries and there was significant spatial heterogeneity in abundance and composition of the subtidal meiobenthos communities along these environmental gradients. Accordingly, three distinct sections were identified in both estuaries: (i) freshwater sections, where total density, and density of nematodes and Harpacticoid copepods reached minimum values; (ii) oligohaline and mesohaline sections, where the total density was low and diversity was poor; and (iii) polyhaline and euhaline sections, where both total density and diversity reached the highest values.

The similar spatial distribution of meiobenthos assemblages in both estuaries suggests that natural stressors may be the major factors controlling the physicochemical conditions that determine meiobenthos community patterns. The mesoscale variability of subtidal meiobenthos density and composition within estuaries (in the order of kilometres) seems to be more important than the variability between estuaries (at the scale of hundreds of kilometres), a common feature in intertidal systems. From the management point of view, these results, based on higher taxa resolution, represent an obvious constraint to the applicability of ecological quality evaluation tools.

Stomach contents were analysed from 23 cetaceans, including individuals of 12 species from the families Delphinidae, Physeteridae, Kogiidae and Ziphiidae, stranded between 1996 and 2006 in the Canary Islands. Cephalopod mandibles (beaks) were found in 21 stomachs and fish remains (otoliths and jaw bones) appeared in 4 stomachs. Two stomachs contained only eye lenses. Cephalopods eaten by dolphins were mainly from the families Ommastrephidae, Sepiidae and Enoploteuthidae, whereas whales had mainly taken specimens of the oceanic squid families Histiotheutidae and Cranchiidae. Fish remains included a pelagic species (i.e. garfish, Belone belone) in dolphin stomachs and bathypelagic (i.e. black scabbard fish, Aphanopus carbo, lantern fish, Lampadena luminosa) and demersal species (Lophius sp.) in a pygmy sperm whale (Kogia breviceps) stomach. Most of the prey species identified are not of commercial interest but one of the sperm whales (Physeter macrocephalus) contained a fishing hook among the stomach contents. Five (22%) of the cetaceans examined had also plastic debris in their stomachs, with big plastic items being taken by deep diving teuthophagous whales.

The present study aims to evaluate the vertical distribution of intertidal benthic organisms in different periods of the year, relating them to tide, air temperature, height and wave periodicity in breakwaters off the northern Rio de Janeiro State, and to compare the zonation at two sites (Pier and Barra) with distinct hydrodynamics, due to different wave swell. Quadrats of 400 cm2 were sampled by a photoquadrat method. The upper limit of the marine organisms was higher at the Barra site (intertidal zone of 3.8 m) than at the Pier site (intertidal zone of 2.2 m). The littoral fringe assemblage did not show significant differences between sites, but a larger range of this fringe and the upper eulittoral band at Barra was quite evident. This site was mostly characterized by species of more exposed areas such as Chaetomorpha sp. and Perna perna in the upper and lower eulittoral bands, and by C. teedii and Ulva fasciata in the sublittoral fringe. A seasonal difference was identified in the air exposure degree at the Pier site, which was higher in October 2005 and February 2006. The air temperature and wave height and periodicity differed significantly among the four studied periods. The typical seasonal species were F. clenchi (July 2005 and October 2005), Gigartina domingensis (July 2005), Grateloupia sp. (October 2005) and Porphyra acanthophora (October 2005 and February 2006). The intermediate benthic band of the intertidal zone occupied a narrow zone, changing its spatial location according to the season of the year. The hypothesis of annual variation of the benthic community zonation according to the seasonal variability of tides, air temperatures and wave's height and periodicity was accepted for the intermediate band of the intertidal zone, due to the taxonomic differences and the abundance of dominant species in the four seasons. The difference in the vertical distribution of the intertidal benthic assemblages of both breakwaters highlights a distinct wave exposure condition, and reflects the breakwaters' orientation and the wave swell at each site.

The composition and structure of a molluscan assemblage was studied in a deep subtidal eelgrass bed located in southern Spain before and after the eelgrass decline experienced during 2005 and 2006 due to illegal trawling by fishermen. Sampling was undertaken in summer 2004 (with eelgrass) and summer 2007 (without eelgrass) in an extensive eelgrass bed located in Cañuelo Bay (12–14 m depth) and in the same area once the eelgrass bed disappeared. Eelgrass was completely absent in those samples of summer 2007 and an increase of the organic content and mud was registered in the sediment between 2004 and 2007. The density and the richness of molluscan species decreased significantly in summer 2007, especially for epifaunal gastropods associated with the leaf and sediment stratum. Some species disappeared completely in summer 2007 such as the dominant periphyton grazers Jujubinus striatus and Rissoa spp., the egg feeder Mitrella minor and the seagrass feeder Smaragdia viridis as well as the infaunal bivalve Solemya togata. Other species increased their densities such as the carnivores Cylichna crossei or C. cylindracea as well as the bivalve Nucula nitidosa. Some dominant infaunal species, such as Chamelea gallina, Spisula subtruncata or Tellina fabula did not significantly change their densities. The composition and structure of the assemblages in summer 2004 and summer 2007 was significantly different according to the Bray–Curtis similarity index using qualitative and quantitative data and considering the entire assemblage (epifaunal and infaunal species) or only the infaunal species. The registered changes in the molluscan assemblage may have produced cascade effects in higher trophic levels because molluscs generally represent an important food source for some decapods and fish. Urgent conservation measures are needed for protecting the remaining fragmented eelgrass beds of southern Spain from further illegal fisheries activities and other types of human impacts (e.g. sand extraction and coastal infrastructures), because they support the most diverse faunistic communities for eelgrass beds in Europe due to their bathymetry and geographical location.

The trophic composition of macrobenthic communities in intertidal and subtidal soft-bottoms of the Ensenada de San Simón (north-western Spain) was found to be related to a number of environmental variables. Distribution and abundance of trophic groups have been studied, to provide essential baseline information for monitoring the area, after its designation as a Natura 2000 Special Conservation Zone. Analyses of trophic data showed a numerical predominance of the herbivores in the inner part of the inlet, while sites at the oceanic-influenced area were numerically dominated by surface-deposit feeders. These dominances were mainly due to Hydrobia ulvae in the intertidal area and to polychaetes at the subtidal one. Both univariate and multivariate statistical analyses showed that the sediment composition (organic matter and silt–clay contents) and temperature of the bottom water influenced the benthic macrofauna and were correlated with their trophic composition, abundance and distribution.

The assemblage and the temporal changes of benthic macrofauna inhabiting the Phyllochaetopterus socialis (Polychaeta: Chaetopteridae) aggregates were analysed during 2004 and May 2005 in the Mar del Plata harbour, Buenos Aires (Argentina). Species composition, abundance, richness and diversity were estimated from monthly or bimonthly samples obtained by SCUBA diving. Multivariate (MDS) and SIMPER analyses were applied to analyse the structure of benthic communities. In the mats, a total of 57 species (invertebrates and chordates) belonging to 11 phyla were associated to P. socialis: crustaceans and molluscs were the most abundant species and crustaceans and polychaetes were the most diverse groups (14 and 11 species richness, respectively). The mean abundance ranged from 79.67±57.47 ind/250 ml to 718.75 ind/250 ml (mean±SD). The amphipod Monocorophium insidiosum, the gastropod Anachis isabellei and the tanaidacean Leptognathia sp. were the most representative species in the mats. Richness and diversity in P. socialis aggregates were higher than in surrounding sediments. Results show significant differences among months in composition, abundance and feeding guilds of the macrofauna associated with the mats. The assemblage of benthic macrofauna with permanent and temporary organisms in P. socialis aggregates suggests the existence of microhabitats in the mats that provide substrate, refuges for predation and availability of food increasing richness and diversity. These results allow considering P. socialis as an autogenic ecosystem engineer in the Mar del Plata harbour.

Sampling was carried out in the Celtic Sea in May 1987 over Great Sole and Cockburn Banks, and in June 1991 over Little Sole Bank, to study relationships between bank topography, hydrography and plankton distribution.

Over Great Sole and Cockburn Banks, there were various patterns in the hydrography and plankton which could be related to the banks, although there were no significant correlations with water depth. Away from the shelf-edge, stratification was lower over the banks. Higher water temperatures (at 5 m and 100 m depth) and increased concentrations of copepod nauplii and adults occurred on either side of Cockburn Bank. Abundance of mackerel (Scomber scombrus) eggs and larvae increased towards the shelf-edge, with lower numbers over Cockburn Bank.

Over Little Sole Bank, water column stratification was negatively correlated with water depth. However, this was strongly influenced by shelf-edge mixing, which was reflected in reduced stratification towards the shelf-edge. Background levels of chlorophyll-a also increased from on-shelf towards the shelf-edge. Copepod adults and nauplii, as well as mackerel eggs and larvae were more abundant with distance onto the shelf.

There was partial retention of four Argos tracked drift buoys on the south-east flank of Little Sole Bank. The mean displacement rate of the buoys was 1.35 km day−1 over 10 days, with a mean dispersion of 1.2 km day−1. A simple one-dimensional coupled physical–biological model showed the potential influence of banks resulting in earlier stratification and resultant spring bloom. Considerations of the delay in transfer of production from primary to secondary production and the effects of drift and diffusion, suggested it was unlikely that any influence of the banks on production would be directly related to bank topography, but there might be some regional enhancement of production.

Wet biomass of principal plankton components and whole plankton standing stock were assessed in waters of the Heron Island ring reef and surrounding deep lagoon. Biomass of phytoplankton ranged between 30 to 120 mg m−3, without its pronounced depletion over the reef shallows. Picocyanobacteria and prochlorophyte algae contributed over 70% of this biomass. Biomass of bacterioplankton varied between 75 to 340 mg m−3, with its maximum over the reef flat. Biomass of planktonic protozoa's ciliates and zooflagellates ranged between 20 to 110 mg m−3. The daytime biomass of zooplankton varied between 490 to 1590 mg m−3 in the deep lagoon in the zone of intense tidal currents. Over the reef shallows, it was 10–20 mg m−3. At night, it rose there up to 800 to 4000 mg m−3 as the result of emerging demersal zooplankton from the benthic substrates. The time scale of nocturnal emerging by different taxa was also documented. Biomass of whole demersal zooplankton communities hiding by the daytime in bottom substrates at the reef flat was found to be over 100 g m−2. Problems of nutrition planktivore reef fauna related to the plankton production and abundance are discussed.

This study evaluates the influence of man-made activities on the benthic environment at two different marinas: Southsea Marina on the south coast of England, and Minimes Marina on the Atlantic coast of France. We assessed the differences in: (1) sediment percentage organic matter, particle size and heavy metal concentration, using copper (Cu), cadmium (Cd), zinc (Zn) and lead (Pb) as contamination indicators; (2) sediment elutriate toxicity (LC50) using algal (Fucus serratus) bioassay; and (3) benthic community characteristics (number of species, abundance, most contributing species (SIMPER) and biotic index (AMBI)). Canonical correspondence analysis (CCA) was performed to relate the abundance of species to the environmental variables. At both marinas, we observed an increasing gradient of contamination from outside to the innermost sites. At both marinas, the lowest macrofaunal abundance was recorded at the innermost sites and differences in benthic community structure were observed between sites. At Southsea Marina, the cirratulids Tharyx marioni and T. killariensis and the cossurid Cossura pygodactylata dominated sites outside, while the opportunistic species Capitellides girardi dominated the innermost sites. At Minimes Marina, the cirratulid Streblospio shrubsolii was abundant outside and at the middle sites but was almost absent at the innermost sites. The biotic index—AMBI—indicated that sediments in the innermost sites were heavily disturbed at Southsea Marina and slightly to moderately disturbed at Minimes Marina. In Southsea, the AMBI was positively correlated to the sediment metal concentrations (Cu, Zn and Cd) and elutriate toxicity (LC50), while in Minimes the AMBI was positively correlated to the % of sediment fine particle and elutriate toxicity (LC50).

In order to provide a better characterization and understanding of the brine shrimp Artemia salina life-cycle, different ecological and biological parameters were taken out monthly during two periods from November 2005 to April 2006 and from November 2006 to April 2007 in Sabkhet El Adhibet (south-east Tunisia). Variation of water temperature, salinity, pH, dissolved oxygen, nutrients (orthophosphate, nitrites, nitrates and ammonium) and phytoplankton density were monitored. The Artemia population was also surveyed. Artemia were present in the site with salinity between 32.2 and 281.7 g l−1 and water temperature between 12.1 and 25.4°C. The pH ranged from 7.6 to 9 and dissolved oxygen concentration from 3.4 to 17.5 mg l−1. Minimum and maximum values of phytoplankton density were 0.19 and 14.59 106 cell l−1. In addition, the nutrient analysis registered showed that nitrate and ammonium represent the major nutrient. The Artemia population density fluctuated between 0.22 and 38.57 individuals per litre. The male:female ratio was dominated by the males. Artemia from Sabkhet El Adhibet showed variability in fecundity (total offspring and brood size) as well as in the ratio encystment/oviviparity. The individual fecundity fluctuates between 29.4 and 70.2 cysts and 17.8 and 69.8 nauplii. Finally, the influence of physical and chemical parameters as well as phytoplankton density over the Artemia population was noticed.

During satellite tagging of harbour porpoises (Phocoena phocoena), heart rate, respiration rate and cortisol value were measured to evaluate stress effects during handling and tagging. Respiration rates were obtained using video recordings, heart rates were recorded and serum cortisol levels were analysed from blood samples. Differences in heart rates, respiration rates and cortisol levels before and during the tagging events were investigated. An overall significant decrease of 31.5% in respiration rate was found during the tagging event period, while mature porpoises respired significantly more often than immature individuals. Though significant differences in heart rates were found for some individuals, no general significant change for all animals was detected. We found no correlation between cortisol concentration and either heart rate or respiration rate, nor did we find any relationships between cortisol and month of year, sex and body length. As high individual variations occurred in response to tagging of harbour porpoises, it is not possible to give general advice based on the factors investigated, on how to reduce stress during handling. However, pouring water over the animal and lowering it into the water seem to stabilize a stressed animal. Therefore, general precaution and individual judgement based on experience is essential when handling wild harbour porpoises.