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The aim of the present study was to propose a biotic index (North Adriatic Mesophotic BiogEnic Reefs, NAMBER) suitable for assessing the ecological quality of the mesophotic biogenic reefs of the northern Adriatic continental shelf based on photographic sampling.At each of the 20 study sites, the degree of bioconstruction (expressed as percentage cover of crustose coralline algae), the α‐diversity (expressed as the mean number of taxa), and the degree of sensitivity to human disturbance and climate change (based on literature data and expert judgement) of the benthic assemblages were selected as descriptors and combined in the NAMBER index, using the best values that the three metrics can currently achieve in the studied region as a reference.The study highlighted that there was large spatial heterogeneity among reefs and high variability in the ecological quality values obtained by NAMBER, ranging from bad to high. The index indicates that reefs lying furthest from the coast, under substantially lower anthropogenic pressure, have a generally higher status of environmental quality. However, a clear geographical pattern did not emerge, as reefs close together often had different ecological qualities.The NAMBER index, which combines three ecological descriptors, in accordance with the requirements of the European Marine Strategy Framework Directive, represents a specific adaptation to the northern Adriatic Sea of a multimetric index previously developed for the north‐western Mediterranean Sea, capitalizing on previous knowledge and research efforts.This multimetric biotic index provides an effective standardized tool for monitoring programmes and environmental impact assessments in the northern Adriatic mesophotic biogenic reefs and lays the foundation for ecosystem‐based management and conservation in this basin. [ABSTRACT FROM AUTHOR]

The coral reef system Jardines de la Reina ( JR) includes one of the most remarkable Marine Protected Areas in the Caribbean due to its extension and high level of conservation. However, the diversity of small invertebrates (organisms with body size less than 0.5 mm) in JR is unknown. For this reason, we propose to make the first taxonomic checklist of free-living marine nematodes associated with coralline bottoms in JR. During the Alucia expedition in 2017, we studied six sites in the reef terrace (5m–10 m depth), distributed in the west, center and east of the JR archipelago. We identified 1 546 nematodes belonging to 70 species, 20 families, and six orders. The best represented orders were Chromadorida (20 genera), Desmodorida (18 genera) and Enoplida (13 genera). The most abundant species were Croconema cinctum, Euchromadora vulgaris, Desmodora communis, Chroma- dora brevipapillata, and Dichromadora amphidiscoides. Ten species were new records for Cuba Chromadorina epidemos, Desmoscolex campbelli, Draconema ophicephalum, Meta- desmodora amphidiscata, Oncholaimus sp., Paracyatholaimus intermedius, Perepsilonema ritae, Praeacanthonchus sp, Prochromadorella mediterranea and Zalonema vicentei. Received: 21-04-2022 Accepted: 09.08.2022 Editor: Yander L. Diez

The coral reef system Jardines de la Reina (JR) includes one of the most remarkable Marine Protected Areas in the Caribbean due to its extension and high level of conservation. However, the diversity of small invertebrates (organisms with body size less than 0.5 mm) in JR is unknown. For this reason, we propose to make the first taxonomic checklist of free-living marine nematodes associated with coralline bottoms in JR. During the Alucia expedition in 2017, we studied six sites in the reef terrace (5m--10 m depth), distributed in the west, center and east of the JR archipelago. We identified 1 546 nematodes belonging to 70 species, 20 families, and six orders. The best represented orders were Chromadorida (20 genera), Desmodorida (18 genera) and Enoplida (13 genera). The most abundant species were Croconema cinctum, Euchromadora vulgaris, Desmodora communis, Chromadora brevipapillata, and Dichromadora amphidiscoides. Ten species were new records for Cuba Chromadorina epidemos, Desmoscolex campbelli, Draconema ophicephalum, Metadesmodora amphidiscata, Oncholaimus sp., Paracyatholaimus intermedius, Perepsilonema ritae, Praeacanthonchus sp, Prochromadorella mediterranea and Zalonema vicentei. [ABSTRACT FROM AUTHOR]

This paper proposes the most simplified, concise and reliable method for preparing sediment distribution maps using conditional strings in the Arc GIS 10.X series. This methodology is an updated version of USGS Arc Map Sediment Classification since the latter is a customized toolbar in Arc GIS 9.X. The geostatistical method is used for generating rasters of sediment classes from the sampling points, and then pasting the conditional strings from the 'SedType' freeware in the raster calculator of Arc GIS produces a quantitative sediment distribution map. This study explicates about the advantage and efficacy of the conditional string methodology over the conventional 'discrete number methodology' while using the ground truth values for preparing the sediment distribution map. The study also discusses about the thematic representation of seabed having a hard bottom along with sediments, which was a new attempt made by the authors. Further, the present work also illustrates that the user has to consider any barriers, caused by geomorphology or by human interventions in the study area, while preparing the sediment distribution map using the conditional string methodology. Moreover, the spatial representation of two ternary classification diagrams, pertaining to gravel, sand and mud (GSM) and sand, silt and clay (SSC) along with the hard bottom, is also discussed here. Since this updated methodology uses only sediment class data, the sediment distribution map thus generated is more useful to geologists, and further this aids in first generation mapping. [ABSTRACT FROM AUTHOR]

In marine systems, behaviorally-mediated indirect interactions between prey, mesopredators, and higher trophic-level, large predators are less commonly investigated than other ecologic interactions, likely because of inherent difficulties associated with making observations. Underwater videos (n = 216) from SharkCam, a camera installation sited beneath Frying Pan Tower, a decommissioned light house and platform, on a natural, hard bottom site approximately 50 km off Cape Fear, North Carolina, were used to investigate association behavior of round scad Decapterus punctatus around sand tiger sharks Carcharias taurus. Videos containing sand tiger sharks were analyzed for the simultaneous presence of round scad, and six species of scad mesopredators, with scad-shark interactions assigned to one of three categories of association: no visible interaction, loosely associated, or tightly associated. The likelihood of scad being loosely or tightly associated with sharks was significantly higher in the presence of scad mesopredators, suggesting that sharks provide a predation refuge for scad. This behaviorally-mediated indirect interaction has important implications for trophic energy transfer and mesopredator control on hard bottoms, as scad are one of the most abundant planktivorous fish on hard bottoms in the western Atlantic Ocean. Although we were not able to provide statistical evidence that sand tiger sharks also benefit from this association behavior, we have clear video evidence that round scad association conceals and attracts mesopredators, enhancing predation opportunities for sand tiger sharks. These interactions potentially yield additional trophic consequences to this unique association and highlight the value of exploring behaviorally-mediated interactions in marine communities.

In marine systems, behaviorally-mediated indirect interactions between prey, mesopredators, and higher trophic-level, large predators are less commonly investigated than other ecologic interactions, likely because of inherent difficulties associated with making observations. Underwater videos (n D 216) from SharkCam, a camera installation sited beneath Frying Pan Tower, a decommissioned light house and platform, on a natural, hard bottom site approximately 50 km off Cape Fear, North Carolina, were used to investigate association behavior of round scad Decapterus punctatus around sand tiger sharks Carcharias taurus. Videos containing sand tiger sharks were analyzed for the simultaneous presence of round scad, and six species of scad mesopredators, with scad-shark interactions assigned to one of three categories of association: no visible interaction, loosely associated, or tightly associated. The likelihood of scad being loosely or tightly associated with sharks was significantly higher in the presence of scad mesopredators, suggesting that sharks provide a predation refuge for scad. This behaviorally-mediated indirect interaction has important implications for trophic energy transfer and mesopredator control on hard bottoms, as scad are one of the most abundant planktivorous fish on hard bottoms in the western Atlantic Ocean. Although we were not able to provide statistical evidence that sand tiger sharks also benefit from this association behavior, we have clear video evidence that round scad association conceals and attracts mesopredators, enhancing predation opportunities for sand tiger sharks. These interactions potentially yield additional trophic consequences to this unique association and highlight the value of exploring behaviorally-mediated interactions in marine communities. [ABSTRACT FROM AUTHOR]

Growing salmon in sea cages results in the deposition of uneaten feed and wastes which can smother organisms, increase biological oxygen demand, and alter seafloor communities. At some sites with mainly hard-bottom substrates, opportunistic annelids and mat-forming bacteria are used as visual indicators of aquaculture waste and are monitored via drop camera imaging. Additionally, high organic matter sedimentation rates can result in the proliferation of microbes that release gas; this offgassing could also serve as a useful visual enrichment indicator. Little is known of how the distribution of opportunistic annelids, microbial mats, and offgassing might change over time and space, although coverage has important repercussions in some regulatory schemes. Here, we explore spatiotemporal distributions of offgassing, bacterial mats, annelids, and epibenthic taxon richness based on existing video-monitoring data collected along transects at four Newfoundland aquaculture sites in 2011–2012. A high degree of spatial and temporal patchiness was observed at both fallow and production sites, and combinations of time, transect, and distance to cage explained the distribution of bacterial mats, annelids, and taxon richness. Expected successional patterns resulting from organic enrichment or remediation were evident in some patches. Offgassing was observed only at fallow sites and may signal a distinct and persistent phase in organic matter degradation. Results highlight the spatial heterogeneity of benthic organic enrichment indicators across transects at Newfoundland aquaculture sites, with indicators appearing to form a mosaic of patches undergoing different stages of enrichment or recovery. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the structure of molluscan communities in shallow subtidal rocky bottoms of Acapulco, Mexico. Thirteen samplings were performed at 8 stations in 2012 (seven samplings), 2014 (four), and 2015 (two). The collection of the mollusks in each station was done at a maximum depth of 5 m for 1 h by 3 divers. A total of 2086 specimens belonging to 89 species, 36 families, and 3 classes of mollusks were identified. Gastropoda was the most diverse and abundant group. Calyptreaidae, Columbellidae, and Muricidae had >5 species, but Pisaniidae, Conidae, Fasciolariidae, and Muricidae had =15% of relative abundance. Most species found in this study were recorded in the rocky intertidal zone, and 10 species were restricted to the rocky subtidal zone. The affinity in the composition of the species during 2012-2015 had a low similarity (25%), but we could differentiate natural and anthropogenic effects according to malacological composition. In addition, 46% of the species recorded in this study are commercial fishing resources. We concluded that the rocky subtidal malacological fauna of Acapulco is highly diverse (89 species), and it has remained similar in space and time during this study. [ABSTRACT FROM AUTHOR]

The intense shipping traffic characterising the Adriatic Sea favours the spread of marine organisms. Yet, a study of 12 Adriatic ports (4 on the western side and 8 on the eastern side of the basin) found that non-indigenous species (NIS) accounted for only 4% of the benthic communities settled on hard substrates. The cirripeds Amphibalanus amphitrite and Balanus trigonus , found in 8 harbours, were the most common invaders followed by Amphibalanus eburneus , the ascidian Styela plicata , and the bivalve Magallana gigas. The highest percentage of NIS was recorded in Venice and Ploče, the harbours with the least rich native communities; the lowest percentage was retrieved in Trieste, Koper, Pula, and Rijeka, the harbours hosting the highest species diversity. In contrast, the ports of Bari and Ancona showed both high NIS percentages and highly diversified communities. • Harbours represent a suitable receptacle for non-indigenous species (NIS). • Fouling macrobiota were investigated from twelve western and eastern Adriatic ports. • Highest percentages of NIS were obtained where total Richness was low. • Biotic and abiotic factors are crucial in defining the vulnerability to invasibility. [ABSTRACT FROM AUTHOR]

At high latitudes, the marine transitional zone between the highly productive kelp communities and the devoid of vegetation deep-waters is occupied mainly by number of red algae species, both encrusting and cespitose, which associate with rich and diverse fauna. However, zoologists and botanists never scrutinized these communities in equal manner up to present. We investigated the transition red algae zone in the White Sea in summer 2016 and 2017 using scuba equipment. The photic depth is limited to 18–23 m at different locations. Sessile species prevail among 315 epibenthic organisms in species number (~ 80%) and biomass (~ 90%). Communities of the red algae zone are rich in species (from 54 to 177). The most distinct differences were observed between the communities of Kandalaksha and Onega Bays. Vertical heterogeneity of the red algae zone was revealed; at most locations, Rhodophyta predominate in the upper subzone and Cirripedia predominate in the lower parts of the red algae zone. At the investigated depths, shallow-water and deep-water sets of species were defined. Interspecific spatial interactions between sessile organisms are revealed: 72.2 ± 3.5% of them were recorded as epibionts, and 29.1 ± 2.5% were registered as basibionts. These interactions provide evidence of the increase of species diversity: 32.7 ± 6.8% of sessile taxa were recorded exclusively as epibionts. Algae Phycodrys rubens, Odonthalia dentata, and Coccotylus truncatus, ascidian Styela rustica, barnacles Balanus crenatus, Verruca stroemia, and polychaete Pista maculata are foundation species, each supporting multi-level suites (up to four levels) of dependent species. [ABSTRACT FROM AUTHOR]

Abstract Unlike the soft bottom meiofauna, meiofauna associated to hard substrata is poorly studied, despite its ecological relevance. Since communities of hard substrata are usually characterized by species with different life cycles and strategies from those of soft bottom assemblages, information on hard substrata meiofauna is still needed. In this study, sessile macrobenthos and the associated meiofaunal assemblages of two sites of Portofino (NW Mediterranean) were investigated in two seasons at three different depths on both sub-vertical and inclined reefs. The study aimed to assess the abundance, diversity and composition of the meiofauna and the factors structuring its assemblages. Moreover, as meiofauna is known to be dependent upon the substrate characteristics, the study investigated whether the meiofaunal patterns could be related to the sessile macrobenthos structure and composition, and to which extent. Macroalgae dominated the sessile macrobenthic assemblages, while Nematoda and Copepoda were the main meiofaunal groups. Meiofaunal higher-taxa richness and diversity resulted very high, due to the large number of different microhabitats offered by macroalgae. Macrobenthic assemblages were dominated by Rodophyta and Ochrophyta in summer, the latter dramatically collapsing in winter. The meiofaunal abundance and composition changed significantly with the season, consistently with the sessile macrobenthic assemblages, and resulted strongly correlated with Ochrophyta. Shaping the meiofaunal assemblages, macroalgae appeared to act as ecosystem engineer for the meiofauna. Highlights • Macroalgae dominated macrobenthic assemblages, Nematoda and Copepoda the meiofauna. • Meiofaunal diversity was high, due to the many habitats offered by sessile macrobenthos. • Meiofaunal abundance and community structure resulted related to Ochrophyta. • Sessile macrobenthos acted as ecosystem engineer for the associated meiofauna. [ABSTRACT FROM AUTHOR]

Highlights • Ninety-nine articles of studies of benthos of Brazilian reefs were found. • Communities of 764 sampled sites have been studied to date. • Eleven methods have been used to make comparison of communities and syntheses difficult. • 50.5% of the articles can not be replicated in relation to the information given. • Studies should at least describe how, where and when communities were surveyed. [ABSTRACT FROM AUTHOR]

A gap in the European Water Framework Directive (WFD) is addressed, aiming for the development of an ecological quality status assessment tool based solely on the Biological Quality Element benthic macroinvertebrates from intertidal rocky shores. The proposed Rocky shore Macroinvertebrates Assessment Tool (RMAT) was tested and validated along disturbance gradients (organic enrichment). During the whole process, the response of widely used metrics (e.g. Hurlbert index, Shannon-Wiener index, AZTI’s Marine Biotic Index; Bentix biotic index) and models (i.e., metrics combined) was compared to results provided by the Marine Macroalgae Assessment Tool to the same sampling sites. The RMAT is a multimetric index compliant with the WFD based on the benthic macroinvertebrates community, combining ‘abundance’ (Hurlbert index) and ‘taxonomic composition’ (Bentix index using density and biomass data) metrics. It performed well along anthropogenic disturbance gradients, showing ecological quality increasing from close to far away from the disturbance. The RMAT is a promising tool for rocky shore ecological assessment in the scope of the WFD or other monitoring activities worldwide. [ABSTRACT FROM AUTHOR]

In the frame of the COST ACTION ‘EMBOS’ (Development and implementation of a pan-European Marine Biodiversity Observatory System), coverage of intertidal macroalgae was estimated at a range of marine stations along the European coastline (Subarctic, Baltic, Atlantic, Mediterranean). Based on these data, we tested whether patterns in macroalgal diversity and distribution along European intertidal rocky shores could be explained by a set of meteo-oceanographic variables. The variables considered were salinity, sea surface temperature, photosynthetically active radiation, significant wave height and tidal range and were compiled from three different sources: remote sensing, reanalysis technique and in situ measurement. These variables were parameterized to represent average conditions (mean values), variability (standard deviation) and extreme events (minimum and maximum values). The results obtained in this study contribute to reinforce the EMBOS network approach and highlight the necessity of considering meteo-oceanographic variables in long-term assessments. The broad spatial distribution of pilot sites has allowed identification of latitudinal and longitudinal gradients manifested through species composition, diversity and dominance structure of intertidal macroalgae. These patterns follow a latitudinal gradient mainly explained by sea surface temperature, but also by photosynthetically active radiation, salinity and tidal range. Additionally, a longitudinal gradient was also detected and could be linked to wave height. [ABSTRACT FROM PUBLISHER]

Submerged marine debris alters local species compositions and the characteristics of benthic communities. However, few studies have explored species composition and characteristics within benthic communities. Here, we investigate the effects of submerged marine debris on the species compositions of the macrobenthos, as well as the characteristics of debris distribution, in subtidal sediments and rocky areas. Our results indicated that, when debris is present in subtidal sediment areas, mobile species (arthropods), which do not typically occur in the subtidal sediment area, are highly abundant dominant. In debris-covered rocky subtidal areas, the number of species, density, diversity, and biomass are all low. The Iwagaki oyster (Magallana nippona ; megabenthos; > 1 cm) only occurred at debris-free sites. Our study provides evidence that submerged marine debris affects macrobenthos; however, due to the small number of surveys and short distances between sites, some of these effects remain unclear. As such, we will supplement these data in a future study. • High density and appearance of mobile species when debris was present in the subtidal sediment area was confirmed. • Giant benthic species appear only when debris was absence in the subtidal rocky area. • Submerged marine debris affects the macrobenthos. [ABSTRACT FROM AUTHOR]

When a tractor works in a paddy field, road roughness is the main factor affecting its running, however, there has been no research on road roughness of paddy field. For the study of vibration characteristics of tractor in the condition of paddy field operation, the experiment was conducted in June 2014. Nanking Jiangpu Farm Agronomy Experiment Center which has clayey paddy soil was chosen as the experiment site, and tire rolling was adopted as the experiment method. By a self-designed measuring device, the vertical section function of hard bottom of paddy field was measured and obtained. Then the obtained data was conducted with auto-correlation test, and the power spectral density(PSD) of paddy field was analyzed with hard bottom of vertical displacement. The CF700 tractor was the research object. In addition to the stiffness and damping of the tire, soft and wet paddy soil was another factor affecting the vibration characteristics of the tractor. Based on the tire-soil system, in accordance with the main parameters of the tractor, the three degree of freedom vibration differential equation and simulation model were established under the condition of paddy field operation. The time function of hard bottom profile was set as an inputted incentive. The vibration characteristics of tractor were studied by simulation. In order to verify the reliability of the simulation model, the experiment which CF700 tractor working under the condition of paddy field operation was carried out, and vertical vibration acceleration of front axle, seat surface and rear axle of tractor were measured respectively at the speed of 6km/h. Then time-domain signal of acceleration was translated to frequency-domain signal, and a comparative analysis was conducted between the results of simulation and experiment. The results showed that there existed statistical correlation among paddy hard bottom elevations, and the change of elevation was steady and random; the roughness coefficient Gx(0.1)= 316.7×10-6 m3, and the fit index w=-1.651. When the spatial frequency was below 0.7m-1(wavelength λ≥1.43m), the road level of paddy hard bottom was C; when the spatial frequency was above 0.7 m-1(wavelength λ≤1.43 m), the road level of paddy hard bottom was between D and E. PSD amplitudes varied a lot within the whole spatial frequency range. The power of low frequency(long wave) was significantly higher than that of the high frequency(short wave). When the tractor moved on this type of road at a certain speed, the excitation frequency range was wide and the tractor could effectively isolate the excitation caused by short waves(high frequency input). And the excitation caused by long waves(low frequency input) was transmitted to the tractor. When the excitation frequency approached the natural frequency, the tractor would vibrate violently due to the potentiation of transfer function. The experiment results showed that the vertical vibration frequencies of front axle, rear axle and seat of the tractor were 2.91 Hz, 3.6Hz and 2.5Hz, respectively. The error rates of the results between the experiment and simulation were 19.9%, 7.2% and 16.0%, respectively. The causes of error might be: 1) The simulation used tractor plane vibration model. It did not take the roll-direction vibration into account. In the experiment, there existed a coupling between the roll-direction vibration and vertical vibration; 2) When the tractor worked in the paddy field, its greater driving resistance leaded to increasing vibration of the engine and gearbox. In conclusion, the results above provide a road reference model for tractor vibration in paddy field. They prove that it is effective to establish three degrees of freedom plane vibration model of the tractor based on the tire-soil system. Meanwhile, the results provide theoretical justification for the tractor design of shock mitigation system. [ABSTRACT FROM AUTHOR]

Benthic species associated with hard substrate are known to form communities characterized by high abundance and biomass. Although the bottom of the Southern Baltic Sea is dominated by soft sediments, such communities find favorable conditions to thrive on artificial substrates of offshore constructions. The aim of this research was to characterize both short-term and long-term benthic communities associated with artificial hard bottom provided by man-made structures in the Southern Baltic Sea. Species composition as well as the abundance and biomass were examined at various sites. An inactive World War II torpedo testing facility in the Gulf of Gdansk served as a site for sampling long-term communities while short-term communities were sampled using settlement panels and PVC cylinders. Panels were deployed at the torpedo testing facility for 127 days. PVC cylinders were deployed for 141-190 days in the Polish Exclusive Economic Zone. Twenty six macrofaunal taxa, including 12 crustaceans, were identified during the research. Mytilus edulis and Amphibalanus improvisus were the most abundant invertebrates at sampled surfaces. Six non-indigenous species were found. For the first time adult individuals of Mytilopsis leucophaeata were found in the Polish Marine Areas indicating that it is possible for this non-indigenous species to reproduce in this region. [ABSTRACT FROM AUTHOR]

Aquatic community structure and dynamics are generally controlled by a variety of biological and physical factors. Among these factors in marine ecosystems, salinity is known to have a significant effect on species occurrence and composition. In this study, we investigated the large-scale distribution and abundance of encrusting fauna along a salinity gradient on the shallow Baltic Sea rocky coast. Rock samples collected from 14 locations distributed between the Gulf of Bothnia (salinity 0.6) and Skagerrak (salinity 28) supported a total number of 24 encrusting species. The faunas were composed mostly of marine species with opportunistic life histories; however, some brackish water specialists were also present. The number of species and abundance counts is strongly positively correlated with increases in salinity. No encrusting faunas were recorded below salinity level 4. Multivariate analysis (nMDS) revealed three major groups based on species composition that differed in terms of abundance and number of species. Each group was associated with specific salinity conditions. The first assemblage type occurred within salinity 4–7, the second within salinity between 22 and 27, and the third type was a mixture between the two observed at a salinity of approximately 17. This study indicates that to determine the assemblage structure of the Baltic Sea encrusting fauna, analyses at the family level were found to be a reliable surrogate for species composition. [ABSTRACT FROM AUTHOR]

The ALien Biotic IndEX (ALEX) has been recently proposed to evaluate biological invasions in soft-bottom macro-invertebrate assemblages. The present paper proposes the use of ALEX in sessile assemblages of Mediterranean hard bottom habitats and tests it along gradients of invasion. For five invasive macroalgae a variable number of case studies per each of four habitats were examined from the available data sets. For each case study samples were attributed to four levels of invasion depending on the abundance of the invading macroalgae. Results showed that the application of ALEX to sessile assemblages of hard bottoms allows to qualify the level of invasion along the considered gradients. Moreover, the decline of index values matched the impact of invasion on species number of the assemblages. Results also suggest that the concurrent use of ALEX and indices of benthic quality status can be a valuable tool to assess biopollution in hard bottom habitats. [ABSTRACT FROM AUTHOR]

Analytical calculations of the first order of smallness show that the size of an increment of the Kelvin-Helmholtz instability depends on the thickness of the liquids. Upon growth of the Weber and Tonks-Frenkel parameters, the instability increment increases. [ABSTRACT FROM AUTHOR]

Abstract: During four years we surveyed the southernmost population of the sea star Asterina stellifera, which has been declared endangered in the central and northern parts of its distribution, and studied their feeding ecology by in situ observations and a short-term manipulative experiment. Contrary to our expectation we found abundant populations with densities up to 72ind.m−2. The individuals grew slowly over four years with no replacement in the smaller size classes. In the short term, presence of A. stellifera negatively impacted the abundance of all macrobenthic species analyzed, including sessile and moving animals and algae. We demonstrate that this sea star feeds in a non-selective way on several items belonging to different trophic levels. In addition, it displays a microphagous feeding behavior, so its direct impact might extend to settlers, modifying the recruitment of benthic populations. Indirect effects were not detected, likely due to the experiments lasting for a very short period. As an abundant omnivore, A. stellifera is likely affecting the stability of trophic webs of which they are part. [Copyright &y& Elsevier]

The composition and structure of a molluscan assemblage inhabiting an outcrop with a coralligenous community was studied in southern Spain. A total of 117 molluscan species were identified, with gastropods as the dominant group. Calyptraea chinensis was the dominant species and the family Conidae presented the highest number of species. The Shannon–Wiener diversity index and the Evenness showed non-significant changes between cold and warm months, displaying high values (~4 bits and ~0.8 bits respectively). Some of the dominant and/or frequent species are strictly associated with coralligenous-building organisms, such as Neosimnia spelta with gorgonians. Regarding trophic guilds, carnivores are the dominant group, followed by filter feeders due to the high abundance of C. chinensis. Regarding biogeographical distributions, most of these species (<95%) are widely distributed in European waters, the number of strictly Mediterranean species being very low. The Alboran Sea represents the distributional limit towards the Mediterranean for some species found in this bottom, such as the Atlantic Bela powisiana. Rocky–coralligenous bottoms are scarce in the western Alboran Sea but support a high species richness molluscan assemblage, displaying higher diversity values than the surrounding soft bottoms and increasing the biodiversity at local scale. This high biodiversity is partly explained by the coexistence of different taxa with contrasting biogeographical affinities promoted by the geographical location of the area. Due to this, conservation efforts should be required to protect this stretch of coastline where one of the most biodiverse invertebrate assemblages along the European coasts can be found. [ABSTRACT FROM PUBLISHER]

Abstract: Victoria Beach (Cadiz, Spain) comprises a rocky flat outcrop in its northern zone and a sand-rich southern zone. These natural features allowed for a 5-year monitoring period and subsequent analysis of two different profiles (one in each zone) based on differences in bottom contours. Topo-bathymetric data were analysed using empirical orthogonal functions (EOFs) to determine changes over the short-, medium- and long-term. Several morphologic phenomena were identified (generalised erosion, seasonal or summer–winter tilting of the profile around different hinge points, berm development and its posterior destruction, etc.) in terms of their importance in explaining the variability of the collected data for both profiles. It is worth mentioning that both profiles undergo parallel regression in the medium-term. Thus, the 1st eigenfunction enabled us to identify the true regression of the beach shoreline, independent of seasonal or summer–winter slope changes. Reconstruction of profiles using EOF components demonstrated that though accretion periods in the medium-term were similar for both types of profiles, the accretion speed was much faster in the sand-rich profile than in the reef-protected profile (1.01m3/day versus 0.33m3/day). Moreover, the seasonal erosion rate and the subsequent shoreline retreat for the sand-rich profile were much larger than for the reef-protected profile (121m3/year versus 29m3/year). Analysis in the short-term (changes induced by a single day''s storm) showed an instantaneous tilting of the profile, with the mobilised sand volume being much greater for the sand-rich than for the reef-protected profile (68m3/m versus 12m3/m). In brief, we can assume that the wave energy attenuation provoked by the existence of a reef flat acted as a geological control for profile evolution, which is essentially different for both profiles. Among the most important differences, special attention should be given to the larger slope, smaller mobilised sand volume and slower accretion rate of the reef-flat profile versus the non-protected profile. [Copyright &y& Elsevier]

The Water Framework Directive (WFD) 2000/60/EC, adopted by the European Community in 2000 with the goal of maintaining and improving the aquatic environments, requires that member states achieve and maintain a good ecological status of all water bodies by 2015. In the marine context, the ecological status has to be quantified applying indexes based on appropriate key biological elements, which allow the categorization of water bodies into five Ecological Status (ES) classes. The CARLIT index is a cartographic monitoring tool enabling the Ecological Quality Ratio (EQR) to be calculated using macroalgae in coastal hard bottoms as a key biological element; at present it is being applied in Spain, France and Italy. To detect actual changes of water quality and, consequently, rely on the application of indexes for the assessment of the ecological status in the marine environment, it is necessary to evaluate their sensitivity to natural variability at different temporal and spatial scales. In this study we present a first quantification of natural (spatial and temporal) variability of EQR-CARLIT quality assessment in 2006 and 2007 along the Ligurian coast (North-Western Mediterranean, Italy). The EQR-CARLIT values recorded along the Ligurian coastline show that natural variability of EQR-CARLIT is low and that it does not affect the attribution of a given stretch of coast to a particular ES class, in agreement with the major human pressures acting in the area (urbanization, river load, sea-farming). A small-scale variability was detected, strengthening the use of cartography of the whole rocky shore, whenever possible, or, alternatively, the assessment of the ecological status for long stretches of coast, to encompass the small-scale variability due to local factors. [ABSTRACT FROM AUTHOR]

In the current study, we investigated the primary succession of seaweeds over different time periods at different water depths. Furthermore, we followed the succession of field-grown benthic communities of different successional age, developing on ceramic tiles, prior to and after transplantation from 8 to 0.5 m water depth. The transplantation simulated changes associated with the break up of sea-ice cover, e.g. light regime or wave exposure. For this purpose, we transplanted 12 and 21-month old communities, grown at 8 m water depth, together with a set of sterile tiles, onto rafts, floating in 0.5 m water depth. Our results describe for the first time the succession of macroalgal communities in the Arctic and give important insights into the effect of disturbance of differently aged communities. The primary succession at 0.5 m water depth was mainly driven by Bacillariophyta and filamentous green algae like Urospora sp. and Ulothrix implexa. Twelve-month old communities at 8 m water depth are dominated by members of the Ectocarpales (Phaeophyceae), like Pylaiella littoralis, P. varia, and Ectocarpus siliculosus and the green alga U. implexa, whereas the 21-month old community showed a higher cover of the green algal class Ulvophyceae and sessile invertebrates. After transplantation to near surface conditions, species composition of the communities changed, but this effect was differently strong between communities of different age. [ABSTRACT FROM AUTHOR]

The sessile and mobile macrobenthos on artificial hard bottoms was studied in 12 stations of the Sacca di Goro lagoon, a brackish, highly stressed water basin in the delta of the river Po, open to the Northwestern Adriatic Sea. Three sampling surveys were carried out in June and September 2000 and June 2001 in order to make three types of temporal comparisons: (i) on a seasonal scale, before and after a summer dystrophic event; (ii) on an annual basis, before and after the works of excavation of a canal through the outer sand bank; (iii) on a multiannual scale, comparing the data with those of a survey carried out in 1988. The biocoenoses did not show large fluctuations after a moderately severe summer dystrophic crisis, while the digging of the canal caused clear changes in the macrobenthos community structure after one year. The long-term comparison showed a shift in the community patterns after a decade. [Copyright &y& Elsevier]

Despite substantial survey effort and a large body of literature on abiotic and biotic factors in temperate reef ecosystems, knowledge of the complex and interactive effects of environmental variables on those communities is limited. Various survey methods have been developed to study environmental predictors of biodiversity, but there remains a gap in our understanding of how survey results are influenced by environmental factors. Here, we surveyed the fish assemblage associated with southeastern U.S. temperate marine reefs with simultaneous, paired trap, and camera gears throughout a ~50,000 km2 area during 2011–2013 and assessed the influence of environmental variables on the trap‐ and video‐surveyed assemblages. Predictor variables in the multivariate general linear models included depth, temperature, month, year, location, substrate relief, percent sessile biota, biota type, and turbidity. Depth and latitude had the greatest influence on the fish assemblage for both gears. The influence of habitat variables differed between methods and percent biota explained more variation in the fish assemblage when assessed by traps, while substrate relief and biota type explained more variation in the fish assemblage when assessed by video. In general, habitat complexity was positively related to the abundance of fishes in the video survey, but there was a negative relationship in the trap survey. Differences between gears were species‐specific and the influences of environmental variables were similar for some species such as Haemulon plumierii and Hyporthodus niveatus. The methods presented here can be used to assess method‐dependent differences in fish assemblages, which is a necessary precursor to assess the effect of environmental variables on the accuracy of surveys. [ABSTRACT FROM AUTHOR]