Most lithistids occur worldwide in deep-water environments, but can be found in some places in shallow water. They are not well known in the tropical western Atlantic, despite the fact that they were first described in the late 1800s. We report here two species of poorly known theonellid demosponges (Astrophorina), Discodermia dissoluta and Theonella atlantica, and one new species, Theonella wrightae, from the north-west, south-west and south Florida shelf. There is considerable variability in habitus, colour and spiculation in this species. If samples are taken randomly from different specimens and from functionally and structurally different locations on the sponge, the specimens could be mistakenly identified or individuals of the same species could be described as different species. This report increases the number of lithistid sponges reported from the tropical western Atlantic region to 30 species, but our unpublished data suggest a much higher number of species present in this region. It is also the second report of the relatively deep-water (81 m) occurrence of D. dissoluta that is mostly known from depths as shallow as 10–30 m.

The model diatom Thalassiosira pseudonana is believed to be a single species with a global distribution, but it has not been confirmed previously whether isolates from different environmental and geographic origins are genotypically and phenotypically identical. In the present study, a polyphasic approach was employed to characterize nine clonal isolates, plus an additional replicate of one of the isolates, of the diatom T. pseudonana from culture collections to investigate whether there was any cryptic speciation in the publicly available strains of this species. Morphological analysis using scanning electron microscopy concluded that the strains were indistinguishable. Furthermore, conventional DNA barcoding genes (SSU rDNA, ITS1 and ITS2 rDNA and rbcL), revealed no nucleotide variation among the strains tested. On employing a whole genome fingerprinting technique, Amplified Fragment Length Polymorphism (AFLP), three clusters were revealed, although the level of variation between the clusters was surprisingly low. These findings indicate a low level of diversity among these cultured T. pseudonana strains, despite their wide spatial and temporal distribution and the salinity range of their original habitats. Based on the limited number of available strains, this suggests that T. pseudonana is a highly conserved diatom that nevertheless has an ability to tolerate wide ranges of salinity and populate varied geographic locations.

The composition and structure of sublittoral faunal assemblages inhabiting soft bottoms (15–72 m depth) within the Marine Protected Area ‘Acantilados y Fondos Marinos de Calahonda-Castell de Ferro’ in southern Spain (North Alboran Sea, Mediterranean) have been studied in relation to sediment and water column variables. Three assemblages were identified and corresponded to mixed bottom, unstable bottom and coastal detritic bottom assemblages, based on Pérès & Picard's (1964) benthic classification. A total of 14,318 individuals were collected and 218 species identified, molluscs being the best represented group (141 species). Species richness displayed significant differences with depth and transect, with the highest values observed in the medium to very fine sand and muddy bottoms with bioclasts located at the shallowest sampling stations. The presence of some rare and poorly known invertebrates that are scarce in other areas of the Mediterranean Sea is remarkable, such as the crustacean decapods Bythocaris cosmetops and Pagurus mbizi, Atlantic species with no records in the Mediterranean Sea, and the bathyal molluscs Poromya granulata and Alvania testae, collected at shallow depths. The spatial distribution of faunal assemblages was mainly related to depth and percentage of gravel and clay according to the canonical correspondence analysis. The geographic location of the area, the heterogeneity of soft bottoms and the presence of upwellings in the area may favour the high biodiversity found in the studied soft bottoms. This study increases the scarce knowledge of the circalittoral fauna of sedimentary habitats of the Alboran Sea, providing a baseline for the management of this interesting SCI and for the EU Marine Strategy Framework Directive.

Kelps, fucoids and other large brown seaweeds are common and important features of temperate coastal zones. The British Isles is a centre for seaweed diversity in the NE Atlantic, but, despite numerous surveys, an incomplete picture of the distribution remains. Survey data and herbarium specimens were used to examine the environmental preference of 15 species of large brown seaweeds, covering the orders Laminariales (kelps), Fucales (wracks) and one species of Tilopteridales. Habitat suitability models were developed to estimate broad-scale distribution and area of habitat created by these species around the British Isles. Topographic parameters were important factors limiting distributions. Generally, temperature did not appear to be a limiting factor, probably because the British Isles lies in the centre of the NE Atlantic distribution for most species, and not at climatic tolerance limits. However, for the recent migrant Laminaria ochroleuca, temperature was found to be important for the model, thus range expansion could continue northwards provided dispersal is possible. In contrast, the widespread Alaria esculenta showed a negative association with warmer summer temperatures. The total potential habitat around the British and Irish coastline is more than 19,000 km2 for kelps and 11,000 km2 for wracks, which represents a significant habitat area similar in scale to British broadleaf forest. We conclude that large brown algal species need to be managed and conserved in a manner that reflects their scale and importance.

The colonization dynamics in trophic-functional structure of biofilm-dwelling ciliate fauna were studied using two methods based on an artificial substratum in Korean coastal waters of the Yellow Sea during April 2007. Polyurethane foam enveloped slide (PFES) and conventional slide (CS) systems were used to collect ciliate samples at a depth of 1 m. The ciliate fauna represented similar colonization dynamics in trophic-functional patterns that were driven mainly by the algivores, bacterivores and non-selectives in both systems. Simple trophic-functional patterns (e.g. algivores and non-selectives) occurred within the ciliate fauna at the initial stage (1–3 days), while complex patterns (e.g. algivores, non-selectives and bacterivores) were established at the transitional (5–7 days) and equilibrium (9–19 days) stages. However, the time in which ciliate fauna reached a stable trophic-functional pattern was shorter in the PFES than in the CS system. Among four trophic-functional types, the algivores and bacterivores significantly fitted the MacArthur-Wilson and logistic models in colonization and growth curves in both systems, respectively. Furthermore, the species richness and diversity of algivores and bacterivores were significantly higher in the PFES system than in the CS. These results suggest that the PFES system was more effective than the conventional slide method for a colonization survey on trophic-functional patterns of biofilm-dwelling ciliate fauna in marine ecosystems.

The heteronemertean species Micrura dellechiajei is thus far only known from its type locality in the Gulf of Naples (Italy) and has not been recorded in 120 years. During two oceanographic surveys conducted in Spanish Mediterranean waters, several nemertean specimens were collected, and thorough morphological examination indicated that some of these pertained to the species M. dellechiajei, suggesting that populations may be more widespread than previously thought. Because of the rarity of this species coupled with the fact that its last morphological narrative was given 120 years ago, we here provide a redescription of the species based on the new specimens, complete with illustrations and new data concerning its morphology, and we also place some of the collected specimens in a molecular phylogenetic framework.

The first offshore liquefied natural gas (LNG) terminal in Italy and the first gravity based structure (GBS) in the world for unloading, storing and re-gasifying liquefied natural gas, was authorized and realized. The Institute for Environmental Protection and Research (ISPRA, formerly ICRAM) formulated and implemented a multidisciplinary monitoring plan at verifying possible impacts of the project on marine environment. Data from June 2006 to July 2012 on the soft-bottom macrozoobenthic assemblages around the LNG terminal are presented, with the aim of verifying possible disturbances on these assemblages associated with the LNG terminal, by comparing the structure of the benthic communities before and after installation of the terminal, and during its operation. Well-structured assemblages were observed for the entire period investigated, with all taxa normally represented both quantitatively and qualitatively. A temporary disturbance due to the construction of the LNG terminal was detected in the surrounding sediments, while the presence of the concrete structure did not show significant effects at the investigated distances.

Sanya Bay lies at the southern part of Hainan Island, 18°15′N 109°28′E. The seawater in the bay has been catastrophically polluted during the past two decades with urban sewage from the rapidly developing Sanya City. The marine flora research in Sanya Bay was started at the beginning of the 1930s and the most detailed studies were performed by two German-Chinese expeditions in 1990 (October–December) and in 1992 (March–April). In April, October, November and December 2008–2010 the marine flora of Sanya Bay was studied by the authors at three localities: Luhuitou Peninsula, Xiaodong Hai and Dadong Hai. Marine algae were sampled in the intertidal and upper subtidal zones (to 4–5 m depth). The list of species (including varieties and forms) of the marine algae for Sanya Bay sampled during the period from 2008 to 2010 is compared with those collected at the same localities in 1990/1992. Comparative analysis of the floristic composition of the marine red, brown and green algae (found during different time periods) revealed that considerable changes have taken place between 1990/1992 and 2008–2010 at Sanya Bay. There was an increase in filamentous, tubular and fine blade-like green and red algae (mainly epiphytes with a high surface to volume ratio) and a displacement of upright-growing fleshy, foliose and other large green, brown and red algae with a low surface to volume ratio. It is assumed that the changes reflect mainly increased pollution by urban sewage and mariculture pond wastes and probably by coral bleaching events of 1998.

The abundance and community composition of phytoplankton are influenced by a suite of interacting environmental factors. Hong Kong's marine environment features a hydrographic gradient from an estuarine zone in the west to a transition zone in the middle and an oceanic zone in the east. Size fractionation combined with high performance liquid chromatography (HPLC) pigment analyses were used to investigate the phytoplankton communities in different hydrographic zones during summer (July–August 2009) and winter (December 2009–January 2010). Clear temporal and spatial variations in environmental parameters occurred among hydrographic zones. Results of principal component analysis (PCA) revealed that the major deviating factors among hydrographic zones were turbidity and salinity in summer and nitrate and phosphate in winter. Phytoplankton abundance showed significant temporal variations, but no zonal variations. Phytoplankton communities in all hydrographic zones were dominated by cells >5 µm in both summer and winter. Chlorophyll a concentrations for most size fractions correlated significantly with temperature. The high concentration of fucoxanthin indicated that the phytoplankton community was dominated by diatoms in both summer and winter, while dinoflagellates, cryptophytes, cyanobacteria and other minor groups occurred sporadically in low abundance. The spatial pattern of phytoplankton in Hong Kong's coastal seas did not reflect the hydrographic zonation, but the phytoplankton in the semi-enclosed Tolo Harbour and Deep Bay were different from those in the other zones.

Sea-cage fish farms impact the seabed within their immediate vicinity, potentially affecting recipient communities. We assessed whether proximity to three sea-cage fish farms at the Canary Islands altered patterns in the abundance, assemblage structure and richness of soft-bottom macrofauna. We related among-farm variability in dissimilarities in macrofaunal assemblage structure between seabeds beneath cages and controls to differences in hydrodynamics, production and seabed topography. Contrasting patterns of species abundances with varying proximity to fish farms were observed: some species decreased while other species increased their abundances with increasing distance at some farms. Although faunal assemblages at 0 m (i.e. beneath the cages) were different, in terms of assemblage structure, from those found at controls, pairwise differences in assemblage structure among distances away varied among the studied fish farms. Species richness showed inconsistent patterns with proximity to cages among fish farms. In summary, inconsistent patterns of macrofaunal assemblages with varying proximity to aquaculture facilities preclude confident predictions on the way offshore aquaculture alters macrofauna in the study region.

The study presents Cladorhizidae collected during Ifremer cruises in the Atlantic Ocean from 1981 to 2004. Fifteen species are described from the genera Abyssocladia, Asbestopluma, Chondrocladia and Cladorhiza, with complete descriptions of five new species. While a couple of species were collected at 670–1010 m depth at the Rockall Bank, most species were collected at middle to lower bathyal and abyssal depths (~2000–5000 m), ranging from the northern Atlantic to the Mid-Atlantic Ridge and the coast of Africa at Gabon–Congo. A biogeographic analysis of currently known Arctic, Atlantic and some Antarctic species shows that the majority of included cladorhizids are described from the north-east Atlantic and Arctic Oceans while a lower number of species are known from other parts of the Atlantic Ocean. Large regions are poorly investigated, and previously undescribed species can be expected when sampling in these areas. A regional mostly endemic cladorhizid fauna is predicted for shelf and upper slope areas. Species in the lower bathyal and abyssal seem on the other hand to have a wider geographical distribution.

In many coastal areas substrate is the limiting resource for benthic organisms. Some sessile species can be used as secondary substrate, reducing competition and increasing coexistence. In southern Chile, annual populations of Macrocystis pyrifera recruit and grow on the shells of Crepipatella fecunda. This study describes ecological interactions between the kelp and the slipper limpet over an annual cycle. The degree of kelp overgrowth was established by collecting sporophytes and through in situ submarine photography over a 10 month period (starting when kelp recruits became visible and ending when sporophytes were no longer present). Changes in the biochemical composition of the limpet tissue were also recorded by chemical analyses, to evaluate the potential effects (positive/neutral/negative) of kelp on C. fecunda nutritional condition. The results indicate that both species coexist, although kelp overgrowth may cause a decrease in carbohydrates in C. fecunda tissues, restricted to the period when the kelp forest reaches its maximum biomass. Individually, the short duration of the maximum overgrowth period and the size reached by C. fecunda females (up to 65 mm shell length) may enable rapid limpet recovery, avoiding competitive exclusion. On a population level, the M. pyrifera annual cycle generates the needed ‘break’ for C. fecunda populations, reducing the effects of kelp overgrowth. Thus, in the view of the neutral effect of kelp overgrowth, together with the positive effect of C. fecunda on M. pyrifera recruitment described somewhere else, this ecological interaction can be categorized as commensalism.

We describe a new species of Crambionella, C. helmbiru, from central Java, Indonesia. The combination of the mean number of lappets per octant (14), presence of foliaceous appendages amongst frills on oral-arms, absence of tubercles on the velar lappets, proportion of terminal club length to oral-arm length (0.28), and the body colour distinguish this species from three previously described congeners. In addition, the analysis of partial sequences of the cytochrome c oxidase subunit I gene indicate substantial genetic differences from both Crambionella orsini and Crambionella stuhlmanni, supporting the validity of this new species. A combination of morphological and genetic approaches determined that the remarkable differences in exumbrellar colours observed in specimens are simply intra-specific variation. Surprisingly, this species has been commercially harvested for more than 20 years and is well-known to the local people in the region, yet it had remained unknown to science until this point. The commercial fisheries targeting this formerly unknown species are also described in detail.

For the first time the meiofauna of the rocky walls of a submarine cave was studied. The cave, known as il Ciolo (Strait of Otranto, south-east Italy) is a closed tunnel about 125 m long, with a maximum depth of 6 m below sea level. The meiofauna was collected from artificial panels and natural rocky walls. This double approach enabled: (1) the description of the community's initial organization (on artificial substrata), and (2), especially for Harpacticoida, its mature composition (on rocky walls), which also helped to establish spatial differences. The collected samples yielded 70 taxa in total. Harpacticoida represented the most important group of organisms in terms of both abundance and identified taxa. The meiofauna assemblage appeared not to be affected by community age, with the exception of the very early stage. The meiofauna of the cave showed assemblage differences from the entrance to the innermost positions, but not as evident as in the case of the macrobenthos. The similarity of community composition at different ages (6, 12 and 24 months) and at different positions along the cave could be the consequence of the specimens’ vagility.

This paper deals with a new species of Myrianida collected from Rhodes Island at 1 m depth among algae in April 2014. This new species is mainly characterized by having flattened dorsal cirri; high number of falcigers in parapodia; a trepan with 16 unequal teeth; and a brownish patch (in fixed specimen) on dorsum of each segment. Individuals are at the stage of reproduction, with developing stolons.

Thraustochytrids, the exclusively marine organisms of kingdom Stramenopila and a source of essential fatty acids in the marine milieu, possess an osmoheterotrophic mode of nutrition and are therefore affected by type and source of available organic matter and pollution. To study their response to heavy metal pollution, they were isolated from the brown alga Sargassum cinereum from the coastal waters of Dona Paula, Goa, India. A total of 22 isolates were obtained from two samples collected during February and March 2012. Based on their 18S rRNA gene sequencing, the majority of the isolates were identified as Thraustochytrium kinnei. The rest were identified to be Sicyoidochytrium minutum, Ulkenia visurgensis and species of Thraustochytrium and Aurantiochytrium. Six isolates were screened for various enzymatic activities. Characteristic and distinctive enzyme profile was obtained from isolates of different genera. All isolates were also screened for their tolerance to heavy metals. They showed good growth in the presence of Mn2+. The other metals that were tolerated by most of the isolates were in the order Ni2+ > Cr6+ > Zn2+. Seven isolates grew in the presence of Cu2+, and six in the presence of Cd2+. The isolates growing on metals showed vast differences from their normal morphology such as small colony size, shrunken cells etc. Scanning electron micrographs revealed holes or depressions in the cell wall in the presence of metals. On the whole, the isolates belonging to Ulkenia visurgensis and Aurantiochytrium sp. showed tolerance to more metals than Thraustochytrium kinnei. Cluster analysis showed no peculiar trend of metal tolerance to any particular genus as the characters were scattered in the clusters.

The phytoplankton community structure and abundance in the south-eastern Black Sea was measured from February to December 2009 using and comparing high performance liquid chromatography pigment and microscopy analyses. The phytoplankton community was characterized by diatoms, dinoflagellates and coccolithophores, as revealed by both techniques. Fucoxanthin, diadinoxanthin, peridinin and 19′-hexanoyloxyfucoxanthin were the main accessory pigments showing significant correlation with diatom-C r2 = 0.56–0.71, P < 0.05), diatom-C (r2 = 0.85–0.91, P < 0.001), dinoflagellate-C (r2 = 0.39–0.88, P < 0.05) and coccolithophore-C (r2 = 0.80–0.71, P < 0.05), respectively. Microscopy counts indicated a total of 89 species, 71% of which were dinoflagellates, 23% were diatoms and 6% other species (mainly coccolithophores). Pigment-CHEMTAX analysis also indicated the presence of pico- and nanoplankton. Phytoplankton carbon (phyto-C) concentrations were highest in the upper water column, whereas chlorophyll-a (Chl-a) showed a deep maximum. Average phyto-C was higher at the coastal station (291 ± 66 µg l−1) than at the offshore station (258 ± 35 µg l−1), not statistically different (P > 0.05). The coastal station also had higher Chl-a concentrations (0.52–3.83 µg l−1) compared to the offshore station (0.63–2.55 µg l−1), not significant (P > 0.05). Our results are consistent with other studies and indicate that the southern Black Sea is shifting towards mesotrophy with the increasing prevalence of dinoflagellates compared to diatoms.

This study examined the reproductive ecology of eight Eastern Pacific deep-sea octocorals, collected from Washington to Southern California. The sexuality, reproductive mode, oocyte size, and fecundity of each species were identified using histological techniques. This research increases the knowledge of basic life histories of deep-sea corals. Swiftia simplex had the highest total fecundity of 42.53 (±9.82 SE) oocytes per polyp. Mean oocyte diameters in S. simplex and S. pacifica females differs among sample months. Swiftia pacifica and S. kofoidi had the lowest total fecundity: 4.6 (±2.06 SE) and 3 (±1.53 SE) oocytes per polyp, respectively.

The coastline of Tabasco State in the Gulf of Mexico represents a highly deteriorated ecosystem, where densely populated human settlements and large offshore petroleum developments are negatively affecting the marine biodiversity. Previous work on marine ascomycetes reported that in the Gulf of Mexico the diversity of these fungi might be threatened by anthropogenic activities. Therefore we evaluated the diversity of marine ascomycetes in this area, and registered 19 taxa. Ceriosporopsis capillacea was recorded for the first time for Mexico. The highest diversity was obtained in the beach of Sánchez Magallanes, which receives a great quantity and diversity of organic remains originating from El Carmen/Machona mangrove forests via the Santa Ana mouth, benefiting the proliferation of marine fungi. The lowest diversity was documented in the beach of Paraíso, which is close to the delta of one of the most polluted rivers in Mexico and to off-shore oil extraction platforms. We found a significant correlation between the community composition and abundance, implying that the overall abundance is defined by the community structure, perhaps as a result of competition. Additionally, our results indicated that there is no relationship between the grain size and the biodiversity observed.