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11 pages, 5 figures, 2 tables, supplementary information https://doi.org/10.1038/s42003-021-02165-3.-- Data availability: The authors declare that the data supporting the findings of this study are available within the paper and its Supplementary Data files, The last hundred years have seen the introduction of many sources of artificial noise in the sea environment which have shown to negatively affect marine organisms. Little attention has been devoted to how much this noise could affect sessile organisms. Here, we report morphological and ultrastructural changes in seagrass, after exposure to sounds in a controlled environment. These results are new to aquatic plants pathology. Low-frequency sounds produced alterations in Posidonia oceanica root and rhizome statocysts, which sense gravity and process sound vibration. Nutritional processes of the plant were affected as well: we observed a decrease in the number of rhizome starch grains, which have a vital role in energy storage, as well as a degradation in the specific fungal symbionts of P. oceanica roots. This sensitivity to artificial sounds revealed how sound can potentially affect the health status of P. oceanica. Moreover, these findings address the question of how much the increase of ocean noise pollution may contribute in the future to the depletion of seagrass populations and to biodiversity loss, With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)

13 pages, 9 figures, supplementary data https://doi.org/10.1016/j.envpol.2022.119853.-- Data availability: Data will be made available on request, The installation of marine renewable energy devices (MREDs, wind turbines and converters of wave, tidal and ocean thermal energy) has increased quickly in the last decade. There is a lack of knowledge concerning the effects of MREDs on benthic invertebrates that live in contact with the seabed. The European common cuttlefish (Sepia officinalis) is the most abundant cephalopod in the Northeast Atlantic and one of the three most valuable resources for English Channel fisheries. A project to build an offshore wind farm in the French bay of Saint-Brieuc, near the English Channel, raised concern about the possible acoustic impact on local cuttlefish communities. In this study, consisting of six exposure experiments, three types of noise were considered: 3 levels of pile-driving and 3 levels of drilling. The objectives were to assess possible associated changes in hatching and larva survival, and behavioural and ultrastructural effects on sensory organs of all life stages of S. officinalis populations. After exposure, damage was observed in the statocyst sensory epithelia (hair cell extrusion) in adults compared to controls, and no anti-predator reaction was observed. The exposed larvae showed a decreased survival rate with an increasing received sound level when they were exposed to maximum pile-driving and drilling sound levels (170 dB re 1 μPa2 and 167 dB re 1 μPa2, respectively). However, sound pressure levels's lower than 163 dB re 1 μPa2 were not found to elicit severe damage. Simulating a scenario of immobile organisms, eggs were exposed to a combination of both pile driving and drilling as they would be exposed to all operations without a chance to escape. In this scenario a decrease of hatching success was observed with increasing received sound levels, We acknowledges the institutional support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX 2019-000928-S). Funding for this project was provided by Ailes Marines SAS (Iberdrola Group). Project: Noise influence for cuttlefish invertebrate - St Brieuc Wind Farm Site (Ref. CPCS – 771596). France

Special issue Ocean Noise: From Science to Management.-- 15 pages, 8 figures, Global change is the origin of increased occurrence of disturbance events in natural communities, with biological invasions constituting a major threat to ecosystem integrity and functioning. The apple snail (Pomacea maculata) is a freshwater gastropod mollusk from South America. Considered one of the 100 most harmful invasive species in the world, due to its voracity, resistance, and high reproductive rate, it has become a global problem for wetland crops. In Catalonia, it has affected the rice fields of the Ebre Delta since 2010 with significant negative impact on the local economy. As a gastropod mollusc it possesses statocysts consisting of a pair of sacs, one located on each side of the foot, that contain multiple calcium carbonate statoconia. This study shows the first ultrastructural images of pathological changes in the sensory epithelium of the statocyst of apple snail adults with an increase in the severity of the lesions over time after exposure to low frequency sounds. Sound-induced damage to the statocyst could likely result in an inhibition of its vital functions resulting in a potential reduction in the survival ability of the apple snail and lead to an effective mitigation method for reducing damage to rice fields, With the institutional support of the ‘Severo OchoaCentre of Excellence’ accreditation (CEX2019-000928-S)

Special issue Ocean Noise: From Science to Management.-- 20 pages, 22 figures, 1 table, supplementary materials www.mdpi.com/article/10.3390/jmse9101114/s1, The use of bioacoustic methods to address sea lice infestation in salmonid farming is a promising innovative method but implies an exposure to sound that could affect the fish. An assessment of the effects of these techniques related to the salmon’s welfare is presented here. The fish were repeatedly exposed to 350 Hz and 500 Hz tones in three- to four-hour exposure sessions, reaching received sound pressure levels of 140 to 150 dB re 1 µPa2, with the goal of reaching total sound exposure levels above 190 dB re 1 µPa2 s. Gross pathology and histopathological analysis performed on exposed salmons’ organs did not reveal any lesions that could be associated to sound exposure. The analysis of their otoliths through electron microscopy imaging confirmed that the sound dose that was used to impair the lice had no effects on the fish auditory organs, Funding for this project was provided by SEASEL SOLUTIONS AS. Project: An acoustic and Bioacoustic solution to sea lice infestation on salmon- P.O.BOX 93 N-6282 BRATTVÅG. Norway, With the institutional support of the ‘Severo OchoaCentre of Excellence’ accreditation (CEX2019-000928-S)

18 pages, 50 figures, 1 table, supplementary information http://dx.doi.org/10.1080/09670262.2021.1914861.-- Related Research Data: Detection of the widespread presence of the genus Ansanella along the Catalan coast (NW Mediterranean Sea) and the description of Ansanella catalana sp. nov. (Dinophyceae). Source: Taylor & Francis, Many dinoflagellate groups have been overlooked because of their small size compared with their larger counterparts; consequently, little is known about their diversity, distribution, and contribution to the planktonic community. Ansanella is a recently described genus of small marine planktonic dinoflagellates belonging to the order Suessiales. In this study, morphological observations together with molecular SSU and LSU rDNA analyses of clonal strains from the Catalan coast (NW Mediterranean Sea) allowed the identification of A. cf. natalensis and a newly reported species, Ansanella catalana. The cells of A. catalana are oval and 9.6–15.5 μm long; the cell surface is covered with amphiesmal vesicles arranged in 10–13 latitudinal rows; the episome has an apical furrow complex with a single elongated apical vesicle; a type E eyespot is also present. This newly identified species can be distinguished from congeneric species by morphological details of the cell surface, the presence of mucocysts and an extrusome type not previously reported in dinoflagellates. The characterization of this structure could provide insights into extrusome evolution in dinoflagellates. Metabarcoding analysis of plankton and sediment samples from the Catalan coast revealed a wide distribution of Ansanella and the remarkable contribution of this genus to the dinoflagellate communities from three different coastal habitats, Financial support was provided by COPAs project (CTM2017-86121-R). J. Matos was also supported by a grant from Brazil (PE 88881.146191/2017-01). This work acknowledges the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S)

24 pages, 21 figures, 4 tables, The salmon louse Lepeophtheirus salmonis is a major disease problem in salmonids farming and there are indications that it also plays a role in the decline of wild salmon stocks. This study shows the first ultrastructural images of pathological changes in the sensory setae of the first antenna and in inner tissues in different stages of L. salmonis development after sound exposure in laboratory and sea conditions. Given the current ineffectiveness of traditional methods to eradicate this plague, and the strong impact on the environment these treatments often provoke, the described response to sounds and the associated injuries in the lice sensory organs could represent an interesting basis for developing a bioacoustics method to prevent lice infection and to treat affected, Funding for this project was provided by SEASEL SOLUTIONS AS. Project: An acoustic and Bioacoustic solution to sea lice infestation on salmon P.O. BOX 93 N-6282 BRATTVÅG. Norway.-- With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S)

Minidiscus comicus is a marine centric diatom that has cells with diameters as small as 1.9 μm, which brings it close to the lower limit of diatom cell size and also near to the lower limit of photosynthetic eukaryote cells. One of the questions that this raises is whether the cycle of size decline and size restoration used by most diatoms to time their life cycle can operate in such small cells. In samples collected from the western Mediterranean during 2009, M. comicus cells were found with diameters ranging from 1.9 to 6.0 μm. The larger cells were initial cells after size restoration, and these still had the valves of their parent cells attached, making it possible to determine the diameter of the threshold below which size restoration could be induced (3.1 μm). During size decline, M. comicus cell shape changed from discoid to spherical. This adaptation helped to reduce and even halt the rate of cell volume decrease, allowing cells to continue to use diameter decline as a clocking mechanism. The results show how adaptable the diatom cell wall can be, in spite of its rigid appearance.

Corrigendum: Evidence of Cnidarians sensitivity to sound after exposure to low frequency underwater sources Scientific Reports 6: 37979 (2016) https://dx.doi.org/10.1038/srep37979.-- 2 pages

The morphological study of the Odontocete organ of Corti, together with possible alterations associated with damage from sound exposure, represents a key conservation approach to assess the effects of acoustic pollution on marine ecosystems. By collaborating with stranding networks from several European countries, 150 ears from 13 species of Odontocetes were collected and analyzed by scanning (SEM) and transmission (TEM) electron microscopy. Based on our analyses, we first describe and compare Odontocete cochlear structures and then propose a diagnostic method to identify inner ear alterations in stranded individuals. The two species analyzed by TEM (Phocoena phocoena and Stenella coeruleoalba) showed morphological characteristics in the lower basal turn of high-frequency hearing species. Among other striking features, outer hair cell bodies were extremely small and were strongly attached to Deiters cells. Such morphological characteristics, shared with horseshoe bats, suggest that there has been convergent evolution of sound reception mechanisms among echolocating species. Despite possible autolytic artifacts due to technical and experimental constraints, the SEM analysis allowed us to detect the presence of scarring processes resulting from the disappearance of outer hair cells from the epithelium. In addition, in contrast to the rapid decomposition process of the sensory epithelium after death (especially of the inner hair cells), the tectorial membrane appeared to be more resistant to postmortem autolysis effects. Analysis of the stereocilia imprint pattern at the undersurface of the tectorial membrane may provide a way to detect possible ultrastructural alterations of the hair cell stereocilia by mirroring them on the tectorial membrane.

Special volume: Planet Ocean. Scientia Marina 80(Suppl.1) 2016.-- 8 pages, 6 figures, [EN] Minidiscus comicus is a marine centric diatom that has cells with diameters as small as 1.9 μm, which brings it close to the lower limit of diatom cell size and also near to the lower limit of photosynthetic eukaryote cells. One of the questions that this raises is whether the cycle of size decline and size restoration used by most diatoms to time their life cycle can operate in such small cells. In samples collected from the western Mediterranean during 2009, M. comicus cells were found with diameters ranging from 1.9 to 6.0 μm. The larger cells were initial cells after size restoration, and these still had the valves of their parent cells attached, making it possible to determine the diameter of the threshold below which size restoration could be induced (3.1 μm). During size decline, M. comicus cell shape changed from discoid to spherical. This adaptation helped to reduce and even halt the rate of cell volume decrease, allowing cells to continue to use diameter decline as a clocking mechanism. The results show how adaptable the diatom cell wall can be, in spite of its rigid appearance, [ES] Minidiscus comicus es una diatomea céntrica marina cuyas células pueden alcanzar diámetros mínimos de tan solo 1.9 μm, lo que las acerca al límite inferior de tamaño de las células de diatomeas y en general de las células eucariotas fotosintéticas. Una de las preguntas que surgen es si el ciclo de disminución y restauración de tamaño usado por la mayoría de las diatomeas para medir los tiempos de su ciclo de vida pueda realizarse en estas pequeñas células. En muestras del Mediterráneo occidental tomadas durante 2009, las células de M. comicus presentaron diámetros de 1.9 a 6.0 μm. Las células mayores eran células iniciales después de la restauración de tamaño y aún tenían pegadas las valvas de las células progenitoras, lo cual hace posible determinar el umbral de diámetro que puede inducir a la restauración (3.1 µm). Se observó que al disminuir el tamaño, la forma de la célula cambiaba de discoidea a esférica. Esta adaptación ayuda a reducir e incluso detiene la tasa de disminución del volumen de la célula, lo que permite a las células continuar usando la disminución del diámetro como un mecanismo cronometrador. Los resultados muestran cuán adaptable puede ser la pared celular de las diatomeas, a pesar de su rígida apariencia, This work was supported by the projects FAMOSO (CTM2008-06261-C03), JSPS Grants-in-Aid for Scientific Research 26291085 and 15K14784 and Open Partnership Joint Projects of JSPS Bilateral Joint Research Projects

Electron-probe X-ray microanalysis (XRMA) is a technique that can be used to simultaneously quantify C, N, O, Na, Mg, Al, Si, P, S, Cl, K, and Ca present in single cells collected from the sea, with a minimal treatment of the samples. The technique has been used to determine elemental composition in plankton using scanning electron microscopes (SEM) or transmission electron microscopes (TEM). The methodologies used have shown some drawbacks. Here we present an improved methodology focusing on the analysis of the elemental concentration of marine microplankton cells, including light elements, based on the methodology of Norland et al. (1995). The most important modification is the use of a SEM microscope but reproducing TEM conditions by placing the sample grid at a distance from the holder bottom. This modification eliminates the interference of the SEM stub from the analysis of the cells, and improves the limit of detection of elements that are present in low concentrations. Experimental and theoretical data on the beam penetration depth using low incident beam energies (15 kV) are presented. The results show that a 15 kV accelerating voltage, invoked as a limitation in using XRMA for the analysis of samples thicker than 0.1 µm (Twining et al. 2008), is sufficient to analyze whole microplankton cells, and that there is no absorption of X-rays during the analysis. The method has been applied to diatoms and dinoflagellates from the Western Mediterranean Sea. The cell elemental composition results fall within the range of historical data in the literature.

4 pages, 2 figures, 1 table, [EN] Otolith marking provides a reference point for otolith growth patterns by validating the temporal significance of growth increments. This widespread method is primarily implemented using fluorescent dyes. The incorporation of a trace element that appears naturally in otoliths offers an alternative approach. Diplodus annularis and Serranus scriba otoliths were marked with an intramuscular injection of SrCl2 diluted in 0.9% sterile saline solution (55 mg Sr ml-1 saline solution), given at a dose of 100 mg Sr kg-1 fish. At 277 to 366 days after marking, the fishes showed little or no mortality and experienced growth in length and weight. All of the otoliths analyzed showed a clear Sr mark detected with backscattered or secondary electron imaging during a scanning electron microsope (SEM) analysis. The mark was confirmed by Sr analysis using an X-ray detector and an energy dispersive spectrometer system with the SEM. The otoliths continued to grow after the mark, and background Sr values in this new growth were much lower than at the mark. This method was feasible and yielded good results. However, the method’s cost may limit its applicability to experimental studies, [ES] El marcado de los otolitos permite establecer una referencia que valida el significado temporal de los incrementos de crecimiento. Este método muy extendido en estudios de validación utiliza preferentemente agentes fluorescentes. Un método alternativo puede ser el marcado con un elemento que aparece de forma natural en la composición de los otolitos. Los otolitos de Diplodus annularis y Serranus scriba se marcaron mediante una inyección intramuscular de SrCl2 diluída en solución salina estéril al 0.9% (55 mg Sr ml-1 solución salina) a una dosis de 100 mg Sr kg-1 individuo. Los individuos mostraron crecimiento en peso y talla y muy baja mortalidad después de 277 a 366 días tras el marcado. Todos los otolitos analizados con SEM mostraron una marca nítida, detectada tanto con los electrones retrodisperados como con los electrones secundarios. Mediante microanálisis de rayos X con un sistema EDS acoplado al SEM, dicha marca fue identificada como Sr. Los otolitos continuaron su crecimiento tras el marcado con una baja concentración de Sr comparada con la presente en la marca. La aplicabilidad del método se discute considerándose que ofrece buenos resultados. Sin embargo, el relativo coste del mismo limita su aplicabilidad en estudios experimentales, This is a contribution of the MICINN-funded project CGL2008-00958

8 pages, 5 figures, 3 tables, Most pennate diatoms are allogamous, and various types of mating systems have been described. In Pseudo-nitzschia, reproductive stages have been identified in some species, and it is generally accepted that the genus is mainly heterothallic. Here we report homothallic auxosporulation of Pseudo-nitzschia brasiliana Lundholm, Hasle et G. A. Fryxell. To our knowledge, this is the first verified description of homothallic sexual reproduction in the genus. Auxospore formation was observed in all 16 subclones derived from three initial clonal cultures of P. brasiliana. Pairing was followed by production of two gametes per gametangium, which fused to give two zygotes. Each zygote (early auxospore) was initially spherical and adhered to one girdle band of the parental frustule. The two auxospores tended to expand parallel to each other and perpendicular to the parental frustule. Elongation was synchronous, slightly asynchronous, or totally asynchronous. The entire process of sexual reproduction, from gamete formation to the appearance of the initial vegetative cells, took 2–4 d. The occurrence of sex in a homothallic species seems an advantageous life strategy for this species in that any encounter between cells of the right size class is potentially sexual, This study was supported by the EC funded Research Project SEED (Life cycle transformations among HAB species, and the environmental and physiological factors that regulate them), GOCE-CT-2005-003875, and the CRA (Centre de Referencia en Aquicultura, CIRIT-Generalitat de Catalunya, Spain). E. Garcés work was supported by a Ramon y Cajal contract of the Spanish Ministry of Education and Science. S. Quijanós work was supported by a PROMEP grant (Mexico), Colima University

26 pages, 7 figures, 4 tables, supporting information https://doi.org/10.1371/journal.pone.0154050.s001 https://doi.org/10.1371/journal.pone.0154050.s002 https://doi.org/10.1371/journal.pone.0154050.s003, Here we present, for the first time, the elemental concentration, including C, N and O, of single phytoplankton cells collected from the sea. Plankton elemental concentration and stoichiometry are key variables in phytoplankton ecophysiology and ocean biogeochemistry, and are used to link cells and ecosystems. However, most field studies rely on bulk techniques that overestimate carbon and nitrogen because the samples include organic matter other than plankton organisms. Here we used X-ray microanalysis (XRMA), a technique that, unlike bulk analyses, gives simultaneous quotas of C, N, O, Mg, Si, P, and S, in single-cell organisms that can be collected directly from the sea. We analysed the elemental composition of dinoflagellates and diatoms (largely Chaetoceros spp.) collected from different sites of the Catalan coast (NW Mediterranean Sea). As expected, a lower C content is found in our cells compared to historical values of cultured cells. Our results indicate that, except for Si and O in diatoms, the mass of all elements is not a constant fraction of cell volume but rather decreases with increasing cell volume. Also, diatoms are significantly less dense in all the measured elements, except Si, compared to dinoflagellates. The N:P ratio of both groups is higher than the Redfield ratio, as it is the N:P nutrient ratio in deep NW Mediterranean Sea waters (N:P = 20–23). The results suggest that the P requirement is highest for bacterioplankton, followed by dinoflagellates, and lowest for diatoms, giving them a clear ecological advantage in P-limited environments like the Mediterranean Sea. Finally, the P concentration of cells of the same genera but growing under different nutrient conditions was the same, suggesting that the P quota of these cells is at a critical level. Our results indicate that XRMA is an accurate technique to determine single cell elemental quotas and derived conversion factors used to understand and model ocean biogeochemical cycles, This work was supported by project PUDEM (REN2003-06637-C02, Spanish Ministry of Science and Technology, now Spanish Ministry of Economy and Competitiveness); and by an I3P fellowship (CSIC, Spanish Ministry of Education and Culture) to M. Segura-Noguera. Both funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Guerreiro, Catarina ... et al.-- Special issue Submarine Canyons: Complex Deep-Sea Environments Unravelled by Multidisciplinary Research.-- 24 pages, 37 figures, 3 tables, 2 appendix, This paper presents a first attempt to characterize coccolithophore assemblages occurring in the context of an active submarine canyon. Coccolithophores from the upper-middle sections of the Nazaré Canyon (central Portuguese margin) - one of the largest canyons of the European continental margin - were investigated during a late winter period (9-12 March 2010). Species distributions were analyzed in a multiparameter environmental context (temperature, salinity, turbidity, Chl-a and nutrient concentrations). Monthly averaged surface water Chl-a concentrations between 2006 and 2011 assessed from satellite data are also presented, as a framework for interpreting spatial and temporal distribution of phytoplankton in the Nazaré Canyon. The Nazaré Canyon was observed to act as a conduit for advection of relatively nutrient-poor oceanic waters of ENACWst origin into nearshore areas of the continental shelf (less than 10. km off the coast), whilst at the surface a nutrient-rich buoyant plume resulting from intensive coastal runoff prior and during the beginning of the cruise was spreading in oceanward direction. Two distinct coccolithophore assemblages appear representative for the coast to open-ocean gradient: (1) Emiliania huxleyi together with Gephyrocapsa ericsonii and Coronosphaera mediterranea dominated the more productive assemblage present within coastal-neritic surface waters; and (2) Syracosphaera spp. and Ophiaster spp. displayed a higher affinity with open-ocean conditions, and also generally a broader vertical distribution. Local >hotspots> of coccolithophore and phytoplankton biomass potentially associated with perturbations of surface water circulation by the canyon are discussed. © 2013 Elsevier Ltd., This research was supported by the HERMIONE project (EC contract 226354) funded by the European Commission and the Cd Tox-CoN project (FCT-PTDC/MAR/102800/2008) funded by the Portuguese Science Foundation FCT. The first author benefited from an FCT PhD grant( FRH/BD/41330/2007)

The morphological study of the Odontocete organ of Corti, together with possible alterations associated with damage from sound exposure, represents a key conservation approach to assess the effects of acoustic pollution on marine ecosystems. By collaborating with stranding networks from several European countries, 150 ears from 13 species of Odontocetes were collected and analyzed by scanning (SEM) and transmission (TEM) electron microscopy. Based on our analyses, we first describe and compare Odontocete cochlear structures and then propose a diagnostic method to identify inner ear alterations in stranded individuals. The two species analyzed by TEM (Phocoena phocoena and Stenella coeruleoalba) showed morphological characteristics in the lower basal turn of high-frequency hearing species. Among other striking features, outer hair cell bodies were extremely small and were strongly attached to Deiters cells. Such morphological characteristics, shared with horseshoe bats, suggest that there has been convergent evolution of sound reception mechanisms among echolocating species. Despite possible autolytic artifacts due to technical and experimental constraints, the SEM analysis allowed us to detect the presence of scarring processes resulting from the disappearance of outer hair cells from the epithelium. In addition, in contrast to the rapid decomposition process of the sensory epithelium after death (especially of the inner hair cells), the tectorial membrane appeared to be more resistant to postmortem autolysis effects. Analysis of the stereocilia imprint pattern at the undersurface of the tectorial membrane may provide a way to detect possible ultrastructural alterations of the hair cell stereocilia by mirroring them on the tectorial membrane.

Special issue Advances in marine biogeochemistry, ecotoxicology and contamination of coastal systems.-- 5 pages, 3 figures, 1 table, [EN] Coccolithophores produce calcium carbonate platelets, the coccoliths, and play a significant role in the C and Ca cycles. Coccoliths are important components of marine biogenic carbonate sediments and their chemical analysis can provide tools for paleoceanographic investigation. In particular, the Mg/Ca ratio of coccoliths has been proposed as a paleotemperature proxy. The present study uses X-ray microanalysis to evaluate the Ca and Mg composition of heterococcoliths and holococcoliths of different coccolithophore species. Our measurements indicate that the Mg values in heterococcoliths do not exceed a low threshold and do not show any consistent relationship with the Ca content, while the Mg content of holococcoliths spans a wider range, can reach much higher values and shows a linear relationship with the Ca content. Several heterococcolithophore species tend to form separate clusters according to their Mg and Ca values. Within each cluster, there were no consistent differences in the Mg/Ca ratios of specimens sampled at different temperatures or seasons, suggesting that using the Mg/Ca ratio as a paleothermometer may be problematic. Our findings could have implications for the interpretation of the fossil record because Mg-rich calcite dissolves more easily, [ES] Los cocolitóforos producen unas plaquitas de carbonato de calcio denominadas cocolitos, y juegan un papel significativo en los ciclos biogeoquímicos del C y el Ca. Los cocolitos constituyen un componente importante del registro sedimentario y su análisis químico puede proporcionar herramientas para la investigación paleoceanográfica. En particular, se ha sugerido que la relación Mg/Ca podría ser usada como un indicador de paleotemperatura. En este trabajo presentamos un estudio, realizado mediante la técnica de microanálisis por rayos X, de la composición elemental de holo- y heterococolitos pertenecientes a diferentes especies de cocolitóforos. Se ha observado que el contenido de Mg en los heterococolitos no supera un umbral muy bajo y no presenta relación con el de Ca, mientras que en los holococolitos el contenido de Mg es en general más elevado, abarca un rango más amplio y guarda una relación lineal con el de Ca. Diversas especies de heterococolitóforos tendían a formar grupos separados en función de su contenido en Ca y Mg. Dentro de cada especie, no se detectaban diferencias consistentes en la relación Mg/Ca de especímenes de muestras de agua de distintas temperaturas o tomadas en diferentes estaciones del año, lo que indica que el uso de la relación Mg/Ca como paleotermómetro puede ser problemático. Nuestras observaciones pueden tener implicaciones para la interpretación del registro sedimentario, ya que la calcita rica en Mg se disuelve más rápidamente, The analyses were carried out at the Servei de Microscòpia Electrònica of the Institut de Ciències del Mar (CSIC). This work was supported by Grup de Recerca Consolidat 2009 SGR 588 of the Generalitat of Catalunya, Spanish project CTM2008-06261-C03-01/MAR and EU Training Network CODENET (FRMXET97-0113)

Guerreiro, Catarina ... et al.-- 19 pages, 13 figures, 3 tables, 2 apendix, Coccolithophore communities collected during late winter (9-19 March of 2010) over the central Portuguese margin showed a major change in species abundance and composition within a few days' time, closely related to the highly transient meteorological and oceanographic conditions.Particularly favourable conditions for coccolithophore growth resulted from late winter continental runoff combined with northerly winds prevailing over the shelf, under clear sky conditions. A nutrient-rich Buoyant Plume (BP) resulting from intense river water runoff prior to and during the start of the cruise, was observed to spread out over the denser winter mixed layer water beneath, and extend equatorwards and offshore under influence of Ekman superficial dynamics. Stabilization of buoyancy, settling of suspended sediment from the BP and the prevailing clear sky conditions in the transition to the 2nd leg of the cruise resulted in optimum conditions for coccolithophores to develop, at the expense of nutrient availability in the superficial sunlit layer. Within a few days, coccolithophore cell densities and associated phytoplankton biomass more than tripled, reaching maximum values of 145,000. cells/l and ~13. μg/l Chl-a, respectively.Often considered as a uniform functional group of calcifying phytoplankton thriving in low-turbulence, low-nutrients and high-light environments, results presented in this study clearly show that coccolithophore life strategies are much more diverse than expected. The increase of cell densities was mainly due to the bloom of Emiliania huxleyi and Gephyrocapsa oceanica in the coastal region west off Cape Carvoeiro, together with other opportunistic phytoplankton genera (Chaetoceros s.l., Thalassiosira s.l and Skeletonema s.l.). This confirms their role as early succession r-selected taxa, capable of rapid growth within nutrient-rich environments. On the contrary, Syracosphaera spp. and Ophiaster spp. displayed the characteristics of K-selected species, being consistently more abundant in more oceanic and less eutrophic waters, away from the influence of the BP, during both low- and high-productive periods.A general description of coccolithophore communities as well as the environmental conditions during this period is presented in this study (i.e. hydrography and nutrient availability). Multivariate analysis was used to investigate the impact of short-term environmental changes on the productivity and ecology of this group. In view of the observed dominance of coccolithophores off Portugal during winter, this transitional period appears particularly favourable for coccolithophores to develop. The results highlight the importance of taking short-term hydrographic and meteorological variability into account when interpreting the ecological preferences of coccolithophores from coastal-neritic-oceanic transitional settings. © 2013 Elsevier Ltd., This research was supported by the HERMIONE project (EC contract 226354) funded by the European Commission and the Cd Tox-CoN project (FCT-PTDC/MAR/102800/2008) funded by the Portuguese Science Foundation FCT. The first author benefits from an FCT PhD grant (FRH/BD/41330/2007)

16 páginas, 6 figuras, 6 tablas, [EN] Proliferations of the genus Pseudo-nitzschia recur along the Catalan coast (NW Mediterranean) throughout the year. The establishment of 58 clonal cultures facilitated morphological studies with scanning electron microscopy (SEM) and ITS 5.8S rDNA sequence characterization. Moreover, strains of each species were examined with respect to sexual compatibility and toxicity. The results of the morphological and phylogenetic studies confirmed nine species of the genus Pseudo-nitzschia: P. brasiliana, P. calliantha, P. delicatissima clade A/del 2, P. arenysensis, P. fraudulenta, P. galaxiae, P. linea, P. multistriata and P. pungens clade I. Moreover, two Pseudo-nitzschia species, P. caciantha and P. cf mannii, could only be identified following SEM analysis of their morphology. None of the cultured strains of Pseudo-nitzschia analyzed produced domoic acid in amounts above the limit of detection. The current distributions of the Pseudo-nitzschia species in the Mediterranean Sea were plotted on maps, which led to the following observations: i) diversity within this genus is much greater than previously considered, ii) some species have a broad distribution (e.g. P. calliantha), iii) whereas the distribution of others is narrowly restricted (e.g. P. pungens clade I). Moreover, this study reports the first detection of P. linea in the Mediterranean Sea and is the first description of P. galaxiae and P. cf mannii along the Catalan coast. Morphological studies coupled with molecular biological characterization, mating tests and biogeographic distribution analyses provide a critical theoretical basis for testing and/or implementing the current phylogenetic framework in the genus Pseudo-nitzschia, [ES] Las proliferaciones del género Pseudo-nitzschia son recurrentes durante todo año en la costa catalana (Mediterráneo NO). El establecimiento de 58 cultivos clonales han facilitado la comparación morfológica por medio del microscopio óptico y electrónico de barrido y la secuenciación del gen ADN ribosomal ITS 5.8S. Además se examinó la compatibilidad sexual de las cepas de cada una de las especie juntamente con el análisis de toxicidad. Los resultados del estudio morfológico y filogenético confirmaron nueve especies del género Pseudo-nitzschia: P. brasiliana, P. calliantha, P. delicatissima clade A/del 2, P. arenysensis, P. fraudulenta, P. galaxiae, P. linea, P. multistriata y P. pungens clade I. Se identificaron morfológicamente dos especies de Pseudo-nitzschia con SEM: P. caciantha y P. cf manii. Ningún cultivo clonal de Pseudo-nitzschia mostró producción de acido domóico por encima del límite de detección. Se muestra la distribución actual de especies de Pseudo-nitzschia en el mar Mediterráneo y esto permite concluir que: i) la diversidad del género es más amplia que lo considerado previamente, ii) algunas especies tienen una amplia distribución (por ejemplo. P. calliantha), iii) la distribución de otras especies es muy restringida (por ejemplo. P. pungens clade I). Este estudio presenta la primera detección de P. linea en el mar Mediterráneo y se describen por primera vez P. galaxiae y P. cf mannii en la costa catalana. Los estudios morfológicos conjuntamente con la caracterización molecular, compatibilidad sexual y análisis de la distribución biogeográfica constituyen una base teórica crítica para complementar el marco de trabajo filogenético en el género Pseudo-nitzschia, This study was funded by ACA (Generalitat de Catalunya), CSIC, the EC-funded Research Project SEED, GOCE-CT- 2005-003875 and the Programa de seguiment de la qualitat de les aigües, mol.luscs i fitoplancton tòxic a les zones de producció de marisc del litoral català de la DGPIAM and the Xarxa de Referència de Recerca i Desenvolupament en Aqüicultura. IRTA acknowledges financial support from the Instituto Nacional de Investigación Agraria (INIA) through the project RTA2006-00103-00-00. S. Quijano-Scheggia’s work was supported by a PROMEP grant, Universidad de Colima, México. E. Garcés’s work was supported by a Ramon y Cajal contract from the Spanish Ministry of Science and Education

Publicación online disponible en: http://www.icm.csic.es/scimar/index.php, [EN] Potentially toxic species of the genus Pseudo-nitzschia were studied along the Spanish NW Mediterranean coast from January 2005 to May 2006. Observation in electron microscopy revealed the presence of Pseudo-nitzschia brasiliana, P. calliantha, P. delicatissima, P. fraudulenta, P. multistriata and P. pungens. Several strains were isolated from coastal waters and their clonal cultures were compared by combined techniques, including light and electron microscopy and internal transcribed spacer (ITS-1, 5.8S and ITS-2) rDNA sequencing. Cultured isolates were submitted to HPLC analysis of pigments to evaluate the possibility of taxonomic discriminations by means of a simple chemotaxonomic approach. The genus Pseudo-nitzschia showed high cell concentrations during most of the year, but the population initiated a sharp decline at all stations in the period between April and May. P. delicatissima with P. calliantha were found at the northern stations between February and April, and at the southern stations between August and November. P. brasiliana and P. multistriata were only occasionally detected in the southern region. None of the environmental variables considered was significant to explain the observed spatial and temporal distributions of Pseudo-nitzschia species in the area studied. Differences in the growth rate and cell yield of the species indicate that biotic factors may play a role in the observed distributional patterns, [ES] Se estudiaron especies potencialmente tóxicas de Pseudonitzschia en la costa española del Mediterráneo NO de enero 2005 a mayo 2006. Observaciones al microscopio electrónico revelan la presencia de Pseudo-nitzschia brasiliana, P. calliantha, P. delicatissima, P. fraudulenta, P. multistriata y P. pungens. Se aislaron varias cepas de las aguas costeras y fueron comparadas entre si mediante técnicas combinadas que incluyen microscopia óptica, electrónica, secuenciación del ITS-1, 5.8S e ITS-2 rDNA. Cultivos de las cepas aisladas fueron analizadas con HPLC para estudiar la posibilidad de discriminarlas por medio de un método quemotaxonómico simple. El género Pseudo-nitzschia muestra concentraciones celulares altas durante la mayor parte del año, pero la población inicia un declive brusco en todos los puntos de muestreos en el periodo entre abril y mayo. P. delicatissima y P. calliantha fueron encontradas en las estaciones del norte entre febrero y abril, y en las del sur entre agosto y noviembre. P. brasiliana y P. multistriata fueron detectadas sólo ocasionalmente en las estaciones del sur. Ninguna de las variables ambientales consideradas explica satisfactoriamente la distribución temporal y espacial de las especies de Pseudo-nitzschia en el área de estudio. Diferencias en la tasa de crecimiento y producción celular de las especies indica que los factores bióticos pueden jugar un papel importante en los patrones de distribución observados

Potentially toxic species of the genus Pseudo-nitzschia were studied along the Spanish NW Mediterranean coast from January 2005 to May 2006. Observation in electron microscopy revealed the presence of Pseudo-nitzschia brasiliana, P. calliantha, P. delicatissima, P. fraudulenta, P. multistriata and P. pungens. Several strains were isolated from coastal waters and their clonal cultures were compared by combined techniques, including light and electron microscopy and internal transcribed spacer (ITS-1, 5.8S and ITS-2) rDNA sequencing. Cultured isolates were submitted to HPLC analysis of pigments to evaluate the possibility of taxonomic discriminations by means of a simple chemotaxonomic approach. The genus Pseudo-nitzschia showed high cell concentrations during most of the year, but the population initiated a sharp decline at all stations in the period between April and May. P. delicatissima with P. calliantha were found at the northern stations between February and April, and at the southern stations between August and November. P. brasiliana and P. multistriata were only occasionally detected in the southern region. None of the environmental variables considered was significant to explain the observed spatial and temporal distributions of Pseudo-nitzschia species in the area studied. Differences in the growth rate and cell yield of the species indicate that biotic factors may play a role in the observed distributional patterns., Se estudiaron especies potencialmente tóxicas de Pseudonitzschia en la costa española del Mediterráneo NO de enero 2005 a mayo 2006. Observaciones al microscopio electrónico revelan la presencia de Pseudo-nitzschia brasiliana, P. calliantha, P. delicatissima, P. fraudulenta, P. multistriata y P. pungens. Se aislaron varias cepas de las aguas costeras y fueron comparadas entre si mediante técnicas combinadas que incluyen microscopia óptica, electrónica, secuenciación del ITS-1, 5.8S e ITS-2 rDNA. Cultivos de las cepas aisladas fueron analizadas con HPLC para estudiar la posibilidad de discriminarlas por medio de un método quemotaxonómico simple. El género Pseudo-nitzschia muestra concentraciones celulares altas durante la mayor parte del año, pero la población inicia un declive brusco en todos los puntos de muestreos en el periodo entre abril y mayo. P. delicatissima y P. calliantha fueron encontradas en las estaciones del norte entre febrero y abril, y en las del sur entre agosto y noviembre. P. brasiliana y P. multistriata fueron detectadas sólo ocasionalmente en las estaciones del sur. Ninguna de las variables ambientales consideradas explica satisfactoriamente la distribución temporal y espacial de las especies de Pseudo-nitzschia en el área de estudio. Diferencias en la tasa de crecimiento y producción celular de las especies indica que los factores bióticos pueden jugar un papel importante en los patrones de distribución observados.

18 pages,16 figures, 3 tables, A series of seasonal, monthly and short-term samplings was conducted in open and confined waters of the Algiers area in 2001-2002 and summer 2003 in order to detect potentially harmful microalgae species (HAB). A total of 14 potentially toxic and 18 bloom-forming species were recorded, of which some were found for the first time in Algerian coastal waters: the potential toxin producers Alexandrium minutum, Dinophysis sacculus (dinoflagellates) and Pseudo-nitzschia calliantha (diatom), as well as the bloom-forming species Lepidodinium chlorophorum (dinoflagellate), Cyclotella meneghiniana (diatom) and Holococcolithophora sphaeroidea (holococcolithophorid). The latter produced a very important bloom with considerable water discoulouration. The occurrence and duration of this event in the Algiers Harbour underline the importance of this enclosed structure as a growth area for HAB species. The transport of a H. sphaeroidea bloom toward off-shore waters by an anticyclonic eddy demonstrates the effect of Algerian current mesoscale instabilities on the spatial distribution of phytoplankton communities., H. Illoul was supported by a grant of the Agencia Española de Cooperación Internacional (AECI-MAE) and the Conselleria de medi ambient, Govern de les Illes Balears and CSIC through the contract " Evaluación y monotorización de la calidad de las aguas costeras de las Islas Baleares. The authors wish to thank L. Arin, D. Blasco, M. Estrada, E. Garcès, S. Quijano, N. Sampedro, M. Vila ( ICM,CSIC, Barcelona ), S.Fraga (IEO, Vigo), F.L. Samson-Kechacha (USTHB, Algiers) for help and useful suggestions. Also A. Mamache and the ship crews of R/V "ibtacim, Baba Arroudj" and M.S. Ben,Yahia during the research cruises.

8 páginas, 6 figuras., Hexamethyldisilizane (HMDS) and tetramethylsilane are organic compounds that are volatile at ambient temperature and which can therefore be used for air-drying biological samples for SEM studies. The techniques using these compounds provide results that are comparable with those obtained by critical point drying, but which involve a very simple process that saves time and money. Both techniques were applied to SEM studies of Ephemeroptera and Plecoptera eggs in order to assess their suitability as alternative methods to critical point drying for these kinds of biological material. The results show no morphological differences between eggs HMDS air-dried and critical point-dried.

The present Atlas contains a detailed study, based in scanning electron microscopy (SEM) observations, of living coccolithophores from NW Mediterranean waters. The study contains 103 figures with 411 micrographs, which correspond to 168 coccolithophores (including different taxonomic and morphotypic entities). The figured specimens were collected during different cruises carried out from 1995 to 1999. Classification of the organisms follows modern taxonomy of living calcareous nannoplankton. Measures of the specimens and notes on their taxonomy are given in addition to abridged descriptions of the studied taxa. The atlas contains a large number of previously undescribed forms, specially in the genera Syracosphaera, Papposphaera, Polycrater, Anthosphaera, Corisphaera and Sphaerocalyptra. Several species never illustrated in the literature are presented here for the first time. Coccospheres having coccoliths of different recognized species are presented. These combination coccospheres are nowadays considered as transitional steps between different phases in the cellular life-cycle. An introduction with a brief overview of the actual coccolithophore knowledge and an abridged glossary with figures of the basic terminology are included, This research was supported by the C.S.I.C. and projects MAR91-0359, GRQ93-8041, AMB94-0853; MAS2-CT93-0063, MAS3-CT96-0051 and MAR98-0932. Samples were provided by, projects MAS2-CT930063, MAS3-CT95-0037, MAS3-CT95-0016 and programe MEC-HF98-207. The EC TMR project CODENET, Coccolithophorid Evolutionary Biodiversity and Ecology Network (FRMXET97-0113), financed part of this research and the present volume