SE Bay Of Biscay Research Articles

Response of the phytoplankton community to the cessation of wastewater discharges in the urdaibai estuary (SE bay of biscay) based on PIGMENTUM analysis of HPLC pigments

Phytoplankton responds rapidly to nutrient availability variations, becoming a useful indicator for eutrophication and/or management actions to reduce it. The present study evaluated the medium-term response of the phytoplankton community of a temperate estuary (Urdaibai estuary) to the cessation of discharges from a wastewater treatment-plant (WWTP), comparing the physicochemical conditions and the phytoplankton community before (2020) and after (2022) the sewerage works. The cessation led to a decrease of ammonium and phosphate, causing decreases of phytoplankton biomass in the outer and middle estuary and increases in the surroundings of the WWTP. Community composition also changed, recording an increase of prasinoxanthin-containing algae's contribution to total biomass, and a composition shift in the inner estuary, from mainly flagellates (alloxanthin-containing and chlorophyll b-containing algae) to the increase of diatoms, which could be prompted by the change of nutrient-ratios and the nitrogen source, and might indicate the recuperation of the system.

Predicting important fishing grounds for the small-scale fishery, based on Automatic Identification System records, catches, and environmental data

Abstract Effective and sustainable management of small-scale fisheries (SSF) is challenging. We describe a novel approach to identify important fishing grounds for SSF, by implementing a habitat modelling approach, using environmental predictors and Automatic Identification System (AIS)-B data coupled with logbook and First Sales Notes data, within the SE Bay of Biscay. Fishing activity patterns and catches of longliners and netters are used to determine the main environmental characteristics of the fishing grounds, and a habitat modelling approach is implemented to predict the zones that fulfil similar environmental characteristics across a larger geographical extent. Generalized additive mixed models (GAMMs) were built for 24 fish species, and to identify other zones that fulfil similar characteristics and, thus, could be considered relevant for the species targeted by each gear type. Most of the models showed a good prediction capacity. The models included between one and four predictor variables. ‘Depth of mixing layer’ and ‘benthic rocky habitat’ were the variables included more frequently for fish species captured by netter’s fleet. For longliners, the ‘seafloor slope’ and ‘benthic rocky habitat’ were the two most important variables. The predictive maps provide relevant information to assist in management and marine spatial planning.

Phytoplankton community composition in relation to environmental variability in the Urdaibai estuary (SE Bay of Biscay): Microscopy and eDNA metabarcoding

Phytoplankton monitoring is essential for the global understanding of aquatic ecosystems. The present research studies the phytoplankton community of the Urdaibai estuary, combining microscopy and eDNA metabarcoding for the first time in the area. The main aims were to describe the phytoplankton community composition in relation to the environmental conditions of the estuary, and to compare the two methods used. Diatoms Minutocellus polymorphus and Chaetoceros tenuissimus dominated the outer estuary, being replaced by Teleaulax acuta (cryptophyte), Kryptoperidinium foliaceum (dinoflagellate) and Cyclotella spp. (diatom) towards the inner area. This change was mainly prompted by salinity and nutrients. Metabarcoding revealed the presence of 223 species that were not observed by microscopy in previous studies in the estuary. However, several characteristic species (e.g., K. foliaceum) were only detected with microscopy. Additionally, microscopy covered the limitations of eDNA metabarcoding concerning quantification. Thus, to give a full insight, a combination of techniques is recommended.

Modelling the morphological response of the Oka estuary (SE Bay of Biscay) to climate change

Adaptation in and around estuaries, to ensure the future resilience of both the natural environment and the communities that are located alongside is an increasingly pressing need. As part of an adaptation planning program for the Basque estuaries (northern Spain, south-eastern Bay of Biscay), a modelling system to simulate the morphological response of the Oka estuary to climate change has been developed. Existing knowledge was used as the basis to frame this pilot modelling examining both the short-term change (storm, seasonal, annual) and the longer-term changes (decades to eons). In this paper, we focus on the long-term response and consideration of the output from the process model is limited to the data that was extracted to help parameterize the long-term model. The latter was then used to examine the response of the estuary to the past changes over a historical time scale, where observations from foraminiferal analysis and saltmarsh response were used to establish the predictive validity of the model.Forcing the model with a linear rate of sea level rise representative of the 20th century, the estuary keeps pace with sea level rise in agreement with the observations. An 18.6-year periodic variability was identified over the saltmarshes, by including the effect of the nodal tide, with the last deposition maximum occurring in 2020.The effect of the opening of a saltmarsh that was drained at the beginning of the 18th century was investigated using a simplified schematization and showed sedimentation rates of up to one order of magnitude larger than in natural marsh, in general agreement with the rates obtained in previous studies.To predict the future response of the estuary, simulations with an exponential sea level rise were performed using scenarios obtained from the latest IPCC projections. The estuary fails to keep pace with sea level rise in any of the scenarios considered. The attendant increase in the hydroperiod over the saltmarshes is also likely impact to saltmarsh species productivity and distribution.Despite the simplifications inherent to the model, and the simplifications made in the representation of the estuary and forcing conditions, the methods presented here provide additional insights into long-term behaviour that complement information obtained from more detailed, but short-term, process models. The combined modelling approach allows adaptation measures to climate change to be considered over longer timescales.

Multi-source and multi-scale data integration for the assessment of the marine environmental status of the Basque Coast (SE Bay of Biscay)

In the context of the European Marine Strategy Framework Directive (MSFD, 2008/56/EC), Member States are required to assess the environmental status of marine waters. With the aim to support practitioners in this effort, and guide them in the identification of management solutions, a team of researchers has brought together available information for the Basque coastal zone (SE Bay of Biscay), and assessed the marine environmental status of these waters. To undertake the study, the area was divided into Marine Reporting Units (MRUs), following the MSFD terminology, which had specific areas assigned. The information used for the assessment was obtained from a variety of open sources (i.e., in-situ long-term monitoring data, biological data from annual/triannual surveys, multibeam echosounder data, satellite data, and had been collected at different spatial scales, from the coastline to offshore, covering the whole Exclusive Economic Zone. A total of 67 indicators were used, covering some ecosystem components: physico-chemistry of sediments and waters, phytoplankton, benthic fauna and flora, fish, birds, mammals, and alien species. The associated data, for 2010 to 2019, were then collated and integrated to assess the environmental status in a holistic way, using NEAT (Nested Environmental status Assessment Tool). The analyses included spatial scenarios (coastline to offshore), as well as filtering by different MSFD descriptors (i.e., biodiversity, alien species, eutrophication, seafloor integrity and contamination). Overall, the Basque coast is in good status, with no clear spatial gradient. But when focusing on specific ecosystem components (e.g., seabirds, mammals, some commercial fish species), it is possible to identify some components in bad status, with scope for improvement through the implementation of management measures. The integrated assessment approach presented and the outputs that are obtained can be used to guide European practitioners in their efforts to prioritize management measures. Furthermore, results are comparable to those reported in official MSFD assessments, confirming the power of the NEAT software.

Stocking density effect on the growth and mortality of juvenile European flat oyster (Ostrea edulis Linnaeus, 1758)

AbstractThe effect of stocking density on the growth and mortality of the European flat oyster (Ostrea edulis Linnaeus, 1758) reared in lantern nets was evaluated, starting from spat up to the end of juvenile phase. Oysters were deployed in a raft on the Basque coast (SE Bay of Biscay) for 18 months. Oysters were divided into four densities ranging from 25% to 100% of surface coverage. At the end of the experiment, oysters from an initial mean height and wet weight of 22.79 ± 3.70 mm and 1.00 ± 0.30 g reached mean values of 55.86 ± 8.21 mm and 19.08 ± 9.66 g, respectively. Although significant differences were detected in the growth of oysters reared at different stocking densities, these differences were not density dependent. On the other hand, mortality increased with time showing relatively high values (27%–38%), but especially at the end of the study when oysters at the highest density showed values up to 50%. In conclusion, stocking density had no effect on the growth, but had a negative effect on the survival at the highest density. A stocking density of 75% is recommended as the optimum for rearing O. edulis in the Basque coast.

Defining Cost-Effective Solutions in Designing Marine Protected Areas, Using Systematic Conservation Planning

Environmental conservation is currently one of the main objectives of marine management. It is agreed that effective management requires evaluating the tradeoffs between protection and economic costs for negatively impacted maritime activities. For these reasons, integrated approaches combining ecological and socio-economic aspects are needed to achieve nature conservation and sustainability targets. Here, we present an approach to identify cost-effective priority marine areas for protection through a Systematic Conservation Planning method, adopting the Basque Country as case study (SE Bay of Biscay). Eight protection scenarios were defined, targeting a combination of protection features: benthic habitats, biological value of cetaceans, birds, macroalgae, and macroinvertebrates, potential provision of ecosystem services, and habitat sensitivity to human activities. In turn, the total fishing pressure produced by artisanal fisheries was adopted as a measure of the socio-economic costs of protection (assuming, for this research, that fishing would be banned in the protected areas). The results indicated that existing marine protected areas (MPAs) were very close to achieving prescribed protection targets, while these targets could be achieved by increasing the size of the existing MPAs. Higher costs were associated with the declaration of areas that were targeting a larger number of protection features. Nevertheless, cost/effectiveness was higher in these cases, with the environmental benefits outweighing a comparatively smaller increase in cost. However, the most cost-effective scenarios were those that included the extension of already existing MPAs. The method implemented can assist managers and decision makers in identifying conservation gaps and ecosystem components that require special attention. In addition, the approach can be used to develop management strategies that may be adopted under different protection scenarios. Thus, the approach proposed here could be used to inform ecosystem-based marine spatial planning.

Bathyal cumacean assemblages from the southern margin of the Cap Ferret Canyon (SE Bay of Biscay)

The structure of the cumacean assemblages from the southern margin of the Cap Ferret Canyon was studied at 13 stations ranging from 346 to 1099 m depth with a modified Macer-GIROQ suprabenthic sledge (four superimposed nets; 0.5 mm mesh size). A total of 1885 specimens were collected and classified into 5 families and 42 species. The total abundances fluctuated between 2.8 ind./100 m2 (station TS04; 484-485 m) and 55.8 ind./100 m2 (station TS08; 714-708 m). The highest values of species richness and diversity were recorded at station TS13 (1097-1099 m): S=25 species; H’(log2)=4.05. The near-bottom vertical distribution of the cumacean fauna showed the same pattern at all stations: at least 60% of the individu­als were sampled by the lower net of the sledge and a drastic abundance decrease occurred between the two lowermost water layers sampled by the sledge. The multivariate analysis carried out on abundance data discriminated three main groups of stations distributed across depth (TS09 excluded): group Ia (346-485 m) characterized by the dominance of Nannastacidae (57.2%) at family level and Campylaspis sulcata, Leptostylis macrura at species level; group Ib (522-714 m) characterized by the dominance of Nannastacidae (66.1%) at family level and Campylaspis squamifera, C. laevigata and Leptostylis ma­crura at species level; and group II (790-1099 m) characterized by the dominance of Diastylidae (40.3%) at family level and Makrokylindrus (Adiastylis) josephinae, Leucon (Epileucon) pusillus and Diastyloides serratus at species level. According to this analysis, the main faunal change occurs between group I and II between 714 and 790 m, in relation to changes in the texture of surficial sediments. Although bathyal cumacean assemblages appear to be less abundant than those studied on continental shelves, they are significantly more diverse. However, such results could be in part related to the use of different sampling methods.

Eusirus bonnieri sp. nov. (Crustacea: Amphipoda: Eusiridae), a new deep speciesfrom the southeastern Bay of Biscay (NE Atlantic Ocean).

A new bathyal eusirid, Eusirus bonnieri sp. nov., is described from the SE Bay of Biscay, mainly characterized by its strongly deflexed rostrum (not mentioned for any other known Eusirus species) and by a long spiniform process at the posterodistal corner of pereopods 5-7 merus. It was sampled with a suprabenthic sledge between 370 and 1099 m on southern margin of the Cap Ferret Canyon and within the Capbreton Canyon. It was relatively scarce on the open slope and its maximum abundance was registered within the upper part of the Capbreton canyon. Beside some ecological/biological data, an identification key is provided for all known species in this genus.

Transcription pattern of reproduction relevant genes along the brain-pituitary-gonad axis of female, male and intersex thicklip grey mullets, Chelon labrosus, from a polluted harbor

The reproductive cycle of teleost fishes is regulated by the brain-pituitary-gonad (BPG) axis. The transcription profile of genes involved in the reproduction signalling in the BPG-axis differs in females and males during the gametogenic cycle. Impacts of endocrine disrupting chemicals on these signalling pathways in fish are known, but the participation of the BPG-axis in the development of the intersex condition is not well understood. Intersex thicklip grey mullets (Chelon labrosus) have been identified in several estuaries from the SE Bay of Biscay, revealing the presence of feminizing contaminants in the area. In previous studies, transcription patterns of genes related with steroidogenesis and gamete growth have been shown to differ among female, male and intersex mullets. However, many components of the reproduction control have not been studied yet. The aim of this study was to assess the transcription levels of target BPG-axis genes in female, male and intersex mullets captured in the polluted harbour of Pasaia, during their gametogenic cycle. After histologically examining the gonads, the transcription levels of previously sequenced target genes were measured by qPCR: kiss2, gpr54 and gnrh1 in brain, fshβ and lhβ in pituitary and fshr and lhr in gonads. In both females and males, brain genes were most transcribed in early gametogenesis, proving their relevance in the onset of both oogenesis and spermatogenesis. Pituitary gonadotropins in females showed upregulation as oogenesis progressed, reaching the highest transcription levels at vitellogenic stage, while in males transcript levels were constant during spermatogenesis. Transcription levels of gonadotropin receptors showed different patterns in ovaries and testes, suggesting differing function in relation to gametogenesis and maturation. Intersex mullets showed transcription levels of brain target genes similar to those observed in females at cortical alveoli stage and to those in mid spermatogenic males. In intersex testes the transcription pattern of gonadotropin receptor fshr was downregulated in comparison to non-intersex testes.

Towards an understanding of the spatial relationships between natural capital and maritime activities: A Bayesian Belief Network approach

Economic activities are dependent upon natural capital (NC), which are responsible for ‘Ecosystem Services’ (ES). Understanding dependencies on NC provides insight into the ecosystem’s capacity to maintain and develop activities into the future. To determine ‘NC dependencies’, we present a framework linking maritime activities (bottom trawling, artisanal fisheries, aquaculture and tourism) to their demand for ES and further, to the NC components responsible for their production. The framework was operationalised using a spatially-explicit Bayesian Belief Network (BBN), using the Basque coast (SE Bay of Biscay) to illustrate our approach, in identifying trends in the strength and spatial distribution of NC dependencies. For example, benthic trawling was dependent on sedimentary habitats, with ‘moderate’ to ‘high’ dependency of 52% of the study area. The model can also extrapolate NC dependencies to a larger area where the activity currently does not operate, where benthic trawling was estimated to have higher utilisation of ES in deeper waters. When NC dependencies are combined with economic and legislative factors, the current spatial distribution of the activity can be explained, and the potential socio-economic impacts of management decisions could be predicted. The integrative approach contributes towards ecosystem-based spatial planning.

Una nueva especie del género <em>Prionospio</em> Malmgren, 1867 (Annelida, Spionidae) procedente del sureste del golfo de Vizcaya

Una nueva especie, Prionospio rikardoi n. sp. ha sido identificada en fondos circalitorales de las costas del País Vasco (SE del golfo de Vizcaya). La nueva especie se caracteriza por poseer crestas dorsales en varios segmentos corporales y cuatro pares de branquias lisas, apinnadas y relativamente cortas en los setígeros 2-5. En el presente artículo se describe, ilustra y compara la nueva especie con especies próximas. Además, se aporta una clave de identificación de todas las especies válidas del género Prionospio Malmgren, 1867 con sólo branquias apinnadas que comienzan en el segundo setígero. El material tipo ha sido depositado en el Museo Nacional de Ciencias Naturales de Madrid.
 
 urn:lsid:zoobank.org:pub:6F3B8DDB-1E72-47E6-8454-08E7B68524E0

Multi-annual survey of health status disturbance in the Bilbao estuary (Bay of Biscay) based on sediment chemistry and juvenile sole (Solea spp.) histopathology

The Bilbao estuary (SE Bay of Biscay) is a recovering ecosystem whose sediments are still contaminated. They represent a potential risk for the biota including benthic and demersal species living in direct contact with the sediment. In this context, the present study aims to survey trends of the health status of the Bilbao estuary based on sediment chemistry and sole (Solea spp.) histopathology. Monitoring campaigns were carried out every autumn from 2011 to 2017 along the estuary. Contaminant levels were measured in sediments; liver, gills and gonads of juvenile fish were collected for histopathology. Overall, contaminant levels fluctuated throughout the years, with highest values recorded in the earlier years of the study period. Sole histopathology showed alterations of mild severity. Results permitted to assess the environmental health status of the Bilbao estuary during 7 years, although no clear temporal trend was detected. Longer-term monitoring programmes are necessary to confirm the ecosystem recovery.

Una nueva especie de <em>Paradoneis</em> Hartman, 1965 (Annelida: Paraonidae) procedente del NE de la península Ibérica (SE del golfo de Vizcaya, NE del océano Atlántico)

Una especie nueva del género Paradoneis Hartman, 1965 (Annelida, Paraonidae) ha sido identificada en fondos blandos del País Vasco (NE de la península Ibérica, SE del golfo de Vizcaya). La nueva especie se caracteriza principalmente por su pequeña talla, tres segmentos setígeros prebranquiales, cinco (excepcionalmente seis) pares de delgadas branquias simples, notosedas modificadas liriformes, y una región pigidial con siete cirros. En el presente artículo se realiza una descripción, ilustración y discusión de la nueva especie, aportándose también información sobre su ecología y distribución. Complementariamente, se aporta una clave de identificación de todas las especies conocidas de Paradoneis. El Material Tipo ha sido depositado en el Museo Nacional de Ciencias Naturales, Madrid.

Settlement and recruitment pattern variability of the mussel Mytilus galloprovincialis Lmk. from SE Bay of Biscay (Basque Country)

The annual settlement and recruitment patterns of Mytilus galloprovincialis Lmk. were assessed using collector ropes deployed at five sites along the Basque coast inhabited by wild mussel populations. The study was carried out over two periods of ten months each in three estuarine and two coastal sites, and enabled the discovery of a potential relationship between observed primary settlement and the spawning period of wild mussel populations, shedding light on the recruitment of these populations. Primary settlers were present throughout the year with highest abundances from early summer to fall. A spatial settlement pattern was also observed, with eastern estuaries showing higher settlement rates than western ones and coastal sites showing intermediate settlement rates. These spatial and temporal settlement variations could be partially explained by seasonal fluctuations in environmental factors, such as temperature and nutrients, as well as by spawning differences observed at these estuarine and coastal sites. Some inter-annual variability of settlement and recruitment was observed, with higher settlement rates in the second studied year. This inter-annual variability was consistent with the inter-annual variability of the environmental factors. The recruitment of juvenile mussels was shown to be more determined by post-settlement processes than by initial settlement abundance. Indeed, there was a substantial loss of post-larvae during fall and winter, which was due to these post-settlement processes. Thus, it is advised that ropes, which were deployed in spring and collected in winter, to be collected earlier to avoid such losses. Little space is available (i.e., due to user conflict) on the Basque Coast. Despite these limitations, these sites, particularly Bidasoa estuary, could be suitable for future seed gathering for the mussel aquaculture industry in the Basque Country.

Eddy-induced cross-shelf export of high Chl-a coastal waters in the SE Bay of Biscay

Different remote sensing data were combined to characterise a winter anticyclonic eddy in the southeastern Bay of Biscay and to infer its effects on cross-shelf exchanges, in a period when typical along shelf-slope currents depict a cyclonic pattern. While the joint analysis of available satellite data (infrared, visible and altimetry) permitted the characterisation and tracking of the anticyclone properties and path, data from a coastal high-frequency radar system enabled a quantitative analysis of the surface cross-shelf transports associated with this anticyclone. The warm core anticyclone had a diameter of around 50km, maximum azimuthal velocities near 50cms−1 and a relative vorticity of up to −0.45f. The eddy generation occurred after the relaxation of a cyclonic wind-driven current regime over the shelf-slope; then, the eddy remained stationary for several weeks until it started to drift northwards along the shelf break. The surface signature of this eddy was observed by means of high-frequency radar data for 20 consecutive days, providing a unique opportunity to characterise and quantify, from a Lagrangian perspective, the associated transport and its effect on the Chl-a surface distribution. We observed the presence of mesoscale structures with similar characteristics in the area during different winters within the period 2011–2014. Our results suggest that the eddy-induced recurrent cross-shelf export is an effective mechanism for the expansion of coastal productive waters into the adjacent oligotrophic ocean basin.

Suprabenthic assemblages from the Capbreton area (SE Bay of Biscay). Faunal recovery after a canyon turbidity disturbance

In the Capbreton area, suprabenthic assemblages were sampled with a sledge towed over the bottom, at different sites located within the upper part of a ‘gouf-type’ canyon (8 hauls between 642m and 797m, on the axis of the thalweg or on flat perched flank terraces such as site K), on the northern adjacent open slope (2 hauls between 500 and 567m) and on the northern adjacent shelf margin (2 hauls between 151m and 158m). A multivariate analysis carried on the faunal data discriminated different assemblages in this area: a near-canyon shelf assemblage (55 species, mainly amphipods and decapods; 3496 ind./100m2, 40% mysids; dominant species: Nyctiphanes couchii, Leptomysis gracilis, Weswoodilla rectirostris, Anchialina agilis, Scopelocheirus hopei and Philocheras bispinosus); an open slope assemblage (111 species, mainly amphipods and isopods; 249 ind./100m2, 36% amphipods; dominant species: Disconectes phalangium, Munnopsurus atlanticus and Boreomysis arctica); a canyon E assemblage (129 species, mainly amphipods, mysids and cumaceans; 1172 ind./100m2, 58% amphipods; dominant species: Melphidippa sp. B, Chelator insignis); a canyon E’ assemblage (107 species, mainly amphipods and mysids; 507 ind./100m2, 73% amphipods; dominant species: Cleonardopsis carinata, Bonnierella abyssorum, Rhachotropis caeca and Arcturopsis giardi); and a temporary canyon assemblage at site K (34 species, mainly amphipods and mysids; 899 ind./100m2, 85% amphipods; dominant species: Tmetomyx similis, Caeconyx caeculus, Nebalia sp. A and Cleonardopsis carinata). Site K was sampled only four months after a turbidity event, detected on sediment cores (18cm thick Bouma sequence) taken during the same cruise and triggered by the violent storm (‘ouragan Martin’, wind up to 200km/h) which affected the French Atlantic coast on 27 December 1999. The corresponding suprabenthic assemblage showed evidence of deep structural changes after this catastrophic event, characterized by relative low values of species richness and diversity indices and by the exceptional dominance of opportunistic pioneer colonizers such as the scavenger Tmetonyx similis (61% of total density). Partial assemblage recovery was noticed 18 months after the turbidite deposition, attested by higher values of structural indices and by the inclusion of the corresponding sample within the climax canyon assemblage cluster.

Variability of the reproductive cycle in estuarine and coastal populations of the mussel Mytilus galloprovincialis Lmk. from the SE Bay of Biscay (Basque Country)

Mussel commercial production depends on wild populations to obtain the seed. Therefore, any new farming initiative needs deep knowledge on reproductive cycle of native mussel populations. The reproductive cycle of Mytilus galloprovincialis Lmk. from five sites, three estuarine and two coastal, along the coast of the Basque Country were assessed using gonad index and stereology over 2 consecutive years (2010 and 2011). Sex ratios, developmental stages of gonads, as well as reserve tissue cycle were analyzed. The onset of gametogenesis was observed from winter to spring, with spawning occurring from spring till summer. A resting phase followed with an increase in reserve tissues (adipogranular cells) was observed in fall. Mussels stayed ripe during winter until favorable environmental conditions were met in spring. Differences in reproductive cycles were found among populations, and also, year-to-year variability was observed within each population. In two of the studied sites asynchrony in the timing of spawning was observed between genders. These timing differences, however, did not prevent mussels at those sites from reproducing successfully. The Bidasoa estuary points to the potential of such studied sites for becoming the main source of wild mussel spats for future expected commercial mussel farming in the Basque Country. To ensure year-to-year maximum reproductive output, however, wild mussels harvest should be avoided from spring to the end of summer in this region.

Deep-sea benthic response to rapid climatic oscillations of the last glacial cycle in the SE Bay of Biscay

Paleoclimatic evolution of the last 140ka (Marine Isotopic Stages MIS 1 to MIS 5) in the South Bay of Biscay has been studied by considering microfossil changes in sediment samples of deep core PP10-17. This core was retrieved at 2882m water depth (mwd) in the Landas Plateau and is formed by 1792cm of clay-silt continuously deposited sediment. For this study, a total of 114 samples have been examined, yielding approximately 60 thousands of specimens of foraminifers (181 benthic species, BF) and ostracods (70 spp.). Reconstruction of the benthic response is based on the main foraminifer and ostracod species by considering their oxic/anoxic character as well as other ecological features of the assemblages. Detailed quantification of microfossils (planktonic and benthic foraminifers, ostracods) together with grain size analyses and magnetic susceptibility of the sediments allow us to characterize many of the climatic events registered in this core. Based on a robust chronostratigraphy by correlation with reference core MD95-2002 and Greenland ice core records (GICC05modelext), we are able to characterize a detailed response of benthic environments to cooling/warming, oxygen-content and productivity cycles in the region. MIS 5 has been characterized by oscillations of the planktonic/benthic foraminifer ratio (Oceanity index, OI; 60–90%); this index was higher (90–100%) and stable through the MIS 4–MIS 3 intervals. We found BF species indicators of different climatic-related events. Thus, MIS 5a, c, e interstadials are evidenced by Bulimina gibba and B. aculeata while the stadials MIS 5b, d are shown by the occurrence of Melonis pompilioides. Heinrich events, with massive iceberg discharges into the N Atlantic Ocean, are indicated by presence of Globobulimina affinis, particularly during the MIS 4 to MIS 2 interval. The beginning of MIS 4 is indicated by the appearance of new species of BF and an increase of Cassidulina laevigata. Krithe spp. and C. laevigata are good indicators of the LGM (Last Glacial Maximum, 19–23ka) when the OI decreased. Other cooling periods (e.g. Younger Dryas, YD, around 12–13ka) are shown as well by an increase of M. pompilioides, similar to that of the MIS 5d stadial. The Holocene (11.5ka to present) is marked by an increase in the oceanity index, disappearance of cold-water indicators and the occurrence of Uvigerina peregrina. A shallow infaunal microhabitat of benthics foraminifers (Cibicides, Cassidulina, Uvigerina) and ostracods (Krithe, Argilloecia) has been linked to favorable bottom conditions, with oxic to slightly suboxic conditions (high diversity and equitability of assemblages) reflecting an active Atlantic Meridional Overturning Circulation (AMOC) during many D/O interstadials. The opposite conditions were established for deep infaunal BF (Bulimina, Globobulimina) where the strong dysoxic bottom conditions are indicative of poor ventilation produced by a reduction or shutdown of the AMOC during Heinrich stadials.

A sensory and nutritional validation of open ocean mussels (Mytilus galloprovincialis Lmk.) cultured in SE Bay of Biscay (Basque Country) compared to their commercial counterparts from Galician R\xedas (Spain)

Mussel shell biometry, nutritional quality as well as consumer sensory evaluation of experimental open ocean cultured mussel Mytilus galloprovincialis (Lamarck 1819) were analyzed and compared to that of commercial mussels from Galician Rías available in the local market. Both mussel products were of the same commercial size. In this study, open ocean mussels were significantly higher and wider than those of Galician Rías. In addition, with the exception of ash content, both mussel products showed similar biochemical composition. Regarding fatty acid profiles, however, statistical differences were detected. These differences were not fully reflected in the sensory assessment. In terms of consumer acceptability, both mussel products were considered equally satisfactory.