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Mercator mud volcano has been explored by direct visual observations using a ROV at 350 to 370 m depth. Underwater images, taken mainly at the summit, have allowed characterizing the fluid venting environment, where different microforms, habitats and associated biota, with typical seepage components have been identified. Chemosynthetic bacterial communities were detected and sampled at the northeastern side of the summit at 350 m, next to pockmark-like depressions with diameters ranging 1 to 3 m, bioturbation marks, sediment mounds and authigenic carbonates of different sizes (0.1-5m length). Chemosynthesis-based communities were mainly composed by bacterial mats (patch diameter 10-30 cm), however some remains of cold seep chemosymbiotic bivalves (Lucinoma asapheus) were also found on the sediment. Habitat types at Mercator MV are influenced by oceanographic and sedimentation processes deposition and favouring fauna colonizing diverse substrate types, such as large sponges on slabs and sea-pens and annelids on soft bottoms.

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Se ha analizado la morfología del fondo, las características sub-superficiales y los hábitats bentónicos de un sector del talud continental del Golfo de Cádiz. El objetivo es reconocer los tipos morfológicos y los procesos geológicos y oceanográficos para entender la relación con dichos procesos, así como su influencia sobre los hábitats y las especies bentónicas asociadas. Se han estudiado las características morfológicas, el tipo de sedimento y las especies bentónicas dominantes en cuatro estructuras volcánicas y en los fondos marinos adyacentes. Los tipos morfológicos identificados se han agrupado en formas relacionadas con escapes de fluidos desde el subsuelo, con corrientes de fondo, con movimientos en masa, formas estructurales y biogénicas. Además, se han identificado las especies bentónicas dominantes y asociadas a escapes de fluidos, a sustratos duros (costras de carbonatos autigénicos) y a sustratos blandos. Los principales factores que controlan la morfología y las comunidades bentónicas asociadas son los procesos relacionados con escapes de fluidos, aunque existen otros procesos, como los gravitacionales, y las propiedades de las masas de agua profunda. Los sedimentos de brecha fangosa y los organismos quimiosimbióticos se localizan principalmente en la cima de los edificios volcánicos, indicando que la actividad de expulsión de fluidos podría ser elevada en algunos casos. La presencia de coladas de fango y cuerpos lóbulados sobre los flancos son indicativos de un proceso de extrusión que tuvo lugar en diferentes fases. Los carbonatos autigénicos se han localizado en los flancos y en la base de las estructuras volcánicas y están relacionados con una actividad de expulsión de fluidos moderada, siendo desenterrados por la actividad de las corrientes de fondo y colonizados por especies de sustratos duros. Las depresiones en las zonas adyacentes están formadas por procesos de colapso, debido a escapes de fluido activos y bajo la influencia de las corrientes profundas. Seabed morphology, sub-bottom characteristics and benthic habitats of a sector of the Gulf of Cadiz continental slope have been analyzed. The aim is to recognize morphological features, geological processes and near-bottom water masses for understanding the relationships between the occurrence of fluid venting related edifices and their associated habitats and benthic communities. Morphological characteristics, sediment types and dominant benthic species of four volcanic structures and their adjacent areas have been studied. Identified morphological characteristics were grouped in fluid escape related features, bottom current features, mass movement features, structural features and biogenic related features. Additionally, dominant benthic species associated with seepage, hard substrates (authigenic carbonates) or soft bottoms have also been found in these features. A major factor controlling these features and their associated biota is mud flow and fluid-escape-related processes, although other factors such as gravitational and deep water masses related processes are involved. Mud breccia sediments and chemosymbiotic metazoans are mainly located at the summit indicating a higher mud flow and seepage activity. The presence of mass flows deposits and mud lobes on the flanks are indicative of mud extrusion process in different phases. Authigenic carbonates on the flanks and the base of the volcanic structures are related to a moderate seepage activity, being exhumed by bottom currents and colonized by hard substrate associated species. Adjacent depressions are linked to collapse processes, where active fluid escape and bottom current effects have been identified. Proyectos LIFE+ INDEMARES/CHICA y ATLAS (EU Horizon 2020). Grupo PAIDI RNM-328. Proyecto SUBVENT (CGL2012-39524-C02-01)

Habitat characterization using underwater images has been carried out in 4 mud volcanoes (Gazul, Almazán, St. Petersburg and Aveiro) and one mud volcano/diapir complex (Hespérides) located at the middle slope of the Spanish margin of the Gulf of Cádiz (360-1200m depth). A total of 126 species, mostly cnidarians, sponges, brachiopods, crustaceans and echinoderms and 19 habitats have been observed in the underwater images, including anoxic bottoms with cold seep fauna or remains (Siboglinum sp., Lucinoma asapheus, Solemya elarraichensis), bottoms with authigenic carbonates colonized by gorgonians and anthipatharians, extensive muddy bottoms with sea pens (Kophobelemnon sp., Protoptilum sp.) and bamboo corals (Isidella elongata) and cold-water coral banks (Madrepora oculata). Habitat type and distribution seem influenced by sedimentary features, presence of hard substrates with authigenic carbonates, seepage activity, depth and hydrodynamic conditions. Cold seep related species and heterotrophic species not directly linked to fluid venting represent seepage activity indicators and induce habitat and biodiversity differentiation among the fluid venting edifices.

In March 2014, the Spanish R/V Sarmiento de Gamboa equipped with the Portuguese multi-operational Remotely Operated Vehicle (ROV) "Luso 6000" explored and sampled five mud volcanoes of the Gulf of Cádiz during SUBVENT2 expedition. The explored mud volcanoes were Mercator, Yuma, Algacel, Mvseis and Madrid located offshore Moroccan Atlantic margin at water depths between 350 and 1650 meters. In addition, bathymetric data were acquired using the Atlas Hydrosweep DS multibeam echo-sounder and were processed with CARIS HIPS & SIPS yielding a bathymetric grid resolution of 15 m. The characterization of habitats and associated biota was based on high resolution videos and captured photographic material with MAGIX software as well as samples collected with the ROV. The observation was done during scanning the sea floor by TV camera at the altitude of 1-5 meters above the seafloor at low velocity of approximately 0.2-0.5m/s. Digital data analyses and their cartographical representation were performed with ArcMap 10.3.1 and Fledermaus. Underwater images allowed to characterize the occurrence of cold seeps with different seafloor micro-features, habitats and associated biota. Chemosynthetic bacterial communities, mainly occurring as bacterial mats (e.g., sulfate-oxidizing cf. Beggiatoa sp.), were detected, sampled and related to active bubbling seeps in pockmark-like depressions of different sizes. Sediment mounds and authigenic carbonates of different sizes (0.1-5 m length) were also detected in vent sites. Six different species of chemosymbiotic bivalves, including Lucinoma asapheus, Acharax gadirae, Solemya elarraichensis, Thyasira vulcoluatre, Isorropodon megadesmus and the deep water mussel Bathymodiulus mauritanicus displayed populations in the studied mud volcanoes. Hard bottoms with exhumated carbonate slabs seem to display a wider biodiversity and complexity, including large size sponges (e.g. Geodia, Phakellia), scleractinians (e.g. Caryophillia, Corallium, Madrepora), gorgonians (e.g. Bebryce, Chelidonisis) and antipatharians (e.g. Stichopathes) as well as different mobile associated species.. Habitat types of these mud volcanoes may be influenced by different oceanographic, sedimentation and venting processes resulting then in a broad biodiversity. SUBVENT project (CGL2012-39524-C02, MINECO, Spain), ATLAS project (EU, Horizon 2020) and EMEPC (Portugal)

Hydropower is a potential large source of electricity supply in Wales. The Upper River Severn in Mid Wales is a typical stream where a high head hydropower scheme could be developed and the river system at Plynlimon has some of the longest records for weather and flow in Wales. A micro-hydropower potential of 99 kW is demonstrated at Plynlimon and the potential impacts of climate change are simulated to assess the effects on flows and power outputs of such schemes under climate uncertainty. Based on UK Climate Projections 2009 (UKCP09) projections, the impacts of climate change are to significantly decrease both the stream flows and energy production during summer months but to increase flows and power production in the winter, with a net tendency to cancel out over the course of a full year. A methodology for assessing impacts of climate change on hydropower is established, which could be applied more widely to other potential hydropower sites such as lowland rivers or high base flow rivers in other parts of the UK. This will be useful for developers, water companies and environmental agencies to assess hydropower potential, economic viability and environmental impacts of micro-hydropower, under future climate change., Sí

The analysis of a data set of multibeam bathymetry plus high resolution seismic and parametric profiles allow us to characterize the geomorphologic units on the Alboran Sea-floor as well as the evolution of morpho-sedimentary systems along the Pliocene and Quaternary, later than the main erosive Messinian event. Since the opening of the Gibraltar Straits, the sedimentary evolution of this basin has been controlled by the interchange of water masses between the Atlantic Ocean and the Mediterranean Sea. Basin physiography is also a consequence of the Pliocene-Quaternary compression which has progressively uplifted the sourrounding reliefs and deforms the interior and the margins of the basin. On this scenario, several submarine canyons and gullies have been developed in this basin which traverse especially the northern margin and the flanks of the Northern Alboran Ridge, without affecting the African margins. This fact must be related to the action of bottom contour currents which constitute the main morpho-sedimentary process. The influence of water masses distributed the sedimentary input carried by rivers and coming from the erosion of surrounding ranges. In the southern margin of this basin this influence is stronger and inhibits the development of transversal submarine canyons.

European anchovy recruitment to the Guadalquivir estuary mainly occurs when the environmental conditions show more stability. Unusual changes in the environmental conditions of this estuary negatively impacted on key preys of anchovy and therefore on its nursery function. In this way, nutritional condition should determine strongly the physiological state of this species in estuaries and thus its survival and recruitment. RNA:DNA ratio has been applied with success as indicator of nutritional condition and growth in marine organisms. We study RNA:DNA ratio in anchovies of the coupled system Guadalquivir estuary-coastal influenced area in the Gulf of Cádiz in order to evaluate the condition seasonal variability of this species along this spatial gradient. Spatial differences in the size distribution of anchovy and high values of RNA:DNA in the Guadalquivir estuary compared to its influence coastal area suggest that anchovies migrate to the estuary and they acquire a very good condition. We conclude that RNA:DNA is an useful tool to understand the ecological mechanisms by which the coupled system Guadalquivir estuary-coastal influenced area in the Gulf of Cádiz control the success or failure of the recruitment of this important fishery resource in the region.

The Guadalfeo submarine delta is located on the northern Alboran Sea shelf in the western Mediterranean Sea. The sedimentary dynamics of the deltaic system is governed by the discharge of one of the major rivers in this area draining the western sector of the near-coastal Sierra Nevada Mountains. The area is under the influence of a Mediterranean climate, with high spatial and temporal (i.e., inter- and intra-annual) rain variability. Major anthropogenic forcing affected the river system during the 1930’s, with the deviation of the main river channel 2.5 km to the west, to its present position. More recently, the construction of Béznar (1977-1985) and Rules (1993-2003) dams have also contributed to limit the amount of sediments exported to the deltaic system. In order to understand the interaction between river discharges and the evolution of the submarine delta at different timescales, sediment cores were collected off the ancient (core 13) and present-day (cores12 and 15) river courses. A chronological framework was performed and combined with sedimentological and benthic foraminiferal analyses. Radiocarbon dating of plant debris from the base of the cores indicates that the sedimentary record goes back 200 years. In core 13, the variations between coarse and fine fractions along the core and the upward increase of benthic foraminiferal population density, would indicate that deposition possibly occurred until the deviation of the main river course to its present position. In the lower part of core 12, the strong alternation between coarse and fine sediment textures and the variable amounts of benthic foraminiferal species are interpreted as the result of an active fluvial regime. The upper part, with high percentages of fine sediments and high values of population density, could be attributed to the stabilization of the river course in its present-day location. Core 15, located at 11 m water depth, showed the highest content of gravel in the lower part of the core, high contents of silt at two core depths and increased percentages of sand to the top, indicating the strong influence of human interventions in the river basin and consequent changes in the sediment supply to the Guadalfeo submarine delta. info:eu-repo/semantics/publishedVersion

2nd Deep-Water Circulation Congress: The Contourite Log-book, 10-12 September 2014, Ghent, Belgium.-- 2 pages, 2 figures, The Gulf of Cadiz records the interplay of a variety of sedimentary processes related to the circulation of water masses. The most important one is the Mediterranean Outflow Water (MOW) that exits the Mediterranean Sea, but other water masses also affect the seafloor, with complex variations along time and space. This work studies the interplay between oceanographic and gravitational sedimentary processes on the Guadalquivir Ridge, based on bathymetry and high-resolution seismic profiles. A series of morphological features including flat terraces, circular/elliptical depressions, semicircular scarps and valley-shaped features are analysed in order to better understand the interaction between water masses circulation and mass-wasting processes of the Gulf of Cadiz, This research has been funded by MINECO through the projects MONTERA (CTM2009-14157-C02-02) and MOWER (CTM2012-39599-C03-02)

La bahía de Málaga se localiza dentro en un punto caliente de biodiversidad, como es el mar de Alborán, y además representa una zona con importantes recursos pesqueros, tanto pelágicos como bentónico-demersales. La información sobre comunidades de fondos blandos circalitorales es hasta la fecha muy limitada tanto para esta bahía como para el Mar de Alborán. Por otro lado, los moluscos son importantes componentes de dichas comunidades e incluyen numerosas especies de interés pesquero. El presente estudio se incluye en el proyecto “Estudio previo para la protección, ordenación y determinación de una reserva de pesca en el área marítima de la Bahía de Málaga”, y tiene como objetivo realizar una caracterización espacio-temporal de la composición y estructura de las taxocenosis de moluscos, incluyendo las especies de interés pesquero (fundamentalmente bivalvos y cefalópodos). Las muestras biológicas se recolectaron con dos métodos de muestreo: a) Draga de arrastre (8 muestras recogidas entre 40 y 80 metros de profundidad en diciembre de 2013) y b) Arrastre con puertas (8 lances de pesca entre 50 y 80 metros en diferentes estaciones del año). Se identificaron, cuantificaron y pesaron (sólo en los lances de pesca) todos los moluscos de cada una de las muestras. Finalmente, se realizaron diferentes análisis univariantes (riqueza específica, abundancia, biomasa) y multivariantes (ANOSIM, MDS, CLUSTER y SIMPER) para el estudio espacial y temporal de las asociaciones de moluscos y de aquellos moluscos de interés pesquero. Por otro lado, se caracterizó la columna del agua (temperatura, salinidad) y el sedimento superficial (contenido en materia orgánica y granulometría) usando datos procedentes del proyecto TESELA, con el objetivo de estudiar las relaciones entre variables ambientales y bióticas (moluscos) mediante BIOENV. Se han recolectado más de 9000 moluscos, la mayoría procedentes de los lances de pesca, identificándose unas 70 especies, de las cuales 48 fueron capturadas mediante draga de arrastre. En las muestras obtenidas con draga, los gasterópodos fueron dominantes (41,7%), especialmente Turritella communis (18,31%), Nassarius ovoideus (17,82%) y Bela brachystoma (11,91%), seguido de los bivalvos (33,3%) y cefalópodos (6,25%). Estadios adultos y juveniles (< 1cm) del bivalvo comercial Venus nux se encontraron en las zonas más profundas (>50 m de profundidad). En los lances de pesca, los cefalópodos (86,99%) fueron dominantes, seguidos de bivalvos (10,52%) y gasterópodos (2,48%), siendo casi todas las especies dominantes de interés pesquero como Allotheutis media (80,89%), Venux nux (7,77%) y Sepia elegans (2,4%). Los análisis multivariantes han mostrado la existencia de 3 asociaciones de moluscos ligadas a: a) Fondos de arenas finas fangosas del circalitoral somero (

The seabed morphology and the sub-superficial characteristics of the Cristóbal Colón diapir located on the continental slope of the Gulf of Cadiz have been analysed from data obtained in the framework of the LIFE+INDEMARES/CHICA project. The aim of this study is to recognize the morphological features and the geological processes generated by the bottom water masses and their influence on the habitats and associated benthic communities. The NACW affects the generation of morphological features on the summit, revealing that different oceanographic conditions favoured the carbonate mound growth in the past. The interface between the NACW and the MOW sweeps the bottom from the SE to the NW and the presence of benthic communities dominated by filter feeders on the contouritic drift indicates that this current is strong enough to favour the availability of nutrients and organic particles and to develop both the contouritic deposits on the SE flank and the moats on the N and W flanks., SI

The Gulf of Cádiz represents an area of extensive seepage activity in the Atlantic Ocean, with the presence of ca. 50 mud volcanoes located in Spanish, Portuguese and Moroccan waters (200-4000 m depth). Recent studies have revealed the presence of a wide variety of habitats and species due to the heterogeneous characteristics of these cold seeps and of the seabed of the Gulf of Cádiz where different geological processes, water masses and substrate types occur. Information on some components of these bathyal benthic communities (e.g. polychaetes) is very scarce, especially for those mud volcanoes located in Spanish waters of the Gulf of Cádiz. In order to study the polychaetes assemblages, samples were collected in different areas (summit, flanks, depression, adjacent bottoms) of ten mud volcanoes located within Spanish waters (300-1100 m depth), during the INDEMARES/CHICA 0610, 0211 and 0412 surveys. Sampling was carried out using different methods such as box-corer (BC) (ca. 0.09 m2 of sampling area, n=82), benthic dredge (DA) (ca. 300 m2, n=56) and beam-trawl (BT) (ca. 2000 m2, n=40) on board R/V Emma Bardan, Cornide de Saavedra and Ramón Margalef. Sediments collected with the box-corer were sectioned at 5 cm intervals and sieved (0.5 mm) in order to study the vertical distribution of polychaetes. Material collected with the benthic dredge was sieved on a sieve column of 10, 5 and 1 mm mesh sizes. Sedimentological (Eh, grain size distribution, organic matter content) and water column (temperature, salinity, current speed) features were measured in order to characterize the environment where the different species occur. A total of 115 spp. have been found in the material collected, with the "Sedentaria" taxa represented by more species (ca. 60%) and individuals (ca. 80 %) than the "Errantia". The best represented families were Serpulidae (12 spp.), Sabellidae (7 spp.), Spionidae (6 spp.), Maldanidae (6 spp.), Eunicidae (5 spp.), Onuphidae (5 spp.) and Glyceridae (5 spp.). Some species were only collected in beam-trawl samples or benthic dredges (e.g. Hyalinoecia tubicola, Aphrodita alta, Haplosyllis spongicola) and others in box-corer samples (e.g. Spiophanes kroeyeri, Chone longiseta, Gesaia elegans, Poecilochaetus fauchaldi, Pherusa flabellata). This suggests that the combination of different sampling methods is needed to document more accurately the polychaete biodiversity in these habitats. New records for the area or at this depth range are Tetreres varians, Pherusa flabellata, Glycerella magellanica, Subadyte pellucida (associated with Leptometra phalangium) and Ophelia radiata, among others. Frenulate polychaetes (Siboglinidae) were the top dominant group, particularly at the summit of some MV. These thread-like worms occurred in anoxic reduced sediments, displaying their highest densities in Hespérides and Aveiro (> 1000 indiv. m-2) and the lowest (< 100 indiv. m-2) in Gazul, Pipoca and Tarsis. Non-chemosymbiotic polychaetes such as maldanids (Euclymene santanderensis), paraonids (Aricidea assimilis, Tauberia gracilis) and chaetopterids (Phyllochaetopterus socialis) also occurred in these reduced sediments. In sedimentary habitats, such as those with sea-pen communities, bamboo corals or hexactinellids (Pheronema carpenteri), the assemblage was dominated by Aglaophamus pulcher, Paradiopatra hispanica, Hyalinoecia tubicola, Eunice vittata and Fimbriosthenelais cf. zetlandica, among other species. In hard bottoms with authigenic carbonates, serpulids were numerically dominant components, especially Filograna implexa, Serpula vermicularis and Vermiliopsis infundibulum, together with some mobile species (e.g. Phyllodoce cf. maderensis). In hard bottoms with cold water corals, Eunice norvegica and Glycerella magellanica were found inside live and dead coral colonies, respectively. Polychaete assemblages of mud volcanoes with hard bottoms or mixed bottoms (Gazul) displayed the highest numbers of species in relation to those of adjacent bottoms or of mud volcanoes with soft bottoms and high densities of siboglinids (Hespérides, Aveiro).

In October 2011, the shallow submarine eruption of the southern part of El Hierro (Canary Islands) caused severe effects in the seafloor morphology and substrate composition (e.g. lava extrussion and construction of the volcanic edifice), the water column (e.g. acidification, deoxygenation and fertilization) and the biological communities (e.g. changes in the composition and functioning of communities) (Fraile-Nuez et al. 2012; Santana-Casiano et al. 2013). Due to this natural event, habitats and associated biota have experimented changes at different levels and in different parts of this new seafloor volcanic structure. Underwater images obtained with VOR Aphia 2012 (October 2013) and ROV Liropus 2000 (March 2014) as well as samples collected with a benthic dredge in March and October 2013 have made possible the study of the benthic and demersal organisms that persisted after this acute natural event as well as those that are recolonizing the recently formed volcanic bottoms. During the eruption, material of variable size and texture buried previous existing habitats and associated biota, except in certain bathyal bottoms close to the base of this new seafloor structure (200 - 500 m depth) where slow-growing suspension-feeders such as antipatharians (e.g. Stichopathes cf. gracilis, Antipathes furcata), small gorgonians (e.g. Acanthogorgia, Bebryce) and lithistid sponges still increase the bottom complexity when compared to those buried bottoms. Among them, small colonies of cold-water corals (probably Dendrophyllia cornigera and Cladocora debilis) also occur, but mostly represented by dead specimens. In both March and October 2013, benthic dredge samples collected lava rocks and gravels that were poorly colonized by invertebrates, together with remains of antipatharians and dead cold-water corals. In shallower parts of the flanks of the volcano (ca. 200m depth), most previously existing habitats formed by antipatharians have been buried after the eruptive processes and the recent lava rocks are starting to be colonized by small and scarce colonies of hydrozoans, serpulids and small size echinoids (e.g. Coelopleurus floridianus), among other species. Nevertheless, the gravel bottoms at this bathimetric level display a higher degree of colonization, with higher abundances of polychaetes (e.g. Glyceridae, Polynoidae), decapods (e.g. Alpheus spp., Heterocrypta maltzami) and some molluscs (e.g. Nassaridae), probably linked to previous succesful recruitment events or horizontal movements from adjacent unimpacted bottoms. The fish Anthias anthias and the decapod P. narval are two of the top dominant demersal organisms that have recolonized this area after the eruption. Close to the summit, one of the top-dominant sessile macroinvertebrates is the oyster Neopycnodonte cochlear, which occurs at densities of more than 100 indiv. m􀀀�2 in some of the large lava rocks and represent one of the first sessile colonizers of the lava erupted by the vulcano. This filter feeder is also very abundant on black-corals and undisturbed hard substrates located nearby at similar depths and may have benefited from the new micro-habitats available in the hard bottoms formed and the fertilization process after the eruptive event. In general, a pattern of decreasing species richness of benthic-demersal organisms has been found from close to the summit to the base of the volcano, where the low colonization rate is a result of the lower number of potential species that are able to recolonize these substrates, the specific biological features of these species (e.g. slow growth rates, small reproductive outputs) and the oligotrophic character of the water masses when compared to the summit. The findings highlight that the volcanic eruption firstly buried most previously existing habitats and later on created a highly unstable and corrosive environment that affected some slow-growing organisms (e.g. cold-water corals) but not others (e.g. antipatharians). Nevertheless, the eruption provided nutrients that are important for primary pelagic production that may have also promoted the establishment of dense populations of some sessile suspension feeders (e.g. N. cochlear, hydrozoans) in the newly formed hard substrates. This study has been funded by the project VULCANO (CTM2012-36317) and MONTERA (CTM2009- 14157-C02) and we deeply appreciate the help of the Captains and all the crews of R/V A´ ngeles Alvarin˜o and R/V Ram´on Margalef as well as other colleagues during the sampling expeditions. FEDER funding assigned to construction of R/V Ramo´n Margalef (FICTS-2011-03-01) and R/V A´ ngeles Alvarin˜o (FICTS-2011-03-02) is also acknowledged.

Fundación Biodiversidad Postprint

Memoria del Informe Cintífico-Técnico de la campaña oceanográfica SUBVENT-1.Anexos de operatividad y de las distintas técnicas utilizados a lo largo de la misma. La campaña SUBVENT1-0913 se ha realizado a lo largo del talud inferior del margen continental de las Islas Canarias, área que también es conocida en la literatura como Cuenca Canaria. Esta zona se caracteriza por la presencia de una serie de estructuras geológicas recientes, así se encuentran la parte distal de los depósitos de debris procedentes de las avalanchas volcánicas generadas desde las Islas Canarias, a favor de la pendiente y probablemente en relación con episodios eruptivos. En la parte meridional se encuentra además un conjunto de montes submarinos, de diversa entidad, de origen volcánico y, en general, aparece todo un conjunto de montículos con desniveles comprendidos entre 30 y 300 m que han constituido el principal objetivo de esta campaña. Así mismo, en este sector existen numerosos escarpes lineales de orientación subparalela a la del propio talud a los que se encuentran asociados en ocasiones los citados montículos. La adquisición de nuevos datos geofísicos y el muestreo llevado a cabo durante la campaña permitirá conocer mejor el origen de estos montículos y el proceso de emisión que los ha generado. Por otro lado, el conocimiento de las relaciones entre los sedimentos de debris y hemipelágicos junto con los asociados a las posibles emisiones de la zona permitirá conocer no sólo la evolución sedimentaria de este margen, sino establecer los episodios de emisión que generaron los montículos y conocer sus patrones de crecimiento. Así mismo, se podrá evaluar la tasa de sedimentación de la zona y el papel de la masa de agua de fondo antártica (AABW) en esta evolución. The SUBVENT1-0913 cruise has been carried out along the lower slope of the continental margin of the Canary Islands. This area is characterized by the presence of several recent geological structures. Among these are the distal parts of the volcano-clastics debris deposits originated by volcanic avalanches of the Canary Islands, transported by gravity along the slope and probably related in origin to eruptive episodes. In the southern part, numerous and different reliefs (seamounts, hills or mounds) of volcanic origin occur. The most frequents features display heights between 30 and 300 m and they have constituted one of the main aims of this survey. Moreover, in this sector there are several subparallel linear scarps with similar directions to the slope trend that could be associated with the aforementioned mounds. The acquisition of new geophysical data and samples during this campaign will allow a better understanding of the origin of these mounds and the emission processes that have generated them. On the other hand, the knowledge of the relationships between debris and hemipelagic sediments together with those associated with possible venting processes in the area, will reveal not only the sedimentary evolution of this margin, but also to establish emission episodes generating mounds and to know their growth patterns. Furthermore, it would be possible to evaluate the sedimentation rate in the area and the role played by the Antarctic Bottom Water (AABW) mass on this process. Plan Nacional de I+D, Ministerio de Economía y Competitividad. Investigación fundamental no Orientada. Proyecto de Investigación Coordinado SUBVENT “Emisiones submarinas de fluidos en los márgenes continentales de las Islas Canarias y del Golfo de Cádiz: Análisis comparativo de las construcciones asociadas” (CGL2012‐39524‐C02). Acción Complementaria EXARCAN “Trabajos científico-técnicos para la preparación, presentación y defensa de las propuestas de España ante Naciones Unidas para la Extensión de la Plataforma Continental de las Islas Canarias y Galicia” (CTM2010-09496-E).

Benthic foraminifera have a wide distribution in space and time and also respond rapidly to environmental changes. The northern Alboran Sea is influenced by a torrential regime with sporadic, intense rainfalls and extended periods of aridity. In addition, anthropogenic activities such as river channel deviation have taken place during the last ca. 150 years. In order to understand the interaction between natural and anthropogenic impacts through time, shifts of most abundant benthic foraminiferal species, species richness and diversity indices were combined with sedimentological analyses and radiocarbon dating of sediment cores collected from the Adra shelf prodeltaic deposit, in the northern Alboran Sea. The strong variations of benthic foraminiferal assemblages involving significant population density changes occurred until ca. 1870 AD, and are interpreted as response to natural processes. Low population densities correlate with rainfall-driven periods of increased sediment supply to the shelf. In contrast, intervals with increased population densities, followed by a raise of successful colonizers and opportunistic species, indicate the establishment of an environment with new ecological constraints. After ca. 1870 AD, the impact of anthropogenic activities with the deviation of the main river course to the east, are responsible for a drastic reduction of sedimentation rates in the study area. info:eu-repo/semantics/publishedVersion

Seismic profiles and sedimentological data (bulk fraction) of two sediment cores recovered from the Djibouti Ville Drift (SW Mediterranean Sea) indicate that bottom currents have played a fundamental role in shaping the sediment drift. The deposits are composed of biogenous to mixed muddy and silty contourites. A grain size analysis of the terrigenous fraction together with mineralogical, magnetic susceptibility, 14C-AMS dating and stable oxygen isotope data have been analysed to reconstruct glacial and interglacial changes in the bottom currents during the last 133kyr. The sharp vertical grain size changes in the moat and drift indicate that there were substantial bottom current acceleration and deceleration events with faster flow speeds being registered in the moat environment. In sediments from glacial periods (MIS2, MIS3, and MIS6) and stadials 5b and 5d, there is a low carbonate content, high levels of terrigenous elements and paleocurrent proxy values suggest faster flows with the exception of MIS4. Deposits from the interglacial period (MIS1) and interstadials 5a, 5c and 5e, have a high carbonate content, low levels of terrigenous elements, and the paleocurrent proxy values indicate slower flows.

The Portimao Bank is a structural high situated at the westernmost part of the Gulf of Cadiz continental margin, in the lower slope of the South Portuguese sector, between 3500 and 1200 m depth. This high has a W-E orientation and is bounded on the north by the D. Carlos valley and on the south by the Cadiz valley. This morphostructure has been related to a Variscan basement high strongly deformed by NW Africa-Eurasia convergence during Pliocene-Quaternary times and has been defined like a pop-up structure controlled by reverse faults both northwards and southwards with Pliocene-Quaternary activity. From a structural point of view, this bank exhibits a clear differentiation between western and eastern sectors. The main objective of this work is to contribute to the knowledge of the Pliocene-Quaternary and actual tectonic evolution of the Portimao Bank. This has been possible by the interpretation of the high resolution singled airguns and parametric profiles obtained in the MONTERA 0412 cruise, and two previous MCS profiles acquired in the TASYO 2000 cruise. Bank morphology shows a southern flank steeper and more gravity eroded than in the northern one, where also intense erosion is observed related to the D. Carlos valley. The summit shows a ramp-like morphology down westwards. However, this morphology is broken by the presence of the D. Carlos diapir in the center part of this bank, which marks also the boundary between western and eastern structural styles. In the eastern sector a basement high has been observed southwards which is interpreted as a reactivated reverse fault, which uplifted Pliocene-Quaternary units that thinning on the top. Northwards a longitudinal ridge is delimited at seafloor surface in relation to an anticline fold which is caused by a blind thrusts. In this sector the Pliocene-Quaternary uplift of the Portimao Bank is controlled by blind thrusts bounding the north and south. Their central part corresponds to an uplifted basin with syncline geometry and could be described as an inverted relief. Meanwhile, in the western sector the Pliocene-Quaternary units show a general antiform or tilted-southwards structure. In this area northern flank is related also to a blind thrusts whose activity show a major control on morphology. The recent and active deformation is observed along the northeastern sector of this high and significantly affects their morphology. In this way it is interpreted a marked deformation of actual sedimentary units by the diapirism activity probably related to D. Carlos diapir that causes a conical shape in the central part of the high. This recent deformation could be related to diapirism or reverse faults reactivation mainly along the north Portimao Bank sector

Dialogue Between Contourite and Oceanography processes International Workshop, University of Hull, 28-26 January 2013, University of Hull, UK, The analysis of high-resolution (sparker, 3-channel Airgun) and very high-resolution (TOPAS, Parasound) seismic reflection profiles and multibeam bathymetry compiled during several oceanographical cruises in the northern Alboran Sea (SW Mediterranean), have allowed to study the morphology and origin of negative-relief features located on the contourite deposits developed in the vicinity of the seamounts - Avempace, Herradura, and Djibouti Ville (Al-ldrissi) - on the Motril Marginal Plateau (northern Alboran Sea). Two types of negative-relief features have been identified according to their circular or elongated morphology. Circular-like shapes match with pockmark and scour mark morphologies. The pockmarks are placed at the N and NW of the Avempace Seamount from 672 to 740 m water depth. 48 pockmarks have been described and they al1 display V-shaped cross-section. They are 1-19 m high and 50-400 m wide and but only some show higher backscatter than the surrounding areas. The scour marks occur isolated or clustered in the surroundings of the Herradura Seamount at 750-900 water depth. These negative-relief features are both V- and U-shaped in cross-sections. Ushaped scour marks display flat-bottom and truncated reflectors along their walls. Elongated-like shapes match with tectonic depressions and furrows. Tectonic depressions are NNE-SSW linear features, isolated and forming groups with a rhombshape distribution, that locate at 650-1,000 m water depth. The furrows are smallsized erosive ENE-WSW features 1-5 m high and 200 m wide, located at the NW of Avempace and Herradura seamounts from 720 to 900 m water depth. They show Ushaped cross-section running parallel the regional slope. The pockmark formation is attributed to the escape of seepage of gas and interstitial fluids from contourite sediments they affect. The Pockmark field location could be also related to normal basement faults that have favoured the upward migration of the fluid following pre-existing pathways. Scour marks are associated with the vorticity arising when bottom currents flow around a seamount. Upstream of the seamount, a turbulence are develops favouring the whirls occurrence that erode seafloor creating the scour marks. Tectonic depressions are related to the vertical displacement of a NNW-SSE strike-slip fault system and associated to seafloor rupture along the Pliocene Quaternary Faults that have affected even the most recent sediments. Additionally, they can perform as small channels that control the water flow to the SW. Furrows

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A morpho-structural analysis of several mud volcanoes on the Moroccan Atlantic margin (Gulf of Cádiz) is presented. Multibeam data (bathymetry and backscatter), very high resolution seismic profiles from ultra-high resolution topographic parametric sounder (TOPAS) and gravity core data have been used. Analysis reveals an episodic mud extrusion dynamic evidenced by the presence: (1) levels of mud breccia interbedded between hemipelagic layers, (2) lobated and terraced profiles with different backscatter values, (3) crater-like depressions and/or internal domes with patches of very high backscatter values. This episodic dynamic is framed in an evolutionary model constituted by periods of high activity of mud extrusions separated by quiescence ones. Depending on the tectonic setting and oceanographic conditions, a wide possibility of sedimentological and geomorphological features can take place in quiescent periods. Latent periods are located between active and quiescence ones, and are characterized by occurrence of gravitational collapses, landsliding and the precipitation of authigenic carbonates and polimetalic nodules and crusts. En este trabajo se presenta un análisis morfo-estructural de los volcanes de fango del margen atlántico marroquí del Golfo de Cádiz. Se han utilizado datos multihaz (batimetría y backscatter), sísmica de muy alta resolución (TOPAS) y testigos de gravedad. El análisis revela una dinámica extrusiva episódica que se pone de relieve por la presencia: (1) capas de brecha fangosa separada por niveles de sedimentación hemipelágica, (2) perfiles lobulados y aterrazados con diferentes valores de backscatter, (3) depresiones y/o domos internos con áreas de valores de backscatter muy altos. Esta dinámica episódica se enmarca dentro de un modelo evolutivo constituido por periodos de alta actividad de extrusión de fangos separados de periodos de quiescencia. En función del marco tectónico y oceanográfico, los periodos de quiescencia abarcarían un amplio abanico sedimentario y geomorfológico. Entre los periodos de alta actividad y quiescencia se ubicarían periodos de actividad latente caracterizados por un flujo de fluidos moderado caracterizado por la existencia de procesos de colapso gravitacional del edificio y deslizamiento y la precipitación de carbonatos autigénicos, nódulos y costras polimetálicas. 0

The bottom-current component of ocean circulation contributes significantly to shaping the deep seafloor and the settlement and development of benthic communities. In this paper, a data integration of speed and direction of bottom flow, geomorphology and habitat-forming benthic species distribution is shown from data collected within the framework of the INDEMARES CHICA project. The main aim is to understand the interaction between hydrodynamics, the submarine seabed morphology and the distribution of habitats in the middle slope of the Gulf of Cadiz. The interaction of these factors is reciprocal, mutually conditioning them, which are added the tectonic processes and seepages from the sediment, into a longer timescale. La componente de fondo de las corrientes marinas contribuye de manera decisiva al modelado del relieve submarino y al asentamiento y desarrollo de comunidades bentónicas. En este trabajo se presenta una integración de datos de la velocidad y dirección de la corriente de fondo, de la geomorfología y de distribución de especies bentónicas formadoras de hábitats, adquiridos en el ámbito del proyecto INDEMARES CHICA. El objetivo principal de esta comunicación es conocer la interacción entre la hidrodinámica, el relieve submarino y la distribución de hábitats en el talud medio del golfo de Cádiz. La interacción de estos factores es recíproca, condicionándose mutuamente, a los que se le suman los procesos tectónicos y de expulsión de fluidos desde el sedimento, a una escala temporal mayor. 0

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