Organic matter accumulation during the Holocene in the Guadalquivir marshlands (SW Spain)

The distribution of biomarker compounds and magnetic susceptibility observed in the sediment from a 20 m core drilled in the marshlands of the estuarine region of the Guadalquivir River (southwest coast of Spain) has allowed us to reconstruct the palaeoenvironmental evolution of this area during the Holocene. Several organic compounds (n-alkanes, ra-ketones, n-alkanols, n-alkanoic acids and organic sulphur), as well as different biomarker ratios, have been used to show changing environmental conditions through time. These geochemical proxies suggest good preservation of the organic matter, although some diagenesis has occurred to particular organic compounds, especially the n-alkanoic acids. Our data indicate a major allochthonous supply of terrestrial plants, with less influence from aquatic plants or algae through the core. There are markedly different palaeoenvironmental conditions between the uppermost 5 m (last 6ka cal. B.P.) and the rest of the core. From 5 m (ca 6ka cal. B.P.) to 19 m (ca 8ka cal. B.P.) depth the palaeoenvironmental conditions were almost constant. Based on organic sulphur content and n-alkane content logs, anoxic conditions prevailed from 8 to 6ka cal. B.P., while oxic conditions with enhanced convection of water (prevalence of fluvial input), and consequently a greater organic matter supply, predominated in the upper 5 m of the core. Similarly, little variation in the magnetic susceptibility profile below 5 m indicates stable environmental conditions, while in the upper 5 m conditions shifted to one with elevated water input and clastic sediment supply. This is linked to palaeofloral alterations in the Guadiamar/Guadalquivir drainage basins and/or anthropogenic effects. We propose that from ca 8 to 6 ka cal. B.P. a stable landscape physiognomy in the surroundings of the estuarine area of the Guadalquivir River, with a predominance of pines and grassland. However, over the last 6ka cal. B.P. a variation in the terrestrial plant biomarker compounds suggests an alternation of relatively dry and humid phases and/or the impact of human populations on altering the vegetation community have occurred

The Interactive Role of Hydrocarbon Seeps, Hydrothermal Vents and Intermediate Antarctic/Mediterranean Water Masses on the Distribution of Some Vulnerable Deep-Sea Habitats in Mid Latitude NE Atlantic Ocean

In this work, we integrate five case studies harboring vulnerable deep-sea benthic habitats in different geological settings from mid latitude NE Atlantic Ocean (24–42° N). Data and images of specific deep-sea habitats were acquired with Remoted Operated Vehicle (ROV) sensors (temperature, salinity, potential density, O2, CO2, and CH4). Besides documenting some key vulnerable deep-sea habitats, this study shows that the distribution of some deep-sea coral aggregations (including scleractinians, gorgonians, and antipatharians), deep-sea sponge aggregations and other deep-sea habitats are influenced by water masses’ properties. Our data support that the distribution of scleractinian reefs and aggregations of other deep-sea corals, from subtropical to north Atlantic could be dependent of the latitudinal extents of the Antarctic Intermediate Waters (AAIW) and the Mediterranean Outflow Waters (MOW). Otherwise, the distribution of some vulnerable deep-sea habitats is influenced, at the local scale, by active hydrocarbon seeps (Gulf of Cádiz) and hydrothermal vents (El Hierro, Canary Island). The co-occurrence of deep-sea corals and chemosynthesis-based communities has been identified in methane seeps of the Gulf of Cádiz. Extensive beds of living deep-sea mussels (Bathymodiolus mauritanicus) and other chemosymbiotic bivalves occur closely to deep-sea coral aggregations (e.g., gorgonians, black corals) that colonize methane-derived authigenic carbonates.Versión del edito

A relict oasis of living deep-sea mussels Bathymodiolus and microbial-mediated seep carbonates at newly-discovered active cold seeps in the Gulf of Cádiz, NE Atlantic Ocean

Extensive beds of the deep-sea mussel Bathymodiolus mauritanicus (currently also known as Gigantidas mauritanicus) linked to active cold seeps related to fissure-like activity on Al Gacel mud volcano, Gulf of Cádiz, were filmed and sampled for the first time during the oceanographic expedition SUBVENT-2 aboard R/V Sarmiento de Gamboa. Al Gacel mud volcano is one of up to 80 fluid venting submarine structures (mud volcanoes and mud volcano/diapir complexes) identified in the Gulf of Cádiz as result of explosive venting of hydrocarbon-enriched fluids sourced from deep seated reservoirs. This mud volcano is a cone-shaped edifice, 107 m high, 944 m in diameter constituted by mud breccias and, partially covered by pavements of seep carbonates. Extensive beds of this deep-sea mussel were detected at the northern flank at 810–815 m water depth associated with bacterial mats around intermittent buoyant vertical bubble methane plumes. High methane concentrations were measured in the water column above living mussel beds. Other chemosymbiotic species (Siboglinum sp., Solemya elarraichensis, Isorropodon sp., Thyasira vulcolutre and Lucinoma asapheus) were also found in different parts of Al Gacel mud volcano. Al Gacel mud volcano may currently represent one of the most active mud volcanoes in the Gulf of Cádiz, delivering significant amounts of thermogenic hydrocarbon fluids which contribute to foster the extensive chemosynthesis-based communities detected. This finding is of paramount importance for linking extremophile bivalve populations along the North Atlantic, including cold seeps of the Gulf of México, hydrothermal vents of the Mid-Atlantic Ridge and now, detailed documented at the Gulf of Cádiz.Versión del edito

Micro-morphologies, habitats and associated biodiversity in a fluid venting submarine structure using ROV underwater images: Mercator mud volcano (Gulf of Cádiz)

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

INFORME CIENTÍFICO – TÉCNICO de la Campaña SUBVENT1

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)

Habitat quality affects the condition of Luciobarbus sclateri in the Guadiamar River (SW Iberian Peninsula): Effects of disturbances by the toxic spill of the Aznalcóllar mine

This study analyzes the somatic condition of southern Iberian barbel Luciobarbus sclateri (Günther, 1868) in the Guadiamar River (SW Iberian Peninsula). This river was seriously affected by a toxic spill of about 4 million cubic meters of acidic water and 2 million cubic meters of mud rich in heavy metals. Once the spill removal works concluded, sites affected and unaffected by the accident were sampled to study its effects on the fish fauna. The ecological variables registered were related to water quality, physical state of reaches, ecological quality, resources exploited by fish, and potential intra-specific interactions. From an initial 15 ecological variables, seasonal water flow and pH explained most of the variation in barbel condition. This study shows that the Guadiamar River, 56 months after the accident, is still undergoing a recovery process where, beyond ecological variables, proximity to the affected area is the most influential factor for fish condition. © 2012 Springer Science+Business Media B.V

Co-infection with Bartonella bacilliformis and Mycobacterium spp. in a coastal region of Peru

Abstract Objective This study investigated an outbreak of Bartonellosis in a coastal region in Peru. Results A total of 70 (n = 70) samples with clinical criteria for the acute phase of Bartonellosis and a positive peripheral blood smear were included. 22.85% (n = 16) cases of the samples were positive for Bartonella bacilliformis by PCR and automatic sequencing. Of those positive samples, 62.5% (n = 10) cases were positive only for B. bacilliformis and 37.5% (n = 6) cases were positive to both Mycobacterium spp. and B. bacilliformis. The symptom frequencies were similar in patients diagnosed with Carrion’s disease and those co-infected with Mycobacterium spp. The most common symptoms were headaches, followed by malaise and arthralgia

La corta inundada de Aznalcóllar y su uso como vertedero de residuos mineros (Sevilla, España)

Desde su cierre en 1995 y el accidente de la balsa de lodos en 1998, la corta minera de Aznalcóllar ha sido utilizada como vertedero de diversos materiales, como los suelos contaminados retirados del área del río Guadiamar o residuos mineros de estériles, lodos piríticos y cenizas de tostación de pirita. La corta minera está parcialmente inundada y contiene un lago ácido (pH 2,7) con un volumen de ~6 Mm3 de agua enriquecida en metales y sulfato. Las investigaciones detalladas realizadas en la mina durante estos últimos años, han demostrado que los vertidos y la entrada de aguas ácidas de mina están modificando de manera notable la calidad del agua del lago. La mayor afección a la calidad del agua del lago de Aznalcóllar se debió al vertido de 1,4 Mm3 de una escombrera de pirita, entre 2005 y 2006. La disolución oxidativa de este mineral ha causado (i) un consumo total de oxígeno disuelto, (ii) un aumento notable de la conductividad eléctrica (de 8,6 a 12 mS/cm), (iii) una fuerte acidificación (pH de 4,2 a 2,7) y un calentamiento debido al carácter exotérmico de la oxidación de la pirita. A pesar de la ausencia de los agentes que oxidan a la pirita en el lago, como O2 y Fe (III) (Fe (III) <5 % Fetotal), la pirita continúa oxidándose con un incremento de las concentraciones de SO4 2- y Fe. [ABSTRACT] Since its closure in 1995 and the subsequent failure of the slurry deposit dam in 1998, the Aznalcóllar pit has been used as a disposal site for diverse metal-rich materials, such as the polluted soils removed during the cleaning-up of areas along the Guadiamar river together with waste rock, pyrite sludge and ashes deriving from pyrite roasting. At present the pit is partly flooded with a highly acidic (pH 2.7) lake holding some 6 Mm3 of metal- and sulphate-rich water. Detailed research undertaken in the area during recent years has proved that the dumping of wastes and the inflow of acidic mine waters are having a dramatic effect on the quality of the water in the lake. The greatest effect upon the Aznalcóllar lake water was due to the dumping of 1.4 Mm3 of pyritic wastes during 2005 and 2006. The oxidative dissolution of this mineral has resulted firstly in the total consumption of dissolved oxygen, secondly, a notable increase in electric conductivity (from 8.6 to 12 mS/cm), thirdly, considerable acidification (from pH 4.2 to 2.7) and finally, heating due to the exothermic character of pyrite oxidation. Despite the almost total lack of oxidizing agents such as O2 and Fe(III) (Fe(III)<5% Fetotal) in the pit lake, pyrite continues to oxidize, producing a concomitant increase in SO4 2- and Fe.Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEpu