Dissolved Organic Matter in the Gulf of Cadiz: Distribution and Drivers of Chromophoric and Fluorescent Properties

The Gulf of Cadiz (GoC) connects the Mediterranean Sea with the Atlantic Ocean through the Strait of Gibraltar. Particular hydrographic processes take place in the GoC, such as riverine discharges and surface circulation marked by wind-induced seasonal upwelling. Although physical processes have been widely studied, little is known about the biogeochemical processes that occur in the basin, especially those involving organic matter. Therefore, vertical and seasonal dynamics of dissolved organic carbon (DOC) and optical properties of dissolved organic matter (DOM, absorbance and fluorescence) were measured in 766 samples collected between 5 and 800 m depth during four oceanographic cruises to obtain quantitative and qualitative information about DOM in the GoC. We performed parallel factor analysis (PARAFAC) to identify the main fluorophores present in the GoC, and an optimum multiparameter water mass analysis to differentiate the effect of water mass mixing from the biogeochemical processes in deep waters. PARAFAC analysis validated six fluorescent components; three humic-like, two protein-like, and a possible mixture of polycyclic aromatic hydrocarbon-like with protein-like material. DOC average concentration was 77.0 +/- 12.7 mu M, with higher values in surface and coastal waters during summer, mainly related to primary production. Linear relationships between DOC and apparent oxygen utilization indicate differences in oxygen consumption within the deep waters, which could be related to upwelling zones. Seasonal and spatial differences were also observed in the distribution of fluorescent DOM. Protein-like components were the most abundant fraction, with an average contribution of 64.75% +/- 7.85%, being higher in summer and surface waters, associated with an increase in biological activity. Our results indicate that water mass mixing is the main driver of the major humic-like components, while biogeochemical processes at a local scale explain DOC and protein-like components distribution. Our findings suggest that modeling DOM dynamics in the GoC is complicated due to its complex hydrography and the presence of multiple sources and sinks of DOM

Submarine mud volcanoes as a source of chromophoric dissolved organic matter to the deep waters of the Gulf of Cadiz

Seafloor structures related to the emission of different fluids, such as submarine mud volcanoes (MVs), have been recently reported to largely contribute with dissolved organic matter (DOM) into the oceans. Submarine MVs are common structures in the Gulf of Cadiz. However, little is known about the biogeochemical processes that occur in these peculiar environments, especially those involving DOM. Here, we report DOM characterization in the sediment pore water of three MVs of the Gulf of Cadiz. Estimated benthic fluxes of dissolved organic carbon (DOC) and chromophoric DOM (CDOM) were higher than in other marine sediments with an average of 0.11 +/- 0.04 mmol m(-2) d(-1) for DOC and ranging between 0.11 and 2.86 m(-1) L m(-2) d(-1), for CDOM. Protein-like components represented similar to 70% of the total fluorescent DOM (FDOM). We found that deep fluids migration from MVs (cold seeps) and anaerobic production via sulfate-reducing bacteria represent a source of DOC and FDOM to the overlying water column. Our results also indicate that fluorescent components can have many diverse sources not captured by common classifications. Overall, MVs act as a source of DOC, CDOM, and FDOM to the deep waters of the Gulf of Cadiz, providing energy to the microbial communities living there

Contaminación por metales pesados del estuario del Guadalquivir. Efectos del accidente minero de Aznalcollar sobre el medio físico y los organismos marinos

En esta publicación se resume las aportaciones de diversos Grupos de Investigación participantes en la cuantificación de los efectos del desastre minero ocurrido en Aznalcóllar sobre el estuario del Guadalquivir. La presentación de los resultados obtenidos se hace de manera desagregada de forma que, a pesar de la limitación que supone un texto que tiene un carácter eminentemente divulgativo, se pueda obtener de su lectura una visión suficientemente detallada del trabajo realizado y del grado de consecución del objetivo que desprende del título del proyecto de investigación que se ha llevado cabo

pCO(2) variability in the surface waters of the eastern Gulf of Cadiz (SW Iberian Peninsula)

Spatio-temporal variations in the partial pressure of CO2 (pCO(2)) were studied during eight oceanographic cruises conducted between March 2014 and February 2016 in surface waters of the eastern shelf of the Gulf of Cadiz (SW Iberian Peninsula) between the Guadalquivir river and Cape Trafalgar. pCO(2) presents a range of variation between 320.6 and 513.6 mu atm with highest values during summer and autumn and lowest during spring and winter. For the whole study, pCO(2) shows a linear dependence with temperature, and spatially there is a general decrease from coastal to offshore stations associated with continental inputs and an increase in the zones deeper than 400 m related to the influence of the eastward branch of the Azores Current. The study area acts as a source of CO2 to the atmosphere during summer and autumn and as a sink in spring and winter with a mean value for the study period of -0.18 +/- 1.32 mmol M-2 d(-1). In the Guadalquivir and Sancti Petri transects, the CO2 fluxes decrease towards offshore, whereas in the Trafalgar transect fluxes increase due to the presence of an upwelling. The annual uptake capacity of CO2 in the Gulf of Cadiz is 4.1 Gg C yr(-1)

VII Seminario de química marina

Celebrado en Cádiz el 25 y 26 de enero de 199

Evolución cognitiva de los enfermos de alzhimer en pruebas neuropsicológicas frontales

El presente estudio se decidió para comprobar los aspectos cognitivos asociados al lóbulo frontal de los pacientes con enfermedad de Alzheimer en fase 1 y si las pruebas neuropsicológicas frontales podían detectarlos. Se evaluaron nueve sujetos diagnosticados de Enfermedad de Alzheimer mediante la Batería Neuropsicológica Sevilla (BNS). La BNS resume pruebas empleadas en la evaluación del lóbulo frontal: Atención, Torre Hanoi y Efecto Stroop. La evaluación se realizó en una primera y segunda fase, separadas por un intervalo entre seis/nueve meses. En las dos se registraron idénticas medidas que se compararon para comprobar la evolución cognitiva de los aspectos frontales de los pacientes. Los resultados muestran cómo las pruebas neuropsicológicas frontales detectan los déficits asociados al lóbulo frontal que padecen estos enfermos y cómo estas dificultades se incrementan con la progresión de la enfermedad. Los resultados indican que los pacientes de Alzheimer presentan serios déficits en los mecanismos de activación/inhibición asociados a los lóbulos frontales, que afectan de manera clara a la regulación de su cognición y pensamiento. De igual manera se obtiene que la BNS es un instrumento altamente sensible al deterioro progresivo de los pacientes con probable demencia de Alzheimer

Perspective of cognitive impairment of Alzheimer patients in frontal neuropsychological tasks

El presente estudio se decidió para comprobar los aspectos cognitivos asociados al lóbulo frontal de los pacientes con enfermedad de Alzheimer en fase 1 y si las pruebas neuropsicológicas frontales podían detectarlos. Se evaluaron nueve sujetos diagnosticados de Enfermedad de Alzheimer mediante la Batería Neuropsicológica Sevilla (BNS). La BNS resume pruebas empleadas en la evaluación del lóbulo frontal: Atención, Torre Hanoi y Efecto Stroop. La evaluación se realizó en una primera y segunda fase, separadas por un intervalo entre seis/nueve meses. En las dos se registraron idénticas medidas que se compararon para comprobar la evolución cognitiva de los aspectos frontales de los pacientes. Los resultados muestran cómo las pruebas neuropsicológicas frontales detectan los déficits asociados al lóbulo frontal que padecen estos enfermos y cómo estas dificultades se incrementan con la progresión de la enfermedad. Los resultados indican que los pacientes de Alzheimer presentan serios déficits en los mecanismos de activación/inhibición asociados a los lóbulos frontales, que afectan de manera clara a la regulación de su cognición y pensamiento. De igual manera se obtiene que la BNS es un instrumento altamente sensible al deterioro progresivo de los pacientes con probable demencia de Alzheimer.This research was choosen to prove the cognitive impairment of the frontal lobe in patients Alzheimer in pase 1, and to prove the way neuropsychological lobe forntal task was able to detect progressive cognitive impairment in Alzheimer patients. Nine Alzheimer patients was evaluated with the Neuropsychological Seville Test-Battery (BNS). BNS summarizes a siting ot tests that have been used traditionally in frontal lobe functions evaluation: Attention test, Hanoi Tower and Stroop Effect. The evaluation was produced in two phases, first and second, separate in the Interval 6/9 months. Identical measure was registered and compared to prove progressive cognitive frontal impairment in Alzheimer. The results reveal the manner in which the neuropsychological frontal task is able to detect the frontal deficits in patients Alzheimer, and the manner in which neupsychological frontal task is able to detect the progressive advanced of frontal illness