Sertularia marginata (Cnidaria: Hydrozoa) in the Mediterranean: an alien species in expansion?

Mature and dense populations of the tropical hydroid species Sertularia marginata were detected in the Alboran Sea (Western Mediterranean) and along the Atlantic coast of the Strait of Gibraltar. Until now, it had only been recorded in the eastern basin of the Mediterranean Sea. This species has previously been recorded in estuaries and anthropogenic habitats but, in the area studied here, we only found it in natural zones. These observations could indicate early expansion and naturalization in the Mediterranean Sea. Due to its limited dispersion capacity and the history of its records, the observations provided here support the hypothesis of an arrival and a spread by anthropogenic vectors. A pathway of arrival and dispersion of alien species into the Mediterranean Sea is proposed for future monitoring: from Macaronesia (particularly Canary Islands) to the Atlantic coast of the Strait of Gibraltar and from there to the Mediterranean.Financiado por el Ministerio de Economía y Competitividad, proyecto CTM2010-16363. Cofinanciación con fondos FEDER

Underwater Cultural heritage risk assessment methodology for wave-induced hazards: The showcase of the Bay of Cadiz

Coastal areas are characterized by high energetic conditions associated to the wave transformation process and by numerous underwater cultural heritage (UCH) sites whose preservation is crucial given their cultural and economic value. UCH management requires a decision support system to prioritize UCH interventions and actions for long-term preservation. This paper presents a novel UCH risk assessment methodology to quantitatively assess the impact of wave-induced hazards on UCH in coastal environments at a local level and the screening of UCH sites at risk. The UCH risk is calculated as a function of vulnerability (depending on archaeological materials, slope, and seabed type), hazard (decontextualization, scouring, and erosive wear), and exposure computed for the UCH sites registered in an archaeological database. The procedure was validated at two shipwreck sites, Bucentaure and Fougueux, in the Bay of Cadiz. An agreement between the risk index value and the in situ measurements of the rates of scouring and corrosion (used as a proxy of erosive wear) was observed. The methodology was tested in the Bay of Cadiz using an archaeological database containing 56 UCH sites. It allowed identifying the UCH sites at high risk: six are at risk of decontextualization, four are in peril of scouring erosion, and two are at risk of erosive wear. Two UCH sites at high risk of at least two hazards were also identified. This UCH risk assessment methodology is a stepping stone towards a decision support system that will give priority to research, prospection, management, and protection measures in the UCH sites analyzed to ensure their preservation in a context of climate change in the era of a sustainable blue economy.18 página

Aplicación de Técnicas Analíticas SEM/Edx y Metalográficas para la datación y restauración de una pieza de orfebrería religiosa del Siglo XIX

En este trabajo se presentan los estudios analíticos de los materiales metálicos y de la técnica de ejecución del Palio Procesional de la Virgen del Mayor Dolor de Aracena. Se emplearon técnicas de análisis mediante SEM/EDX, observación a microscopio óptico metalográfico y análisis químico mediante espectrometría de emisión de chispa. Se analizaron 12 muestras correspondientes a los distintos elementos decorativos que componen el Palio, incluyendo piezas originales sin restaurar, originales intervenidas y piezas de sustitución. Los resultados obtenidos han permitido, por un lado, conocer la composición y estado del Palio con vistas a la selección de los procesos de restauración más idóneos. Por otro lado, se ha podido establecer la técnica de ejecución del mismo, a través de la constancia en la pieza de la llamada plata Ruolz, que confirma los indicios documentales sobre la manufactura del broncista y platero barcelonés Francesc de Paula Isaura i Fargas (1824-1885)

Effects of substrata and environmental conditions on ecological succession on historic shipwrecks

An understanding of the interactions between biological, chemical and physical dynamics is especially important for the adequate conservation of the Underwater Cultural Heritage. However, while physical and chemical processes are relatively well-investigated, the biological communities associated with these habitats are poorly studied. We compared the sessile community developed on panels of different materials placed on two historical shipwrecks, the Fougueux and the Bucentaure, from the Battle of Trafalgar (October 1805). Six materials used at the construction of vessels at the 18th and 19th centuries were selected: copper, brass, cast iron, carbon steel, pine and oak. The sessile community developed on the panels was studied two and 15 months after their immersion at the water to determine the effects of materials and environmental conditions (sediments, waves, hydrodynamic conditions, temperature and salinity) on ecological succession and the possible implications at the conservation of historical shipwrecks. On the Fougueux, the environmental conditions more strongly influenced the biological succession than the material type, with pioneer colonisers dominating the communities in both sampling periods. On the Bucentaure, exposed to more stable environmental conditions, the sessile community showed differences between sampling periods and among materials at the end of the experiment. Under these more stable environmental conditions, the material type showed a higher influence on the sessile community. Species that produce calcareous concretions developed on metallic panels, but were absent on wood panels, where the shipworm Teredo navalis was more abundant. The relationship between environmental conditions, sessile organisms and material type can influence the conservation status of the archaeological sites

Tradición e innovación en las artes industriales: el palio de plata de 1871 de Francesc Isaura

Con esta restauración el IAPH inicia la incorporación de piezas del patrimonio industrial a sus programas de intervención. El desarrollo de este trabajo innovador, complejo, y extenso (diciembre de 2002-julio de 2008), ha supuesto un significativo reto metodológico y operativo. La novedosa técnica empleada por Francesc de Paula Isaura i Fargas (1824-1885) para la producción de esta obra, fue la denominada plata Ruolz, consistente en la aplicación de un sistema electrolítico que daba aspecto plateado a objetos mediante electrodeposición de una capa de plata. Con el uso de este método la industria del metal daba un nuevo impulso al desarrollo de las artes decorativas en la España del siglo XIX. El estudio analítico de los materiales metálicos ha permitido conocer la composición y la técnica de ejecución del mismo, quedando constancia de la aplicación del sistema Ruolz en las piezas originales. El Centro de Intervención en el Patrimonio Histórico ha llevado a cabo la restauración en tres fases: documentación de la posición exacta de cada uno de los elementos metálicos y valoración de daños y piezas a reproducir; aplicación de distintas técnicas para la restauración (limpieza, reposición de volúmenes, eliminación de elementos no originales, soldado y refuerzo de fisuras, reposición de piezas desaparecidas, adaptación cromática y protección de la capa exterior); y diseño del soporte de madera donde se han fijado todas las piezas. El trabajo realizado ha originado importantes aportaciones en materia de investigación histórica sobre esta singular pieza de la industria artística catalana de la segunda mitad del siglo XI

Influence of Aerospace Standard Surface Pretreatment on the Intermetallic Phases and CeCC of 2024-T3 Al-Cu Alloy

A standard three-step surface pretreatment employed in the aerospace sector for Al alloys have been investigated prior to the generation of cerium conversion coatings (CeCC) on aluminiumcopper alloy 2024. Two pretreatments were analysed, one without final acid etching (Pretreatment 1) and another with this step (Pretreatment 2). Both pretreatments affect the alloy intermetallic phases, playing a key role in the development of the CeCC, and also in the susceptibility to localised corrosion in NaCl medium. Scanning electron microscopy coupled with energy-dispersive X-ray analysis (SEM-EDX) revealed that after Pretreatment 2, Al(Cu,Mg) phases were partially or totally removed through dealloying with their subsequent copper enrichment. Conversely, none of these intermetallic phases were affected when the final acid step was not employed (Pretreatment 1). Meanwhile, Al-Cu-Fe-Mn-(Si) phases, the other major Al–Cu alloys intermetallics, suffers minor changes through the whole pretreatments chain. The protective efficiency of CeCC was evaluated using electrochemical techniques based on linear polarisation (LP) and electrochemical impedance spectroscopy (EIS). Samples with CeCC deposited after the Pretreatment 1 gave higher polarisation resistance and impedance module than CeCC deposited after Pretreatment 2. SEM-EDX and X-ray photoelectron spectroscopy analysis (XPS) indicate that the main factors explaining the corrosion resistance of the coatings is the existence of Al(Cu,Mg) intermetallics in the surface of the alloy, which promote the deposition of a cerium-based coating rich in Ce4+ compounds. These Al(Cu,Mg) intermetallics were kept in the 2024 alloy when acid etching was not employed (Pretreatment 1)

Application of Commercial Surface Pretreatments on the Formation of Cerium Conversion Coating (CeCC) over High-Strength Aluminum Alloys 2024-T3 and 7075-T6

The selection of appropriate surface pretreatments is one of the pending issues for the industrial application of cerium-based chemical conversion coatings (CeCC) as an alternative for toxic chromate conversion coating (CrCC). A two-step surface pretreatment based on commercial products has been successfully used here to obtain CeCC on AA2024-T3 and AA7075-T6. Specimens processed for 1 to 15 min in solutions containing CeCl3 and H2O2 have been studied by scanning electron microscopy coupled with energy-dispersive X-ray analysis (SEM-EDX), glow discharge optical emission spectroscopy (GDOES), potentiodynamic linear polarization (LP), electrochemical impedance spectroscopy (EIS), and neutral salt spray (NSS) tests. SEM-EDX showed that CeCC was firstly observed as deposits, followed by a general coverage of the surface with the formation of cracks where the coating was getting thicker. GDOES confirmed an increase of the CeCC thickness as the deposition proceed, the formation of CeCC over 7075 being faster than over 2024. There was a Ce-rich layer in both alloys and an aluminum oxide/hydroxide layer on 7075 between the upper Ce-rich layer and the aluminum matrix. According to LP and EIS, CeCC in all samples offered cathodic protection and comparable degradation in chloride-containing media. Finally, the NSS test corroborated the anti-corrosion properties of the CeCC obtained after the commercial pretreatments employed.This research was funded by the Ministry of Economy, Industry and Competitiveness of Spain/FEDER Program of the EU. Project: Optimizacion y viabilidad industrial del proceso de preparacion de capas de conversion basadas en cerio sobre aleaciones de aluminio. Reference MAT2014-60857-R. The APC was funded by Instituto Universitario de Investigacion Marina (INMAR) of the University of Cadiz and the Programa de Fomento e Impulso de la Actividad de Investigacion y Transferencia of the University of Cadiz

Tradición e innovación en las artes industriales : el palio de plata de 1871 de F. Isaura

Con esta restauración el IAPH inicia la incorporación de piezas del patrimonio industrial a sus programas de intervención. El desarrollo de este trabajo innovador, complejo, y extenso (diciembre de 2002-julio de 2008), ha supuesto un significativo reto metodológico y operativo. La novedosa técnica empleada por Francesc de Paula Isaura i Fargas (1824-1885) para la producción de esta obra, fue la denominada plata Ruolz, consistente en la aplicación de un sistema electrolítico que daba aspecto plateado a objetos mediante electrodeposición de una capa de plata. Con el uso de este método la industria del metal daba un nuevo impulso al desarrollo de las artes decorativas en la España del siglo XIX. El estudio analítico de los materiales metálicos ha permitido conocer la composición y la técnica de ejecución del mismo, quedando constancia de la aplicación del sistema Ruolz en las piezas originales. El Centro de Intervención en el Patrimonio Histórico ha llevado a cabo la restauración en tres fases: documentación de la posición exacta de cada uno de los elementos metálicos y valoración de daños y piezas a reproducir; aplicación de distintas técnicas para la restauración (limpieza, reposición de volúmenes, eliminación de elementos no originales, soldado y refuerzo de fisuras, reposición de piezas desaparecidas, adaptación cromática y protección de la capa exterior); y diseño del soporte de madera donde se han fijado todas las piezas. El trabajo realizado ha originado importantes aportaciones en materia de investigación histórica sobre esta singular pieza de la industria artística catalana de la segunda mitad del siglo XI

Large-scale conservation treatment of cast-iron heavy artillery pieces from underwater origin. Methodological procedures

Este trabajo describe el tratamiento simultáneo de limpieza y extracción de iones cloruro, mediante electrolisis, de 17 cañones de hierro del siglo XVIII, de origen subacuático, procedentes de un hallazgo casual. En un contexto de bajo presupuesto, se desarrollaron cubas a medida y herramientas específicas para la desconcreción de las piezas: una barrena de alta precisión para acceder al ánima de los cañones y bases de trabajo giratorias. Además, se aplicó una nueva técnica de estabilización para piezas grandes de fundición mediante envolturas en material absorbente impregnado en NaOH. La selección de la densidad de corriente para los tratamientos de electrolisis se estableció mediante un ensayo previo, que demostró la mayor eficiencia de 50 μAcm¯ ² frente a 1000 μAcm¯ ². La descripción de las tareas realizadas, junto con las novedades metodológicas aportadas, conforman una valiosa información para futuras actuaciones en materia de conservación a gran escala del Patrimonio Cultural Subacuático (PCS)