New depth record of the precious red coral Corallium rubrum for the Mediterranean

Live colonies of the precious red coral Corallium rubrum have previously been recorded at depths of 600 -800 m in the Sicily Channel, but deep -water populations of this species remain poorly known. During a recent research expedition within the 25 nautical mile Fisheries Management Zone around the Maltese Islands, numerous colonies growing deeper than 800 m, down to depths of 1016 m were observed. These colonies were part of a diverse community of habitat -forming species of scleractinians, gorgonians and antipatharians.peer-reviewe

On the occurrence of Coronaster briareus (Echinodermata, Forcipulatida, Asteriidae) in the Mediterranean Sea

The sea star Coronaster briareus (Verrill Am J Sci (Ser III), 1882) is reported for the first time from the Mediterranean Sea. A total of 26 individuals were sighted in Maltese waters during ROV surveys made in July 2015 and June–July 2016. The identity of the species was confirmed through morphological examination of a specimen collected in June 2016. This identification is discussed in the light of inconsistencies in the published descriptions of species of Coronaster recorded from the Atlantic, and of individuals belonging to this genus recorded from the eastern Atlantic and whose coloration does not match that of C. briareus or C. volsellatus (the only species of Coronaster hitherto known from the Atlantic). The presence of numerous individuals of C. briareus in Maltese waters, recorded on two occasions a year apart over a relatively large area, indicates that there is an established population. This represents a considerable expansion of the distribution range of this species, which is mostly known from the western Atlantic. Possible reasons for its presence in Maltese waters are discussed, but the dynamics of the occurrence of C. briareus in the central Mediterranean remain unknown.peer-reviewe

Recent evidence that the deep sea around Malta is a biodiversity hotspot

Recent ROV surveys of deep-sea areas around the Maltese Islands resulted in the discovery of highly diverse habitats, including extensive rocky areas dominated by living cold water corals and gorgonians at depths of 300–1000 m, a sub-fossil lithistid sponge reef at a depth of ca. 300 m, deep-water caves located at 270–450 m, and vast expanses of soft-bottom habitats, each of which had a rich variety of associated fauna. Most of these habitats are of high conservation interest, highlighting the need for the establishment of offshore marine protected areas in order to protect these very diverse, but highly vulnerable, deep-sea habitats.peer-reviewe

Synthesis and H+, Cu2+, and Zn2+ Coordination Behavior of a Bis(fluorophoric) Bibrachial Lariat Aza-Crown

The synthesis, protonation behavior, and Cu2+ and Zn2+ coordination chemistry of the novel bibrachial aza lariat ether (naphthalen-1-ylmethyl)[2-(20-{2-[(naphthalen-1-ylmethyl)amino]ethyl}-3,6,9,17,20,23,29,30-octaazatricyclo[23.3.1.1*11,15*]triaconta-1(29),11(30),12,14,25,27-hexaen-6-yl)ethyl]amine (L) are discussed. The macrocycle, which has two aminoethyl naphthyl moieties symmetrically appended to a 2:2 azapyridinophane structure, displays, in the pH range 2−11, six protonation steps that correspond to the protonation of the secondary amino groups. Steady-state fluorescence measurements show emissions due to the monomer and to the excimer formed between the two naphthalene fragments of the macrocycle. The time-resolved fluorescence data, obtained by the time-correlated single photon counting technique, show that a significant percentage of excimer is preformed as ground-state dimers. The ligand L forms with the metal ions Cu2+ and Zn2+ mono- and dinuclear complexes in aqueous solution. The influence of metal coordination in the fluorescence emission of L is analyzed. The acid−base, coordination capabilities, and emissive behavior of L are compared with those presented by its synthetic precursor L1, which has a tripodal tris(2-aminoethyl)amine structure functionalized at one of its terminal amino groups with a naphthyl moiet

Un Parque Jurásico… en el Mediterráneo

Los arrecifes modernos son básicamente estructuras calcáreas, construidas principalmente por la actividad calcificadora de los corales, muchas veces con la ayuda de algas calcáreas incrustantes. Sin embargo, previamente a la existencia de los corales modernos, hubo un tiempo en que los arrecifes eran estructuras construidas esencialmente de silicio. Durante parte de la era Mesozoica, particularmente en los periodos Jurásico y Cretácico (entre 163 y 65 millones de años), dos tipos de esponjas con esqueletos masivos de sílice (las hexactinélidas dictioninas y las demosponjas litístidas) fueron importantes constructores de arrecifes en las plataformas continentales cálidas del Mar de Tethys. El registro fósil indica que estos arrecifes silíceos entraron en declive durante el Terciario (Paleógeno, entre 65 y 23 millones de años) y, finalmente, se extinguieron. Para sorpresa general, en los años 80 se descubrió un equivalente vivo de los arrecifes Mesozoicos. Un arrecife constituido por sólo tres especies de esponjas hexactinélidas y sin la contribución de las esponjas litístidas. La estructura se extiende irregularmente sobre un área de unos 700 km2 en la frías y nutritivas aguas del Pacífico canadiense (Estrecho de Georgia, Canadá), a una profundidad de unos 250 m, en la zona de transición entre la plataforma continental y el talud. Por su singularidad, esté hábitat ha atraído la atención de científicos y medios de comunicación durante los últimos 20 años y su estudio aún continúa, estimulado por los avances en la tecnología de trabajo en ambientes marinos profundos. En esta ponencia informamos que durante 2013 se ha descubierto en el Mediterráneo un segundo equivalente vivo de los arrecifes silíceos mesozoicos. Se trata de una variante aun más rara, construida no por esponjas hexactinélidas, sino por esponjas litístidas, que constituyen una fauna relicta en el Mediterráneo. Se resumen aquí los datos disponibles sobre este excepcional hábitat, único en el planeta, y se discute su vulnerabilidad y necesidad de protección, ilustrando las explicaciones con material fotográfico y vídeos obtenidos mediante el uso de un robot submarino

Metodología de diseño basada en FPGA para la predistorsión digital de amplificadores de potencia

Este artículo describe el diseño e implementación de un sistema de predistorsión digital (DPD) sin memoria para la linealización de amplificadores de potencia. El prototipo del sistema y la arquitectura se implementaron usando un kit de desarrollo DSP-FPGA. La metodología de diseño es descrita en bloques prácticos y analizada en detalle con énfasis especial en el dominio digital, donde se ejecutaron los algoritmos propuestos. La estrategia del sistema predistorsionador está basada en una tabla de búsqueda compleja que permite programar las curvas de conversión inversas de AM-AM y AM-PM de un amplificador de potencia

Action plan for the conservation of habitats and species associated with seamounts, underwater caves and canyons, aphotic hard beds and chemo-synthetic phenomena in the Mediterranean Sea (Dark Habitats action plan)

Dark habitats are environments where the luminosity is extremely weak, or even absent (aphotic area) leading to an absence of macroscopic autochthonous photosynthesis. The bathymetric extension of this lightless area depends to a great extent on the turbidity of the water and corresponds to benthic and pelagic habitats starting from the deep circa-littoral. Caves which show environmental conditions that favour the installation on of organisms characteristic of dark habitats, are also taken into account. Dark habitats are dependent on very diverse geomorphological structures (e.g. underwater caves, canyons, slopes, isolated rocks, abyssal plains, cold seeps, brine anoxic lakes, hydrothermal springs and seamounts). Dark habitats represent outstanding and potential ecosystems with regard to their: Frailty and vulnerability to any land-based pressure Play an important part in the way the Mediterranean ecosystem functions, insofar as they constitute the main route for transferring matter between the coast and the deep sea Considered as biodiversity hotspots and recruiting areas forming a veritable reservoirs of knowledge and biodiversity Natural habitats that come under Habitat Directive on the conservation of natural habitats and of wild fauna and flora and appear as such as priority habitats requiring protection (Directive 92/43). A certain number of underwater caves enjoy protection status because they fall within the geographical boundaries of Marine Protected Areas (MPAs) Understanding of these functions is necessary for a better understanding and management of the biodiversity of Mediterranean coastal zones and continental shelf.peer-reviewe

Benthic Fauna of Littoral and Deep-Sea Habitats of the Alboran Sea: A Hotspot of Biodiversity

En prens

Especies forestales y arbustivas asociadas a Maconellicoccus hirsutus (Green) (Hemiptera: Pseudococcidae) en el norte de Nayarit, México

The presence of pink hibiscus mealybug (PHM), Maconellicoccus hirsutus (Green) (Hemiptera: Pseudococcidae), causes environmental and socioeconomic damage in Nayarit, México. Thispest demands studies in order to help develop a management program that includes the knowledge of their hosts. The objectives of this study were to determine the hosts of this pest, such as trees or shrubs, and to know the levels of infestation on them. In 2009 there were selected and sampled 9235 points that included areas such as marginal, urban, agricultural, forestry and nurseries in seven municipalities of northern Nayarit. Also there 37 species were checked as possible host. The insect was present in 1070 points (11.6%), of them 94% presented an infestation at level one (low), to level two 5.6% (medium), and only 0.4% to level three (high). The most infested areas were the marginal (69.3%) and urban (24.9%); the municipalities with higher infestations were Tuxpan, Ruiz, and Rosamorada with an average of 35.2, 22.3, and 12.4%, respectively. About host plants there were recorded 24 species, included in nine botanical families, predominantly those belonging to the family Leguminosae; five of the identified plant species corresponded to new reports with PHM presence in the world. The most abundant and preferred to PHM were three leguminous species; however, the plant species that was present in all municipalities and predominant was Acacia cochliacantha Schlecht & Cham (30.9% infestation), followed by Mimosa pigra L. (19.3%) and Albizia lebbeck (L.) Benth (14.5%).La presencia de cochinilla rosada del hibisco (CRH), Maconellicoccus hirsutus (Green) (Hemiptera: Pseudococcidae), causa serios daños ecológicos y socioeconómicos en Nayarit, México, por lo que demanda la realización de estudios que contribuyan a establecer un programa de manejo de esta plaga, entre los cuales resalta el conocimiento de sus hospederos. Los objetivos del estudio fueronconocer en que especies forestales y arbustivas del norte del estado se presenta este insecto y cuáles son sus niveles de infestación. Durante 2009 se seleccionaron 9235 puntos de muestreo, incluyendoáreas marginales, urbana, agrícola, forestal y viveros en siete municipios del norte de Nayarit; también se inspeccionaron 37 especies vegetales como posibles hospederos. El insecto estuvo presente en 1070 de los puntos muestreados (11.6%) y de ellos el 94% presentó un nivel de infestación 1 (bajo), para el nivel 2 (medio) 5.6% y para el 3 (alto) sólo el 0.4%. Las áreas que presentaron las mayores infestaciones fueron: las marginales (69.3%) y la urbana (24.9%); los municipios más afectados fueron Tuxpan, Ruíz y Rosamorada, con infestaciones promedio de 35.2, 22.3 y 12.4%, respectivamente. Con respecto a las plantas hospederas se registraron 24 especies, mismas que se encuentran incluidas en nueve familias botánicas, con predominio de las Leguminosae; cinco de las especies identificadas correspondieron anuevos registros como hospederos de CRH en el mundo. Tres leguminosas resultaron ser las más abundantes y también de las más preferidas por CRH, Acacia cochliacantha Schlecht & Cham fue la especie  predominante ya que se encontró en todos los municipios (30.9% de infestación), seguida por Mimosa pigra L. (19.3%) y Albizia lebbeck (L.) Benth (14.5%)