New records for the benthic marine flora of Chafarinas Islands (Alboran Sea, western Mediterranean)

Nuevas citas para la fl ora bentónica marina de las Islas Chafarinas (Mar de Alborán, Mediterráneo occidental

Eukaryotic microbial diversity of phototrophic microbial mats in two Icelandic geothermal hot springs

The composition of the eukaryotic community and the three-dimensional structure of diverse phototrophic microbial mats from two hot springs in Iceland (Seltun and Hveradalir geothermal areas) were explored by comparing eukaryotic assemblages from microbial mats. Samples were collected in July 2007 from 15 sampling stations along thermal and pH gradients following both hot springs. Physicochemical data revealed high variability in terms of pH (ranging from 2.8 to 7), with high concentrations of heavy metals, including up to 20 g Fe/l, 80 mg Zn/l, 117 mg Cu/l, and 39 mg Ni/l at the most acidic sampling points. Phylogenetic analysis of 18S rDNA genes revealed a diversity of sequences related to several taxa, including members of the Bacillariophyta, Chlorophyta, Rhodophyta, and Euglenophyta phyla as well as ciliates, amoebae, and stramenopiles. The closest relatives to some of the sequences detected came from acidophilic organisms, even when the samples were collected at circumneutral water locations. Electron microscopy showed that most of the microecosystems analyzed were organized as phototrophic microbial mats in which filamentous cyanobacteria usually appeared as a major component. Deposits of amorphous minerals rich in silica, iron, and aluminium around the filaments were frequently detected. [Int Microbiol 2010; 13(1):21-32

Locating water in the dehydrated thallus of lichens from extreme microhabitats (Antárctica)

Nueve páginas y 6 figurasMicrobial ecology deals with interactions among microorganisms, between microorganisms and their environment, and with water relations in the microhabitat. In the desiccated state, many lichens tolérate long periods of intense stress. The present report describes the use of scanning electrón microscopy with backscattered electrón imaging (SEM-BSE) to observe - on the spatial nanometer scale - relationships among the epilithic thallus of an Antarctic Lichen, microorganisms belonging to epilithic, chasmoendolithic and cryptoendolithic communities and minerals. The main aim of the study was to determine the precise location of minute quantities of water that the thallus may maintain probably obtained from the mineral microenvironment of its rock habitat. Through low temperature scanning electrón microscopy (LTSEM), it was possible to observe ice crystals indicative of the presence of water in the dehydrated hyphae of the fungal partner of the lichen when these were crossfractured. Ice crystals were also detected among the mineral particles of the lithic substrate. Besides implications ¡n the highly controversia! topic of water distribution in the lichen thallus, the present findings suggest that under conditions of drought, the presence of small quantities of water in the apoplast may explain the survival of the dehydrated thallus.Grants BOS2000-1121 and ANT99-0680-CO2-02 from the DGICYT. The authors gratefully aknowledge Ana Burton for the English revision and Fernando Pinto for skilful technical assistence.Peer reviewe

Primera cita de Caulerpa cylindracea (Caulerpaceae, Chlorophyta) en Andalucía (Sur de España)

Three different species of Caulerpa (Caulerpaceae, Chlorophyta) co-occur in the Mediterranean Sea: two of them are found at the central-eastern basin and are typically considered non aggressive components of the Lessepsian flora [(C. chemnitzia(Esper) J.V. Lamouroux and C. racemosa var. lamourouxii (Turner) Weber-van Bosse f. requienii(Montagne) Weber van Bosse)]; a third taxon, C. cylindracea Sonder has aggressively expanded its range since its first observation in 1990, and it is nowadays reported from nearly all the Mediterranean countries. We report a population of C. cylindracea from Almería (Andalusia, Southern Iberian Peninsula) at −30 m depth as to be the westernmost record of the invasive variety on the Mediterranean European coast. Therefore, we made use of morphological description and molecular phylogenetics to provide a complete identification of this invasive seaweed in Southern Spain. Our findings are discussed in light of the composition of the receptor communities, such as maërl bed, edges of Posidonia oceanica (Linnaeus) Delile, and their ecology. Our results confirmed the suggested directionality of the invasive pathway to be westward to the Strait of Gibraltar, mainly supported by sea currents and vectors of anthropogenic origin.En el Mar Mediterráneo se encuentran tres especies diferentes de Caulerpa (Caulerpaceae, Chlorophyta): dos de ellas se localizan en la cuenca centro oriental y se consideran componentes no agresivos de la flora Lessepsiana (C. chemnitzia (Esper) J.V. Lamouroux and C. racemosa var. lamourouxii (Turner) Weber-van Bosse f. requienii (Montagne) Weber van Bosse); un tercer taxon, C. cylindracea Sonder ha expandido de manera agresiva su rango de distribución desde su primera observación en 1990, y actualmente se registra en casi todos los países de la cuenca mediterránea. En este trabajo se informa sobre una población de C. cylindracea en Almería (Andalucía, Sur de España), a −30 m de profundidad, que representaría la cita más occidental de la variedad invasora en las costas mediterráneas europeas. Se realiza una completa identificación de esta alga invasora en el Sur de España mediante una descripción morfológica y filogenia molecular. Los datos obtenidos se discuten en relación a la composición de las comunidades receptoras, tales como fondos de maërl y bordes de Posidonia oceanica (Linnaeus) Delile, y su ecología. Los resultados confirman la direccionalidad de la ruta invasora de la especie hacia el oeste en las proximidades del Estrecho de Gibraltar, principalmente debido a corrientes marinas y vectores de origen antropogénico.This work has been founded by the projects CGL2008/01549/BOS and CGL2008/02298/BOS (Ministerio de Ciencia e Innovación), P09-RNM-5187 (Consejería de Innovación, Ciencia y Empresa, Junta de Andalucía), 806/5.03.3553 and 806/5.03.3673 (Instituto de Estudios Ceutíes), and has been developed in the framework of the Research Collaboration Agreement between Consejería de Medio Ambiente de la Junta de Andalucía and the University of Málaga

Insight into the melt processed Polylimonene oxide/Polylactic acid blends

In this work, the polymerization of limonene oxide (LO) has been optimized at room temperature with two different aluminium-based catalysts [AlMeX{2,6-(CHPh$_2$)$_2$-4-tBu-C$_6$H$_2$O}] (X = Me (1), Cl (2)). A fully bio-based ether, polylimonene oxide (PLO), has been synthesized with low molecular weight and good thermal stability, being a potential sustainable polymeric additive for other bio-based and biodegradable polymers such as polylactic acid (PLA). Hence, we have explored its ability to influence the thermal, mechanical and morphological properties of PLA by preparing their blends by melt processing. The addition of a low amount of PLO led to a nearly 10 $^\circ$C decrease in the PLA glass transition temperature. Moreover, a decrease in the PLA melting temperature and the degree of crystallinity was observed. Interestingly, a remarkable increase in the flexibility of PLA-based films was noticed. All the results point to the existence of strong interactions between the components, suggesting their partial miscibility.Comment: Polymer Chemistry (2023

The Cyborg Astrobiologist: Testing a Novelty-Detection Algorithm on Two Mobile Exploration Systems at Rivas Vaciamadrid in Spain and at the Mars Desert Research Station in Utah

(ABRIDGED) In previous work, two platforms have been developed for testing computer-vision algorithms for robotic planetary exploration (McGuire et al. 2004b,2005; Bartolo et al. 2007). The wearable-computer platform has been tested at geological and astrobiological field sites in Spain (Rivas Vaciamadrid and Riba de Santiuste), and the phone-camera has been tested at a geological field site in Malta. In this work, we (i) apply a Hopfield neural-network algorithm for novelty detection based upon color, (ii) integrate a field-capable digital microscope on the wearable computer platform, (iii) test this novelty detection with the digital microscope at Rivas Vaciamadrid, (iv) develop a Bluetooth communication mode for the phone-camera platform, in order to allow access to a mobile processing computer at the field sites, and (v) test the novelty detection on the Bluetooth-enabled phone-camera connected to a netbook computer at the Mars Desert Research Station in Utah. This systems engineering and field testing have together allowed us to develop a real-time computer-vision system that is capable, for example, of identifying lichens as novel within a series of images acquired in semi-arid desert environments. We acquired sequences of images of geologic outcrops in Utah and Spain consisting of various rock types and colors to test this algorithm. The algorithm robustly recognized previously-observed units by their color, while requiring only a single image or a few images to learn colors as familiar, demonstrating its fast learning capability.Comment: 28 pages, 12 figures, accepted for publication in the International Journal of Astrobiolog

Infrared and ultraviolet laser removal of crustose lichens on dolomite heritage stone

8 páginas y 8 figurasLaser removal of biodeteriogen layers warrants detailed studies due to the advantages it brings withrespect to mechanical elimination or the use of biocides. We have investigated elimination of biologicalcrusts on dolomite stones from heritage sites in central Spain. The samples were colonized by epilithiccrustose lichens of different species, such as Caloplaca sp. and Verrucaria nigrescens. A comparative studywas carried out by applying infrared (1064 nm) and ultraviolet (355 nm) nanosecond laser pulses andsequences pulses of the two wavelengths using a Q-switched Nd:YAG system. To detect anatomical andultrastructural damage to the lichens, and to assess possible morphological and chemical changes on theunderlying stone induced by laser irradiation, we used stereomicroscopy, scanning electron microscopywith backscattered electron imaging and Fourier transform Raman spectroscopy. The optimal conditionsfor removal of the colonization crust, while ensuring preservation of the lithic substrate, were obtainedfor dual infrared-ultraviolet sequential irradiation.Work funded by Program Geomateriales 2 (S2013/MIT-2914)financed by Comunidad de Madrid and Structural Funds (FSE andFEDER) S2013/MIT-2914. M.O acknowledges contract by CSIC. Weare grateful to M. Furio, A. Jorge and L. Tormo from Servicio de Micro-scopia, MNCN-CSIC and to support by Red de Ciencia y Tecnología para la Conservación del Patrimonio Cultural (Ministerio de Ciencia e Innovación, Spain, Acción Complementaria HAR2010-11432-E).Peer reviewe

『青山評論』記者三浦泰一郎論 -北村透谷との接点を辿って-

This research work is centred on continental lacustrine gypsum deposits of Miocene age cropping out in the easternmost part of the Madrid Basin. These gypsum deposits, accumulated in a continental saline lake, are characterized by a spectacular, distinctive Christmas-tree morphology and a peculiar dolomite replacement. A combination of microscopic (petrography and scanning electron microscopy) and analytical techniques (fluid inclusion microthermometry, X-ray energy dispersive spectroscopy and X-ray diffractometry) was used in order to study the crystallographic distribution and the composition of the fluid inclusions within the gypsum. The objectives were to characterize the continental brine from which the mineral precipitated, and to detect mineral and element traces that could indicate early diagenetic processes altering the gypsum deposits. Data from primary fluid inclusions indicated that gypsum precipitated from an aqueous fluid (lake water) of low to moderate total salinity (between 20 and 90 g/L NaCl). Secondary fluid inclusions represent interstitial lake brine in contact with gypsum, slightly enriched in total salt content as crystal formation proceeded. Textural, ultrastructural and microanalytical analysis indicate that the presence of dolomite precipitates inside the gypsum layers is related to the microbial colonization of the gypsum deposits and the biomineralization of the cell walls and extracellular polymeric substances around the cells. Our investigation emphasizes necessity of a multidisciplinary approach to assess geobiological processes

Titanium-catalyzed synthesis of polymyrcene and polyanethol and application as sustainable additives for poly(lactic acid)

The replacement of fossil-derived plastics with those obtained from bio-based resources, which present suitable performance to be employed as commodity plastics is currently an important field of research, given the urgent need to transition from a fossil-based to a more sustainable economy. In this context, this work is focused on the application of a catalytic system based on silsesquioxane-cyclopentadienyl titanium complexes for the preparation of bio-based polymers, which can be used as additives to improve the poor material properties of a biodegradable polymer such as poly(lactic acid) (PLA). These titanium complexes, when activated with methylaluminoxane or with triflate salts, are shown to be capable of the polymerization of two bio-based monomers: myrcene and anethole. It is notable that polymerizations with these two distinct monomers take place through different mechanisms. The resulting polymyrcene (PMy) and polyanethol (PAN) have been applied as modifiers for PLA. Binary blends of PMy and PLA exhibited a considerable decrease in Tg and the promotion of PLA crystallization for a PMy content below 15 wt%. The mechanical properties of the PLA/PMy blends also displayed plasticization, with a decrease in the elastic modulus and enhanced plasticity, which resulted in less fragile systems compared to pure PLA. Morphological analysis has indicated a partially miscible, phase-separated system with micron-sized domains. In contrast, PAN completely inhibited PLA crystallization and the PLA/PAN blends were immiscible, but well-dispersed, a phase-separated system was obtained in solvent-casting film preparation with very small PAN domains. The blends showed higher tensile modulus than pure PLA and an absence of plastic behaviour, resulting in more fragile systems upon the addition of PAN to PLA