Influencia de la temperatura sobre la asimetría de pilancones en ambiente granítico. Aplicación de un modelo de regresión lineal

Las pilas representan un tipo de forma presente en casi todos los ambientes climáticos. El trabajo estudia el papel de los ciclos térmicos como un agente importante del modelado y asimetría que presentan las paredes de las pilas en un clima Mediterrá- neo templado - frío. El estudio se ha realizado en el macizo granítico de la Pedriza de Manzanares, zona protegida de gran valor ambiental, incluida en el Parque Nacional de la Sierra de Guadarrama (Madrid, España). El análisis de la variabilidad térmica mediante modelos de regresión perió- dica múltiple, pone de manifiesto la influencia de los ciclos diario y anual en función de las orientaciones norte y sur de las paredes de las pilas. Un modelo matemático de regresión lineal muestra cómo la variabilidad térmica diaria influye en la alteración de las paredes de las pilas, generando superficies planas o de concavidad más o menos pronunciada. El trabajo también establece relaciones entre el grado de alteración de las diferentes partes de las pilas, con la presencia de líquenes y dureza relativa de la roca. Los resultados avalan la hipótesis de relación causal entre la variabilidad térmica y alteración de las paredes de las pilas según su orientación norte o sur

Protist Diversity Responses to Experimental N Deposition in Biological Crusts of a Semiarid Mediterranean Ecosystem

Biological soil crusts (BSC) are associations of different macro and microorganisms and aggregated soil particles located on the surface of soils in many different habitats. BSC harbour a diverse and complex community of ciliates and testate amoebae. These phagotrophic protists play an important role in C and N recycling in soil ecosystems but have not been frequently studied in BSC. In this context, the effects of three increasing N inputs on ciliates and testate amoebae in crusts from a semi-arid Mediterranean ecosystem were evaluated. A field experiment with artificial N-deposition was designed to mimic the effects caused by anthropogenic N depositions. The results have shown that the protist populations of these semi-arid Mediterranean environments have lower species richness than other soil environments. The increase in N produces a net loss of diversity in the populations studied and shifts in the community structure. It has also been shown that some ciliates and testate amoebae, due to their population responses to increased N concentrations, could potentially be used as bio-indicators of N contamination in these BSCs

Rain-fed granite rock basins accumulate a high diversity of dormant microbial eukaryotes

Rain fed granite rock basins are ancient geological landforms of worldwide distribution and structural simplicity. They support habitats that can switch quickly from terrestrial to aquatic along the year. Diversity of animals and plants, and the connexion between communities in different basins have been widely explored in these habitats, but hardly any research has been carried out on microorganisms. The aim of this study is to provide the first insights on the diversity of eukaryotic microbial communities from these environments. Due to the ephemeral nature of these aquatic environments, we predict that the granitic basins should host a high proportion of dormant microeukaryotes. Based on an environmental DNA diversity survey, we reveal diverse communities with representatives of all major eukaryotic taxonomic supergroups, mainly composed of a diverse pool of low abundance OTUs. Basin communities were very distinctive, with alpha and beta diversity patterns non-related to basin size or spatial distance respectively. Dissimilarity between basins was mainly characterised by turnover of OTUs. The strong microbial eukaryotic heterogeneity observed among the basins may be explained by a complex combination of deterministic factors (diverging environment in the basins), spatial constraints, and randomness including founder effects. Most interestingly, communities contain organisms that cannot coexist at the same time because of incompatible metabolic requirements, thus suggesting the existence of a pool of dormant organisms whose activity varies along with the changing environment. These organisms accumulate in the pools, which turns granitic rock into high biodiversity microbial islands whose conservation and study deserve further attention.Ministerio de Economía, Industria y Competitividad, Gobierno de Españ

The Olive Ridley Project (ORP): a successful example of how to engage researchers, conservation practitioners and civil society

The Olive Ridley Project (ORP) was set up to protect sea turtles and their habitats. The project was formed in 2013, and it became a registered charity in the UK in 2016. From its inception, ORP took a multidisciplinary approach to achieve its goals. Part of its objectives, and the reason why the charity came to fruition, are related to the issue of olive ridley sea turtle (Lepidochelys olivacea) entanglement in abandoned, lost or discarded fishing gear (also known as ‘ghost gear’ or ‘ghost nets’), and the search for ghost gear and turtle entanglement ‘hot spots’ throughout the Indian Ocean. The initial ORP research questions were soon challenged by societal interests to develop inclusive educational programmes in local communities and tourist resorts that could raise awareness about the need for conservation of all sea turtle species. In February 2017, ORP opened the first veterinarian-run, fully equipped Marine Turtle Rescue Centre in the Maldives, bringing together the work of researchers, citizen scientists, volunteers, environmentalists, marine biologists and veterinarians. The present work of ORP sits on a strong and scientifically robust collaborative plan. Current ORP research projects range from sea turtle population analyses, spatial ecology, rehabilitation of injured and sick individuals, epibiont parasite analyses, precise turtle identification through photo-ID research, linking ghost gear to responsible fisheries, and analyses of ghost gear drift patterns. The programme enhances community education and outreach by engaging schoolchildren, organizing workshops, promoting sustainable use of ghost gear waste, and training citizen scientists and local fishing communities. The ORP programme encompasses many principles of research engagement, effectively combining scientific knowledge, education and action. This article explores all stages of the process (from research planning and design, to knowledge exchange and inter- and trans-disciplinary impact assessments), describing the active engagement originated by the ORP initiative. A reflective insight into the learning, enrichment and challenges of engaging researchers and community actors is also included, considering the current social and scientific framework

La curación de contenidos científicos como estrategia didáctica y divulgativa en Microbiología y otras áreas afines

Fac. de Ciencias BiológicasFALSEsubmitte

Easy Visualization of the Protist Oxyrrhis marina Grazing on a Live Fluorescently Labelled Heterotrophic Nanoflagellate

Planktonic heterotrophic flagellates are ubiquitous eukaryotic microorganisms that play a crucial role in carbon and nutrient fluxes through pelagic food webs. Here we illustrate for the first time a grazing model of planktonic dinoflagellate, Oxyrrhis marina, on the heterotrophic nanoflagellate Goniomonas amphinema, using the DNAbinding fluorescent dye Hoechst 33342. A solution of 1 lg/mL of the fluorochrome allowed viability of the prey for at least 48 hours, provided low fluorescence quenching, and labelled the flagellate without masking the cytoplasm. After 2 hours of contact between the fluorescent prey and the predator, O. marina population had preyed on live G.amphinema at an ingestion rate of 2.2 prey Oxyrrhis-1 h-1. Results show that this model is a time-effective and inexpensive approach for the direct observation of heterotrophic flagellate grazing. The fact that prey remain alive while predation occurs, as well as the low rate of quenching, could be of help in studying the fate of realtime trophic interactions between protists in microbial webs.European Community. Marie Curie FellowshipDepto. de Genética, Fisiología y MicrobiologíaFac. de Ciencias BiológicasTRUEpu

An investigation of the fine structure, cell surface carbohydrates, and appeal of the diatom Extubocellulus sp. as prey for small flagellates

This study was supported by a Marie Curie Fellowship of the European Community under contract number HPMF-CT-2002-01861 to M.M.-C.The fine structure and surface exopolymers of a coastal planktonic nanodiatom of the sparsely reported genus Extubocellulus were studied respectively by scanning electron microscopy and confocal microscopy in conjunction with fluorescent lectins. Monitoring the suitability of the species as prey food for other protists was also investigated by video microscopy coupled with digital film. Cells are rectangular in girdle view, with a pervalvar axis longer than the apical axis. Valves are almost circular with a diameter of 2.8 to 3.6 m. The valve face bears randomly distributed areolae (ca. 50 in 10 m), which may be either open or occluded. Two small raised ocelluli occur at the apices, with a rim devoid of perforations and about 6–7 porelli. Glucose and N-acetylglucosamine moieties present on the surface of the live diatom were labelled with fluorescent lectins, and a differential pattern of distribution for both carbohydrates was observed. The potential role of fluorescent lectins as cellular probes of taxonomic value in small diatoms is compared with that of nucleotide and antibody probes. We provide the first illustrative evidence of the presence of Extubocellulus sp. in the cytoplasm of the nanoflagellate Goniomonas amphinema and of the egestion of diatom frustules. Results obtained are discussed in the light of the present knowledge of the role of carbohydrate–protein interactions in phagocytosis of prey by free-living protozoa.Depto. de Genética, Fisiología y MicrobiologíaFac. de Ciencias BiológicasTRUEpu

Endemicity and climatic niche differentiation in three marine ciliated protists

Primary occurrence data are fully and openly accessible via the Global Biodiversity Information Facility (GBIF; http://www.gbif.org/) and Ocean Biogeographic Information System (OBIS; http://www.iobis.org/). Environmental coverages were drawn from National Oceanic and Atmospheric Administration’s (NOAA) World Ocean Atlas (NOAA 1999)The biogeographic pattern of single-celled eukaryotes (protists), including ciliates, is poorly understood. Most marine species are believed to have a relatively high dispersal potential, such that both globally distributed and geographically isolated taxa exist. Primary occurrence data for three large, easily identified ciliate species, Parafavella gigantea, Schmidingerella serrata, and Zoothamnium pelagicum, and environmental data drawn from the National Oceanic and Atmospheric Administration’s World Ocean Atlas were used to estimate each species’ spatial and environmental distributions using Maxent v3.3.3k. The predictive power of the models was tested with a series of spatial stratification studies, which were evaluated using partial receiver operating characteristic (ROC) statistics. Differences between niches occupied by each taxon were evaluated using background similarity tests. All predictions showed significant ability to anticipate test points. The null hypotheses of niche similarity were rejected in all background similarity tests comparing the niches among the three species. This article provides the first quantitative assessment of environmental conditions associated with three species of ciliates and a first estimate of their spatial distributions in the North Atlantic, which can serve as a benchmark against which to document distributional shifts. These species follow consistent, predictable patterns related to climate and environmental biochemistry; the importance of climatic conditions as regards protist distributions is noteworthy considering the effects of global climate change.Depto. de Genética, Fisiología y MicrobiologíaFac. de Ciencias BiológicasTRUEpu