Archaeal Communities in a Heterogeneous Hypersaline-Alkaline Soil

In this study the archaeal communities in extreme saline-alkaline soils of the former lake Texcoco, Mexico, with electrolytic conductivities (EC) ranging from 0.7 to 157.2 dS/m and pH from 8.5 to 10.5 were explored. Archaeal communities in the 0.7 dS/m pH 8.5 soil had the lowest alpha diversity values and were dominated by a limited number of phylotypes belonging to the mesophilic Candidatus Nitrososphaera. Diversity and species richness were higher in the soils with EC between 9.0 and 157.2 dS/m. The majority of OTUs detected in the hypersaline soil were members of the Halobacteriaceae family. Novel phylogenetic branches in the Halobacteriales class were detected in the soil, and more abundantly in soil with the higher pH (10.5), indicating that unknown and uncharacterized Archaea can be found in this soil. Thirteen different genera of the Halobacteriaceae family were identified and were distributed differently between the soils. Halobiforma, Halostagnicola, Haloterrigena, and Natronomonas were found in all soil samples. Methanogenic archaea were found only in soil with pH between 10.0 and 10.3. Retrieved methanogenic archaea belonged to the Methanosarcinales and Methanomicrobiales orders. The comparison of the archaeal community structures considering phylogenetic information (UniFrac distances) clearly clustered the communities by pH

Variables ambientales que afectan la densidad de diez especies forestales en la Sierra Norte de Oaxaca

Caracterizar las condiciones ambientales en las que se desarrollan las especies forestales es importante, porque permite conocer parte de su hábitat; información útil para tomar decisiones encaminadas a un aprovechamiento integral de los bosques, que incluya medidas preventivas que contrarresten su degradación o su extinción. El objetivo de este estudio fue identificar las variables ambientales que afectan significativamente la abundancia de 10 especies arbóreas que crecen en los bosques templados de Santiago Comaltepec, al norte de Oaxaca, México. Para ello, se utilizaron tres métodos de análisis: 1) componentes principales, 2) coeficientes de correlación no paramétrica, y 3) modelos lineales generalizados. Se evaluaron un total de 23 variables medioambientales, principalmente, registros de temperaturas mínimas y máximas; precipitaciones en el verano, en invierno y en primavera; así como atributos fisiográficos que incluyeron la pendiente, la exposición y la altitud. Todas mostraron una correlación significativa (p<0.001) con al menos tres especies, varias con coeficientes de correlación superior a 0.90. Se identificaron tres taxa que son más sensibles a las variables de temperatura, en particular, a la temperatura mínima, la superior a 5 °C, y al índice de aridez; otras tres que parecen tener mayor sensibilidad a la cantidad de lluvia registrada en la primavera, en el verano, en el invierno y en las precipitaciones de abril a septiembre

Nuestros microcompañeros

This work seeks to explain some aspects of microorganisms and other entities (viruses). To accomplish this, we write about their structure, habitat, and interactions. As well as to mention their importance in some areas of the industry (biotechnology). In the end, we will have an approach with micro-beings and other infectious agents (viruses), as well as the way in which our life can coexist with them. Knowing the surrounding world, allows us to be more conscious with the reality we are currently living. It also helps to understand we are surrounded by micro-beings and other entities. Once we realize we are not alone, it is easy to answer the following question: Who coexists with us? Our response must include organisms we do not perceive.&nbsp;Se explican algunos aspectos de los microorganismos y demás entes (virus), así como su importancia que tienen en algunas áreas de la industria (biotecnología). Se usaron las estructuras, hábitats e interacciones. A partir de los elementos desarrollados se tendrá un acercamiento de las características de estos microseres y demás agentes infecciosos (virus), así como su manera en que nuestra vida puede coexistir con ellos. Conocer nuestro entorno permite acercarnos a la realidad en la que actualmente estamos y comprender que hay microseres y otros entes que no vemos, pero con los que cotidianamente convivimos de tal manera que al preguntarnos “quién nos acompaña” nuestra respuesta tenga inmersa a los organismos que no percibimos por nuestros sentidos.&nbsp

The Potential Distribution of Tree Species in Three Periods of Time under a Climate Change Scenario

Species distribution models have become some of the most important tools for the assessment of the impact of climatic change, and human activity, and for the detection of failure in silvicultural or conservation management plans. In this study, we modeled the potential distribution of 13 tree species of temperate forests distributed in the Mexican state Durango in the Sierra Madre Occidental, for three periods of time. Models were constructed for each period of time using 19 climate variables from the MaxEnt (Maximum Entropy algorithm) modelling algorithm. Those constructed for the future used a severe climate change scenario. When comparing the potential areas of the periods, some species such as Pinus durangensis (Mart&iacute;nez), Pinus teocote (Schiede ex Schltdl. &amp; Cham.) and Quercus crassifolia (Bonpl.) showed no drastic changes. Rather, the models projected a slight reduction, displacement or fragmentation in the potential area of Pinus arizonica (Engelm.), P. cembroides (Zucc), P. engelmanni (Carr), P. leiophylla (Schl), Quercus arizonica (Sarg), Q. magnolifolia (N&eacute;e) and Q. sideroxila (Humb. &amp; Bonpl.) in the future period. Thus, establishing conservation and reforestation strategies in the medium and long term could guarantee a wide distribution of these species in the future