Variación espacial y temporal de las características fisicoquímicas del agua y sedimento en la laguna costera Yalahau, Quintana Roo

In the Yalahau coastal lagoon, Quintana Roo, we analyzed spatial (Outer, Sea-lagoon, South, and North zones) and temporal weather-season variations (rainy, nortes, and dry), in physicochemical characteristics of water and sediment. The salinity, soluble reactive silicate (SiRS), and sediment grain size were the variables with the highest spatial and temporal variability: (1) The Outer zone is characterized by marine salinity with little temporal variation, low concentrations of SiRS (<11 ?M), and predominantly fine sands; (2) The Sea-lagoon zone has the lowest mean salinity (35.5 psu) and little temporal variation, SiRS concentrations of about 10-15 ?M in rainy, and nortes that increased four times in dry, and predominantly coarse sands. (3) The South zone is characterized by mixoeuhaline conditions in nortes and hyperhaline conditions during rains, SiRS concentrations of about 15-20 ?M in rains and nortes that increased twofold in dry and predominantly coarse sands; (4) The North zone is characterized by a permanent trend to hyperhaline conditions, concentrations of SiRS > 10 ?M during the three seasons that increased up to six times in dry weather, when increased concentrations of ammonium and soluble reactive phosphorus were also observed, and predominantly fine sand. The relatively pristine condition of this protected area suggests that natural factors such as the presence of Thalassia testudinum meadows, the magnitude of freshwater inputs, the decomposition of organic matter, and the entry of exogenous nutrients (e.g., seabird droppings) have a great influence on the environmental heterogeneity of the Yalahau lagoon.Se analizó entre zonas (Externa, Mar-laguna, Sur y Norte) y épocas climáticas (lluvias, nortes y secas) la variación de las características fisicoquímicas del agua y sedimento en la laguna costera Yalahau, Quintana Roo. La salinidad, el silicato reactivo soluble (SiRS) y el tamaño de grano del sedimento fueron las variables que presentaron la mayor variabilidad espacial y temporal: (1) zona Externa, caracterizada por salinidades marinas con escasa variación temporal, concentraciones bajas de SiRS (< 11 ?M) y predominio de arenas finas; (2) zona Mar-laguna, presentó la salinidad media mínima (35.5 ups) y escasa variación temporal, concentraciones de SiRS de ~10 a 15 ?M en lluvias y nortes que se incrementaron hasta cuatro veces en secas y predominio de arenas gruesas; (3) zona Sur, caracterizada por condiciones mixoeuhalinas en nortes y hiperhalinas en lluvias, concentraciones de SiRS de ~15 a 20 ?M en lluvias y nortes que se incrementaron al doble en secas, y predominio de arenas gruesas; y (4) zona Norte, caracterizada por una tendencia permanente a la hiperhalinidad, concentraciones de SiRS > 10 ?M durante las tres épocas climáticas que se incrementaron hasta seis veces en secas, cuando también se observaron concentraciones elevadas de amonio y fósforo reactivo soluble, en esta zona predominaron arenas finas. La condición relativamente prístina de esta área natural protegida sugiere que factores naturales como la presencia de praderas del pasto marino Thalassia testudinum, la magnitud de los aportes de agua dulce, la descomposición de materia orgánica y el aporte de nutrientes exógenos (e.g., excretas de aves marinas) ejercen gran influencia sobre la heterogeneidad ambiental de la laguna Yalahau

Environmental and anthropogenic factors affecting the probability of occurrence of Oncomegas wageneri (Cestoda: Trypanorhyncha) in the southern Gulf of Mexico

BACKGROUND: Understanding the environmental and anthropogenic factors influencing the probability of occurrence of the marine parasitic species is fundamental for determining the circumstances under which they can act as bioindicators of environmental impact. The aim of this study was to determine whether physicochemical variables, polyaromatic hydrocarbons or sewage discharge affect the probability of occurrence of the larval cestode Oncomegas wageneri, which infects the shoal flounder, Syacium gunteri, in the southern Gulf of Mexico. METHODS: The study area included 162 sampling sites in the southern Gulf of Mexico and covered 288,205 km(2), where the benthic sediments, water and the shoal flounder individuals were collected. We used the boosted generalised additive models (boosted GAM) and the MaxEnt to examine the potential statistical relationships between the environmental variables (nutrients, contaminants and physicochemical variables from the water and sediments) and the probability of the occurrence of this parasite. The models were calibrated using all of the sampling sites (full area) with and without parasite occurrences (n = 162) and a polygon area that included sampling sites with a depth of 1500 m or less (n = 134). RESULTS: Oncomegas wageneri occurred at 29/162 sampling sites. The boosted GAM for the full area and the polygon area accurately predicted the probability of the occurrence of O. wageneri in the study area. By contrast, poor probabilities of occurrence were obtained with the MaxEnt models for the same areas. The variables with the highest frequencies of appearance in the models (proxies for the explained variability) were the polyaromatic hydrocarbons of high molecular weight (PAHH, 95 %), followed by a combination of nutrients, spatial variables and polyaromatic hydrocarbons of low molecular weight (PAHL, 5 %). CONCLUSIONS: The contribution of the PAHH to the variability was explained by the fact that these compounds, together with N and P, are carried by rivers that discharge into the ocean, which enhances the growth of hydrocarbonoclastic bacteria and the productivity and number of the intermediate hosts. Our results suggest that sites with PAHL/PAHH ratio values up to 1.89 promote transmission based on the high values of the prevalence of O. wageneri in the study area. In contrast, PAHL/PAHH ratio values ≥ 1.90 can be considered harmful for the transmission stages of O. wageneri and its hosts (copepods, shrimps and shoal flounders). Overall, the results indicate that the PAHHs affect the probability of occurrence of this helminth parasite in the southern Gulf of Mexico. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13071-015-1222-6) contains supplementary material, which is available to authorized users

A genome-wide association scan implicates DCHS2, RUNX2, GLI3, PAX1 and EDAR in human facial variation

We report a genome-wide association scan for facial features in B6,000 Latin Americans. We evaluated 14 traits on an ordinal scale and found significant association (P valueso5 10 8) at single-nucleotide polymorphisms (SNPs) in four genomic regions for three nose-related traits: columella inclination (4q31), nose bridge breadth (6p21) and nose wing breadth (7p13 and 20p11). In a subsample of B3,000 individuals we obtained quantitative traits related to 9 of the ordinal phenotypes and, also, a measure of nasion position. Quantitative analyses confirmed the ordinal-based associations, identified SNPs in 2q12 associated to chin protrusion, and replicated the reported association of nasion position with SNPs in PAX3. Strongest association in 2q12, 4q31, 6p21 and 7p13 was observed for SNPs in the EDAR, DCHS2, RUNX2 and GLI3 genes, respectively. Associated SNPs in 20p11 extend to PAX1. Consistent with the effect of EDAR on chin protrusion, we documented alterations of mandible length in mice with modified Edar funtion

The effect of the geomagnetic field on cosmic ray energy estimates and large scale anisotropy searches on data from the Pierre Auger Observatory

We present a comprehensive study of the influence of the geomagnetic field on the energy estimation of extensive air showers with a zenith angle smaller than $60^\circ$, detected at the Pierre Auger Observatory. The geomagnetic field induces an azimuthal modulation of the estimated energy of cosmic rays up to the ~2% level at large zenith angles. We present a method to account for this modulation of the reconstructed energy. We analyse the effect of the modulation on large scale anisotropy searches in the arrival direction distributions of cosmic rays. At a given energy, the geomagnetic effect is shown to induce a pseudo-dipolar pattern at the percent level in the declination distribution that needs to be accounted for.Comment: 20 pages, 14 figure

Com o diabo no corpo: os terríveis papagaios do Brasil colônia

Desde a Antiguidade, papagaios, periquitos e afins (Psittacidae) fascinaram os europeus por seu vivo colorido e uma notável capacidade de interação com seres humanos. A descoberta do Novo Mundo nada faria além de acrescentar novos elementos ao tráfico de animais exóticos há muito estabelecido pelos europeus com a África e o Oriente. Sem possuir grandes mamíferos, a América tropical participaria desse comércio com o que tinha de mais atrativo, essencialmente felinos, primatas e aves - em particular os papagaios, os quais eram embarcados em bom número. Contudo, a julgar pelos documentos do Brasil colônia, esses voláteis podiam inspirar muito pouca simpatia, pois nenhum outro animal - exceto as formigas - foi tantas vezes mencionado como praga para a agricultura. Além disso, alguns psitácidas mostravam-se tão loquazes que inspiravam a séria desconfiança de serem animais demoníacos ou possessos, pois só três classes de entidades - anjos, homens e demônios - possuíam o dom da palavra. Nos dias de hoje, vários representantes dos Psittacidae ainda constituem uma ameaça para a agricultura, enquanto os indivíduos muito faladores continuam despertando a suspeita de estarem possuídos pelo demônio. Transcendendo a mera curiosidade, essa crença exemplifica o quão intrincadas podem ser as relações do homem com o chamado “mundo natural”, revelando um universo mais amplo e multifacetado do que se poderia supor a princípio. Nesse sentido, a existência de aves capazes de falar torna essa relação ainda mais complexa e evidencia que as dificuldades de estabelecer o limite entre o animal e o humano se estendem além dos primatas e envolvem as mais inusitadas espécies zoológicas.Since ancient times, parrots and their allies (Psittacidae) have fascinated Europeans by their striking colors and notable ability to interact with human beings. The discovery of the New World added new species to the international exotic animal trade, which for many centuries had brought beasts to Europe from Africa and the Orient. Lacking large mammals, tropical America participated in this trade with its most appealing species, essentially felines, primates and birds - especially parrots - which were shipped in large numbers. It should be noted, however, that at times these birds were not well liked. In fact, according to documents from colonial Brazil, only the ants rank higher than parrots as the animals most often mentioned as agricultural pests. On the other hand, some of these birds were so chatty that people suspected them to be demonic or possessed animals, since only three classes of beings - angels, men and demons - have the ability to speak. Nowadays, several Psittacidae still constitute a threat to agriculture, and the suspicion that extremely talkative birds were demon possessed has also survived. More than a joke or a mere curiosity, this belief exemplifies how intricate man’s relationships with the “natural world” may be. In this sense, the existence of birds that are able to speak adds a further twist to these relationships, demonstrating that the problem of establishing a boundary between the animal and the human does not only involve primates, but also includes some unusual zoological species

Temperature time series analysis at Yucatan using natural and horizontal visibility algorithms.

Several methods to quantify the complexity of a time series have been proposed in the literature, which can be classified into three categories: structure/self-affinity, attractor in the phase space, and randomness. In 2009, Lacasa et al. proposed a new method for characterizing a time series called the natural visibility algorithm, which maps the data into a network. To further investigate the capabilities of this technique, in this work, we analyzed the monthly ambient temperature of 4 cities located in different climatic zones on the Peninsula of Yucatan, Mexico, using detrended fluctuation analysis (structure complexity), approximate entropy (randomness complexity) and the network approach. It was found that by measuring the complexity of the dynamics by structure or randomness, the magnitude was very similar between the cities in different climatic zones; however, by analyzing topological indices such as Laplacian energy and Shannon entropy to characterize networks, we found differences between those cities. With these results, we show that analysis using networks has considerable potential as a fourth way to quantify complexity and that it may be applied to more subtle complex systems such as physiological signals and their high impact on early warnings

Estudio anual del zooplancton: composición, abundancia, biomasa e hidrología del norte de Quintana Roo, mar Caribe de México Annual study of zooplankton: composition, abundance, biomass and hydrology from the north of Quintana Roo, Mexican Caribbean Sea

Se llevaron a cabo muestreos de zooplancton en la zona lagunar y costera del Caribe mexicano, desde Puerto Morelos hasta Cancún. Las recolectas se llevaron a cabo de enero a diciembre de 2004 en 12 localidades. Se identificaron 41 grupos del zooplancton donde los copépodos fueron los más abundantes (61%) seguidos de las larvas de equinodermos (17%) y decápodos (5%). El copépodo Acartia tonsa fue la especie más abundante de este grupo en el Sistema Lagunar Nichupté (SLN). En la zona marina adyacente los copépodos estuvieron representados en orden de importancia por Acartia spinata, Pseudocalanus sp. y Calanopia americana. En todas las estaciones se capturaron equinodermos del tipo equinopluteus-ofiopluteus, pero con mayor abundancia en el SLN. El quetognato Ferosagitta hispida fue la única especie que se encontró en el SLN, donde fue más abundante. Los decápodos estuvieron representados principalmente por larvas zoeas; las larvas de peces por 54 familias, de las cuales los góbidos de los géneros Ctenogobius sp., Gobionellus sp. y Gobiosoma sp. fueron los mejor representados, particularmente para el SLN. La biomasa fue mayor en el SLN.<br>Zooplankton sampling was carried out in the northern coast of the Mexican Caribbean Sea, from Puerto Morelos to Cancun. Captures were made with a conic net 0.4m diameter, 1.40m length and 0.330 mm mesh from January to December 2004 at twelve locations. A total of 41 zooplankton groups were identified. Copepods were the most abundant taxa making up 61%, followed by echinoderms (17%) and decapods (5%). Acartia tonsa at the Nichupte Lagoon System (SLN) over numbered the copepod fauna and occasionally the whole zooplankton population. Along the coast Acartia spinata, Pseudocalanus sp, and Calanopia americana were the most important copepods. Echinoderms larvae such as echinopluteus-ophiopluteus were present at all sampled stations but were more abundant at the NLS. For chaetognaths, Ferosagitta hispida dominated, the species was the most abundant and in fact the only species found within the NLS. Decapod larvae were mainly represented by zoea larvae (brachiura). Fish larvae were made up by 54 families, from those, Gobids of the genera Ctenogobius sp., Gobionellus sp. and Gobiosoma sp. were the most abundant, particularly for SLN. Biomass was higher at stations located within the SLN

Effect of Operating Parameters on the Performance Evaluation of Benthic Microbial Fuel Cells Using Sediments from the Bay of Campeche, Mexico

Benthic microbial fuel cells (BMFC) are devices that remove organic matter (OM) and generate energy from sediments rich in organic nutrients. They are composed of electrodes with adequate different distances and floating air cathodes in an aqueous medium with saturated oxygen. In this study we proposed to design, build, analyze and evaluate a set of BMFCs with floating air cathodes to test the optimal distance between the electrodes, using sediment from the Bay of Campeche as a substrate. For the analysis of OM removal, COD tests, volatile solids (VS), E4/E6 study and FTIR analysis were performed. Power generation was evaluated through polarization curves, cyclic voltammetry and electrochemical impedance spectroscopy (EIS). We achieved a current density and power density at 10 cm depth of 929.7 &plusmn; 9.5 mA/m2 and 109.6 &plusmn; 7.5 mW/m2 respectively, with 54% removal of OM from the sediment, obtaining formation of aliphatic structures. BMFCs are proposed as adequate systems for bioremediation and power generation. The system at 10 cm depth and 100 cm distance between sediment and the floating air cathode had a good performance and therefore the potential for possible scaling

Polarization Potential Has No Effect on Maximum Current Density Produced by Halotolerant Bioanodes

Halotolerant bioanodes are considered an attractive alternative in microbial electrochemical systems, as they can operate under higher conductive electrolytes, in comparison with traditional wastewater and freshwater bioanodes. The dependency between energetic performance and polarization potential has been addressed in several works; however the vast majority discusses its effect when wastewater or freshwater inocula are employed, and fewer reports focus on inocula from highly-saline environments. Moreover, the effect of the polarization potential on current production is not fully understood. To determine if the polarization potential has a significant effect on current production, eight bioanodes were grown by chronoamperometry at positive and negative potentials relative to the reference electrode (+0.34 V/SHE and −0.16 V/SHE), in a three-electrode set-up employing sediments from a hyperhaline coastal lagoon. The maximum current density obtained was the same, despite the differences in the applied potential. Our findings indicate that even if differences in organic matter removal and coulombic efficiency are obtained, the polarization potential had no statistically significant effect on overall current density production