Sectorización trófica en las rías baixas (NW España): nutrientes en aguas y en macroalgas

Marine eutrophication caused by an excess supply of nutrients is a serious problem in many coastal areas throughout the world. In the present study we used the capacity of macroalgae (Ulva and Enteromorpha) to integrate the nutrient regime of a water body in order to examine the trophic categorization in the embayments studied. We found that the trophic categorization established based on nutrient levels in macroalgae differed from that established based on concentrations in the water. The waters of the innermost areas of the inlets were the most nutrient enriched; the algae appeared to be more affected by specific local conditions and did not display the gradient of decreasing nutrient concentrations from inner to outer areas that was observed in the water samples. The lack of correspondence between nutrients in the water and in the algae in the present study may have been due to the heterogeneous nutrient conditions found in coastal areas, so that the intertidal algae did not adequately reflect the nutrient levels of the inner zones of the embayments under study.La eutrofización marina, originada por un excesivo aporte de nutrientes, está considerada actualmente como un grave problema en numerosas áreas costeras de todo el mundo. En este estudio empleamos la capacidad de las macroalgas (Ulva y Enteromorpha) de integrar el régimen nutritivo de un cuerpo de agua para realizar una sectorización trófica de las bahías estudiadas. Los resultados de la sectorización trófica en función de las macroalgas fueron diferentes a la establecida en función de las concentraciones de nutrientes en agua. Las zonas más internas de las rías fueron las más enriquecidas en cuanto a nutrientes en agua, pareciendo estar las algas más afectadas por condiciones locales específicas, éstas no siguen el gradiente de concentración del interior al exterior que se observaba en el agua. La falta de correspondencia entre los nutrientes en agua y algas en este estudio puede ser debido a la gran heterogeneidad en las condiciones nutritivas que encontramos en áreas costeras, de forma que las muestras de algas intermareales no hayan reflejado adecuadamente los niveles de nutrientes del interior de las masas de agua estudiadas

Influence of the storage procedure on the trace element content measured in the aquatic moss Fontinalis antipyretica Hedw

Aquatic bryophytes have been used as pollution biomonitors for decades. Despite this, sample collection and preparation methods have not been standardized, which makes it difficult to compare the results of different studies. Most times, the samples have to be stored before processing, for example, when many of them are collected in a short time, as occurs in extensive pollution studies. Storage must be done in a way that does not change the pollutant concentrations in the samples. We studied whether the concentrations of Al, As, Ba, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, and Zn in the aquatic moss Fontinalis antipyretica were affected by three storage procedures: dry at room temperature, fresh (in refrigerator at 6°C), and frozen at −20°C. In addition, we evaluated whether the subsequent washing of the samples affected the concentrations of these elements differently depending on the storage method. Our results showed that the three methods were, in general, adequate since the concentrations did not change, and we did not observe differences between washed and unwashed samples either. Since the simplest method is refrigeration, we concluded that this is the best of them. However, the concentrations of Hg increased steadily over time in the fresh material, probably because of redistribution after volatilization from the basal parts of the mosses. We believe that the respiration of the plants lowered the concentrations of oxygen inside the hermetically sealed bags containing the samples, thus promoting the reduction of the Hg and its posterior volatilization and redistribution. We did not observe interactions between the storage method and the posterior washing of the samplesMinisterio de Economía y Competitividad(Spain), Grant/Award Number: CTM2015-70578-P; FEDER (EU)S

An efficient method to wash out the particulate matter trapped by aquatic mosses

This work was supported by Ministerio de Ciencia, Investigación y Universidades (Spain) project CTM2015-70578-P. The authors belong to the Galician Competitive Research Group GRC/GPC2016-002. These programs are co-funded by FEDER (EU). The sources of funding did not intervene in the preparation of the research or the paperS

Optimization of the Biomonitoring Technique with the Aquatic Moss Fontinalis antipyretica Hedw.: Selection of Shoot Segment Length for Determining Trace Element Concentrations

Bryophytes, including Fontinalis antipyretica Hedw., are widely used for biomonitoring aquatic environments. However, some methodological aspects, such as the fraction of shoot analysed, have not yet been standardized. The main objective of this study was to establish the length of segments of F. antipyretica shoots that should be used for trace element determination in monitoring studies. For this purpose, we determined the concentrations of 12 different trace elements (11 metals and one metalloid) in five successive 1 cm-long segments of the shoots of F. antipyretica collected from four different locations. We found that the concentrations of most elements increased steadily towards the basal part of the shoots without becoming stable. Sometimes, these increasing trends were concealed by another underlying trend of increasing dry/fresh weight ratios, caused by morphological changes (leaf density, shoot thickness) related with shoot development. The concentration trends were due to factors such as the deposition of Mn oxides on the moss surface. This element showed the largest increases in concentration towards the basal part of the shoot and its concentrations were closely correlated with those of most of the other elements. Considering the results obtained, we recommend the use of 3 cm-long apical segments for determining trace element concentrations in F. antipyretica. This recommendation is based on the following: (1) The change in dry weight beyond this length of segment is small; (2) the workload and the quantity of material to collect in the river is acceptable; (3) Most previous studies have used shoot segments of similar lengthsThis research was funded by MINECO project CTM2015-70578-P. The authors belong to the Galician Competitive Research Group GRC/GPC2016-002 and to the CRETUS Strategic Partnership (AGRUP2015/02). All these programs are co-funded by FEDER (EU)S

Diseño estructural del pavimento flexible para la carretera Panamerica Sur- tramo km 1300+00 a km 1330+00 de la ciudad de Tacna

La inexistencia de la segunda calzada de la carretera Panamericana Sur conlleva a una mala transitabilidad vehicular hacia la hermana ciudad de Arica-Chile, generando malestar en los usuarios perjudicando el confort y salud de las personas desde la ciudad de Tacna. El pavimento flexible debe proporcionar una superficie de rodamiento uniforme, resistente a la acción del tránsito, a la del intemperismo y otros agentes perjudiciales, así como transmitir a los terraplenes los esfuerzos por las cargas del tránsito. La metodología permitió establecer los métodos y técnicas que van relacionados con la durabilidad que está ligada a factores económicos y sociales. La durabilidad que se le desea dar a la segunda calzada de la Panamericana Sur es de 20 años de vida útil. La investigación se realizó en base al problema. ¿En qué medida mejorará el diseño estructural del pavimento flexible para la carretera Panamericana Sur tramo: Km 1300+00 a Km 1330+00 de la ciudad de Tacna?, Tuvo como objetivos diseñar la estructura del pavimentos flexible para la Carretera Panamericana Sur, tramo Km 1300+00 a Km 1330+00 de la ciudad de Tacna, siendo la investigación de tipo aplicada con enfoque cuantitativo para el diseño de la investigación se trabaja con una muestra de 30 kilómetros de estudio de pavimento flexible El presente trabajo de investigación se enfocó en realizar un estudio de tráfico, estudio de suelos CBR y el diseño estructural del pavimento flexible determinándose el índice medio diario igual a 800 vehículos por día, el ESAL de diseño igual 4,5 x 106 la capacidad de soporte CBR igual a 9.1%, el módulo resiliente igual a 12,603 PSI el número estructural 3,88, finalmente se tiene los espesores de diseño, carpeta asfáltica de 6 centímetros, la base granular de 30 centímetros y las sub-base granular de 37 centímetros, en el cual se tiene el espesor estructural del pavimento de 73 centímetros.Tesi

High Hg biomagnification in North Atlantic coast ecosystems and limits to the use of δ15N to estimate trophic magnification factors

Mercury contamination is a global environmental problem. This pollutant is highly toxic and persistent which makes it extremely susceptible to biomagnify, i.e. increase its concentrations as it moves up the food chain, reaching levels that threaten wildlife and, ultimately, ecosystems’ function and structure. Mercury monitoring is thus crucial to determine its potential to damage the environment. In this study, we assessed the temporal trends of the concentrations of Hg in two coastal animal species closely connected by a predator-prey interaction, and evaluated its potential transfer between trophic levels using the δ15N signatures of the two species. For this, we performed a multi-year survey of the concentrations of total Hg and the values of δ15N in the mussel Mytilus galloprovincialis (prey) and the dogwhelk Nucella lapillus (predator) sampled along ∼1500 km of the North Atlantic coast of Spain over a 30-year period (five surveys between 1990 and 2021). Concentrations of Hg decreased significantly between the first and the last survey in the two species studied. Except for the 1990 survey, the concentrations of Hg in mussels were amongst the lowest registered in the literature for the North East Atlantic Ocean (NEAO) and the Mediterranean Sea (MS) between 1985 and 2020. Nonetheless, we detected Hg biomagnification in almost all surveys. Worryingly, trophic magnification factors obtained here for total Hg were high and comparable to the found in the literature for methylmercury, the most toxic and readily biomagnified form of this element. The δ15N values were useful to detect Hg biomagnification under normal circumstances. However, we found that nitrogen pollution of coastal waters differentially affected the δ15N signatures of mussels and dogwhelks limiting the use of this parameter for this purpose. We conclude that Hg biomagnification could constitute an important environmental hazard even when found at very low concentrations in the lower trophic levels. Also, we warn that use of δ15N in biomagnification studies when there is some underlying nitrogen pollution problem might lead to misleading conclusionsAuthors belong to the Grupo de Referencia Competitiva GRC GI-1252/GPC2020–23 (ED431C 2020/19) which is co-funded by Xunta de Galicia and ERDF (EU)S

Historia de la atención a los deficientes auditivos en la provincia de Cáceres hasta 1986

Recopilar datos sobre la atención prestada a los deficientes auditivos en la provincia de Cáceres desde 1925 hasta la publicación de la Ley de Integración de 1986, crear una base de datos como soporte de los datos recopilados y analizar y correlacionar la información obtenida. No se han establecido conclusiones con respecto a los datos obtenidos. Los autores plantean la continuación del trabajo.ExtremaduraES