Significance of atmospheric deposition to freshwater ecosystems in the southern Iberian Peninsula

The Iberian Peninsula is close to the Saharan Desert, which is the biggest source of atmospheric aerosols of the World. Currently, it is recognized that atmospheric deposition of aerosols over ecosystems is a significant source not only of elements with gaseous phases but also of rock-derived ones. In the last years we have been quantifying the atmospheric flux of elements and substances of biogeochemical interest on the aquatic ecosystems of the South Iberian Peninsula, and their impact on their functioning and structure. The results we are obtaining indicate that atmospheric contribution of P and Ca are essential to explain the functioning of high mountain lakes, and that atmospheric input of organic matter partially supports the pelagic food web of these ecosystems. In this article we offer a summary of some of the results obtained to date.La Península Ibérica está próxima al Desierto del Sahara que es la mayor fuente de aerosoles atmosféricos del Planeta. Actualmente, se reconoce que la deposición de aerosoles sobre los ecosistemas es una entrada significativa no sólo de elementos con fases gaseosas sino, también, de elementos derivados de rocas. En los últimos años hemos estado cuantificado el flujo atmosférico de elementos y sustancias de interés biogeoquímico sobre los ecosistemas acuáticos del sur de la Península Ibérica y el impacto sobre su funcionamiento y estructura. Los resultados que estamos obteniendo indican que los aportes atmosféricos de P y Ca son esenciales para explicar el funcionamiento de los lagos de alta montaña y que las entradas atmosféricas de materia orgánica sostienen parcialmente las redes tróficas pelágicas de estos ecosistemas. En este artículo ofrecemos un resumen de algunos de los resultados obtenidos hasta ahora

Microbial food web dynamics in response to a Saharan dust event: results from a mesocosm study in the oligotrophic Mediterranean Sea

BiogeosciencesInternational audienceThe significant impact of dust deposition on het-erotrophic bacterial dynamics in the surface oligotrophic ocean has recently been evidenced. Considering the central role of bacteria in the microbial loop, it is likely that dust deposition also affects the structure and the functioning of the whole microbial food web. In the frame of the DUNE project, aiming to estimate the impact of dust deposition on the oligotrophic Mediterranean Sea through mesocosm ex-periments, the main goal of the present paper was to as-sess how two successive dust deposition events affect the dynamics of the microbial food web. The first dust seeding delivered new P and N to the amended mesocosms and re-sulted in a pronounced stimulation of bacterial respiration. It also induced pronounced, but transient, changes in the bac-terial community composition. No significant effects were observed on the abundances of viruses and heterotrophic nanoflagellates. The second dust seeding also delivered new P and N to the amended mesocosms, but the effect on the microbial food web was very different. Bacterial respira-tion remained constant and bacterial abundance decreased. Compositional changes following the second seeding were minor compared to the first one. The decrease in bacterial abundance coincided with an increase in virus abundance, resulting in higher virus : bacteria ratios throughout the sec-ond seeding period. Our study shows that dust deposition to the surface oligotrophic ocean may involve important mod-ifications of the trophic links among the components of the microbial food web with presumed consequences on C and nutrient cycling

Atmospheric deposition of organic matter at a remote site in the central Mediterranean Sea: implications for the marine ecosystem

Abstract. Atmospheric fluxes of dissolved organic matter (DOM) were studied for the first time on the island of Lampedusa, a remote site in the central Mediterranean Sea (Med Sea), between 19 March 2015 and 1 April 2017. The main goals of this study were to quantify total atmospheric deposition of DOM in this area and to evaluate the impact of Saharan dust deposition on DOM dynamics in the surface waters of the Mediterranean Sea. Our data show high variability in DOM deposition rates without a clear seasonality and a dissolved organic carbon (DOC) input from the atmosphere of 120.7 mmol DOC m−2 yr−1. Over the entire time series, the average dissolved organic phosphorus (DOP) and dissolved organic nitrogen (DON) contributions to the total dissolved pools were 40 % and 26 %, respectively. The data on atmospheric elemental ratios also show that each deposition event is characterized by a specific elemental ratio, suggesting a high variability in DOM composition and the presence of multiple sources. This study indicates that the organic substances transported by Saharan dust on Lampedusa mainly come from a natural sea spray and that Saharan dust can be an important carrier of organic substances even though the load of DOC associated with dust is highly variable. Our estimates suggest that atmospheric input has a larger impact on the Med Sea than on the global ocean. Further, DOC fluxes from the atmosphere to the Med Sea can be up to 6 times larger than total river input. Longer time series combined with modeling would greatly improve our understanding of the response of DOM dynamics in the Med Sea to the change in aerosol deposition pattern due to the effect of climate change

Estudio comparativo del rendimiento académico y la actividad física en dos institutos de enseñanza secundaria de Andalucía (España)

Objective: To assess whether there is some relationship between academic performance and physical condition, a study based on two schools with similar features. Methodology and Method: Quantitative experimental study, in which participated 144 pupils of both sexes and aged between 14 and 18 years who were in the 4th year of Obligatory Secondary Education (ESO). It was analyzed using standardized physical fitness test and have collected data on resistance (Cooper test), speed (50 meters sprint test), flexibility (test of deep trunk flexion) and abdominal strength (abs test for minute). Results and conclusion: There is a significant relationship between academic performance and physical activity of students in the data of resistance, speed and flexibility, although there is no significant relationship between academic performance and test Abs per minute.Objetivo: Valorar si existe alguna relación entre el rendimiento académico y la condición física en un estudio realizado en dos centros educativos con características similares. Material y Método: Estudio experimental cuantitativo, en el que han participado 144 alumnos de ambos sexos de edades comprendidas entre los 14 y los 18 años que cursan 4o curso de Enseñanza Secundaria Obligatoria (ESO). Se ha analizado la condición física mediante test estandarizados donde se han recogido datos referentes a la resistencia (test de Cooper), velocidad (test de 50 metros lisos), flexibilidad (test de flexión profunda de tronco) y fuerza abdominal (test de abdominales por minuto). Resultados y Conclusiones: Los resultados muestran una relación estadísticamente significativa entre el rendimiento académico y la actividad física de los alumnos en las pruebas de resistencia, velocidad y flexibilidad, aunque los mismos no han determinado relación significativa entre el rendimiento académico y la prueba de abdominales por minuto

Immune Microenvironment in Colorectal Cancer: A New Hallmark to Change Old Paradigms

Impact of immune microenvironment in prognosis of solid tumors has been extensively studied in the last few years. Specifically in colorectal carcinoma, increased knowledge of the immune events around these tumors and their relation with clinical outcomes have led to consider immune microenvironment as one of the most important prognostic factors in this disease. In this review we will summarize and update the current knowledge with respect to this intriguing and complex new hallmark of cancer, paying special attention to infiltration by T-infiltrating lymphocytes and their subtypes in colorectal cancer, as well as its eventual clinical translation in terms of long-term prognosis. Finally, we suggest some possible investigational approaches based on combinatorial strategies to trigger and boost immune reaction against tumor cells

Atmospheric deposition impact on bacterial community composition in the NW Mediterranean

Atmospheric deposition is a source of inorganic nutrients and organic matter to the ocean, and can favor the growth of some planktonic species over others according to their nutrient requirements. Atmospheric inputs from natural and anthropogenic sources are nowadays increasing due to desertification and industrialization, respectively. While the impact of mineral dust (mainly from the Saharan desert) on phytoplankton and bacterial community composition has been previously assessed, the effect of anthropogenic aerosols on marine bacterial assemblages remains poorly studied. Since marine bacteria play a range of roles in the biogeochemical cycles of inorganic nutrients and organic carbon, it is important to determine which taxa of marine bacteria may benefit from aerosol fertilization and which not. Here, we experimentally assessed the effect of Saharan dust and anthropogenic aerosols on marine bacterioplankton community composition across a spatial and temporal range of trophic conditions in the northwestern Mediterranean Sea. Results from 16S rDNA sequencing showed that bacterial diversity varied significantly with seasonality and geographical location. While atmospheric deposition did not yield significant changes in community composition when all the experiments where considered together, it did produce changes at certain places and during certain times of the year. These effects accounted for shifts in the bacterial community's relative abundance of up to 28%. The effect of aerosols was overall greatest in summer, both types of atmospheric particles stimulating the groups Alphaproteobacteria, Betaproteobacteria, and Cyanobacteria in the location with the highest anthropogenic footprint. Other bacterial groups benefited from one or the other aerosol depending on the season and location. Anthropogenic aerosols increased the relative abundance of groups belonging to the phylum Bacteriodetes (Cytophagia, Flavobacteriia, and Sphingobacteriia), while Saharan dust stimulated most the phytoplanktonic group of Cyanobacteria and, more specifically, Synechococcus.Funding Agency / Grant Number Spanish Ministerio de Economia y Competitividad CTM2011-23458 CTM2015-65720-R FPI Spanish scholarship program BES-2012-052976 KTH Royal Institute of Technology in Stockholm EEB-I-15-09845 Swiss National Science Foundation (SNSF) PA00P3_145355 Spanish Ministerio de Agricultura, Alimentacion y Medio Ambienteinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/publishedVersio

Atmospheric Deposition Effects on Plankton Communities in the Eastern Mediterranean: A Mesocosm Experimental Approach

The effects of atmospheric deposition on plankton community structure were examined during a mesocosm experiment using water from the Cretan Sea (Eastern Mediterranean), an area with a high frequency of atmospheric aerosol deposition events. The experiment was carried out under spring-summer conditions (May 2012). The main objective was to study the changes induced from a single deposition event, on the autotrophic and heterotrophic surface microbial populations, from viruses to zooplankton. To this end, the effects of Saharan dust addition were compared to the effects of mixed aerosol deposition on the plankton community over 9 days. The effects of the dust addition seemed to propagate throughout the food-web, with changes observed in nearly all of the measured parameters up to copepods. The dust input stimulated increased productivity, both bacterial and primary. Picoplankton, both autotrophic and heterotrophic capitalized on the changes in nutrient availability and microzooplankton abundance also increased due to increased availability of prey. Five days after the simulated deposition, copepods also responded, with an increase in egg production. The results suggest that nutrients were transported up the food web through autotrophs, which were favored by the Nitrogen supplied through both treatments. Although, the effects of individual events are generally short lived, increased deposition frequency and magnitude of events is expected in the area, due to predicted reduction in rainfall and increase in temperature, which can lead to more persistent changes in plankton community structure. Here we demonstrate how a single dust deposition event leads to enhancement of phytoplankton and microzooplankton and can eventually, through copepods, transport more nutrients up the food web in the Eastern Mediterranean SeaVersión del edito

Colombia’s political football: President Santos’ National Unity Project and the 2014 Football World Cup

The Colombian football team's performance in the 2014 World Cup has allowed President Santos to use football in his national unity project. The selección is a rare unifying symbol in Colombia and politicians have previously sought to use football in the construction of a national political project. This article explores why, on this occasion, football has proved a more effective tool than when it was employed by Presidents Gaviria (in 1993–1994) and Pastrana (in 2001). As well as analysing how Santos has appropriated football figures and discourses, consideration will be given to how the selección has become a contested symbol involving other political actors

Functional differences in the allometry of the water, carbon and nitrogen content of gelatinous organisms

We have supplemented available, concurrent measurements of fresh weight (W, g) and body carbon (C, g) (46 individuals, 14 species) and of body nitrogen (N, g) and C (11individuals, 9 species) of marine gelatinous animals with data obtained during the global ocean expedition MALASPINA 2010 (totalling 267 individuals and 33 species for the W vs. C data; totalling 232 individuals and 31 species for the N vs. C data). We then used those data to test the allometric properties of the W vs. C and N vs. C relationships. Overall, gelatinous organisms contain 1.13±1.57% of C (by weight, mean±SD) in their bodies and show a C:N of 4.56±2.46, respectively, although estimations can be improved by using separate conversion coefficients for the carnivores and the filter feeders. Reduced Major Axis Regression (RMA) indicates that W grows isometrically with C in the carnivores (cnidarians and ctenophores), implying that their water content can be described by a single conversion coefficient of 173.78 gW[gC]-1, or a C content of 1.17±1.90% by weight, although there is much variability due to the existence of carbon-dense species. In contrast, W grows faster than C in the filter feeders (salps and doliolids), according to the power relationship W=446.68)C1.54. This exponent is not significantly different from 1.2, which is consistent with the idea that the watery bodies of gelatinous animals represent an evolutionary response towards increasing food capture surfaces, i.e. a bottom up rather than a top down mechanism. Thus, the available evidence negates a bottom up mechanism in the carnivores, but supports it in the filter feeders. Last, N grows isometrically with C in both carnivores and herbivores, with C:N ratios of 3.89±1.34 and 4.38±1.21, respectively. These values are similar to those of compact, non-gelatinous organisms and reflect a predominantly herbivorous diet in the filter feeders, what is confirmed by a difference of one trophic level between filter feeders and carnivores, according to stable N isotope enrichment data.MALASPINA (CSD2008-00077)Versión del editor1,749