Bonnineau C.,Institute of Aquatic Ecology |
Tlili A.,IRSTEA |
Tlili A.,Leibniz Institute of Freshwater Ecology and Inland Fisheries |
Faggiano L.,Institute of Aquatic Ecology |
And 3 more authors.
Aquatic Toxicology | Year: 2013
This study aims to investigate the potential of antioxidant enzyme activities (AEA) as biomarkers of oxidative stress in freshwater biofilms. Therefore, biofilms were grown in channels for 38 days and then exposed to different concentrations (0-150μgL-1) of the herbicide oxyfluorfen for 5 more weeks. Under control conditions, the AEA of biofilms were found to change throughout time with a significant increase in ascorbate peroxidase (APX) activity during the exponential growth and a more important role of catalase (CAT) and glutathione reductase (GR) activities during the slow growth phase. Chronic exposure to oxyfluorfen led to slight variations in AEA, however, the ranges of variability of AEA in controls and exposed communities were similar, highlighting the difficulty of a direct interpretation of AEA values. After 5 weeks of exposure to oxyfluorfen, no clear effects were observed on chl-a concentration or on the composition of other pigments suggesting that algal group composition was not affected. Eukaryotic communities were structured clearly by toxicant concentration and both eukaryotic and bacterial richness were reduced in communities exposed to the highest concentration. In addition, during acute exposure tests performed at the end of the chronic exposure, biofilms chronically exposed to 75 and 150μgL-1 oxyfluorfen showed a higher CAT activity than controls. Chronic exposure to oxyfluorfen provoked then structural changes but also functional changes in the capacity of biofilm CAT activity to respond to a sudden increase in concentration, suggesting a selection of species with higher antioxidant capacity. This study highlighted the difficulty of interpretation of AEA values due to their temporal variation and to the absence of absolute threshold value indicative of oxidative stress induced by contaminants. Nevertheless, the determination of AEA pattern throughout acute exposure test is of high interest to compare oxidative stress levels undergone by different biofilm communities and thus determine their antioxidant capacity. © 2013 Elsevier B.V.
Petrovic M.,Catalan Institution for Research and Advanced Studies |
Ginebreda A.,IDAEA |
Acuna V.,ICRA |
Batalla R.J.,UdL CTFC |
And 13 more authors.
TrAC - Trends in Analytical Chemistry | Year: 2011
Water resources are directly and indirectly affected by anthropogenic activities (e.g., changes in land use) and natural factors (e.g., climate change), that is, global change. The Mediterranean basin is one of the most vulnerable regions of the world to global change, and one of the " hot spots" for forthcoming problems of water availability. The present review provides an overview about the relationship between chemical quality (especially concerning organic microcontaminants) and water scarcity, particularly in the Mediterranean area. We include an overview of environmental contaminants and analytical methodologies and consider the fate and the behavior of organic contaminants, and the effects of pollutants on ecosystems. © 2011 Elsevier Ltd.
Navarro-Ortega A.,CSIC - Institute of Environmental Assessment And Water Research |
Acuna V.,ICRA |
Batalla R.J.,UdL CTFC |
Blasco J.,ICMAN CSIC |
And 15 more authors.
Environmental Science and Pollution Research | Year: 2012
Introduction: The Consolider-Ingenio 2010 project SCARCE, with the full title "Assessing and predicting effects on water quantity and quality in Iberian Rivers caused by global change" aims to examine and predict the relevance of global change on water availability, water quality, and ecosystem services in Mediterranean river basins of the Iberian Peninsula, as well as their socio-economic impacts. Starting in December 2009, it brought together a multidisciplinary team of 11 partner Spanish institutions, as well as the active involvement of water authorities, river basin managers, and other relevant agents as stakeholders. Methods: The study areas are the Llobregat, Ebro, Jucar, and Guadalquivir river basins. These basins have been included in previous studies and projects, the majority of whom considered some of the aspects included in SCARCE but individually. Historical data will be used as a starting point of the project but also to obtain longer time series. The main added value of SCARCE project is the inclusion of scientific disciplines ranging from hydrology, geomorphology, ecology, chemistry, and ecotoxicology, to engineering, modeling, and economy, in an unprecedented effort in the Mediterranean area. The project performs data mining, field, and lab research as well as modeling and upscaling of the findings to apply them to the entire river basin. Results: Scales ranging from the laboratory to river basins are addressed with the potential to help improve river basin management. The project emphasizes, thus, linking basic research and management practices in a single framework. In fact, one of the main objectives of SCARCE is to act as a bridge between the scientific and the management and to transform research results on management keys and tools for improving the River Basin Management Plans. Here, we outline the general structure of the project and the activities conducted within the ten Work Packages of SCARCE. © 2011 Springer-Verlag.
Freixa A.,Institute of Aquatic Ecology |
Ejarque E.,Wassercluster Lunz Biologische Station GmbHLunz am See Austria |
Crognale S.,CNR Water Research Institute |
Amalfitano S.,CNR Water Research Institute |
And 2 more authors.
Limnology and Oceanography | Year: 2016
Heterotrophic bacteria play a key role in the degradation of organic matter and carbon cycling in river sediments. These bacterial communities are directly influenced by environmental variables that differ spatially and temporally in rivers. Here, we studied the longitudinal patterns of sediment bacterial community composition and dissolved organic matter utilization under base flow and drought conditions in a Mediterranean river. Our results indicated that sediment microbial communities were affected by dissolved organic matter quality and origin along the river continuum. In headwaters the potential degradation of cellulose and hemicellulose was greater (i.e., higher β-glucosidase and β-xylosidase activities), suggesting higher microbial utilization of allochthonous detritus from terrestrial origin. Conversely, the accumulation and transport of more recalcitrant compounds (i.e., decrease in the recalcitrant index) became potentially relevant downstream. Furthermore, discharge fluctuations had clear effects on bacterial community composition and dissolved organic matter use. The hydrological fragmentation of the river continuum during drought period generated sediment microhabitats dominated by gamma and delta-Proteobacteria, with a greater potential capacity to degrade a wide range of compounds, particularly nitrogen containing moieties. During base flow conditions, we observed a higher occurrence of alpha-Proteobacteria and a greater potential use of more recalcitrant carbon compounds, mostly of terrestrial origin. Overall, our findings suggest an upstream-downstream longitudinal transition of sediment microbial communities that rely on allochthonous to autochthonous dissolved organic matter, and a shift toward autochthonous dissolved organic matter reliance during drought. © 2016 Association for the Sciences of Limnology and Oceanography.
Rodriguez Castro M.C.,National University of Luján |
Guasch Padro H.,Institute of Aquatic Ecology |
Giorgi A.,National University of Luján
Understanding the Geological and Medical Interface of Arsenic, As 2012 - 4th International Congress: Arsenic in the Environment | Year: 2012
Long-term exposure to pollutants is known to be responsible for structural and functional changes in periphyton communities. This study aimed to evaluate these responses during the colonization period, linking the effect of long-term exposure to arsenate with the effect of phosphate on growth and sensitivity to the pollutant. Long-term exposures to different levels of arsenate and phosphate were conducted in artificial mesocosms with freshwater periphyton communities during growth phase. Growth was measured during the colonization period using a non-destructive Pulse of Amplitude Modulated Fluorometer. High levels of arsenate (100 μg As L -1) delayed the growth only in communities deprived from phosphate (10 μg P L -1). © 2012 Taylor & Francis Group.
Compte J.,Institute of Aquatic Ecology |
Gascon S.,Institute of Aquatic Ecology |
Quintana X.D.,Institute of Aquatic Ecology |
Boix D.,Institute of Aquatic Ecology
Marine Ecology Progress Series | Year: 2010
Jellyfish can act as planktonic top predators, and their effects may cause drastic changes in the plankton structure of marine and freshwater systems. However, the top predator effects may not necessarily be the same in species-poor habitats as they are in species-rich habitats. The present study analyses the effects of the small lacunae jellyfish Odessia maeotica in a speciespoor habitat, Mediterranean salt marshes in the wetlands of Empordà (NE Iberian Peninsula). A field experiment was carried out in March 2008 to assess the direct and indirect effects of O. maeotica on plankton composition. Our results show that the presence of O. maeotica changed the plankton composition through top-down effects. Changes were strong in zooplankton, because O. maeotica can suppress almost the entire trophic level of large zooplankton (>50 μm). Weak indirect effects on phytoplankton composition were observed as well. When O. maeotica was present, changes in the relative abundance of the phytoplankton species were found, but there was no net increase in phytoplankton biomass. Our results suggest that these weak indirect effects may be the result of trophic cascade effects coupled with the oligotrophic conditions of these salt marshes. Thus, trophic cascade effects lead to an increase in ciliate biomass, and these ciliates would feed on small algae (jellyfish-copepods-ciliates-small algae), while oligotrophic conditions would prevent increases in algal biomass. © Inter-Research 2010, www.int-res.com.