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Lapresta-Fernandez A.,University of Seville | Fernandez A.,University of Seville | Blasco J.,Campus Universitario Rio San Pedro
TrAC - Trends in Analytical Chemistry | Year: 2012

Engineered nanoparticles (ENPs) are increasingly being incorporated into commercial products. A better understanding is required of their environmental impacts in aquatic ecosystems.This review deals with the ecotoxicity effects of silver and gold ENPs (AgNPs and AuNPs) in aquatic organisms, and considers the means by which these ENPs enter aquatic environments, their aggregation status and their toxicity. Since ENPs are transported horizontally and vertically in the water column, we discuss certain factors (e.g., salinity and the presence of natural organic materials), as they cause variations in the degree of aggregation, size range and ENP toxicity. We pay special attention to oxidative stress induced in organisms by ENPs.We describe some of the main analytical methods used to determine reactive oxygen species, antioxidant enzyme activity, DNA damage, protein modifications, lipid peroxidation and relevant metabolic activities. We offer an overview of the mechanisms of action of AgNPs and AuNPs and the ways that relevant environmental factors can affect their speciation, agglomeration or aggregation, and ultimately their bio-availability to aquatic organisms.Finally, we discuss similarities and differences in the adverse effects of ENPs in freshwater and salt-water systems. © 2011 Elsevier Ltd. Source

Rodellas V.,Autonomous University of Barcelona | Garcia-Orellana J.,Autonomous University of Barcelona | Tovar-Sanchez A.,CSIC - Mediterranean Institute for Advanced Studies | Tovar-Sanchez A.,Campus Universitario Rio San Pedro | And 6 more authors.
Marine Chemistry | Year: 2014

Submarine Groundwater Discharge (SGD) from a detrital coastal aquifer into the adjacent marine environment was investigated in a Mediterranean bay (Palma Beach, Balearic Islands). In this region, agriculture and tourism are potential sources of groundwater contamination. A survey in the Palma Beach revealed N, Fe and chlorophyll a enhancement associated to areas of preferential groundwater discharge from the nearby coastal aquifer. Groundwater sampling from wells and coastal piezometers indicated high concentrations of dissolved inorganic nitrogen and Fe (up to 2800μmolL-1 and 8100nmolL-1, respectively). Other nutrients, such as DIP, and trace elements were not particularly elevated, which is attributed to the adsorptive characteristics of the carbonated composition of this detrital aquifer and/or the lack of major sources. Cross-shore gradients of 223,224,226Ra isotopes indicated a diffusive shore-based source of these radionuclides and allowed estimates of a SGD flow of 56,000±13,000m3d-1. Our results show that SGD is a major pathway for delivering DIN (1900mmolm-1d-1), dissolved Fe (4.1mmolm-1d-1) and, to a lesser extent, DIP (16mmolm-1d-1) into the nearshore waters. This allochthonous input may sustain a substantial phytoplankton biomass resulting in an onshore-offshore gradient (4.7-7.1mgm-3 in nearshore seawater as compared with <1mgm-3 in offshore stations). This work emphasizes the relevance of SGD-driven nutrient and trace metal inputs in the regulation of nearshore phytoplankton communities of oligotrophic areas. © 2014 Elsevier B.V. Source

Campana O.,Campus Universitario Rio San Pedro | Campana O.,CSIRO | Taylor A.M.,University of Canberra | Blasco J.,Campus Universitario Rio San Pedro | And 2 more authors.
Environmental Science and Technology | Year: 2015

The role of subcellular partitioning of copper on the sublethal effects to two deposit-feeding organisms (41-day growth in the bivalve Tellina deltoidalis and 11-day reproduction in the amphipod Melita plumulosa) was assessed for copper-spiked sediments with different geochemical properties. Large differences in bioaccumulation and detoxification strategies were observed. The bivalve accumulated copper faster than the amphipod, and can be considered a relatively strong net bioaccumulator. The bivalve, however, appears to regulate the metabolically available fraction (MAF) of the total metal pool by increasing the net accumulation rate of copper in the biologically detoxified metal pool (BDM), where most of the copper is stored. In the amphipod, BDM concentration remained constant with increasing copper exposures and it can be considered a very weak net bioaccumulator of copper. This regulation of copper, with relatively little stored in detoxified forms, appears to best describe the strategy applied by the amphipod to minimize the potential toxic effects of copper. When the EC50 values for growth and reproduction are expressed based on the MAF of copper, the sensitivity of the two species appears similar, however when expressed based on the net accumulation rate of copper in the metabolically available fraction (MAFrate), the bivalve appears more sensitive to copper. These results indicate that describing the causality of metal effects in terms of kinetics of uptake, detoxification, and excretion rather than threshold metal body concentrations is more effective in predicting the toxic effects of copper. Although the expression of metal toxicity in terms of the rate at which the metal is bioaccumulated into metabolically available forms may not be feasible for routine assessments, a deeper understanding of uptake rates from all exposure routes may improve our ability to assess the risk posed by metal-contaminated sediments. © 2015 American Chemical Society. Source

Ortiz-Delgado J.B.,Campus Universitario Rio San Pedro | Sarasquete C.,Campus Universitario Rio San Pedro
Journal of Applied Ichthyology | Year: 2012

Vertebral deformities constitute a recurrent problem in farmed teleost fish species. Potential causes of skeletal deformities are associated with genetic, environmental and nutritional factors. Considering nutritional factors, previous studies have shown that nutritional vitamin A (VA) imbalance implied the appearance of vertebral deformities in marine fish larvae; however, information about the effects of VA on bone homeostasis in juveniles is scarce. A study of vertebral bone tissue homeostasis in gilthead sea bream (Sparus aurata) juveniles fed with two dietary VA levels was performed by means of histological (Haematoxylin-Eosin, Alcian blue - PAS, Haematoxylin - VOF and Picrosirius red staining) and histochemical (immunostaining for bone and matrix Gla protein; OC and MGP, respectively) approaches. Fish were fed with two diets containing 2.5×104 (control) and 2.3×106 (hypervitaminosis A group) IU total VA kg-1 during 6months. Results showed that gilthead sea bream juveniles were not affected in terms of growth or survival rate by nutritional hypervitaminosis A, whereas the homeostasis of the vertebral bone was altered. Vertebral bodies from the control and VA fed fish showed differences in their morphological and biochemical composition at the growth zone of the vertebral end-plates. Picrosirius red staining revealed that vertebral end-plates and the trabecular bone layer from control and VA fed fish presented different diameter in collagen fibers. In addition, immunohistochemical analysis revealed increased protein levels of MGP and BGP in the notochord from gilthead sea bream juveniles fed hypervitaminosis A. Results suggest that hypervitaminosis A alter bone homeostasis through an accelerated bone mineralization, which might increase mechanical load between adjacent vertebrae and induce vertebral compression/fusion through a bone remodelling process. © 2012 Blackwell Verlag, Berlin. Source

Ortiz-Delgado J.B.,Campus Universitario Rio San Pedro | Hontoria F.,Institute Acuicultura Of Torre Of La Sal Csic | Sarasquete C.,Campus Universitario Rio San Pedro
Aquaculture | Year: 2012

Proper nutrition at first feeding in marine fish larvae is an important factor for successful larval rearing. However, live prey used to feed marine finfish larvae lack essential fatty acids requiring commercial hatcheries to enrich live prey to provide a balanced diet. Currently, the many commercially available enrichments for live prey present considerable differences in their formulas, and compositions of essential nutrients. Since nutritional requirements are species-specific it is necessary to define those enrichments most appropriate for each species in terms of larval development and quality. This study aimed to evaluate the effect of six enrichments on Senegalese sole larval performance including growth, digestive system development and skeletogenesis, to determine whether any of these products are more suitable for Senegalese sole larval rearing. From 8 to 37 days post hatching (dph), larvae were fed Artemia nauplii previously enriched with six different formulae: Easy Selco© (INVE, ES), Easy Selco© (INVE) half diluted with olive oil (ES/2), Multigain© (BioMar, MG), Red Pepper© (Bernaqua, RP), Aquagrow Gold© (ABN, AGG) and Aquagrow DHA© (ABN, AGD), with the last two being diluted by a third with olive oil. The dietary treatments significantly affected larval growth and performance; larvae fed Artemia enriched with AGG presented significantly higher final dry weight (2.0 ± 0.4 mg), growth and intestinal maturation than larvae fed ES-enriched Artemia (final dry weight: 1.1 ± 0.3 mg). Larvae fed the AGG treatment also were those most advanced in metamorphosis and ossification processes. Larvae fed ES/2, RP, AGD and MG treatments presented intermediary values for all these parameters. No significant effect of the dietary treatments was detected in final survival and incidence of skeletal deformities. We conclude that, among the enrichments tested, AGG is the most appropriate for larvae of Senegalese sole. © 2011. Source

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