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- Comparison of metal accumulation between ‘Artificial Mussel’ and natural mussels (Mytilus galloprovincialis) in marine environmentsPublication . Gonzalez-Rey, Maria; Lau, T. C.; Gomes, Tânia; Maria, Vera L.; Bebianno, Maria João; Wu, R.The passive sampler called 'Artificial Mussel' (AM) developed by Wu et al. (2007) can provide a time-integrated estimate of metal concentrations in the marine environment, and offers a potential device to assess and compare metal concentration in different marine environments worldwide. The aim of this study was to compare metal accumulation on AM and natural mussel Mytilus galloprovincialis at three sites with different metal loads along the Portuguese coast for four months. M. galloprovincialis were placed in cages alongside AMs at each site. Samples were collected monthly and Cd, Cr, Cu, Pb, and Zn concentrations in whole soft tissues and AMs compared. For both Cu and Cd, the results were similar between AMs and natural mussels. Higher concentrations of Zn were observed in natural mussels, whereas the inverse was shown for Pb (about 10-fold higher). Our results showed that AMs are promising tools for assessing metal concentrations in marine environments.
- Incidence of intersex in male clams Scrobicularia plana in the Guadiana Estuary (Portugal)Publication . Gomes, Tânia; Gonzalez-Rey, Maria; Bebianno, MariaEndocrine disrupting chemicals (EDCs) known to be present in the marine environment, have great potential to influence reproductive status in aquatic organisms. A widespread incidence of intersex linked with EDCs exposure has been reported in molluscs and fish species. The species Scrobicularia plana is inherently gonochoristic; nonetheless, the feminisation of male clams was described in estuaries from the United Kingdom. Thus, this study reports the presence of oocytes in the testis of male clams of S. plana collected in the Guadiana River (Portugal). Samples were collected between June and September (2007), and gonad tissue analysed by light microscopy. Intersex with several degrees of intensity was detected during the first three months of sampling, in which the percentage of male clams affected varied between 5.9, 58.3 and 71.4%. Little is known about the causes of intersex in S. plana, being the urban, industrial and agricultural discharges possible major sources of induction. In the Guadiana River, the presence of several EDCs may be directly linked to the incidence of the intersex condition detected in Scrobicularia plana.
- Is gene transcription in mussel gills altered after exposure to Ag nanoparticles?Publication . Bebianno, Maria João; Gonzalez-Rey, Maria; Gomes, Tânia; Mattos, J. J.; Flores-Nunes, F.; Bainy, A. C. D.Nanotechnology is a rapid field of development with the enhancement of the production of different types of nanoparticles (NPs) applied in several industrial and commercial applications which increase the risk of their presence in the aquatic environment. Ag NPs have a wide application in everyday life products. However, there is concern about the exposure effects on aquatic organisms to these NPs. Therefore, this study aims to assess gene transcription alterations in mussels Mytilus galloprovincialis gills exposed for 2 weeks to Ag NPs (42 ± 10 nm, 10 μg.L(-1)). The genes were selected based on previous biomarkers and proteomic results and included superoxide dismutase (SOD), catalase (CAT), glutathione transferase (GST), caspase 3/7-1 (CAS), cathepsin L (CATH), heat-shock protein 70 (HSP 70), cytochrome P450 4YA (CYP 4YA), the elongation factor (EF1), actin and α- tubulin. No significant changes in gene transcription profiles were observed after exposure of M. galloprovincialis to Ag NPs for 15 days. The lack of significant gene transcription responses is in light with previous results obtained for mussels exposed to these NPs and may be related to the fact that enzyme kinetics and relative abundance of proteins (increase of antioxidant enzymes and metalllothioneins (MTs) with the time of exposure) do not always directly reflect their relative mRNA levels. Nevertheless, their overall expression maintenance may signify that, at end of the exposure period (15 days), the transcription of the respective genes is no longer required, pointing out to a possible adaptation effect to nanoparticles or due to the levels of Ag NPs accumulated in this tissue at this exposure time. This study highlights that gene transcription application and role as an additional and/or alternative end point approach is important to understand the mode of action of these emergent contaminants in aquatic organisms. However, in future studies, the time window needs to be adjusted, as genes are likely to respond earlier to the nanoparticle exposure.
- Trace metal concentrations in sediments from the southwest of the Iberian PeninsulaPublication . Blasco, Julián; Gomes, Tânia; García-Barrera, Tamara; Rodríguez-Romero, Araceli; Gonzalez-Rey, M.; Morán-Roldán, Fernando; Tromibini, Chiara; Miotk, Michal; Gómez-Ariza, José Luis; Bebianno, Maria JoãoMetal sediment concentrations (As, Cd, Cu, Hg, Ni, Pb and Zn) in surface sediments (0 to 5 cm) from 11 sampling stations in the southwest of the Iberian Peninsula (the Ria Formosa and the Guadiana River, the Ría de Huelva and the Bay of Cadiz) were determined in two seasonal periods (autumn 2006 and spring 2007). No seasonal metal concentration pattern was identified, as similar values were found in both periods. The highest concentrations of copper, zinc, lead and cadmium were reported in the Ria of Huelva area, and those of mercury and nickel in the Bay of Cadiz. The hazard potential index (HPiM) was determined to assess the potential risk associated with metal contamination (Cu, Cd, Pb and Zn), taking into account extractable (presumed bioavailable) fractions of these metals and site-specific sediment quality values. When the HPiM is >1 there is risk, and according to this index Ría de Huelva is polluted whereas the Bay of Cadiz is not.
- Detoxification mechanisms in shrimp: Comparative approach between hydrothermal vent fields and estuarine environmentsPublication . Gonzalez-Rey, Maria; Serafim, Angela; Company, Rui; Gomes, Tânia; Bebianno, Maria JoãoHydrothermal vents are extreme deep-sea habitats that, due to their singular features, still intrigue scientific communities. Swift growth rates and profuse biomass of biological communities can be observed, despite of their inherently unstable physical-chemical and toxic conditions, indicating that organisms inhabiting this environment must be well adapted to these inhospitable conditions. The caridean shrimp, Chorocaris chacei, Mirocaris fortunata and Rimicaris exoculata, together with bathymodiolid mussels, dominate the vent fauna along the Mid-Atlantic Ridge (MAR). Crustacean species are widely used as biological indicators of environmental alterations, since they play a key ecological role as planktivorous grazers, epibenthic scavengers or as prey species. The biological consequences of the hydrothermal metal-rich environment in shrimp species are still largely unknown. Therefore, the aim of this study was the determination of the metal levels (Ag, Cd, Cu, Fe, Mn and Zn), metallothioneins (MT) and lipid peroxidation (LPO) in shrimp species collected in Rainbow, Lucky Strike and Menez-Gwen vent sites, in order to evaluate their different adaptation strategies toward metals when compared with two common coastal shrimp species (Palaemon elegans and Palaemonetes varians) from a fairly unpolluted estuarine system in south Portugal (Ria Formosa). Results show significant differences in metal concentrations, MT levels and lipid peroxidation between vent and coastal shrimp and also between shrimp species from the same site. This indicates that biochemical responses in both vent and coastal shrimp are affected not only by the environmental characteristics but also by inter-specific differences. Nevertheless, these responses apparently grant a successful adaptation for the survival in a metal-extreme environment.