Metal contamination causes multiple biological dysfunctions, including impairment of key physiological functions by targeting enzymes. This feature is a matter of concern, since it may imply significant disturbances in energy allocation, behaviour, reproduction, and survival. Inhibition of the cholinesterase (ChE) activity of aquatic organisms by metals has been described, and systematically used in biomonitoring studies as effect criterion of environmental exposure to these compounds. The present paper addresses the feasibility of using ChE inhibition to quantify the adverse acute and chronic effects of metals (copper, zinc, lead, and cadmium) on nervous tissue of Gambusia holbrooki. With the exception of acute exposure to copper, ChE activity was not significantly impaired. The meanings of the reported findings are further discussed, aiming at a more comprehensive use of this biomarker in environmental assessment. Based on the obtained results, the role of ChE inhibition in environmental metal contamination scenarios should be questioned or even discarded.

Metal contamination causes multiple biological dysfunctions, including impairment of key physiological functions by targeting enzymes. This feature is a matter of concern, since it may imply significant disturbances in energy allocation, behaviour, reproduction, and survival. Inhibition of the cholinesterase (ChE) activity of aquatic organisms by metals has been described, and systematically used in biomonitoring studies as effect criterion of environmental exposure to these compounds. The present paper addresses the feasibility of using ChE inhibition to quantify the adverse acute and chronic effects of metals (copper, zinc, lead, and cadmium) on nervous tissue of Gambusia holbrooki. With the exception of acute exposure to copper, ChE activity was not significantly impaired. The meanings of the reported findings are further discussed, aiming at a more comprehensive use of this biomarker in environmental assessment. Based on the obtained results, the role of ChE inhibition in environmental metal contamination scenarios should be questioned or even discarded. | The present work was funded by Fundação para a Ciência e a Tecnologia: project “BiOtoMetal” (PTDC/AMB/70431/2006). We would like to acknowledge the contribution of Jonathan Wilson, for his decisive contribution to the final format of this article. | published

Biologically treated wastewater (WW) from the Hammerfest LNG (liquefied natural gas) plant is discharged to the sea. A study using biomarkers in mussels and Atlantic cod was performed to examine whether this discharge meets a zero harmful emission requirement. Caging of mussels close to the outfall and exposure of mussels and fish to WW in the laboratory were conducted, and a suite of contaminant responsive markers was assessed in exposed animals. In mussels the markers included chemical contaminant levels, haemocyte lysosomal instability and nucleus integrity, cellular energy allocation, digestive gland and gonad histopathology and shell-opening behaviour. In fish, biliary PAH metabolites and gill histopathology biomarkers were measured. A consistent cause-effect relationship between WW treatments and markers measured in test animals was not found. The results therefore indicate that the WW emission is unlikely to represent a significant stress factor for the local marine environment under the conditions studied.

Biologically treated wastewater (WW) from the Hammerfest LNG (liquefied natural gas) plant is discharged to the sea. A study using biomarkers in mussels and Atlantic cod was performed to examine whether this discharge meets a zero harmful emission requirement. Caging of mussels close to the outfall and exposure of mussels and fish to WW in the laboratory were conducted, and a suite of contaminant responsive markers was assessed in exposed animals. In mussels the markers included chemical contaminant levels, haemocyte lysosomal instability and nucleus integrity, cellular energy allocation, digestive gland and gonad histopathology and shell-opening behaviour. In fish, biliary PAH metabolites and gill histopathology biomarkers were measured. A consistent cause-effect relationship between WW treatments and markers measured in test animals was not found. The results therefore indicate that the WW emission is unlikely to represent a significant stress factor for the local marine environment under the conditions studied. | acceptedVersion

It is unclear whether habitat degradation correlates with tolerance of marine invertebrates to abiotic stress. We therefore tested whether resistance to climate change-related stressors differs between populations of the green mussel Perna viridis from a heavily impacted and a mostly pristine site in West Java, Indonesia. In laboratory experiments, we compared their oxygen consumption and mortality under lowered salinity (−13 and −18 units, both responses), hypoxia (0.5mg/l, mortality only) and thermal stress (+7°C, mortality only). Mussels from the eutrophied and polluted Jakarta Bay showed a significantly smaller deviation from their normal oxygen consumption and higher survival rates when stressed than their conspecifics from the unaffected Lada Bay. This shows that human induced habitat degradation correlates with mussel tolerance to environmental stress. We discuss possible mechanisms – e.g. the selection of tolerant genotypes or habitat-specific differences in the nutritional status of the mussels – that could explain our observation.

It is unclear whether habitat degradation correlates with tolerance of marine invertebrates to abiotic stress. We therefore tested whether resistance to climate change-related stressors differs between populations of the green mussel Perna viridis from a heavily impacted and a mostly pristine site in West Java, Indonesia. In laboratory experiments, we compared their oxygen consumption and mortality under lowered salinity (�13 and �18 units, both responses), hypoxia (0.5 mg/l, mortality only) and thermal stress (+7 �C, mortality only). Mussels from the eutrophied and polluted Jakarta Bay showed a significantly smaller deviation from their normal oxygen consumption and higher survival rates when stressed than their conspecifics from the unaffected Lada Bay. This shows that human induced habitat degradation correlates with mussel tolerance to environmental stress. We discuss possible mechanisms – e.g. the selection of tolerant genotypes or habitat-specific differences in the nutritional status of the mussels – that could explain our observation.

The main objective of this paper was to evaluate the impact of mercury on the zooplankton communities’ structure and functioning and their bioaccumulation patterns along a contamination gradient in a temperate coastal lagoon. Our results demonstrated that total abundance was not negatively affected by Hg contamination, since the most contaminated areas presented the highest values, being the copepod Acartia tonsa the dominant species, which means that it is a very well adapted and tolerant species to mercury. Nevertheless, negative effects were observed in terms of species diversity, since the most contaminated areas presented the lowest values of species richness, evenness and heterogeneity. Moreover, the spatial mercury gradient was reflected on the bioaccumulation patterns of the zooplankton communities. This reinforces the idea that zooplankton can be considered as an important vehicle of mercury transfer through the food pelagic web since it constitutes a primordial food resource for several commercial fish species.

The main objective of this paper was to evaluate the impact of mercury on the zooplankton communities' structure and functioning and their bioaccumulation patterns along a contamination gradient in a temperate coastal lagoon. Our results demonstrated that total abundance was not negatively affected by Hg contamination, since the most contaminated areas presented the highest values, being the copepod Acartia tonsa the dominant species, which means that it is a very well adapted and tolerant species to mercury. Nevertheless, negative effects were observed in terms of species diversity, since the most contaminated areas presented the lowest values of species richness, evenness and heterogeneity. Moreover, the spatial mercury gradient was reflected on the bioaccumulation patterns of the zooplankton communities. This reinforces the idea that zooplankton can be considered as an important vehicle of mercury transfer through the food pelagic web since it constitutes a primordial food resource for several commercial fish species.

Marine fish farms could cause environmental disturbances on the sediment due to uneaten food and fish faeces that impact the marine benthos. Polychaete assemblages are considered good indicators of environmental perturbations. The present study aimed to establish groups of polychaetes as potential indicators of fish farm pollution. This study was carried out in ten fish farms along the Spanish coast. Changes in polychaete assemblage were analyzed with meta-analysis and multivariate techniques. Abundance, richness and diversity showed significant decreases under fish farm conditions. Distribution patterns of polychaetes responded to combinations of physicochemical variables. The main ones are sulfide concentration, silt and clays percentage, and stable nitrogen isotope ratio. The results showed that some families are tolerant, Capitellidae, Dorvilleidae, Glyceridae, Nereididae, Oweniidae and Spionidae; while others are sensitive to fish farm pollution, Magelonidae, Maldanidae, Nephtyidae, Onuphidae, Paralacydoniidae, Paraonide, Sabellidae and also Cirratulidae in spite of being reported as a tolerant family.

Marine fish farms could cause environmental disturbances on the sediment due to uneaten food and fish faeces that impact the marine benthos. Polychaete assemblages are considered good indicators of environmental perturbations. The present study aimed to establish groups of polychaetes as potential indicators of fish farm pollution. This study was carried out in ten fish farms along the Spanish coast. Changes in polychaete assemblage were analyzed with meta-analysis and multivariate techniques. Abundance, richness and diversity showed significant decreases under fish farm conditions. Distribution patterns of polychaetes responded to combinations of physicochemical variables. The main ones are sulfide concentration, silt and clays percentage, and stable nitrogen isotope ratio. The results showed that some families are tolerant, Capitellidae, Dorvilleidae, Glyceridae, Nereididae, Oweniidae and Spionidae; while others are sensitive to fish farm pollution, Magelonidae, Maldanidae, Nephtyidae, Onuphidae, Paralacydoniidae, Paraonide, Sabellidae and also Cirratulidae in spite of being reported as a tolerant family. | This study is part of the project “Selección de indicadores, determinación de valores de referencia, diseño de programas y protocolos de métodos y medidas para estudios ambientales en acuicultura marina” and was funded by the “Spanish National Plans of Aquaculture” (JACUMAR).