Living under natural conditions of ocean acidification entails energy expenditure and oxidative stress in a mussel species.

We investigated the health conditions of the Mediterranean mussel Mytilus galloprovincialis recruited in the CO2 vents system of Castello Aragonese at Ischia Island (Mediterranean Sea). Individuals of M. galloprovincialis were sampled in three sites along the pH gradient (8.10, 7.7 and up to <7.4). Untargeted metabolomics and biochemical endpoints related to energetic metabolism, oxidative stress/damage, neurotoxicity and immune defense were analyzed. Corrosion of the valves occurred at low pH. A separation of the metabolome was observed along the pH gradient. Metabolites belonging to amino acids, nucleosides, lipids and organic osmolytes were significantly reduced in the organisms from the most acidified sites. The content of reactive oxygen species and the activity of glutathione peroxidase were reduced in organisms from the acidified sites compared to ambient pH, and no oxidative damage was induced. Overall results suggested the presence of an energy cost underpinning long-term survival in acidified conditions for this species.

Unveiling the multilevel impact of four water-soluble polymers on Daphnia magna: From proteome to behaviour (a case study).

The ubiquitous presence of water-soluble polymers (WSPs) in freshwater environments raises concerns regarding potential threats to aquatic organisms. This study investigated, for the first time, the effects of widely used WSPs -polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polyacrylic acid (PAA), and polyethylene glycol (PEG)- using a multi-level approach in the freshwater biological model Daphnia magna. This integrated assessment employed a suite of biomarkers, evaluation of swimming behaviour, and proteomic analysis to investigate the effects of three environmentally relevant concentrations (0.001, 0.5, and 1 mg/L) of the tested WSPs from molecular to organismal levels, assessing both acute and chronic effects. Our findings reveal that exposure to different WSPs induces specific responses at each biological level, with PEG being the only WSP inducing lethal effects at 0.5 mg/L. At the physiological level, although all WSPs impacted both swimming performance and heart rate of D. magna specimens, PAA exhibited the greatest effects on the measured behavioural parameters. Furthermore, proteomic analyses demonstrated altered protein profiles following exposure to all WSPs, with PVA emerging as the most effective.

The genome of the rayed Mediterranean limpet Patella caerulea (Linnaeus, 1758).

Patella caerulea (Linnaeus, 1758) is a mollusc limpet species of the class Gastropoda. Endemic to the Mediterranean Sea, it is considered a keystone species due to its primary role in structuring and regulating the ecological balance of tidal and subtidal habitats. It is currently being used as a bioindicator to assess the environmental quality of coastal marine waters and as a model species to understand adaptation to ocean acidification. Here, we provide a high-quality reference genome assembly and annotation for P. caerulea. We generated ∼30 Gb of Pacific Biosciences high-fidelity data from a single individual and provide a final 749.8 Mb assembly containing 62 contigs, including the mitochondrial genome (14,938 bp). With an N50 of 48.8 Mb and 98% of the assembly contained in the 18 largest contigs, this assembly is near chromosome-scale. Benchmarking Universal Single-Copy Orthologs scores were high (Mollusca, 87.8% complete; Metazoa, 97.2% complete) and similar to metrics observed for other chromosome-level Patella genomes, highlighting a possible bias in the Mollusca database for Patellids. We generated transcriptomic Illumina data from a second individual collected at the same locality and used it together with protein evidence to annotate the genome. A total of 23,938 protein-coding gene models were found. By comparing this annotation with other published Patella annotations, we found that the distribution and median values of exon and gene lengths was comparable with other Patella species despite different annotation approaches. The present high-quality P. caerulea reference genome, available on GenBank (BioProject: PRJNA1045377; assembly: GCA_036850965.1), is an important resource for future ecological and evolutionary studies.

Assessment of behavioural effects of three water-soluble polymers in zebrafish embryos.

The water-soluble polymers (WSPs) are widely used in many industrial applications and are present in several commonly used products due to their physical-chemical characteristics: as their name indicates, despite being synthetic polymers, they are able to solubilize in water. Because of this peculiar property, both the qualitative-quantitative evaluation in aquatic ecosystems and their potential (eco)toxicological effects have been neglected until now. The aim of this study was to evaluate the possible effects of three of the most widely used WSPs as polyacrylic acid (PAA), polyethylene glycol (PEG) and polyvinyl pyrrolidone (PVP) on the swimming behaviour of zebrafish (Danio rerio) embryos after the exposure to different concentrations (0.001, 0.5, 1 mg/L). The exposure lasted from the eggs' collection up to 120 h post fertilization (hpf) also using three different light intensity (300 lx, 2200 lx, 4400 lx) to better evaluate any effects related to different gradients of light/dark transitions. In order to analyze individual behavioural changes in embryos, their swimming movements were tracked and a number of parameters for locomotion and directionality were quantified. The main results showed that all three WSPs resulted in significant (p ≤ 0.05) variations in different movement parameters, suggesting a possible toxicity scale: PVP > PEG â‰« PAA.

Surviving in a changing ocean. Tolerance to acidification might affect the susceptibility of polychaetes to chemical contamination.

This study aimed to assess the combined effects of ocean acidification (OA) and pollution to the polychaete Syllis prolifera inhabiting the CO2 vent system of the Castello Aragonese (Ischia Island, Italy). We investigated the basal activities of antioxidant enzymes in organisms from the acidified site and from an ambient-pH control site in two different periods of the year. Results showed a limited influence of acidified conditions on the functionality of the antioxidant system. We then investigated the responsiveness of individuals living inside the CO2 vent compared to those from the control to face exposure to acetone and copper. Results highlighted a higher susceptibility of organisms from the vent to acetone and a different response of antioxidant enzymes in individuals from the two sites. Conversely, a higher tolerance to copper was observed in polychaetes from the acidified-site with respect to controls, but any significant oxidative stress was induced at sublethal concentrations.