Long-lasting effects of chronic exposure to chemical pollution on the hologenome of the Manila clam

Chronic exposure to pollutants affects natural populations, creating specific molecular and biochemical signatures. In the present study, we tested the hypothesis that chronic exposure to pollutants might have substantial effects on the Manila clam hologenome long after removal from contaminated sites. To reach this goal, a highly integrative approach was implemented, combining transcriptome, genetic and microbiota analyses with the evaluation of biochemical and histological profiles of the edible Manila clam Ruditapes philippinarum, as it was transplanted for 6 months from the polluted area of Porto Marghera (PM) to the clean area of Chioggia (Venice lagoon, Italy). One month post‐transplantation, PM clams showed several modifications to its resident microbiota, including an overrepresentation of the opportunistic pathogen Arcobacter spp. This may be related to the upregulation of several immune genes in the PM clams, potentially representing a host response to the increased abundance of deleterious bacteria. Six months after transplantation, PM clams demonstrated a lower ability to respond to environmental/physiological stressors related to the summer season, and the hepatopancreas‐associated microbiota still showed different compositions among PM and CH clams. This study confirms that different stressors have predictable effects in clams at different biological levels and demonstrates that chronic exposure to pollutants leads to long‐lasting effects on the animal hologenome. In addition, no genetic differentiation between samples from the two areas was detected, confirming that PM and CH clams belong to a single population. Overall, the obtained responses were largely reversible and potentially related to phenotypic plasticity rather than genetic adaptation. The results here presented will be functional for the assessment of the environmental risk imposed by chemicals on an economically important bivalve species

Microplastics in real wastewater treatment schemes: Comparative assessment and relevant inhibition effects on anaerobic processes

Supplementary data are available online at https://www.sciencedirect.com/science/article/pii/S0045653520326102#appsec1 .The occurrence, fate and removal of microplastics (MPs) in a wastewater treatment plant (WWTP) in Central Italy were investigated together with their potential adverse effects on anaerobic processes. In the influent of the WWTP, 3.6 MPs.L−1 were detected that mostly comprised polyester fibers and particles in the shape of films, ranging 0.1–0.5 mm and made of polyethylene and polypropylene (PP). The full-scale conventional activated sludge scheme removed 86% of MPs, with the main reduction in the primary and secondary settling. MPs particles bigger than 1 mm were not detected in the final effluent and some loss of polymers types were observed. In comparison, the pilot-scale upflow granular anaerobic sludge blanket (UASB) + anaerobic membrane bioreactor (AnMBR) configuration achieved 94% MPs removal with the abatement of 87% of fibers and 100% of particles. The results highlighted an accumulation phenomenon of MPs in the sludge and suggested the need to further investigate the effects of MPs on anaerobic processes. Accordingly, PP-MPs at concentrations from 5 PP-MPs.gTS−1 to 50 PP-MPs.gTS−1 were spiked in the pilot-scale UASB reactor that was fed with real municipal wastewater, where up to 58% decrease in methanogenic activity was observed at the exposure of 50 PP-MPs.gTS−1. To the best of our knowledge, the presented results are the first to report of PP-MPs inhibition on anaerobic processes.This study was supported by the Polytechnic University of Marche - MICROWASTE Strategic Project 2017 and by the European Commission with the LIFE program - “LIFE BLUE LAKES” under the Grant Agreement No. LIFE18 GIE/IT/000813. Alessia Foglia kindly acknowledges the Fondazione Cariverona for funding her PhD scholarship

Do microplastic contaminated seafood consumption pose a potential risk to human health?

Microplastics are present in all parts of the ocean and can have deleterious effects on marine resources. The aim of this work was to map the presence of microplastics in commercial marine species such as bivalves (mussels Mytilus galloprovincialis and clams Scrobicularia plana), crabs (Carcinus maenas) as well as fish (Mullus surmuletus) to relate microplastics levels to pollution sources, assess possible impact on marine food chains and on human health. These species were collected from several sites of the Ria Formosa lagoon and along the south coast of Portugal. A quantitative assessment (number, size and color) and typology of microplastics were made in these species. Only one green fragment of polypropylene was detected in the gills of the crabs, while a blue polyethylene fragment was detected in the hepatopancreas of the mullets. Moreover, no microplastics were present in S. plana nor in the crabs whole soft tissues. Among mussels, 86% of microplastics were present from all sites and the number, size and color were site specific. Mussels from the west side of the coast (Sites 1–3) had the highest levels of MPs per mussel and per weight compared to the other sites, probably related to the impact of touristic activity, fishing gears, fresh water and sewage effluents along with the hydrodynamics of the area.FCT JPI OCEANS MICROPLAST/0005/2018; UID/00350/2020info:eu-repo/semantics/publishedVersio

Colonization of plastic debris by the long-lived precious red coral Corallium rubrum: New insights on the “plastic benefits” paradox

Seafloor macrolitter is ubiquitous in world's oceans; still, huge knowledge gaps exist on its interactions with benthic biota. We report here the colonization of plastic substrates by the Mediterranean red coral Corallium rubrum (L. 1758), occurring both in controlled conditions and in the wild at ca. 85 m depth in the Western Mediterranean Sea. Juveniles settled on seafloor macro-litter, with either arborescent or encrusting morphology, ranging from 0.6 to 3.5 mm in basal diameter and 0.2–7.1 years of age, also including a fraction (20%) of potentially sexually mature individuals. In controlled conditions, larvae settled and survived on plastic substrates for >60 days. Our insights show that marine plastic debris can provide favourable substrate for C. rubrum settlement either in controlled conditions or in the wild, suggesting their possible use in restoration activities. However, we pinpoint here that this potential benefit could result in adverse effects on population dynamics

Emerging environmental stressors and oxidative pathways in marine organisms: Current knowledge on regulation mechanisms and functional effects

Oxidative stress is a critical condition derived from the imbalance between the generation of reactive oxygen species and the sophisticated network of antioxidant mechanisms. Several pollutants and environmental factors can affect this system through connected mechanisms, indirect relationships, and cascade effects from pre-transcriptional to catalytic level, by either enhancing intracellular ROS formation or impairing antioxidant defenses. This review summarizes the current knowledge on the pro-oxidant challenges from emerging environmental stressors threatening marine organisms, such as pharmaceuticals, microplastics and climate-related ocean changes. Emphasis will be placed on oxidative pathways, including signaling proteins and transcription factors involved in regulation of antioxidant responsiveness. Mechanistic insights and lack of knowledge will be pointed out by presenting single and combined effects of multiple stressors, unravelling questions to be addressed by future research in marine ecotoxicology

Could molecular effects of Caulerpa racemosa metabolites modulate the impact on fish populations of Diplodus sargus?

The green alga Caulerpa racemosa is a non-native, invasive species in the Mediterranean, and an important stressor for several native organisms. The algal capacity to produce secondary metabolites has been suggested to modulate success of the C. racemosa invasion, although many of potentially involved biological pathways still remain unexplored. In this respect, the aim of the present study was to investigate some molecular and cellular effects in the white seabream Diplodus sargus, an ecologically key species, which included the alien C. racemosa in its diet. Organisms were sampled in 2 seasonal periods from 3 locations of Southern Italy, each characterized by different levels of algal abundance. The level of caulerpin, one of the main secondary algal metabolites, in fish tissues has been used as an indicator of the trophic exposure to the seaweed and related with molecular and cellular responses. Chemical analyses indicated that fish from invaded sites can accumulate caulerpin, with liver concentrations ranging from a few up to hundreds of mg/g. Biomarkers analyses revealed only limited alterations of the main antioxidant defences, such as glutathione reductase and levels of glutathione; on the other hand, increased enzymatic activities of cytochrome P450, glutathione S-transferases and acyl CoA oxidase, as well as enhanced gene transcription for peroxisome proliferator-activated receptor alpha, cytochrome P4501A and vitellogenin 1 were observed in fish more exposed to C. racemosa as indicated by liver concentrations of caulerpin higher than 50 mg/g. Despite a direct molecular relationship with this algal metabolite could not be established, our results suggest that a C. racemosa enriched diet can modulate biotransformation and fatty acids metabolism of D. sargus. Assessing whether similar effects represent short- or long-term effects will be of crucial importance to understand consequences on the general health status and reproductive performance of exposed key fish species in the Mediterranean region

Microplastics and Brominated Flame Retardants in Freshwater Fishes From Italian Lakes: Implication for Human Health

Microplastics (MPs) and brominated flame retardants (BFRs) represent a synergic threat for aquatic environments and organisms' health status, with an additional concern over food quality and food security for species of commercial interest. In this study, the ingestion of MPs, levels of polybrominated diphenyl ethers (PBDEs), and hexabromocyclododecane (HBCDs) were assessed in organisms from two lakes of Central Italy, with the aims of exploring the bioavailability of these pollutants in freshwater environments, the possible translocation of MPs from digestive to edible tissues, and the relationship between MPs ingestion and bioaccumulation of BFRs. The fish Perca fluviatilis, Anguilla anguilla, Carassus auratus, and the crayfish Procambarus clarkii, all species commercialized for human consumption, were caught in Trasimeno Lake; moreover, P. fluviatilis and Rutilus rutilus were also sampled in Piediluco, a lake strongly influenced by industrial and anthropogenic activities, where fishing for commercial purpose is forbidden. With the exception of C. auratus which showed the highest frequency of MPs ingestion (75%), species from Piediluco Lake exhibited a more elevated percentage of organisms positive to MPs ingestion (45%) and higher levels of PBDEs and HBCDs (mean values of 343 and 792 pg/g, respectively, in P. fluviatilis; 445 and 677 pg/g, respectively, in R. rutilus) than Trasimeno species (25% frequency of MPs ingestion, mean values between 6 and 163 pg/g for PBDEs and 5-107 pg/g for HBCDs). Polyester fibers dominated among MP typologies, and a high occurrence of man-made natural fibers was recorded. The number of MPs extracted in the gastrointestinal tracts of fish and soft bodies of crayfishes positive to MPs ingestion ranged between 1 and 2, whereas no MPs were found in fish filets. Given these results, the risk related to human consumption of Trasimeno organisms appears very low, whereas further investigations are required to better elucidate the possible role of MPs pollution in modulating chemical bioaccumulation in edible tissues. This study contributed to assess both environmental quality and food safety, reinforcing the use of bioindicator species for monitoring plans, in accordance with European recommendations

Could molecular effects of Caulerpa racemosa metabolites modulate the impact on fish populations of Diplodus sargus?

The green alga Caulerpa racemosa is a non-native, invasive species in the Mediterranean, and an important stressor for several native organisms. The algal capacity to produce secondary metabolites has been suggested to modulate success of the C. racemosa invasion, although many of potentially involved biological pathways still remain unexplored. In this respect, the aim of the present study was to investigate some molecular and cellular effects in the white seabream Diplodus sargus, an ecologically key species, which included the alien C. racemosa in its diet. Organisms were sampled in 2 seasonal periods from 3 locations of Southern Italy, each characterized by different levels of algal abundance. The level of caulerpin, one of the main secondary algal metabolites, in fish tissues has been used as an indicator of the trophic exposure to the seaweed and related with molecular and cellular responses. Chemical analyses indicated that fish from invaded sites can accumulate caulerpin, with liver concentrations ranging from a few up to hundreds of mg/g. Biomarkers analyses revealed only limited alterations of the main antioxidant defences, such as glutathione reductase and levels of glutathione; on the other hand, increased enzymatic activities of cytochrome P450, glutathione S-transferases and acyl CoA oxidase, as well as enhanced gene transcription for peroxisome proliferator-activated receptor alpha, cytochrome P4501A and vitellogenin 1 were observed in fish more exposed to C. racemosa as indicated by liver concentrations of caulerpin higher than 50 mg/g. Despite a direct molecular relationship with this algal metabolite could not be established, our results suggest that a C. racemosa enriched diet can modulate biotransformation and fatty acids metabolism of D. sargus. Assessing whether similar effects represent short- or long-term effects will be of crucial importance to understand consequences on the general health status and reproductive performance of exposed key fish species in the Mediterranean region

Distribution and characterization of microplastic particles and textile microfibers in Adriatic food webs: General insights for biomonitoring strategies

This study provided a comprehensive characterization on ingestion of different typologies of microplastics in several fish and invertebrate species from the Adriatic Sea, considered as a preferential area of plastic accumulation in the Mediterranean. Almost 500 organisms were sampled in the three sectors of Northern, Central and Southern Adriatic, testing the hypothesis that area of collection, habitat and feeding strategy might influence the occurrence of plastic particles in biota. In this study, the overall characterization considered separately plastic microparticles (MPs) from textile microfibers (MFs) which also included natural and semi-synthetic ones. Ingestion of MPs was a widespread phenomenon, but their number (typically 1 or 2) did not reveal any significant relationship with biometric values, geographical areas or ecological features of the species. Conversely, the frequency of ingestion, ranging from 13 to 35% of organisms containing MPs, appeared a more reliable index to highlight such differences, revealing higher values in species from Central and Southern basins compared to the Northern one, as well as in benthopelagic compared to benthic or pelagic organisms. Geographical differences also occurred in terms of size and typology of ingested particles, suggesting the importance of local river runoffs and surface currents dynamics. Textile microfibers (MFs) were also abundant in Adriatic food webs occurring in all the analyzed species with average numbers (3–10) and frequencies (40–70%) higher than those reported for MPs; further, an elevated percentage of MFs (>80%) was of natural or semi-synthetic origin. Overall, this study provided general insights toward the harmonization of a common biomonitoring strategy, as in the context of MSFD, including the suggestion of a frequency-based index and of a multi-species approach to increase the ecological relevance of assessment, as well as the comparability between different areas and trophic webs. An extensive characterization revealed the distribution of microplastic particles and textile microfibers in several fish and invertebrates from the Adriatic Sea. Frequency of ingestion appeared a more reliable index than number of ingested particles to reveal geographical differences which occurred in terms of size and typology of particles

Microplastics and Polycyclic Aromatic Hydrocarbons Occurrence in a Demersal Fish (Solea solea) in the Adriatic Sea

none8In recent years, microplastics (MPs) are emerging contaminants ubiquitously present in all the compartments of the aquatic ecosystem from surface water to benthic sediment, including aquatic biota. In the aquatic system, MPs pose serious hazards to marine organisms, causing damage by contact, ingestion and uptake. Evidence of MPs ingestion is well documented in marine organisms and harmful consequences of MPs to biota may also derive from the possible transfer of chemicals associated to the plastic debris, especially persistent organic pollutants (POPs), such as polycyclic aromatic hydrocarbons (PAHs). To date, many studies are focusing on the interaction between MPs and POPs, concerning sorption processes and competitive behaviour of chemicals onto MPs, however most of them are experimental studies and very few field studies have been carried out on wild organisms. In the present field study, the most commonly found plastic polymers (polyvinyl chloride [PVC], polypropylene [PP], polyethylene [PE], polyester [PET] and polyamide [PA]) and PAH congeners (phenanthrene [Phe], fluoranthene [Flu] and pyrene [Py]) were analysed in wild sole (Solea solea) caught in the Adriatic Sea. MPs were evaluated in the gastrointestinal tract of the fish, while PAHs were evaluated in sediments and several fish tissues (gills, liver and fillet).noneFrapiccini, Emanuela; Pellini, Giulio; Gomiero, Alessio; Scarcella, Giuseppe; Guicciardi, Stefano; Annibaldi, Anna; Betti, Mattia; Marini, MauroFrapiccini, Emanuela; Pellini, Giulio; Gomiero, Alessio; Scarcella, Giuseppe; Guicciardi, Stefano; Annibaldi, Anna; Betti, Mattia; Marini, Maur