Ocean acidification impact on the uptake of trace elements by mussels and their biochemical effects

This study delves into the intricate interplay between ocean acidification (OA), metal bioaccumulation, and cellular responses using mussels (Mytilus galloprovincialis) as bioindicators. For this purpose, environmentally realistic concentrations of isotopically labelled metals (Cd, Cu, Ag, Ce) were added to investigate whether the OA increase would modify metal bioaccumulation and induce adverse effects at the cellular level. The study reveals that while certain elements like Cd and Ag might remain unaffected by OA, the bioavailability of Cu and Ce could potentially escalate, leading to amplified accumulation in marine organisms. The present findings highlight a significant rise in Ce concentrations within different mussel organs under elevated pCO2 conditions, accompanied by an increased isotopic fractionation of Ce (140/142Ce), suggesting a heightened potential for metal accumulation under OA. The results suggested that OA influenced metal accumulation in the gills of mussels. Conversely, metal accumulation in the digestive gland was unaffected by OA. The exposure to both trace metals and OA affects the biochemical responses of M. galloprovincialis, leading to increased metabolic capacity, changes in energy reserves, and alterations in oxidative stress markers, but the specific effects on other biomarkers (e.g., lipid peroxidation, some enzymatic responses or acetylcholinesterase activity) were not uniform, suggesting complex interactions between the stressors and the biochemical pathways in the mussels.

Bioaccumulation patterns of trace elements by native (M. galloprovincialis) and invasive (X. securis) mussels in coastal systems (Vigo Ria, NW Iberian Peninsula)

A number of trace elements (Mn, Fe, Co, Ni, Cu, Zn, As, Nb, Mo, Ag, Cd, Pb, U and the rare earth elements - REE) were analyzed in the dissolved phase, suspended particulate matter and in different organs (gills, hepatopancreas, and the rest of soft tissue) in mussels of the native Mytilus galloprovincialis and invasive Xenostrobus securis species in the Vigo Ria (NW Iberian Peninsula) in order to assess potential differences in their bioaccumulation patterns. Results obtained do not show significant differences in the bioaccumulation of trace elements by M. galloprovincialis and X. securis, except for Zn and Ag. In the case of Zn, a 4-fold enrichment in M. galloprovincialis compared to X. securis was found. The most important differences between species were observed for Ag, with approximately 40-fold higher concentrations in X. securis. Such elevated Ag bioaccumulation by X. securis can be useful for Ag biomonitoring using these invasive species in this area.

The aquaculture supply chain in the time of covid-19 pandemic: Vulnerability, resilience, solutions and priorities at the global scale

The COVID-19 global pandemic has had severe, unpredictable and synchronous impacts on all levels of perishable food supply chains (PFSC), across multiple sectors and spatial scales. Aquaculture plays a vital and rapidly expanding role in food security, in some cases overtaking wild caught fisheries in the production of high-quality animal protein in this PFSC. We performed a rapid global assessment to evaluate the effects of the COVID-19 pandemic and related emerging control measures on the aquaculture supply chain. Socio-economic effects of the pandemic were analysed by surveying the perceptions of stakeholders, who were asked to describe potential supply-side disruption, vulnerabilities and resilience patterns along the production pipeline with four main supply chain components: a) hatchery, b) production/processing, c) distribution/logistics and d) market. We also assessed different farming strategies, comparing land- vs. sea-based systems; extensive vs. intensive methods; and with and without integrated multi-trophic aquaculture, IMTA. In addition to evaluating levels and sources of economic distress, interviewees were asked to identify mitigation solutions adopted at local / internal (i.e., farm-site) scales, and to express their preference on national / external scale mitigation measures among a set of a priori options. Survey responses identified the potential causes of disruption, ripple effects, sources of food insecurity, and socio-economic conflicts. They also pointed to various levels of mitigation strategies. The collated evidence represents a first baseline useful to address future disaster-driven responses, to reinforce the resilience of the sector and to facilitate the design reconstruction plans and mitigation measures, such as financial aid strategies.