Towards an ecosystem service-based method to quantify the filtration services of mussels under chemical exposure

How human health and well-being depends on healthy marine habitats in the Mediterranean: A review

Human health and well-being, and how they are affected by terrestrial and freshwater ecosystems have been the subject of numerous studies. In contrast, there are very few such studies relating to marine ecosystems. Here, in the context of the Mediterranean Sea, we assess evidence of the broad interplay of relationships between marine habitats and human health and well-being. Our review shows that the major Mediterranean marine habitats provide various provisioning, cultural and regulating services that improve physical and mental health in a number of different ways. These include: (i) the provision of seafood rich in omega-3 fatty acids, which help to reduce the risk of developing certain types of illnesses; and also, species that produce bioactive compounds that are potential sources of new drugs; (ii) the provision of blue spaces - areas of water suitable for leisure and recreational activities able to inspire, educate, and appeal to the aesthetic senses - that not only increase physical and psychological health, but also foster an individual and collective sense of place and identity and contribute to improving social relations; and (iii) the regulation of climate change, and of water quality and pollution, for example via sequestration of carbon and heavy metals, thus reducing the associated health risks. Our results show that Mediterranean marine habitats are valuable for health and well-being, thus highlighting the need to conserve as much of these habitats as possible (particularly through marine protected areas) and to carry out new studies to determine the specific causal pathways by which certain characteristics of marine habitats - including biotic (e.g. marine biodiversity) and abiotic (e.g. water quality) factors - affect human health and well-being.

Quantifying a mass mortality event in freshwater wildlife within the Lower Odra River: Insights from a large European river

In the summer of 2022, the River Odra in Europe witnessed a significant ecological disaster, leading to an unprecedented mass mortality among fish, bivalves, and water snails. The disaster was attributed to toxins released by the haptophyte golden algae, Prymnesium parvum. This study primarily focused on the river's lower section, where the disaster's impacts were exacerbated by the downstream flow of deceased organisms. The Unionidae mussels' mortality rate in this section was estimated at 65 million individuals, marking an 88 % decline in their population. The native mussel, Anodonta anatina, saw the steepest decline at 95 %, while the invasive Sinanodonta woodiana decreased by 15 %. Additionally, a minimum of 147 million dead water snails, predominantly Viviparus viviparus, were found ashore, indicating an 85 % population decline. An estimated 3.3 million fish, predominantly ruffe (Gymnocephalus cernua), bream (Abramis brama), and perch (Perca fluviatilis), were found deceased along the lower Odra, amounting to a biomass of 1025 tons. Across the entire 560 km affected stretch of the river, the estimated fish mortality was 1650 tons, a 60 % decline from pre-disaster levels. The swift deterioration of the river's ecosystem underscores the need for further studies on its adaptive capacity and potential recovery.

Petroleum refinery effluent contribution to chemical mixture toxic pressure in the environment

Petroleum refinery effluents (PRE) are wastewaters from industries associated with oil refining. Within Europe, PREs are regulated through local discharge permits and receive substantial treatment before emission. After treatment, PREs can still contain low levels of various pollutants potentially toxic to organisms. Earlier work, including whole-effluent toxicity assessments, has shown that the toxicity of permitted PREs is often limited. However, the extent to which PREs contribute to chemical pollution already present in the receiving environment is unknown. Therefore, our study aimed to assess the contribution of PREs to mixture toxic pressure in the environment, using the multi-substance potentially affected fraction of species (msPAF) as an indicator. Based on measured chemical concentrations, compiled species sensitivity distributions (SSD) and a mechanistic solubility model, msPAF levels were estimated for undiluted effluents at discharge points and diluted effluents downstream in receiving waters. Median msPAF-chronic and msPAF-acute levels of PREs at discharge points were 74% (P50) and 40% (P95), respectively. The calculated msPAF levels were reduced substantially to <5% downstream for most effluents (82%), indicating low to negligible toxicity of PREs in receiving environments beyond the initial mixing zone. Regardless of differences in endpoints and locations, hydrocarbons (mainly total petroleum hydrocarbons) and inorganics (mainly ammonia) explained at least 85% of the mixture toxic pressure. The msPAF levels of PREs were on average 2.5-4.5 orders of magnitude lower than msPAF levels derived from background pollution levels, suggesting that PREs were minor contributors to the toxic pressure in the environment. This study presents a generic methodology for quantifying the potential toxic pressure of PREs in the environment, identifying hotspots where more effective wastewater treatment could be needed. We explicitly discuss the uncertainties for further refinement and development of the method.

What we know and don't know about the invasive zebra (Dreissena polymorpha) and quagga (Dreissena rostriformis bugensis) mussels

We summarized existing knowledge on Dreissena polymorpha (the zebra mussel) and D. r. bugensis (the quagga mussel), including data on their taxonomy, systematics, evolution, life cycle, reproduction, feeding, growth and longevity, population dynamics, interspecific competition, habitat requirements, and distribution within and among waterbodies. We analyzed the history of spread of both species and the major pathways and vectors of their spread in Europe and North America. Special consideration was given to their ecological and economic impacts and their natural enemies, like waterfowl, fishes, and parasites, as well as the prevention of their introduction, early detection, control, and containment. We also outlined the most salient ecosystem services provided by zebra and quagga mussels, including water purification, nutrient recycling, culling the effects of eutrophication, biomonitoring, and their role as a food resource for fish and waterfowl. Finally, we identified major knowledge gaps and key studies needed to better understand the biology, ecology, and impacts of these aggressive freshwater invaders. Our review indicates that much crucial information on the quagga mussel is still missing, including key life history parameters, like spawning cues, fecundity, and longevity, particularly for the profundal zone of deep lakes.

Ecosystem services provided by the exotic bivalves Dreissena polymorpha, D. rostriformis bugensis, and Limnoperna fortunei

The ecosystem services approach to conservation is becoming central to environmental policy decision making. While many negative biological invasion-driven impacts on ecosystem structure and functioning have been identified, much less was done to evaluate their ecosystem services. In this paper, we focus on the often-overlooked ecosystem services provided by three notable exotic ecosystem engineering bivalves, the zebra mussel, the quagga mussel, and the golden mussel. One of the most significant benefits of invasive bivalves is water filtration, which results in water purification and changes rates of nutrient cycling, thus mitigating the effects of eutrophication. Mussels are widely used as sentinel organisms for the assessment and biomonitoring of contaminants and pathogens and are consumed by many fishes and birds. Benefits of invasive bivalves are particularly relevant in human-modified ecosystems. We summarize the multiple ecosystem services provided by invasive bivalves and recommend including the economically quantifiable services in the assessments of their economic impacts. We also highlight important ecosystem disservices by exotic bivalves, identify data limitations, and future research directions. This assessment should not be interpreted as a rejection of the fact that invasive mussels have negative impacts, but as an attempt to provide additional information for scientists, managers, and policymakers.

Misleading estimates of economic impacts of biological invasions: Including the costs but not the benefits

The economic costs of non-indigenous species (NIS) are a key factor for the allocation of efforts and resources to eradicate or control baneful invasions. Their assessments are challenging, but most suffer from major flaws. Among the most important are the following: (1) the inclusion of actual damage costs together with various ancillary expenditures which may or may not be indicative of the real economic damage due to NIS; (2) the inclusion of the costs of unnecessary or counterproductive control initiatives; (3) the inclusion of controversial NIS-related costs whose economic impacts are questionable; (4) the assessment of the negative impacts only, ignoring the positive ones that most NIS have on the economy, either directly or through their ecosystem services. Such estimates necessarily arrive at negative and often highly inflated values, do not reflect the net damage and economic losses due to NIS, and can significantly misguide management and resource allocation decisions. We recommend an approach based on holistic costs and benefits that are assessed using likely scenarios and their counter-factual.

Bioaccessibility and Intestinal Transport of Deltamethrin in Pacific Oyster (Magallana Gigas) Using Simulated Digestion/NCM460 Cell Models

Deltamethrin (DEL) can be introduced into the food chain through bioaccumulation in Pacific oysters, and then potentially threaten human health. The objective of this study was to investigate the bioaccessibility of DEL in oysters with different cooking methods after simulated digestion. DEL content in different tissues of oysters going from high to low were gills, mantle, viscera, and adductor muscle. Bioaccessibility of DEL in oysters decreased after steaming (65%) or roasting (51%) treatments compared with raw oysters (82%), which indicated that roasting can be used as a recommended cooking method for oysters. In the simulated digestion process, the concentration of DEL in the digestive juice and the bioaccessibility of DEL were affected by the pH in the gastric phase. And the transport efficiency of DEL through the monolayer molecular membrane of NCM460 cells ranged from 35 to 45%. These results can help assess the potential harm to consumers of DEL in shellfish. Furthermore, it provides a reference for the impact of lipophilic toxins in seafood.