Quantifying intangible values of wetlands as instrument for conservation in the Po delta park (Italy).

Wetlands possess intangible values that are usually overlooked in decision-making processes. Based on questionnaire surveys, this work aims to quantify both the non-use and cultural values provided by the different wetlands of the Po Delta Park (Northern Italy), selected as ideal case study, using willingness to pay (WTP) for wetland conservation and travel cost methods, respectively. Their relationships with socio-economic variables and respondents' preferences for current and future use were also analysed. The 61.39% of participants were willing to pay a mean amount of 95.8 € (±40). The average travel cost was 38.68 € (±6.24), with higher values observed for environmental experts than for other citizens. Wetlands differ significantly in travel costs, current and future use, but not in WTP. Poisson regressions showed that non-use and cultural values were significantly dependent on personal information, preference variables and travel distance. Intangible dimensions, such as bequest and existence values, showed higher valuations/rates than option and direct use values. The results highlight that perceptions of the intrinsic value of nature are influenced by demographic characteristics, distance from the area and desired future uses. Non-use values seem abstract and generalised to the whole area, regardless of the ecological characteristics of the wetland, even though a significant relation to wetland uses was observed. In contrast, cultural values are tied to specific wetlands, as indication of the importance of historical relationships between people and nature. Such findings underline that the different dimensions of intrinsic value of nature may act at different scales and help decision-makers to incorporate such values into environmental accounting.

Climate change impacts on eutrophication in the Po River (Italy): Temperature-mediated reduction in nitrogen export but no effect on phosphorus.

Rivers worldwide are under stress from eutrophication and nitrate pollution, but the ecological consequences overlap with climate change, and the resulting interactions may be unexpected and still unexplored. The Po River basin (northern Italy) is one of the most agriculturally productive and densely populated areas in Europe. It remains unclear whether the climate change impacts on the thermal and hydrological regimes are already affecting nutrient dynamics and transport to coastal areas. The present work addresses the long-term trends (1992-2020) of nitrogen and phosphorus export by investigating both the annual magnitude and the seasonal patterns and their relationship with water temperature and discharge trajectories. Despite the constant diffuse and point sources in the basin, a marked decrease (-20%) in nitrogen export, mostly as nitrate, was recorded in the last decade compared to the 1990s, while no significant downward trend was observed for phosphorus. The water temperature of the Po River has warmed, with the most pronounced signals in summer (+0.13°C/year) and autumn (+0.16°C/year), together with the strongest increase in the number of warm days (+70%-80%). An extended seasonal window of warm temperatures and the persistence of low flow periods are likely to create favorable conditions for permanent nitrate removal via denitrification, resulting in a lower delivery of reactive nitrogen to the sea. The present results show that climate change-driven warming may enhance nitrogen processing by increasing respiratory river metabolism, thereby reducing export from spring to early autumn, when the risk of eutrophication in coastal zones is higher.

Distance decay 2.0 - A global synthesis of taxonomic and functional turnover in ecological communities.

Aim: Understanding the variation in community composition and species abundances (i.e., ß-diversity) is at the heart of community ecology. A common approach to examine ß-diversity is to evaluate directional variation in community composition by measuring the decay in the similarity among pairs of communities along spatial or environmental distance. We provide the first global synthesis of taxonomic and functional distance decay along spatial and environmental distance by analysing 148 datasets comprising different types of organisms and environments. Location: Global. Time period: 1990 to present. Major taxa studied: From diatoms to mammals. Method: We measured the strength of the decay using ranked Mantel tests (Mantel r) and the rate of distance decay as the slope of an exponential fit using generalized linear models. We used null models to test whether functional similarity decays faster or slower than expected given the taxonomic decay along the spatial and environmental distance. We also unveiled the factors driving the rate of decay across the datasets, including latitude, spatial extent, realm and organismal features. Results: Taxonomic distance decay was stronger than functional distance decay along both spatial and environmental distance. Functional distance decay was random given the taxonomic distance decay. The rate of taxonomic and functional spatial distance decay was fastest in the datasets from mid-latitudes. Overall, datasets covering larger spatial extents showed a lower rate of decay along spatial distance but a higher rate of decay along environmental distance. Marine ecosystems had the slowest rate of decay along environmental distances. Main conclusions: In general, taxonomic distance decay is a useful tool for biogeographical research because it reflects dispersal-related factors in addition to species responses to climatic and environmental variables. Moreover, functional distance decay might be a cost-effective option for investigating community changes in heterogeneous environments.

Ecology and effects of metazoan parasites of fish in transitional waters.

Given the abundance, heterogeneity and ubiquity of parasitic organisms, understanding how they influence biodiversity, evolution, health and ecosystem functionality is crucial, especially currently when anthropogenic pressures are altering host­parasite balances. This review describes the features, roles and impacts of metazoan parasites of fish occurring in transitional waters (TW). These aquatic ecosystems are highly productive and widespread around the globe and represent most favourable theatres for parasitism given the availability of hosts (invertebrates, fishes and birds) and an increased probability of parasite transmission, especially of those having complex life cycles. Fascinating examples of how parasitism can influence different hierarchical levels of biological systems, from host individuals and populations to entire aquatic communities, through effects on food webs come from this kind of ecosystem. Edible fish of commercial value found in TW can harbour some parasite species, significantly reducing host health, marketability and food safety, with possible economic and public health consequences. Many TW are historically exploited by humans as sources of relevant ecosystem services, including fisheries and aquaculture, and they are highly vulnerable ecosystems. Alteration of TW can be revealed through the study of parasite communities, contributing, as bioindicators, for assessing environmental changes, health and restoration. Fish parasites can provide much information about TW, but this potential appears to be not fully exploited. More studies are necessary to quantify the ecological, economic and medical impacts fish parasites can have on these important ecosystems.

Effect of waterborne exposure to perfluorooctanoic acid on nephron and renal hemopoietic tissue of common carp Cyprinus carpio.

Per- and poly-fluoroalkyl substances (PFAS) are synthetic contaminants of global concern for environmental and public health. Perfluorooctanoic acid (PFOA) is an important PFAS, and considerable attention has been paid to its hepatotoxicity and reproductive and developmental impact, while potential nephrotoxic effects are largely ignored, especially in fish. This study documents the structural and ultrastructural effects on kidney of common carp Cyprinus carpio exposed to waterborne PFOA at an environmentally relevant concentration of 200 ng L-1 and at 2 mg L-1. Dilation of the glomeruli capillary bed, increased vesiculation in the proximal tubular segment, compromised mitochondria, apical blebbing, and sloughing of collecting duct cells occurred in exposed fish, primarily at 2 mg L-1. Perfluorooctanoic acid exposure resulted in higher numbers of rodlet cells (RC), putative immune cells exclusive to fish, mainly in the renal interstitium, than seen in controls, increased association with cells of myeloid lineage and modifications to ultrastructure. No differences in other cells of innate immunity were observed. Despite the absence of severe histological lesions, PFOA was shown to affect both nephron and hemopoietic interstitium at high concentration, raising concern of the impact on renal and immune function in fish. The response of RCs to PFOA concentration of 200 ng L-1 suggests a potential role as a biomarker of PFOA exposure.

Plastic (PET) vs bioplastic (PLA) or refillable aluminium bottles - What is the most sustainable choice for drinking water? A life-cycle (LCA) analysis.

Nowadays, the most important tool to evaluate the environmental impact of both petro-plastics and bioplastics is the life cycle analysis (LCA). LCA determines the overall impact on the environment by defining, calculation and analyzing all the input and output directly related to production, utilization, and disposal of a product or a process. In this work, a LCA (cradle to grave) of bottles for drinking water was developed on three scenarios: polyethylene terephthalate (PET) bottles, as conventional packaging material for outdoor drinking water, polylactic acid (PLA) bottles, as alternative and innovative biodegradable packaging and aluminum bottle, as reusable and almost infinitely refilling packaging. As a result of LCA, ten impacts categories have been accounted for, among which the global warming potential (GWP, measured as kgCO2 eq), the eutrophication potential (EP, measured as kgPO4 eq.), human and eco-toxicity (HTP and ETP, measured as kg 1,4-DB eq.). The average drinking water consumption in Italy has been estimated in 1.5 L per day, corresponding to three 500 ml-plastic bottles and 1 refillable aluminum bottle. LCA has been firstly applied to a single bottle production and use, then to the daily and annual bottles consumption. PET bottles production and use assure the lower environmental impacts compared to PLA bottles, burdened by agricultural phase for corn cultivation, and to aluminum bottles, when the every-day washing with hot water or water and soap is comprehended. Moreover, including the end-of-life options into the analysis, PET recycling permits to reduce up to about 30% the GWP, whereas PLA composting does not lead to any GWP savings. In this study, aluminum bottle has been considered reusable for 2.5 years. The microbiological quality of water in one-way PET and PLA bottles has been compared with the refillable bottle rinsing with hot water and soap and only hot water, highlighting that the level of contamination is alarmingly increased in the latter case.

The achievement of Water Framework Directive goals through the restoration of vegetation in agricultural canals.

Decreasing nitrate concentrations is one of the most relevant Water Framework Directive (WFD) goals, which today is still unreached in several European countries. Vegetated canals have been recognized as effective filters to mitigate nitrate pollution, although rarely included in restoration programs aimed at improving water quality in agricultural watersheds. The Po di Volano basin (713 km2, Northern Italy) is a deltaic territory crossed by an extensive network of agricultural canals (~1300 km). The effectiveness in buffering nitrate loads via denitrification was assessed for different levels of in-stream emergent vegetation maintenance by employing an upscale model based on extensive datasets of field measurements. The scenarios differed for the canal network length (5%, 20%, 40%, and 60%) where conservative management practices were adopted by postponing the mowing operations from the middle of summer, as nowadays, to the early autumn, i.e., the vegetative season end. The scenario simulations demonstrated that the capacity to mitigate diffuse nitrate pollution would increase up to four times, compared to the current condition (5% scenario), by postponing the vegetation mowing to the end of the vegetative season in 60% of the canal network length. By preserving the in-stream vegetation in 20% of the canal network, its denitrification capacity would equal the nitrate load reduction target required for achieving, from May to September, the good ecological status according to the WFD in waters delivered to the coastal areas. Changing the timing of vegetation mowing may create a large potential for permanent nitrate removal via denitrification in agricultural landscapes, thus protecting the coastal areas when the eutrophication risk is higher. Conservative management practices of in-stream vegetation might be promoted as an effective low-cost tool to be included in the WFD implementation strategies.

The effect of water velocity on nitrate removal in vegetated waterways.

The extended networks of canals and ditches in agricultural landscapes provide high buffer capacity towards nitrogen (N) excess. Their N mitigation potential depends on several biotic and abiotic factors, among which water velocity is poorly explored and generally omitted from the parameterization of this remarkable ecosystem service. The present work reports new insights on the role of flow velocity in regulating N removal via denitrification in sediments colonized by Phragmites australis. Denitrification was investigated in outdoor mesocosms in the presence and absence of P. australis and over a small range of flow velocity (0-6 cm s-1) typical of low-gradient water bodies. Simultaneous measurements of NO3- consumption and N2 production based on analyses of N2:Ar by Membrane Inlet Mass Spectrometry were undertaken. Vegetated sediments were found more efficient in converting NO3- to N2 via microbial-mediated denitrification (27-233 mmol N m-2 d-1) than bare sediments (18-33 mmol N m-2 d-1). Vegetation provides multiple interfaces, i.e. in the rhizosphere and on epiphytic biofilms, that support the development and activity of bacterial communities responsible for NO3- dissipation. NO3- removal and denitrification rates exhibited one order of magnitude raise when water velocity passed from 0 to 6 cm s-1 in vegetated sediments. Indeed, in slow-flow vegetated waterways denitrification may be physically limited and the increase of water velocity enhances the rate of NO3- supply through the diffusive boundary layer, thereby promoting its consumption and loss from the system. Water velocity should be taken into account as a key factor for management and restoration actions aimed at maximizing the NO3- buffer capacity of low-flow drainage networks.

Histological and ultrastructural study of Myxobolus mugchelo (Parenzan, 1966) with initial histopathology survey of the Liza ramada host intestine.

This paper provides histological and ultrastructural data on Myxobolus mugchelo (Myxozoa), a parasite of the intestinal wall of thinlip mullet Liza ramada from the Comacchio lagoons (Northern Adriatic Sea, Italy). About 80% of the examined mullets were infected with this myxozoan. In histological sections, the plasmodia appeared rounded to ovoid and spindle shaped, measured 181.61 ± 97 × 122.79 ± 53.16 µm (mean ± standard deviation, SD) in size. Early sporogenic plasmodia were located primarily in the muscle layer where no pronounced inflammatory response was detected. Plasmodia containing mature spores were situated closer to mucosal folds and were encircled by numerous immune cells, especially mast cells. Mature spores were generally oval and 6.06 ± 0.40 × 3.48 ± 0.92 µm in size. The spores showed symmetrical and smooth valves. The anterior end of the spores contained two equal pyriform polar capsules measuring 2.19 ± 0.47 × 1.59 ± 0.29 µm. Inside the polar capsules, an isofilar polar filament displayed 5-6 coils perpendicular or slightly oblique to the longitudinal axis. The wall of the polar capsule was filled with a hyaline substance contrasting with the very dense internal matrix. The mucus layer surrounded the spore surface. A thorough comparison with the Myxobolus species infecting intestine of fish is provided. This is the first report on occurrence of this myxozoan species in L. ramada population of the North Adriatic Sea.

Effects of Moisture and Particle Size on Quantitative Determination of Total Organic Carbon (TOC) in Soils Using Near-Infrared Spectroscopy.

Near-Infrared Spectroscopy is a cost-effective and environmentally friendly technique that could represent an alternative to conventional soil analysis methods, including total organic carbon (TOC). Soil fertility and quality are usually measured by traditional methods that involve the use of hazardous and strong chemicals. The effects of physical soil characteristics, such as moisture content and particle size, on spectral signals could be of great interest in order to understand and optimize prediction capability and set up a robust and reliable calibration model, with the future perspective of being applied in the field. Spectra of 46 soil samples were collected. Soil samples were divided into three data sets: unprocessed, only dried and dried, ground and sieved, in order to evaluate the effects of moisture and particle size on spectral signals. Both separate and combined normalization methods including standard normal variate (SNV), multiplicative scatter correction (MSC) and normalization by closure (NCL), as well as smoothing using first and second derivatives (DV1 and DV2), were applied to a total of seven cases. Pretreatments for model optimization were designed and compared for each data set. The best combination of pretreatments was achieved by applying SNV and DV2 on partial least squares (PLS) modelling. There were no significant differences between the predictions using the three different data sets (p < 0.05). Finally, a unique database including all three data sets was built to include all the sources of sample variability that were tested and used for final prediction. External validation of TOC was carried out on 16 unknown soil samples to evaluate the predictive ability of the final combined calibration model. Hence, we demonstrate that sample preprocessing has minor influence on the quality of near infrared spectroscopy (NIR) predictions, laying the ground for a direct and fast in situ application of the method. Data can be acquired outside the laboratory since the method is simple and does not need more than a simple band ratio of the spectra.

Temporal and spatial changes in the composition and structure of helminth component communities in European eels Anguilla anguilla in an Adriatic coastal lagoon and some freshwaters in Italy.

The composition and diversity of the helminth component communities in eels Anguilla anguilla were determined in three separate localities in Italy: an Adriatic coastal lagoon, Comacchio and two freshwater localities, the River Po and the Lake Piediluco. Data from Comacchio lagoon were analysed over 15 years to determine whether community composition and diversity changed significantly overtime. The community was species rich (nine species, all marine except Proteocephalus macrocephalus) and was dominated by a suite of digeneans: Deropristis inflata, Helicometra fasciata, Lecithochirium musculus and Bucephalus anguillae. The community showed little change in composition over the period, but the relative abundance and dominance of the species did alter. By contrast, the component communities in the freshwater localities were species poor and the dominant species were freshwater acanthocephalans, Pomphorhyncus laevis in River Po and Acanthocephalus rhinensis in Lake Piediluco. The helminth community of Lake Piediluco with five species was richer than that of the River Po with only three species, but was poorer than that of Comacchio lagoons. Similarity indices between samples from Comacchio were high; between the lagoon and the freshwater localities and between the two freshwater localities, similarity indices were very low. Helminth component community structure in coastal lagoons was comparable across Europe. The helminth community in the River Po was similar to those in the River Tiber and other European rivers whilst that in Lake Piediluco was similar to that in other European lakes. Levels of the pathogenic Anguillicoloides crassus in swim bladders were consistently lower in prevalence and abundance in the coastal lagoons than in freshwater localities. This suggests that this parasite may have little impact on migrating eels if they are indeed primarily of marine origin and so it may be of little importance in the recent decline of eel populations throughout Europe.

Nitrogen budget in a lowland coastal area within the Po River basin (northern Italy): multiple evidences of equilibrium between sources and internal sinks.

Detailed studies on pollutants genesis, path and transformation are needed in agricultural catchments facing coastal areas. Here, loss of nutrients should be minimized in order to protect valuable aquatic ecosystems from eutrophication phenomena. A soil system N budget was calculated for a lowland coastal area, the Po di Volano basin (Po River Delta, Northern Italy), characterized by extremely flat topography and fine soil texture and bordering a network of lagoon ecosystems. Main features of this area are the scarce relevance of livestock farming, the intense agriculture, mainly sustained by chemical fertilizers, and the developed network of artificial canals with long water residence time. Average nitrogen input exceeds output terms by ~60 kg N ha(-1) year(-1), a relatively small amount if compared to sub-basins of the same hydrological system. Analysis of dissolved inorganic nitrogen in groundwater suggests limited vertical loss and no accumulation of this element, while a nitrogen mass balance in surface waters indicates a net and significant removal within the watershed. Our data provide multiple evidences of efficient control of the nitrogen excess in this geographical area and we speculate that denitrification in soil and in the secondary drainage system performs this ecosystemic function. Additionally, the significant difference between nitrogen input and nitrogen output loads associated to the irrigation system, which is fed by the N-rich Po River, suggests that this basin metabolizes part of the nitrogen excess produced upstream. The traditionally absent livestock farming practices and consequent low use of manure as fertilizer pose the risk of excess soil mineralization and progressive loss of denitrification capacity in this area.

Perfluorooctanoic Acid Promotes Recruitment and Exocytosis of Rodlet Cells in the Renal Hematopoietic Tissue of Common Carp.

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous environmental contaminants, with perfluorooctanoic acid (PFOA) being a prominent member. PFOA poses a risk to aquatic ecosystems and human health due to its presence in water, environmental persistence, and bioaccumulation. Since rodlet cells (RCs) have emerged as potential biomarkers for chemical stressors, this study aimed to investigate the effects of sub-chronic PFOA exposure on RCs in the renal hematopoietic tissue of common carp. Three groups of fish were used: an unexposed control group and two groups exposed to environmentally relevant (200 ng L-1) and elevated (2 mg L-1) PFOA concentrations. Light and transmission electron microscopy were employed to assess RCs' distribution patterns and exocytosis, while biometry quantified RCs in the hematopoietic tissue. The results showed that, even at environmentally relevant concentrations, PFOA significantly influenced RCs' distribution patterns, leading to increased occurrence and cluster formation, as well as heightened exocytosis activity. This research highlights PFOA's immunotoxicity in fish and suggests the potential of RCs as sentinel cells in the immunological response to environmental contaminants. These findings enhance our understanding of PFAS toxicity and emphasise the importance of monitoring their impact on fish as representative vertebrates and reliable animal models.

Looking back to move forward: Restoring vegetated canals to meet missing Water Framework Directive goals in agricultural basins.

Nitrate pollution and eutrophication remain pressing issues in Europe regarding the quality of aquatic ecosystems and the safety of drinking water. Achieving water quality goals under the Water Framework Directive (WFD) has proven to be particularly challenging in agricultural catchments, where high nitrate concentrations are the main reason for the failure of many water bodies to meet a good ecological status. Canals and ditches are common man-made features of irrigated and drained landscapes and, when vegetated, have recently been identified as denitrification hotspots. By combining experimental data and GIS-based upscaling estimation, the potential capacity of the canal network to reduce nitrate loads was quantified in several scenarios differing in the level of nitrate pollution and in the extent of the canal network length where conservative management practices are implemented. The analysis was carried out in the irrigated lowlands of the Po River basin, which is the largest hydrographic system in Italy and a global hotspot for nitrogen inputs and eutrophication. Scenario simulations showed that maintaining aquatic vegetation in at least 25 % of the canal network length, selecting sites with high nitrate availability (>2.4 mg N L-1), would promote a greater potential for permanent N removal. The increased denitrification capacity would meet the load reduction target required to achieve a WFD good ecological status in waters draining into the Adriatic Sea during the spring-summer months, when the eutrophication risk is higher. Promoting denitrification in the canal network by postponing the mowing of in-stream vegetation to the end of the growing season could be an effective mitigation strategy to improve water quality in agricultural basins and contribute to achieving the WFD goals.

Spatial variability of the Po River food web and its comparison with the Danube River food web.

Freshwater ecosystems are experiencing unprecedented pressure globally. To address environmental challenges, systematic and comparative studies on ecosystems are needed, though mostly lacking, especially for rivers. Here, we describe the food web of the Po River (as integrated from the white literature and monitoring data), describe the three river sections using network analysis, and compare our results with the previously compiled Danube River food web. The Po River food web was taxonomically aggregated in five consecutive steps (T1-T5) and it was also analyzed using the regular equivalence (REGE) algorithm to identify structurally similar nodes in the most aggregated T5 model. In total, the two river food webs shared 30 nodes. Two network metrics (normalized degree centrality [nDC]) and normalized betweenness centrality [nBC]) were compared using Mann-Whitney tests in the two rivers. On average, the Po River nodes have larger nDC values than in the Danube, meaning that neighboring connections are better mapped. Regarding nBC, there were no significant differences between the two rivers. Finally, based on both centrality indices, Carassius auratus is the most important node in the Po River food web, whereas phytoplankton and detritus are most important in the Danube River. Using network analysis and comparative methods, it is possible to draw attention to important trophic groups and knowledge gaps, which can guide future research. These simple models for the Po River food web can pave the way for more advanced models, supporting quantitative and predictive-as well as more functional-descriptions of ecosystems.

Perfluorooctanoic Acid Affects Thyroid Follicles in Common Carp (Cyprinus carpio).

Carp kidney is comprised of nephrons, hemopoietic tissue, and also hormonally-active thyroid follicles. Given this anatomical trait, it has been used to assess the thyroid disrupting potential of perfluorooctanoic acid (PFOA), a widespread and feared per- poly-fluoroalkyl substance and a persistent organic pollutant capable of interfering with the endocrine system in animals and humans. The occurrence and morphology of thyroid follicles in kidneys of carp experimentally exposed to 200 ng L-1 or 2 mg L-1 waterborne PFOA for 56 days were studied. The abundance of thyroid follicles was significantly higher and vesiculation increased in exposed fish as compared to controls. The number of vesiculated follicles/total number of follicles was positively correlated with PFOA blood concentration in fish exposed to the highest dose (2 mg L-1). The structure and ultrastructure of thyroid follicles were affected by PFOA also at the lower, environmentally relevant, concentration (200 ng L-1). Increased cellular projections, enhanced colloid endocytosis, rough endoplasmic reticulum enlargement and fragmentation and cytoplasm vacuolation were the main features displayed by PFOA-exposed carp. These results show that PFOA affects the occurrence and status of follicles and suggest the utility of fish kidney as a multipurpose biomarker organ in environmental pathology research, according to the One Health approach.

Manila clam and Mediterranean mussel aquaculture is sustainable and a net carbon sink.

Aquaculture is a globally expanding industry that contributes to feeding an increasing global population. Shellfish cultivation is one of the largest sectors of aquaculture and one of the few food productions that have the potential capacity of acting as carbon sink. In fact, >90 % of bivalve shells are calcium carbonate (CaCO3), synthetized during biocalcification process, which incorporates a molecule of CO2. Manila clam (Venerupis philippinarum, Adams & Reeves, 1850) and Mediterranean mussel (Mytilus galloprovincialis, Lamarck, 1819) are two of the major groups of cultivated shellfish. Our aim was to assess the potential role of those two bivalve species in the overall marine carbon balance using an ecosystem approach, and to evaluate if they can be definitely regarded as carbon sink. The contribution to CO2 emissions (as CO2 eq./kg of fresh products) due to mollusk farming has been also calculated as carbon-source term by means of Life Cycle Assessment (LCA). LCA is nowadays the most shared and accepted tool for evaluating the environmental impacts of aquaculture productions. As a case study, the Sacca di Goro coastal lagoon (Northern Adriatic Sea, Italy) has been considered, because it is the premier site in Europe for clam farming, and one of the most important for mussels. Our study has shown that for each kilogram of harvested and packaged clams and mussels, shell formation throughout the mollusk growth allows to permanently capture 254 and 146 g of CO2, in the face of 22 and 55 g CO2 eq. emitted for farming, respectively. As a result, clams and mussel aquaculture could be considered as a carbon sink, with a net carbon capture capacity of 233 and 91 g CO2/kg of fresh product, respectively. In a wider context, bivalve aquaculture could be included in the carbon trading system and played a role towards the carbon-neutral economy.

Species-specific efficiency in PM2.5 removal by urban trees: From leaf measurements to improved modeling estimates.

The growing population in cities is causing a deterioration of air quality due to the emission of pollutants, causing serious health impacts. Trees and urban forests can contribute through the interception and removal of air pollutants such as particulate matter (PM). The dry deposition of PM by vegetation depends on air pollutant concentration, meteorological conditions, and specific leaf traits. Several studies explored the ability of different plant species to accumulate PM on leaf structures leading to the development of models to quantify the PM removal. The i-Tree Eco is the most used model to evaluate ecosystem services provided by urban trees. However, fine particulate matter (PM2.5) removal is still calculated with a poorly evaluated function of deposition velocity (which depends on wind speed and leaf area) without differentiating between tree species. Therefore, we present an improvement of the standard model calculation introducing a leaf trait index to distinguish the species effect on PM net removal. We also compared model results with measurements of deposited leaf PM by vacuum filtration. The index includes the effect of morphological and functional leaf characteristics of tree species using four parameters: leaf water storage, deposition velocity, resuspension rate and leaf washing capacity. Leaves of 11 common urban tree species were sampled in representative areas of the city of Ferrara (Italy) and at different times of the year from 2018 to 2021. This includes four deciduous broadleaf trees (Tilia cordata, Platanus acerifolia, Acer platanoides, Celtis australis), three evergreen broadleaf trees (Quercus ilex, Magnolia grandiflora, Nerium oleander), and four conifers (Thuja orientalis, Cedrus libani, Pinus pinaster, Picea abies). The results provide significant advancement in assessing PM removal using decision support tools such as models to properly select tree species for future urban tree planting programs aimed at improving air quality.

Natural and anthropogenic factors drive large-scale freshwater fish invasions.

We analyzed the large-scale drivers of biological invasions using freshwater fish in a Mediterranean country as a test case, and considering the contribution of single species to the overall invasion pattern. Using Boosted Regression Tree (BRT) models, variation partitioning and Redundancy Analysis (RDA), we found that human factors (especially eutrophication) and climate (especially temperature) were significant drivers of overall invasion. Geography was also relevant in BRT and RDA analysis, both at the overall invasion and the single species level. Only variation partitioning suggested that land use was the second most significant driver group, with considerable overlap between different invasion drivers and only land use and human factors standing out for single effects. There was general accordance both between different analyses, and between invasion outcomes at the overall and the species level, as most invasive species share similar ecological traits and prefer lowland river stretches. Human-mediated eutrophication was the most relevant invasion driver, but the role of geography and climate was at least equally important in explaining freshwater fish invasions. Overall, human factors were less prominent than natural factors in driving the spread and prevalence of invasion, and the species spearheading it.

How does invasion degree shape alpha and beta diversity of freshwater fish at a regional scale?

Freshwater ecosystems appear more vulnerable to biodiversity loss due to several anthropogenic disturbances and freshwater fish are particularly vulnerable to these impacts. We aimed to (1) identify the contribution of land use, spatial variables, and invasion degree in determining freshwater fish alpha (i.e., species richness) and beta (i.e., local contributions to beta diversity, LCBD) diversity, evaluating also the relationship between invasion degree and nestedness ( ß nes) and turnover ( ß sim) components of beta diversity. (2) Investigate the relationship between alpha diversity and LCBD, under the hypothesis that alpha diversity and LCBD correlate negatively and (3) investigate the relationship between species contributions to beta diversity (SCBD) and species occurrence, hypothesizing that non-native species show a lower contribution to beta diversity. The linear mixed models and the partition of R 2 retained the invasion degree as the most important variables explaining alpha and beta diversity, having a positive relationship with both diversity components. Furthermore, land use related to human impacts had a positive influence on alpha diversity, whereas it showed a negative effect on LCBD. Regression model further showed that invasion degree related positively with ß sim, but negatively with ß nes, suggesting that non-native species were involved in the replacement of native species in the fish community. Alpha diversity and LCBD showed a weak positive correlation, meaning that sites with low species richness have higher LCBD. SCBD scaled positively with species occurrence highlighting that rarer species contribute less to SCBD. Finally, native and exotic species contributed similarly to beta diversity. These results suggest that invasion degree plays a central role in shaping alpha and beta diversity in stream fish, more than land use features reflecting habitat alteration or other geospatial variables. Furthermore, it is important to evaluate separately the native and the non-native components of biotic communities to identify linkages between invasion dynamics and biodiversity loss.