Po River Delta Research Articles

Evolution of wetlands in the northern part of the Po Delta: The experience of unmanaged realignments

AbstractIt is increasingly recognised that nature‐based solutions in coastal ecosystems provide significant services compared to hard engineering measures. Several restoration projects are now being conducted worldwide to protect coastlines against flood risk and improve the ecosystems' quality. In the case of river deltas, managed realignment through levee breaching is becoming a recognised strategy for coastal wetland restoration. This study focusses on the formation of new wetlands in the Po River Delta after several natural dyke failures that occurred during the last century, when a large part of the land was abandoned and became wetlands. An historical review was performed to quantify the variation of the marsh extent in time developed after natural levee breaching in the easternmost lagoons of the delta and to understand the processes that determined their evolution. The analyses were based on orthophotos from the 1950s to the present‐day integrated with tidal records, water and sediment discharge records, and GPS survey for vegetation distribution. The review indicated that, between the 1950s and 1980s, anthropisation and natural processes caused a strong decline in marsh extent, thus leading to the recent shape of the lagoons. Several breaches and inlets were developed because of a combination of human intervention and erosive processes, and new tidal systems were born. Three main depositional areas connecting the main river branches were identified in three separated lagoons of the delta. These lagoons presented a ‘crevasse splay’ type of deposition which allowed the development of new tidal flats and, in certain cases, of large freshwater marsh systems within less than 8 years after the breach. The newly formed wetland systems (>100 ha) demonstrate the ability of the Po River Delta to build new wetlands, also during periods of human‐induced sediment starvation and high rates of subsidence, suggesting that further levee breaching should be exploited to favour marsh recovery.

Gone with the Clam Multispecies Arrangements and Feral Rhythms in the Goro Lagoon (Po River Delta)

The Goro Lagoon, located at the southern edge of the Po River Delta, is considered a major European site for clam farming. Following the advent of the Manila Clam ‘revolution’ in the 1980s, the local community transitioned from traditional fishing to a mono-focalised ecological infrastructure focused on aquaculture. However, in the last decade, anthropogenic climate alterations have severely impacted the lagoon and its industrial system, triggering a series of accelerated proliferations of macroalgae and non-indigenous species – the Atlantic Blue Crab being the most prominent one. The article investigates the eco-cultural entanglement of the Goro Lagoon and critically explores the multispecies correspondences that excited its biosocial becoming. Thus, the concept of ‘arrangement’ is employed to question both local representations of clam farming and the feral disturbances endangering its feasibility. Finally, ethical and political implications are discussed in light of the cultural expectations of controllability embedded in the technocratic administration of the lagoon.

Low variability of authigenic 10Be/9Be across the Holocene Po plain parasequences reveals suitability of dating method for highstand deltaic deposits

The authigenic 10Be/9Be dating method presents a valuable tool for reconstructing depositional chronologies in sedimentary environments, requiring only ubiquitous mud for sampling. Nevertheless, studies elucidating the variability of the 10Be/9Be record preserved in epicontinental successions are lacking, despite the essential nature of such knowledge for the application of authigenic 10Be/9Be in geochronology. In this study, we investigate the variability of measured natural 10Be/9Be ratios in sediment cores recovered from the Holocene Po River delta plain in Northern Italy, aiming to unveil the influence of changing sedimentary environments and provenance on the beryllium isotopic signature. We identified significant variations in the authigenic 10Be/9Be ratios across parasequences, which correlates with a provenance change from the Eastern Alps to the Po River. The observed variation would cause an age offset of ∼1 Myr if unrecognized in a dated succession. Our analysis revealed consistent ratios between the delta plain (primarily represented by swamp) and delta front consisting of proximal prodelta facies, suggesting a prevalent riverine signature in the proximal prodelta, likely maintained by hyperpycnal flow deposition. Statistical assessments based on random sampling and bootstrapping highlighted the importance of a sample size of n > 10. Furthermore, a standard deviation of the observed variability indicates a necessity of an additional 9% uncertainty in authigenic 10Be/9Be dating studies if the sample size is smaller. Overall, our findings emphasize that the normal regressive highstand settings of a deltaic system maintain relatively stable beryllium isotopic fluxes, which are favourable for the authigenic 10Be/9Be dating application, if provenance changes are known.

Spatio-temporal patterns of whiting (Merlangius merlangus) in the Adriatic Sea under environmental forcing.

Understanding how environmental factors affect species distribution is crucial for the conservation and management of marine organisms, especially in the face of global changes. Whiting (Merlangius merlangus) is a demersal cold-temperate fish, considered a 'relict species' in the Adriatic Sea. Despite its significance to commercial fisheries in the region, the specific drivers behind its spatial and temporal patterns have not been thoroughly examined. Here, we fitted a set of Generalized Linear Mixed Effects Models to data collected in the Northern and Central Adriatic from 1999 to 2019 during the Mediterranean International Trawl Survey to investigate the potential influence of depth, seafloor temperature and seafloor dissolved oxygen on the annual biomass density and spatial distribution of whiting in the spring-summer season. Our results showed that depth, and to a lesser degree temperature and oxygen, are important predictors of whiting distribution in this period, with preferences for depths of ~ 45 m, temperature of ~ 15.4°C and dissolved oxygen > 5.5 ml L-1. We predicted a persistent core area of distribution in front of the Po River Delta, in the Northern Adriatic Sea, while the density progressively declined towards the Central and Southern Adriatic Sea along the Italian coast. Additionally, the temporal trend exhibited high fluctuations over the years, occurring in cycles of 3 to 4 years. Finally, by comparing the biomass density estimates obtained under optimal conditions with those derived from the actual values for each variable, our analysis revealed that temperature had a pronounced and general impact on biomass density in the northern survey area (predictions revealed a density reduction of approximately two-thirds), while oxygen displayed a minor and more localized influence. This work deepens the current knowledge about the ecology of whiting in the Adriatic Sea and provides support for the conservation and management of this species.

Anthropogenic vs. natural habitats: Higher microbial biodiversity pays the trade-off of lower connectivity

Climate change and anthropogenic disturbances are known to influence soil biodiversity. The objectives of this study were to compare the community composition, species coexistence patterns, and ecological assembly processes of soil microbial communities in a paired setting featuring a natural and an anthropogenic ecosystem facing each other at identical climatic, pedological, and vegetational conditions. A transect gradient from forest to seashore allowed for sampling across different habitats within both sites. The field survey was carried out at two adjacent strips of land within the Po River delta lagoon system (Veneto, Italy) one of which is protected within a natural preserve and the other has been converted for decades into a tourist resort. The anthropogenic pressure interestingly led to an increase in the α-diversity of soil microbes but was accompanied by a reduction in β-diversity. The community assembly mechanisms of microbial communities differentiate in natural and anthropic ecosystems: for bacteria, in natural ecosystems deterministic variables and homogeneous selection play a main role (51.92%), while stochastic dispersal limitation (52.15%) is critical in anthropized ecosystems; for fungi, stochastic dispersal limitation increases from 38.1% to 66.09% passing from natural to anthropized ecosystems. We are on calcareous sandy soils and in more natural ecosystems a variation of topsoil pH favors the deterministic selection of bacterial communities, while a divergence of K availability favors stochastic selection. In more anthropized ecosystems, the deterministic variable selection is influenced by the values of SOC. Microbial networks in the natural system exhibited higher numbers of nodes and network edges, as well as higher averages of path length, weighted degree, clustering coefficient, and density than its equivalent sites in the more anthropically impacted environment. The latter on the other hand presented a stronger modularity. Although the influence of stochastic processes increases in anthropized habitats, niche-based selection also proves to impose constraints on communities. Overall, the functionality of the relationships between groups of microorganisms co-existing in communities appeared more relevant to the concept of functional biodiversity in comparison to the plain number of their different taxa. Fewer but functionally more organized lineages displayed traits underscoring a better use of the resources than higher absolute numbers of taxa when those are not equally interconnected in their habitat exploitation. However, considering that network complexity can have important implications for microbial stability and ecosystem multifunctionality, the extinction of complex ecological interactions in anthropogenic habitats may impair important ecosystem services that soils provide us.

The stone artifacts of the National Archaeological Museum of Adria (Rovigo, Italy): a noteworthy example of heterogeneity

This paper reports on the results of the analyses of 56 stone samples from Roman and pre-Roman artifacts from the ancient town of Atria, currently preserved at the National Archaeological Museum of Adria. The city is located in the eastern Veneto lowlands, close to the Po River delta, and far from the main rock outcrops of the region. The objective of this research is to determine the provenance of the stones used in ancient Atria and their trade networks. The analytical techniques adopted include polarized-light optical microscopy (PLM), X-ray fluorescence (XRF), and quantitative phase analysis by X-ray powder diffraction (QPA-XRPD). The results reveal a widespread use of imported stones from the central-western territories of Veneto, primarily comprising trachyte from the Euganean Hills and the soft limestone Vicenza Stone from the Berici Hills/eastern Lessini Mounts. Rosso Ammonitico, Maiolica (Biancone) and Scaglia Rossa limestones are also documented. From neighbouring regions, the imported stone types include Aurisina limestone from the Trieste Karst and Istrian Stone. Sandstone was uniquely recognized in G. Popillius’s milestone. Moreover, advanced geochemical and mineralogical analyses performed on the Euganean trachytes allow tracking accurately the quarry sites, revealing an extensive exploitation of the main historical quarries of M. Oliveto, Monselice and M. Merlo, although some provenances from outcrops less systematically exploited were also detected. Notably, the use of rhyolite for manufacturing a pre-Roman gravestone provides new insights regarding the exploitation of Euganean stone resources before the Roman era.

High-Resolution Real-Time Coastline Detection Using GNSS RTK, Optical, and Thermal SfM Photogrammetric Data in the Po River Delta, Italy

High-resolution coastline detection and monitoring are challenging on a global scale, especially in flat areas where natural events, sea level rise, and anthropic activities constantly modify the coastal environment. While the coastline related to the 0-level contour line can be extracted from accurate Digital Terrain Models (DTMs), the detection of the real-time, instantaneous coastline, especially at low tide, is a challenge that warrants further study and evaluation. In order to investigate an efficient combination of methods that allows to contribute to the knowledge in this field, this work uses topographic total station measurements, Global Navigation Satellite System Real-Time Kinematic (GNSS RTK) technique, and the Structure from Motion (SfM) approach (using a low-cost drone equipped with optical and thermal cameras). All the data were acquired at the beginning of 2022 and refer to the areas of Boccasette and Barricata, in the Po River Delta (Northeastern of Italy). The real-time coastline obtained from the GNSS data was validated using the topographic total station measurements; the correspondent polylines obtained from the photogrammetric data (using both automatic extraction and manual restitutions by visual inspection of orhophotos) were compared with the GNSS data to evaluate the performances of the different techniques. The results provided good agreement between the real-time coastlines obtained from different approaches. However, using the optical images, the accuracy was strictly connected with the radiometric changes in the photos and using thermal images, both manual and automatic polylines provided differences in the order of 1–2 m. Multi-temporal comparison of the 0-level coastline with those obtained from a LiDAR survey performed in 2018 provided the detection of the erosion and accretion areas in the period 2018–2022. The investigation on the two case studies showed a better accuracy of the GNSS RTK method in the real-time coastline detection. It can be considered as reliable ground-truth reference for the evaluation of the photogrammetric coastlines. While GNSS RTK proved to be more productive and efficient, optical and thermal SfM provided better results in terms of morphological completeness of the data.

Saltwater intrusion in the Po River Delta (Italy) during drought conditions: Analyzing its spatio-temporal evolution and potential impact on agriculture

Saltwater intrusion along rivers is a complex process controlled by multiple factors and thus fluctuates with a highly nonlinear nature and time-varying characteristics. It is challenging to monitor saltwater intrusion. The objective of this study was to clarify the spatial-temporal variation of saltwater intrusion and its potential impact on agriculture in the Po River Delta (Italy). 2006 was the most severe year of saltwater intrusion in the period we considered. 2022 was even worse, but the data are still under processing. In this study, the Hilbert-Huang transform (HHT) and rescaled range (R/S) were used to identify the multi-time scales and change trends of the salinity and discharge in 2006. After that, the time-dependent intrinsic correlation (TDIC) was used to depict intrinsic relationships between salinity and discharge at different time scales. The results showed that discharge and salinity exhibited behaviours of positive long-range correlation during different periods. The temporal series of salinity and discharge was decomposed into six intrinsic mode functions (IMF) and residuals based on the ensemble empirical mode decomposition (EEMD). The sum of variance contribution rates of IMF1 (4 days), IMF2 (10 days), and IMF3 (12.1 days) of salinity was more than 75%. All measured TDICs have highlighted strong correlations between salinity and discharge. Furthermore, we used spatial interpolation techniques to map salinity data along rivers. This allowed the investigation of dynamic changes in saltwater intrusion patterns during periods of severe drought. Outcomes show a significant negative correlation between salinity and normalized difference vegetation index (NDVI), indicating that the study area's agricultural greening was affected by saltwater intrusion.

Drought-Induced Salinity Intrusion Affects Nitrogen Removal in a Deltaic Ecosystem (Po River Delta, Northern Italy)

In the summer of 2022, the Po River Delta (Northern Italy), a eutrophication hotspot, was severely affected by high temperatures, exceptional lack of rainfall and saline water intrusion. The effect of saline intrusion on benthic nitrogen dynamics, and in particular the N removal capacity, was investigated during extreme drought conditions. Laboratory incubations of intact sediment cores were used to determine denitrification and DNRA rates at three sites along a salinity gradient in the Po di Goro, an arm of the Po River Delta. Denitrification was found to be the main process responsible for nitrate reduction in freshwater and slightly saline sites, whereas DNRA predominated in the most saline site, highlighting a switch in N cycling between removal and recycling. These results provide evidence that salinity is a key factor in regulating benthic N metabolism in transitional environments. In a climate change scenario, salinity intrusion, resulting from long periods of low river discharge, may become an unrecognized driver of coastal eutrophication by promoting the dissimilatory nitrate reduction to ammonium and N recycling of bioactive nitrogen within the ecosystem, rather than its permanent removal by denitrification.

Satellite tracking identifies important foraging areas for loggerhead turtles frequenting the Adriatic Sea, Central Mediterranean

The Adriatic Sea is one of the main foraging areas for marine turtles of the Mediterranean Sea, but the specific high-use sites are poorly known, due to the scarceness of satellite tracking data available for juvenile turtles frequenting the area. In the present study, we tracked 8 juvenile and adult loggerhead turtles (Caretta caretta) that were released along the north-western Adriatic coast after a rehabilitation period having been equipped with Argos-linked satellite transmitters. Tracked turtles displayed quite variable movement patterns, but mostly remained in the north-western Adriatic, especially during the summer months. A marked preference for specific coastal sites was revealed in many turtles, that actively moved towards these specific locations when released south of it or having spent the winter away. Pooling these data with those obtained in previous studies on a further 10 turtles, we highlighted the presence of two main high-use areas, north and south of the Po River delta, where future conservation actions may then be focused.

Shelf slope, estuarine dynamics and river plumes in a z* vertical coordinate, unstructured grid model

The finite element, unstructured grid model SHYFEM has been used to carry out some fundamental studies on the quality of a specific type of Generalized Vertical Coordinate (GVC) system, the so-called z∗ coordinates versus z−geopotential coordinates. Idealized and realistic test cases are shown to assess the impact of the vertical coordinates on key physical processes, i.e. the internal tide generation at a continental slope, a river plume shape and intensity and the salt water intrusion.The results showed that the z∗ coordinates produce a stronger water column stratification than the z−geopotential ones and together with the unstructured grid modeling they can better solve the coastal sea dynamics.An idealized twin experiment configuration of the model was carried out to verify the proper implementation of the GVC z∗ by simulating the production of internal tides at the continental slope. The results confirmed that the z∗ coordinate model reproduces the expected internal tide fields better than z−geopotential model. A set of realistic experiments in the Po river delta coastal region, demonstrated that the representation of the dynamical processes at the coastal scales is conditioned by the high resolution (25 cm layers), which was only possible by the z∗ formulation in the upper water column.

Dissolved fluxes of nutrients and carbon at the sediment-water interface in the Adriatic Sea: review of early data and methods from the Italian National Research Council (CNR)

We report the measurement of the Fluxes of Dissolved Compounds at the Sediment-Water Interface (DFSWIs), obtained by analyzing data collected in the Italian Exclusive Economic Zone (EEZ) of the Northern and Central Adriatic Sea from 1982. We also describe the methods, honed by Italy’s Consiglio Nazionale delle Ricerche (CNR), employed to measure and calculate DFSWIs, including benthic chambers and landers, sediment-water interface micro-profiling, on-board incubation, and pore water modeling. Data analysis demonstrated that in situ measurements are the most reliable approaches, but that on-board collected data also supply interesting results. The DFSWI data allowed to divide the Adriatic seafloor into areas with similar DFSWI types and intensities and to define the role of sediments as sources or sinks of chemicals such as nutrients, Dissolved Inorganic Carbon (DIC), and metals. DFSWIs mainly depend on dissolved and solid river inputs, Marine Organic Matter (mOM) production, and sediment reworking. They show a seasonal temperature-related trend, which in summer induces increased chemical reaction kinetics and microbial activity. DFSWIs decline from the Po River mouths southward, along the Holocene mud wedge. North of the Po River Delta, the DFSWIs are weaker and confined to the areas in front of the major river mouths, due to poor Organic Matter (OM) inputs and strong reworking of bottom sediments. The area south of the Po Delta cusp is characterized by strong DFSWIs, due to the high deposition of solid inputs from the Po River, strong primary production, and protection from the Western Adriatic Current and Bora storms; in summer, higher temperatures, and calm hydrodynamic conditions generate near-bottom hypoxic to anoxic environments in this area. In Northern and Central Adriatic offshore areas, negative DIC and phosphate fluxes are due to poorly reactive OM reaching this area and to the mainly carbonate composition and oxic environment of local bottom sediments. DFSWI data analysis highlighted the important contribution of sediments to marine carbon and nutrient cycles. This is particularly important for carbon, which plays a major role in seawater acidification and global climate change. The study also provides average DFSWI data for each diagenetic area, which allow calculating the carbon and nutrient budgets in the Adriatic Sea.

A Predictive Model for the Bioaccumulation of Okadaic Acid in Mytilus galloprovincialis Farmed in the Northern Adriatic Sea: A Tool to Reduce Product Losses and Improve Mussel Farming Sustainability

Over the last decades, harmful dinoflagellate (Dinophysis spp.) blooms have increased in frequency, duration, and severity in the Mediterranean Sea. Farmed bivalves, by ingesting large amounts of phytoplankton, can become unsafe for human consumption due to the bioaccumulation of okadaic acid (OA), causing Diarrhetic Shellfish Poisoning (DSP). Whenever the OA concentration in shellfish farmed in a specific area exceeds the established legal limit (160 μg·kg−1 of OA equivalents), harvesting activities are compulsorily suspended. This study aimed at developing a machine learning (ML) predictive model for OA bioaccumulation in Mediterranean mussels (Mytilus galloprovincialis) farmed in the coastal area off the Po River Delta (Veneto, Italy), based on oceanographic data measured through remote sensing and data deriving from the monitoring activities performed by official veterinarian authorities to verify the bioaccumulation of OA in the shellfish production sites. LightGBM was used as an ML algorithm. The results of the classification algorithm on the test set showed an accuracy of 82%. Further analyses showed that false negatives were mainly associated with relatively low levels of toxins (<100 μg·kg−1), since the algorithm tended to classify low concentrations of OA as negative samples, while true positives had higher mean values of toxins (139 μg·kg−1). The results of the model could be used to build up an online early warning system made available to shellfish farmers of the study area, aimed at increasing the economic and environmental sustainability of these production activities and reducing the risk of massive product losses.

Climate change-induced aridity is affecting agriculture in Northeast Italy

CONTEXTThe Mediterranean basin and specifically Northeast Italy are recognised as climate change hotspots. The latter is a key socio-economic area in Europe among the most agriculturally productive. However, increasingly frequent drought periods (typical of drier climates) are threatening agriculture. An extreme event occurred in the summer of 2022. It dramatically affected northern Italy, through high temperatures, water shortages and indirect processes (such as saltwater intrusion in the Po River Delta). OBJECTIVEThe objective is to map and quantify the agricultural areas in Northeast Italy at risk of climate zone shift due to human-induced climate change, providing a comprehensive overview of the main threatened agricultural systems and supporting the use of projections through historical data analysis. METHODSWe compared the distribution of current (1980 > 2016) and future (2071 > 2100; RCP8.5 scenario) climate zones for 8 main agricultural systems in 14 key provinces in Northeast Italy. Further analyses were performed on historical data to support future climate projections and to analyse agricultural drought during extreme events: (1) a multi-temporal Aridity Index (AI) to investigate aridification dynamics; (2) a focus on the 2022 event (drought and temperature extremes, a situation that is likely to occur more often in the future), combining a Vegetation Health Index (VHI) with a zonal investigation of high Land Surface Temperature (LST); (3) a climate focus for the Po River Delta cultural landscape. RESULTS AND CONCLUSIONSThe results show that the climate in Northeast Italy is evolving towards drier conditions, posing a challenge to agriculture. The Adriatic coast could become an Arid zone, a finding in line with historical observations. Rice fields will be most at risk (76% of their surface could become Arid in the future), as well as the irrigated lands that are essential for food security (around 20% expected in the Arid zone). Worthy is what is foreseen for crops on slopes (often not irrigated), which may experience drier summers (60% of the surface). SIGNIFICANCEWe identified the areas at risk of climate change at the farm scale in Northeast Italy, mapping where the threatened fields are located, what their extent is, and which agricultural systems are currently implemented. Such information would facilitate early action, guiding large-scale planning towards more resilient agriculture. Findings could promote sustainable water management plans, open the debate on which crops are worth growing based on future climate, and inspire more localised studies in the design of mitigation measures.

Effects of Organic Enrichment on Bioturbation Attributes: How Does the Macrofauna Community Respond in Two Different Sedimentary Impacted Areas?

We assessed the influence of different organic matter (OM) inputs associated with terrigenous/freshwater allochthonous and sewage derive on bioturbation and irrigation potential community indices (BPc and IPc) of the soft-bottom macrofauna community. The macrofauna was sampled from two different sedimentary impacted areas, in front of the Po River Delta (northern Adriatic Sea) and sewage discharge diffusion zone (Gulf of Trieste). The highest values of BPc and IPc were observed at the northward sampling stations of the prodelta and the stations 25 m distance in front of the main sewage outfall. Species richness showed high values in the prodelta likely due to the OM positive effect from the delta, and it increased with increasing distance from the pipeline due to the effect of OM from the sewage discharge. The bioturbation indices differed due to the presence of surface deposit feeders and the injection depth (from 2 to 5 cm) with limited movement at the station located northwards in the prodelta and 25 m distance in the diffusion zone. We infer that the difference in bioturbation indices was likely due to the effects of grain-size composition and the degree of organic enrichment in both study areas.

Integrating payment for ecosystem services in protected areas governance: The case of the Po Delta Park

The effective inclusion of Ecosystem Services (ES) in the governance of Protected Areas (PAs) is a key challenge for future environmental governance. In this sense, Payments for Ecosystem Services (PES) have been conceived as instruments to internalize costs of environmental management and establish a consequential link between ES users and providers. Thus, while there is a current pressingly need for genuine PES mechanisms, in very rare cases it has been possible to satisfy this requirement. This paves the way for the study of alternative methods, such as PES-like schemes, which may be already in practice in PAs.In order to support and discuss the feasibility of this approach, we present four successful PES-like schemes currently working in the Po River delta Park of the Emilia-Romagna region (Northern Italy). They involve traditional activities, as hunting, fishing, mushroom and truffle (M&T) picking and cultural services, coherent with the UNESCO Man and Biosphere declaration.With the aim of using the peculiar case of the Po Delta Park as a study model, we studied services with direct market value that cover a variety of strategy cases and positive side effects typically observed in genuine PES schemes. The Park authority is a crucial actor with different roles: i) regulator/intermediator in the context of a “command” strategy (for hunting and M&T) and in a public–private partnership (for cultural services) and ii) provider in a trade context (for fishing).Although not originally conceived under the vision of an ES approach, these practices, developed as endogenous processes, were effective in supporting conservation and ES provision. While not accounting for regulating services, PES-like schemes constitute practical evidence of broad interest concerning the role of existing, yet overlooked, mechanisms involving important ES, which could be reframed within the terminology of PES to strengthen their functioning and strategic value.

Understanding through drone image analysis the interactions between geomorphology, vegetation and marine debris along a sandy spit

Marine litter (ML) is recognized as one of the main socio-economic and environmental concerns and monitoring operations have been realized worldwide in order to collect information on the types, quantities and distribution of marine debris. In this study, we used Unmanned Aerial Vehicle (UAV) images to map the presence of ML on a coastal spit in relation to geomorphological aspects and vegetation. Our results show that ML is present everywhere, but concentrates in the beach wrack, dunes, and saltmarshes, highlighting the role of the vegetation in trapping ML. Moreover, ML will most probably remain trapped by the saltmarsh vegetation, since they are not visible and easily accessible to allow cleaning operations. On the contrary, cleaning operations may remove the ML present in the beach wrack. Finally, our results provide useful information to support decision-makers for improving beach cleaning activities in the Po river Delta areas (Italy).

An Integrated InSAR and GNSS Approach to Monitor Land Subsidence in the Po River Delta (Italy)

Land subsidence affects many areas of the world, posing a serious threat to human structures and infrastructures. It can be effectively monitored using ground-based and remote sensing techniques, such as the Global Navigation Satellite System (GNSS) and Interferometric Synthetic Aperture Radar (InSAR). GNSS provides high precision measurements, but in a limited number of points, and is time-consuming, while InSAR allows one to obtain a very large number of measurement points, but only in areas characterized by a high and constant reflectivity of the signal. The aim of this work is to propose an approach to combine the two techniques, overcoming the limits of each of them. The approach was applied in the Po River Delta (PRD), an area located in Northern Italy and historically affected by land subsidence. Ground-based GNSS data from three continuous stations (CGNSS) and 46 non-permanent sites (NPS) measured in 2016, 2018, and 2020, and Sentinel-1 and COSMO-SkyMed SAR data acquired from 2016 to 2020, were considered. In the first phase of the method, InSAR processing was calibrated and verified through CGNSS measurements; subsequently, the calibrated interferometric data were used to validate the GNSS measurements of the NPS. In the second phase, the datasets were integrated to provide an efficient monitoring system, extracting high-resolution deformation maps. The results showed a good agreement between the different sources of data, a high correlation between the displacement rate and the age of the emerged surfaces composed of unconsolidated fine sediments, and high land subsidence rates along the coastal area (up to 16–18 mm/year), where the most recent deposits outcrop. The proposed approach makes it possible to overcome the disadvantages of each technique by providing more complete and detailed information for a better understanding of the ongoing phenomenon.

Isotope Geochemistry for Seafood Traceability and Authentication: The Northern Adriatic Manila Clams Case Study.

In Italy, the production of manila clams (Ruditapes philippinarum, Adams and Reeve, 1850) is mainly localized in northern Adriatic lagoons in the Po River delta, where shellfish farming provides important socio-economic revenue. However, in our globalized world, the seafood market is threated by fraudulent activities, in which agri-food products whose provenance is not certified are sold, posing a risk to consumer health. Multi-isotope ratio analysis is commonly used to trace the provenance of goods produced in different countries with different climatic and environmental conditions. Here, we investigated the reliability of this approach in terms of tracing the exact provenance of manila clams harvested in three Adriatic northern lagoons that are close to each other. We also verified the origin of samples bought at a local supermarket with a certificate of provenance. We carried out elemental analyses of carbon (C), nitrogen (N), and sulfur (S) and the respective isotopic ratios (13C/12C; 15N/14N; 34S/32S) on manila clam tissues, plus isotopic analyses of carbon (13C/12C), oxygen (18O/16O), and strontium (87Sr/86Sr) on manila clam shells. Each isotopic parameter can be used to identify the marine and continental contributions of water and/or nutrient supplies occurring in the lagoons. Therefore, the combination of isotopic parameters in a linear discriminant analysis (LDA) allowed for the identification of the lagoons in which the manila clams were produced.

Single breath nitrogen test as predictor of lung function decline and COPD over an 8-year follow-up

BackgroundThe single breath nitrogen (SBN2) test was proposed for early detection of “small airways disease” in the seventies. Few longitudinal studies have subsequently evaluated the relationships between SBN2 test measurements and lung function decline or COPD incidence. AimThis study evaluates whether SBN2 test abnormalities may be significant predictors of lung function decline and COPD incidence over an 8-year follow-up. Study Design and MethodsIn this longitudinal study, 907 adults (20+ years old; 56% males) from the prospective Po River Delta epidemiological study underwent SBN2 test at baseline and spirometry testing at both baseline and follow-up 8-year apart. Multinomial and multiple regression models were used to assess associations of SBN2 indexes and rates of FEV1 decline or risk of COPD incidence over time, after adjusting for sex, height and baseline age, FEV1 and smoking status. COPD was defined according to either GOLD or ATS-ERS criteria. ResultsAmong SBN2 indexes, only the slope of alveolar plateau (N2-slope) was significantly associated with rates of FEV1 decline (7.93 mL/year for a one-unit change in N2-slope, p<0.0001), and with an increased risk of developing COPD as defined by GOLD (RR 1.81, 95%CI 1.29-2.52, mild; RR 2.78, 95%CI 1.70-4.53, moderate or severe obstruction) and ATS-ERS criteria (RR 1.62, 95%CI 1.14-2.29, mild; RR 3.40, 95%CI 1.72-6.73, moderate or severe obstruction). ConclusionIn this population-based study, N2-slope from SBN2 test is a significant predictor of lung function decline and COPD incidence over an 8-year follow-up, confirming the role of the “small airways disease” in the natural history of COPD.