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The present study explores the effect of salinity and dissolved organic carbon (DOC) gradients on the stability and reactivity of titanium dioxide nanoparticle (TiO2-NP) agglomerates in ambient water from the Lagoon of Venice and their possible effect on nauplii sampled at the same locations. In all ambient water samples, TiO2-NPs formed rapidly micrometre-sized agglomerates. The increase in the salinity and concomitant decrease in DOC content induced the formation of larger agglomerates, with z-average hydrodynamic diameter increasing with TiO2-NP concentration and exposure duration. Under the studied conditions, ζ-potential exhibited negative values. In line with agglomeration results, enhancement of the salinity and lower DOC resulted in less negative ζ-potential with close to 0 values in the dispersions of 100 mg L−1 TiO2-NPs in sea water. Two-hour exposure to micrometre-sized agglomerates of TiO2-NPs resulted in an increase in the fluorescence of propidium iodide (PI) stained nauplii in comparison with unexposed controls, but had no effect at 24-h exposure. The increase in nauplii-associated PI fluorescence was more noticeable in dispersions containing 100 mg L−1 than those containing 10 mg L−1 TiO2-NPs, suggesting membrane permeability alteration in a concentration-dependent manner. However, the PI staining results have to be interpreted with caution because of the possible dye binding to the nauplii surface without penetration of cellular membrane. The effect of TiO2-NPs on nauplii was more pronounced at higher salinity and decreased with increasing DOC concentrations at 2 h, while no trends were found at 24-h exposure, as well as exposure to 100 mg L−1 TiO2-NPs.

We analyzed the phytoplankton abundance and community structure monthly over a 20-year period (1998–2017) at five stations in the Venice lagoon (VL), one of the sites belonging to the Long-Term Ecological Research network of Italy (LTER-Italy). We focused on phytoplankton seasonal patterns, inter-annual variability and long-term trends in relation to water quality. Diatoms numerically dominated (ca. 60% on average), followed by nanoflagellates (37%), while coccolithophorids and dinoflagellates contributed less than 2%. We observed distinct seasonal and inter-annual changes in the abundance and floristic composition of the phytoplankton groups, whilst no clear long-term trend was statistically significant. We also assessed the water quality changes, applying to our dataset the multimetric phytoplankton index (MPI), recently officially adopted by Italy to accomplish the water framework directive (WFD) requirements. The index evidenced a temporal improvement of the water quality from “moderate” to “good” and allowed us to confirm its reliability to address the changes in the water quality, not only spatially—as previously known—but also for following the yearly time trends. Overall, our results highlight the importance of long-term observations, for understanding the variability in the phytoplankton communities of the lagoon as well as the relevance of their use to test and apply synthetic descriptors of water quality, in compliance with the environmental directives.

Dense waters (DW) formation in shelf areas and their cascading off the shelf break play a major role in ventilating deep waters, thus potentially affecting ecosystem functioning and biogeochemical cycles. However, whether DW flow across shelves may affect the composition and structure of plankton communities down to the seafloor and the particles transport over long distances has not been fully investigated. Following the 2012 north Adriatic Sea cold outbreak, DW masses were intercepted at ca. 460 km south the area of origin and compared to resident ones in term of plankton biomass partitioning (pico to micro size) and phytoplankton species composition. Results indicated a relatively higher contribution of heterotrophs in DW than in deep resident water masses, probably as result of DW-mediated advection of fresh organic matter available to consumers. DWs showed unusual high abundances of Skeletonema sp., a diatom that bloomed in the north Adriatic during DW formation. The Lagrangian numerical model set up on this diatom confirmed that DW flow could be an important mechanism for plankton/particles export to deep waters. We conclude that the predicted climate-induced variability in DW formation events could have the potential to affect the ecosystem functioning of the deeper part of the Mediterranean basin, even at significant distance from generation sites.

The coexistence of phytoplankton and macrophytes in the Lagoon of Venice (Northern Adriatic Sea, Italy) was investigated using in situ data collected monthly as part of International Long Term Ecosystem Research (LTER), together with satellite imagery for the period 1998&ndash, 2017. The concentrations of chlorophyll a and hydrochemical parameters were measured in three areas of the lagoon, where the expansion of well-developed stands of submerged vegetation was observed by remote sensing. Our results suggest interaction between phytoplankton and macrophytes (macroalgae and seagrasses) in the last few years of the time series, evidenced by decreasing chlorophyll a concentrations in the vicinity of the macrophyte stands. The integration of LTER and remotely sensed data made it possible to evaluate the interaction of macrophytes and phytoplankton at the ecosystem scale for the first time in the Lagoon of Venice.

Long-term data series (1971&ndash, 2015) of physical and biogeochemical parameters were analyzed in order to assess trends and variability of oceanographic conditions in the northern Adriatic Sea (NAS), a mid-latitude shallow continental shelf strongly impacted by river discharges, human activities and climate changes. Interpolation maps and statistical models were applied to investigate seasonal and spatial variability, as well as decadal trends of temperature, salinity, chlorophyll-a and nutrients. This analysis shows that sea surface temperature increased by +0.36% year&minus, 1 over four decades. Annual mean flow of the Po River markedly changed due to the occurrence of periods of persistent drought, whereas the frequency of flow rates higher than 3000 m3 s&minus, 1 decreased between 2006 and 2015. Moreover, we observed a long-term decrease in surface phosphate concentrations in Po River water (&minus, 1.34% year&minus, 1) and in seawater (in summer &minus, 2.56% year&minus, 1) coupled, however, to a significant increase in nitrate concentration in seawater (+3.80% year&minus, 1) in almost all seasons. These changes indicate that the nutrient concentrations in the NAS have been largely modulated, in the last forty years, by the evolution of environmental management practices and of the runoff. This implies that further alteration of the marine environment must be expected as a consequence of the climate changes.

Open Science is increasingly pervading scientific communities, since the worth of sharing, beyond the results, research ideas, methods and tools, data and metadata is more and more recognized. Open Science principles applied to data, translate in FAIRness of data: data must be Findable, Accessible, Interoperable and Reusable. We present a case study on the Open Science approach applied to the valorization of a long term dataset, composed of abiotic parameters, phyto- and zooplankton, collected in 50 years (1965 to 2015) in the Northern Adriatic Sea (NAS), one of the Long Term Ecological Research (LTER) sites of the LTER-Italy network. We describe and discuss the different operational parts of the case study that are all connected in defining the "open research project lifecycle". Starting from the data, the lifecycle includes each step of the entire research project, with specific sharing strategies. Two main types of actions were undertaken: (i) on data (e.g. data harmonization, metadatation, repository choice) and (ii) on the whole research process (e.g. publication of research ideas and results, sharing of source code and models, other dissemination actions). The lessons learned through the realization of this case study, in particular the assessment of the strengths and weaknesses of the solutions adopted at each stage of the "project lifecycle", might be usefully generalized and extended also to other types of LTER transitional and marine sites. In particular, this might be the case of the Lagoon of Venice (LoV), another LTER-Italy site adjacent and connected to the NAS, where comparable data have been gathered as well. The more the time series on plankton and related variables are made available, according to the FAIR principles, the more it is possible to reconstruct and compare trends and dynamics, providing precious tools for detecting significant changes in response to global or local pressures and impacts.

In this paper we describe a 50 years (1965–2015) ecological database containing data collected in the Northern Adriatic Sea, one of the 25 research parent sites belonging to the Italian Long Term Ecological Research Network (LTER-Italy, http://www.lteritalia.it). LTER-Italy is a formal member of the international (https://www.ilter.network) and European (http://www.lter-europe.net/) LTER networks. The NAS is undergoing a process, led by different research institutions and projects, for the establishment of a marine ecological observatory, building on the existing facilities, infrastructures, and long-term ecological data. Along this process, the implementation of the Open Access and Open Science principles has started, by creating an open research lifecycle that involves sharing ideas and results (scientific papers), data (raw and processed), metadata, methods, and software. The present data paper is framed within this wider context. The database is composed of observations on abiotic parameters, phyto- and zooplankton abundances, collected during 299 cruises in different sampling stations, in particular in the Gulf of Venice: we describe here the sampling and analytical activities, the parameters, and the structure of the database. The database is available at https://doi.org/10.5281/zenodo.3266246 (Acri et al., 2019), it was also uploaded in the DEIMS-SDR repository (Dynamic Ecological Information Management System – Site and Dataset Registry, https://deims.org/), which is the official sites and data registry for LTER International network.

La presentazione è stata tenuta in occasione del seminario sull'Open Access per le scienze ambientali il 24 maggio all'università Politecnica delle Marche (Ancona) e si focalizza sulle forme alternative di condivisione della ricerca (research ideas paper, data paper, open source code, etc) e sul FAIR data management. Pone l'accento sulle azioni intraprese all'interno del progetto EcoNAOSevidenziandone di volta in volta gli aspetti di interesse ai fini della condivisione.

The Northern Adriatic Sea (NAS) is one of the 25 research parent sites belonging to the Italian Long Term Ecological Research Network (LTER-Italy). The NAS is undergoing a process, led by different research institutions and projects, of the establishment of a marine ecological observatory, building on the existing facilities and on long-term ecological data. This process requires the implementation of the Open Access and Open Science principles, by creating an open research/data lifecycle, which involves sharing results, data, metadata, methods, and software. To this purposes, the Ecological Northern Adriatic Open Science Observation System (EcoNAOS), conceived within the RITMARE Flagship Project, was developed, with the aim to practically apply the Open Science principles to each step of the work for long term marine data valorisation: sharing papers on research ideas and outcomes, code, data and metadata. The database we refer to, recently made openly available on DEIMS-SDR (the metadata and site registry of LTER-International), consists of 50 years (1965-2015) of observations (more than 10 thousand) on abiotic parameters, and phyto- and zoo-plankton abundances. In this presentation, we briefly discuss the actions concerning the whole Open Science process and those required to operate on the NAS database. We then report some significant or innovating experiences, discussing as well strength points and shortcomings encountered. Finally, we point out optimal solutions and we evidence the main obstacles (afforded and/or possible) to achieve them.

High environmental variability is a feature of transitional water ecosystems, which also affects temporal and spatial patterns of phytoplankton. The Lagoon of Venice is characterised by a wide range of environmental conditions, high phytoplankton species diversity and abundance variability. Here we focus on morphological traits and specifically, for the first time in transitional waters, on phytoplankton geometric shape. Our hypothesis is that despite high taxonomic diversity, the prevalent features of the lagoon (shallow, permanently nutrient-enriched, turbulent and light-attenuated) should select a small number of dominant morphological types and adaptive strategies. We tested the hypothesis on a 13-year (1998-2010) phytoplankton data series and related abiotic factors. Seven shapes were found to be dominant and widespread in space and time in the lagoon, with two adaptive strategies: high surface area-to-volume ratio (S/V) together with low greatest axial linear dimension (GALD), and low S/V together with high GALD. Certain morphological traits, which allow a high S/V (from 0.8 to >1), appear quite constant: (i) small size (GALD < 15 ?m), in particular in round-shaped organisms, and (ii) high GALD together with shape attenuation, within the same species or across a range of species. We observed that the lagoon regime selects for the coexistence of competing species with similar morphological traits.

Since 1997, CNR-ISMAR has been collecting monthly hydrochemical and phytoplankton data in the northern and central basins of the Lagoon of Venice. The data have been part of the International Long-Term Ecosystem Research (LTER) database since 2007, helping to fill a gap in lagoon environmental studies. Analysing our time series (1998-2017), we were able to observe a rise in water temperature due to climate trends, a reduction in trophic status mainly due to the lower input of inorganic dissolved nitrogen nutrients and an increase in transparency and dissolved oxygen related to the increased biomass of macrophytes (macroalgae and seagrasses). Finally, a reduction in phytoplankton biomass and an accompanying increase in seagrass and macroalgal cover were observed. Present and future studies will help to evaluate the ways in which the Lagoon of Venice ecosystem responds to anthropogenic pressures and global climate change.

The aim of the present study was to investigate the microbial community along the Ligurian coast corresponding to two marine canyons. The study considered pico-, nano- and micro-planktonic fractions, their abundances and composition. Temperature and salinity profiles along the water column showed the same trend at all stations and no significant difference was found among stations of the canyons’ profiles and those of the adjacent slope. A similar trend for abundances and biomasses was observed at all stations: higher values were generally measured at surface and decreased with increasing depth; significant linear regression was highlighted in each of the three transects. Results of the distribution of all microbial heterotrophs from the surface down to 2500 m indicate that prey abundance was generally higher than the feeding threshold of predators; this evidence suggests that the interaction between different size classes is bottom-up regulated in the study area. The slight decrease of the ratio Heterotrophic Bacteria (HB) vs. Heterotrophic NanoFlagellates (HNF) and the weak increase of relative abundance of larger HNF size classes should be the sole evidence of the expected “canyon effect”, and can be ascribed to the major input at the bottom of the canyon of particulate organic matter (POC) that can be used by heterotrophic nanoflagellates directly as a food source. Our results highlighted that the main pattern regulating community composition is depth, and that, in the aphotic layer, the different water masses (WM) present along the column, play a pivotal role in shaping the planktonic assemblage.

Presentazione in occasione dello workshop "Scienza libera tutti!" organizzato da Successione Ecologica, il 26 Novembre 2018 presso l'Università di Milano Bicocca. Il contributo presenta il progetto EcoNAOS: un esperimento di Open Research Project Lifecycle applicato a dati ecologici marini a lungo termine (LTER) nella zona Nord del Mare Adriatico. Particolare attenzione è posta in questa sede al livello di "openness" di ogni misura di condivisione della ricerca adottata.

The European Water Framework Directive (WFD) requires the national classifications of good ecological status to be harmonised through an intercalibration exercise. In this exercise, significant differences in status classification among Member States are harmonized by comparing and, if necessary, adjusting the good status boundaries of the national assessment methods. Intercalibration is performed for rivers, lakes, coastal and transitional waters, focusing on selected types of water bodies (intercalibration types), anthropogenic pressures and Biological Quality Elements. Intercalibration exercises are carried out in Geographical Intercalibration Groups - larger geographical units including Member States with similar water body types - and followed the procedure described in the WFD Common Implementation Strategy Guidance document on the intercalibration process (European Commission, 2011). The Technical report on the Water Framework Directive intercalibration describes in detail how the intercalibration exercise has been carried out for the water categories and biological quality elements. The Technical report is organized in volumes according to the water category (rivers, lakes, coastal and transitional waters), Biological Quality Element and Geographical Intercalibration group. This volume addresses the intercalibration of the Transitional Waters-Mediterranean Sea phytoplankton ecological assessment methods., JRC.D.2-Water and Marine Resources

Spread of alien species (AS) is a serious threat to marine habitats and analysis of principal descriptors of their occurrence is pivotal to set reliable conservation strategies. 2. In order to assess the susceptibility of marine habitats to biological invasions, a dataset was gathered of the occurrence of 3899 species from 29 phyla, taken from 93 marine sites located along the Italian coast in the period 2000-2012.