Assessing glyphosate in water, marine particulate matter, and sediments in the Lagoon of Venice

Lagoon water, suspended particulate matter, and sediment samples from seven sites at Lagoon of Venice were collected from 2019 to 2021 in order to study the presence of the herbicide glyphosate (N-(phosphonomethyl)glycine), among the most widely used agricultural chemicals worldwide, but its occurrence in lagoon water environment has not been deeply investigated. The sites were selected considering a supposed diversity of inputs and of pollution levels. An analytical method based on ion chromatography coupled with tandem mass spectrometry was optimized and validated for lagoon water, marine particulate matter, and sediment samples. Maximum concentrations of glyphosate were 260 and 7 ng L−1 for lagoon water and suspended particulate matter, respectively, and 15 ng g−1 for sediment, with some spatial and temporal fluctuations. Our results demonstrate that glyphosate content in the Venice Lagoon mainly depends on external forcing from river inlets and agricultural lagoon activities.

Potential Disruptive Effects of Copper-Based Antifouling Paints On The Biodiversity of Coastal Macrofouling Communities

In recent years, after the ban on tributyltin (TBT)-based antifouling paints, copper-based paints have become the main coatings for boat hulls due to their efficiency and endurance. Copper(I) compounds like Cu2O and CuSCN are used alone or in combination with booster biocides, i.e. Irgarol 1051, chlorothalonil and dichlofluanid. The expanded use of these paints has increased copper leaching into coastal environments, requiring attention and legislative restrictions for potential long-term effects on benthic populations. This study monitored the ecological succession of macrofouling communities on wooden and stainless steel panels immersed for 10 months in the southern basin of the Lagoon of Venice. The development of macrofouling communities on the panels coated with copper-containing antifouling paints was compared with those on the reference (uncoated) and TBT-coated panels. Series of biodiversity descriptors highlighted the preventing activity of the antifouling paints. The most active paints were those containing booster biocides and with self-polishing copolymers in the matrix. The macrofouling communities appeared dissimilar to those on the reference uncoated panels as regards the species richness, the coverage areas, and the biocoenosis structure. Generally, green algae, bryozoans and barnacles were the most tolerant taxa and a negative species selection occurred for sponges, serpulids and ascidians.

First confirmed breeding of an invasive alien species in the lagoon of Venice (Italy): the Sacred Ibis Threskiornis aethiopicus

After more than a decade of regular occurrence, the first confirmed breeding of the Sacred Ibis Threskiornis aethiopicus in the lagoon of Venice (Italy) was observed in 2020, in three sites. The ibises nested in colonies with of one or more species of Ardeidae and Phalacrocoracidae. The colonies were on islets < 2 ha in size, covered with thick vegetation. Nests were placed on the top of bushes or trees, at a height of 1.5-5 m. The colony sites seemed not occupied by adults until the end of February - half of March; laying took place from early May, with hatchings occurring from the end of that month until July. Overall, 22-24 pairs nested in 2020. Birds were observed feeding at saltmarshes, freshwater wetlands and arable fields; a public garbage collection site was also used regularly. Given the high number of suitable nesting and feeding sites, a rapid growth of the Sacred Ibis population is expected in the next years.

A multi-observer approach to promote the conservation of north Adriatic marine biogenic habitats

&lt;p&gt;Environments along the ocean-land continuum strictly interlink to each other both in horizontal and in vertical. Most of the acting processes require investigation through a multi looking observation approach, integrating coastal oceanography, hydrogeology and marine ecology. This can be achieved by simultaneously looking from different perspectives at the same environmental context and processes. &lt;br&gt;The present study focuses on the northern Adriatic Sea, where a number of peculiar, diverse and valuable coastal and marine ecosystems are localized, characterized by high biodiversity and productivity, such as the Lagoon of Venice and the underwater biogenic-geogenic rocky outcrops named &lt;em&gt;tegn&amp;#249;e&lt;/em&gt;. Their structural complexity and habitat heterogeneity is increased by the role of habitat forming species, bioconstructors and biodemolitors. To understand the ecological and morphogenetic role of these organisms, selected biogenic formations and habitats, such as the fan mussel &lt;em&gt;Pinna nobilis&lt;/em&gt; colonies on both the Lagoon of Venice and the rocky outcrops, were investigated. Innovative approaches are here presented to map and characterize these biogenic habitats at different hierarchical levels, in order to promote their conservation.&lt;/p&gt;

Model-driven optimization of coastal sea observatories through data assimilation in a finite element hydrodynamic model (SHYFEM v. 7_5_65)

Monitoring networks aims at capturing the spatial and temporal variability of one or several environmental variables in a specific environment. The optimal placement of sensors in an ocean or coastal observatory should maximize the amount of collected information and minimize the development and operational costs for the whole monitoring network. In this study, the problem of the design and optimization of ocean monitoring networks is tackled throughout the implementation of data assimilation techniques in the Shallow water HYdrodynamic Finite Element Model (SHYFEM). Two data assimilation methods – nudging and ensemble square root filter – have been applied and tested in the Lagoon of Venice (Italy), where an extensive water level monitoring network exists. A total of 29 tide gauge stations were available, and the assimilation of the observations results in an improvement of the performance of the SHYFEM model, which went from an initial root mean square error (RMSE) on the water level of 5.8 cm to a final value of about 2.1 and 3.2 cm for each of the two data assimilation methods. In the monitoring network optimization procedure, by excluding just one tide gauge at a time and always the station that contributes less to the improvement of the RMSE, a minimum number of tide gauges can be found that still allow for a successful description of the water level variability. Both data assimilation methods allow identifying the number of stations and their distribution that correctly represent the state variable in the investigated system. However, the more advanced ensemble square root filter has the benefit of keeping a physically and mass-conservative solution of the governing equations, which results in a better reproduction of the hydrodynamics over the whole system. In the case of the Lagoon of Venice, we found that, with the help of a process-based and observation-driven numerical model, two-thirds of the monitoring network can be dismissed. In this way, if some of the stations must be decommissioned due to a lack of funding, an a priori choice can be made, and the importance of a single monitoring site can be evaluated. The developed procedure may also be applied to the continuous monitoring of other ocean variables, like sea temperature and salinity.

BENEDETTO CASTELLI’S CONSIDERATIONS ON THE LAGOON OF VENICE: MATHEMATICAL EXPERTISE AND HYDROGEOMORPHOLOGICAL TRANSFORMATIONS IN SEVENTEENTH-CENTURY VENICE

ABSTRACT This paper deals with the geoenvironmental politics of early-modern Venice as a case study of geological agency that enlightens the entanglements of geo-history and human history. It focuses on a controversy that was sparked by Galileo’s pupil Benedetto Castelli, as he claimed that his mathematical treatment of running waters could solve all of the most urgent problems linked to the management of the Lagoon of Venice. From an epistemological viewpoint, the controversy is relevant as a case of clashing ‘styles of thought’, as it constituted a disciplinary conflict that pitted Galileian physico-mathematical abstraction (which resulted from the isolation of a set of quantifiable data) against ‘geological’ concreteness (a form of comprehensive knowledge which aimed to cope with systemic complexity). Castelli was not able to convince the Venetian authorities that his method could solve the main problems relative to the conservation of the lagoon at a time when its depth and navigability were worryingly diminishing. While the Venetian authorities invested in diverting rivers away from the lagoon to reduce sediment supply, Castelli argued, to the contrary, that it was precisely the diversion of the rivers that caused shoaling because of the loss of the great quantity of water discharged by the rivers, which he accurately calculated. His analytical approach was dismissive of the comprehensive knowledge and complex methods that Venetian water experts and engineers had developed towards a systemic understanding of the hydrogeology and the environment of the lagoon with the active involvement of citizens and fishermen in the assessment of the state of the waters.

Diversity and Dynamics of Seaweed Associated Microbial Communities Inhabiting the Lagoon of Venice

Seaweeds are a group of essential photosynthetic organisms that harbor a rich diversity of associated microbial communities with substantial functions related to host health and defense. Environmental and anthropogenic stressors may disrupt the microbial communities and their metabolic activity, leading to host physiological alterations that negatively affect seaweeds’ performance and survival. Here, the bacterial communities associated with one of the most common seaweed, Ulva laetevirens Areshough, were sampled over a year at three sites of the lagoon of Venice affected by different environmental and anthropogenic stressors. Bacterial communities were characterized through Illumina sequencing of the V4 hypervariable region of 16S rRNA genes. The study demonstrated that the seaweed associated bacterial communities at sites impacted by environmental stressors were host-specific and differed significantly from the less affected site. Furthermore, these communities were significantly distinct from those of the surrounding seawater. The bacterial communities’ composition was significantly correlated with environmental parameters (nutrient concentrations, dissolved oxygen saturation, and pH) across sites. This study showed that several more abundant bacteria on U. laetevirens at stressed sites belonged to taxa related to the host response to the stressors. Overall, environmental parameters and anthropogenic stressors were shown to substantially affect seaweed associated bacterial communities, which reflect the host response to environmental variations.

Phytoplankton–Macrophyte Interaction in the Lagoon of Venice (Northern Adriatic Sea, Italy)

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 1998–2017. 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.