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This research investigates the dynamics of contaminant exposure in European hake (Merluccius merluccius, L. 1758) from the Adriatic Sea (Central Mediterranean Sea) by examining the levels of total mercury (THg) and polycyclic aromatic hydrocarbons (PAHs) in the muscle fish tissues. The study explores the correlations between these pollutants and somatic indexes to identify the early warning signals of pollution and ecological effects. The levels of pollutants are influenced by season and sex. Lipids appear to have a minimal effect on the PAH levels, whereas they exhibit a positive correlation with mercury levels in the muscle. No significant relationships between the pollutants and condition indexes were observed, except for a positive correlation between THg and the gonadosomatic index, indicating a potential impact on the reproductive health of fish. In contrast, PAHs showed no meaningful correlation with condition indexes. Differences in contaminant accumulations and lipid levels between sexes reflect variations in metabolic activity, reproductive costs, and adaptive strategies to seasonal changes and energy demands. This study highlights the importance of long-term monitoring to improve pollution management, environmental conservation, and the protection of marine organisms’ health.

Globally positive unbounded solutions, with zero derivative at infinity, are here considered for ordinary differential equations involving the generalized Euclidean mean curvature operator. When p≥2, the results highlight an analogy with an auxiliary equation with the p-Laplacian operator. The results are obtained using some comparison criteria for the principal solutions of a class of associated half-linear equations.

Grape by-products have already been used in cosmetics, food industries, but also animal feed industry, especially monogastrics and in aquaculture. Grape by-products have been studied for a long time and their principal activities are antimicrobial and antioxidant. Concerning aquaculture, the great demand and necessity to replace animal sources with vegetable ones, has placed grape by-products as possible new phytonutrients with beneficial properties. The purpose of this review is to describe the use of grape by-products in aquaculture, during the last decade, concerning their effects on: 1) gut health and welfare status; 2) growth performances; 3) quality of fillets and flesh during the rearing cycle and shelf-life products. Although other studies highlighted that the high supplementation of grape by-products could negatively affect fish health and growth, due to antinutritional factors (tannins), grape by-products are proven to be valuable phytonutrients that can be incorporated into fish feed to enhance growth and health during rearing conditions. Even in fish products, their utilization has proven to elongate the properties and shelf-life of fillets and minces. Further studies to evaluate the possible integrations or replacements with grape by-products in fish feed in order to evaluate their effectiveness in aquaculture from a sustainable circular economy perspective will be desirable to enhance the use of these products.

Seafood constitutes the primary source of exposure to the organic form of mercury in the general population, and the Trieste Gulf is considered a hotspot of mercury contamination. We used a newly developed quantitative food frequency questionnaire to obtain an estimation of the intake of mercury through seafood consumption in a sample of 32 individuals from Trieste. Then, we validated the results obtained from the questionnaire against those of the analysis of total mercury measured in the hair of the same individuals through Spearman rank correlation coefficients, Cohen’s weighted Kappa statistic, and a Bland–Altman plot. The Spearman rank correlation coefficient and Cohen’s weighted Kappa statistic were 0.76 and 0.69, respectively. In the Bland–Altman plot, 93.75% of the data points lay within the acceptability range. The plot revealed an ever-increasing overestimation of mercury intake by the questionnaires as the hair mercury increased. By applying a standardized filtering procedure to the results of the questionnaires, we obtained a Spearman rank correlation coefficient and Cohen’s weighted Kappa statistic of 0.69 and 0.57, respectively. In this Bland–Altman plot, 93.75% of the data points lay within the acceptability range. In this latter plot, the proportionality between the mean difference and the magnitude of the measurement was more subtle compared to that observed in the plot built upon the non-filtered questionnaires. This preliminary study shows the high accuracy of the reported questionnaire in the estimation of habitual mercury intake, similar to the one measured through the analysis of hair.

Low seawater pH impacts trophic dynamics in corals, increasing symbiont density and autotrophic/heterotrophic ratios and varying dinoflagellate haplotypes under ocean acidification.

This Special Issue addresses topics related to the sources of pollutants and their diffusion in ecosystems and aquatic organisms [...]

The paper deals with the coexistence between the oscillatory dynamics and the nonoscillatory one for a generalized super-linear Emden–Fowler differential equation. In particular, the coexistence of infinitely many oscillatory solutions with unbounded positive solutions are proved. The asymptotics of the unbounded positive solutions are described as well.

In the last two decades of the 21st century, a gradual decrease in nitrogen and phosphorus has been observed along the coastal area of the Northern Adriatic Sea. This depletion is attributed to reduced river flows. Studies conducted over the past four decades have indicated that the N/P ratio in the open sea is unlikely to undergo significant change. In fact, it tends to increase due to the unique characteristics of the Northern Adriatic Sea, which experiences slow water turnover and is influenced by strong winds. Additionally, the Northern Adriatic Sea receives a substantial amount of freshwater from rivers, accounting for about one-third of the total freshwater flow into the Mediterranean. These rivers carry nutrient loads that contribute to the high productivity and abundance of fish in this sea, making it one of the most productive areas in the Mediterranean. It has been observed that the cessation of anthropogenic phosphorus input, which has been regulated since the late 1980s with legislation limiting its use in detergents, has significantly affected the trophic chain. The aim of this review is to provide an overview of the eutrophication trend in the Northern Adriatic Sea, highlighting the importance long-term data series.

Mercury (Hg) is a pollutant that has toxic effects on ecosystems and biota. As it biomagnifies in the food chain, its presence in edible fish poses a high risk to human health. Herein, total Hg (THg) content was quantified in 2018–2019 using thermal decomposition amalgamation atomic absorption spectrometry in muscle tissue of red mullet (Mullus barbatus), a commercially important species throughout the Adriatic Sea (Central Mediterranean Sea). Specimens were grouped into 16 pools based on sex, reproductive stages, and sampling area. The overall mean value of THg content was 0.20 ± 0.15 mg kg−1 in terms of wet weight. THg levels in males and females showed no statistically significant differences, whereas specimens that were captured in open sea showed a higher THg content than coastal samples. Statistically significant differences between THg content and the reproductive stages of fish were found in females. However, neither lipid content nor fish length were statistically correlated with THg content. The analyzed specimens were considered to be safe food according to EU directives, but it is necessary to exercise caution and further investigate Italian people in the 0–18 age group, because they were found to be exposed to a higher dose of methylmercury than the safety threshold set by the EFSA.

Climate change is one of the main problems currently strongly conditioning ecosystems all over the world. Coastal lagoons are amongst the most vulnerable habitats, and they are undergoing extensive human impact due to their high production rates and the close proximity of urban and agricultural centers. The Mar Menor, the largest saltwater lagoon in Europe, is an example of a highly impacted ecosystem. In December 2016 and September 2019, climate change-induced DANA (upper-level isolated atmospheric depression) flooding events took place there, temporarily altering the lagoon oceanographic properties. Data gathered throughout the lagoon (11 stations inside and 1 outside the lagoon) from 2016 to 2021 were analyzed in order to assess the variability of seawater parameters: salinity, density, chlorophyll-a, turbidity, and dissolved oxygen, due to DANA events. Results showed a change in seawater parameters that were reestablished at different rates, 4 and 10 months in 2016 and 2019, respectively, following a description of the environmental conditions and effects that have been reported after extreme rainfall in the lagoon. The amount of rainfall correlated with changes in the analyzed seawater parameters, such as an increase in turbidity and chlorophyll-a values. Furthermore, turbidity correlated with chlorophyll-a and oxygen saturation, while density correlated with salinity. Such extreme weather events are worsened by climate change, growing more frequent and between shorter intervals in time. In order to decelerate ecosystem decline, comprehensive management plans are needed to address the various factors that might add to anthropic impacts in natural environments.

Eight research articles and two reviews are included in this Special Issue focused on the transport, persistence, and toxicity of pollutants in different seas: the Western and Central Mediterranean Sea, the Adriatic Sea, the Tyrrhenian Sea, the Baltic Sea, and the South China Sea [...]

The aim of this work was to collect and harmonize the results of several studies achieved over the years, in order to obtain a database of georeferenced observations on polycyclic aromatic hydrocarbons (PAHs) in Western and Central Mediterranean seafood. For each observation, some information on the taxonomy and the ecology of the sampled species are reported, as well as details on the investigated hydrocarbon, and spatial and temporal information on sampling. Moreover, two health risk indexes were calculated for each record and included in the database. Through several statistical methods, we conducted a meta-analysis of the data on some of the species in this database, identifying trends that could be related to the biology of the investigated organisms, as well as to the physico-chemical properties of each hydrocarbon and to the oceanographic characteristic of this part of the Mediterranean. The analysis of the data showed that, at a consumption rate like the one typical of the Italian population, seafood caught from the area considered in the present work seems to pose a minimal risk to health. However, we also found evidence of an increasing trend of PAH concentrations in Mediterranean mussels, pointing to the need for constant monitoring.

Eating seafood has numerous health benefits; however, it constitutes one of the main sources of exposure to several harmful environmental pollutants, both of anthropogenic and natural origin. Among these, methylmercury and polycyclic aromatic hydrocarbons give rise to concerns related to their possible effects on human biology. In the present review, we summarize the results of epidemiological investigations on the genetic component of individual susceptibility to methylmercury and polycyclic aromatic hydrocarbons exposure in humans, and on the effects that these two pollutants have on human epigenetic profiles (DNA methylation). Then, we provide evidence that Mediterranean coastal communities represent an informative case study to investigate the potential impact of methylmercury and polycyclic aromatic hydrocarbons on the human genome and epigenome, since they are characterized by a traditionally high local seafood consumption, and given the characteristics that render the Mediterranean Sea particularly polluted. Finally, we discuss the challenges of a molecular anthropological approach to this topic.

We consider the second order differential equation \[ \bigl(a(t)|x^{\prime}|^{\alpha}\operatorname{sgn\,}x^{\prime}\bigr)^{\prime }+b(t)|x|^{\beta}\operatorname{sgn\,}x=0 \] in the super-linear case $\alpha

We discuss a new integral characterization of principal solutions for half-linear differential equations, introduced in the recent paper of S. Fisnarova and R. Marik, Nonlinear Anal. 74 (2011), 6427-6433. We study this characterization in the framework of the existing results and we show when this new integral characterization with a parameter $\alpha$ is equivalent with two extremal cases of the integral characterization used in the literature. We illustrate our results on the Euler and Riemann-Weber differential equations.

We describe the upper ocean thermal structure and surface nutrient concentrations between New Zealand and Antarctica along five transects that cross the Subantarctic Front, the Polar Front (PF) and the southern Antarctic Circumpolar Current (ACC) front. The surface water thermal structure is coupled with variations in surface nutrient concentrations, making water masses identifiable by both temperature and nutrient ranges. In particular, a strong latitudinal gradient in orthosilicate concentration is centred at the PF. On the earlier sections that extend south-west from the Campbell Plateau, orthosilicate increases sharply southward from 10–15 to 50–55 µmol l−1 between 58° S and 60° S, while surface temperature drops from 7°C to 2°C. Nitrate increases more regularly toward the south, with concentrations ranging from 10–12 µmol l−1 at 54° S to 25–30 µmol l−1 at 66° S. The same features are observed during the later transects between New Zealand and the Ross Sea, but the sharp silica and surface temperature gradients are shifted between 60° S and 64° S. Both temporal and spatial factors may influence the observed variability. The January transect suggests an uptake of silica, orthophosphate and nitrate between 63° S and 70° S over the intervening month, with an average depletion near 37%, 44% and 29%, respectively. An N/P (nitrite + nitrate/orthophosphate) apparent drawdown ratio of 8.8±4.1 and an Si/N (silicic acid/nitrite + nitrate) apparent drawdown ratio >1 suggest this depletion results from a seasonal diatom bloom. A southward movement of the oceanic fronts between New Zealand and the Ross Sea relative to prior measurements is consistent with reports of recent warming and changes in the ACC.

In this paper we deal with the asymptotic problem \begin{equation*} \bigl(a(t)\Phi (x^{\prime })\bigr)^{\prime }+b(t)F(x)=0\,,\quad \lim_{t\rightarrow \infty }x^{\prime }(t)=0\,,\quad x(t)>0\mbox{ for large } t\,.\qquad (\ast ) \end{equation*} Motivated by searching for positive radially symmetric solutions in a fixed exterior domain in ${\mathbb{R}}^{N}$ for partial differential equations involving the curvature operator, the global positiveness and uniqueness of (*) is also considered.

Recessive and dominant solutions for the nonoscillatory half-linear difference equation are investigated. By using a uniqueness result for the zero-convergent solutions satisfying a suitable final condition, we prove that recessive solutions are the “smallest solutions in a neighborhood of infinity,†like in the linear case. Other asymptotic properties of recessive and dominant solutions are treated too.

We study the existence of zero-convergent solutions for the second-order nonlinear difference equation Δ(anΦp(Δxn))=g(n,xn+1), where Φp(u)=|u|p−2u, p>1,{an} is a positive real sequence for n≥1, and g is a positive continuous function on ℕ×(0,u0), 0

There are studied asymptotic properties of solutions of the nonlinear differential equation $L_nx+ p(t)f(x)=0$, where $L_n$ is disconjugate operator, $p$ is of one sign and $f(u)u>0$ for $u\ne 0$. Some comparison theorems in terms of property A and property B between linear and nonlinear equations are also given which generalize known results for $n=3$.

In the noncompact interval $J=[a,infty )$ we consider a linear problem of the form $Lx=y,; x in S$, where $L$ is a first order differential operator, $y$ a locally summable function in $J$, and $S$ a subspace of the Fr'{e}chet space of the locally absolutely continuous functions in $J$. In the general case, the restriction of $L$ to $S$ is not a Fredholm operator. However, we show that, under suitable assumptions, $S$ and $L(S)$ can be regarded as subspaces of two quite natural spaces in such a way that $L$ becomes a Fredholm operator between them. Then, the solvability of the problem will be reduced to the task of finding linear functionals defined in a convenient subspace of $L_{loc}^{1}(J,{mathbb R}^{n})$ whose ``kernel intersection'' coincides with $L(S)$. We will prove that, for a large class of ``boundary sets'' $S$, such functionals can be obtained by reducing the analysis to the case when the function $y$ has compact support. Moreover, by adding a suitable stronger topological assumption on $S$, the functionals can be represented in an integral form. Some examples illustrating our results are given as well.

The performance of empirical band ratio models were evaluated for the estimation of Coloured Dissolved Organic Matter (CDOM) using MODIS ocean colour sensor images and data collected on the North-Central Western Adriatic Sea (Mediterranean Sea). Relationships between in situ measurements (2013–2016) of CDOM absorption coefficients at 355 nm (aCDOM355) with several MODIS satellite band ratios were evaluated on a test data set. The prediction capability of the different linear models was assessed on a validation data set. Based on some statistical diagnostic parameters (R2, APD and RMSE), the best MODIS band ratio performance in retrieving CDOM was obtained by a simple linear model of the transformed dependent variable using the remote sensing reflectance band ratio Rrs(667)/Rrs(488) as the only independent variable. The best-retrieved CDOM algorithm provides very good results for the complex coastal area along the North-Central Western Adriatic Sea where the Po River outflow is the main driving force in CDOM and nutrient circulation, which in winter mostly remains confined to a coastal boundary layer, whereas in summer it spreads to the open sea as well.

Equation with general nonhomogeneous Φ-Laplacian, including classical and singular Φ-Laplacian, is investigated. Necessary and sufficient conditions for the existence of nonoscillatory solutions satisfying certain asymptotic boundary conditions are given and discrepancies between the general and classical Φ are illustrated as well.

We study necessary and sufficient conditions for the oscillation of the third-order nonlinear ordinary differential equation with damping term and deviating argument x‴(t)+q(t)x′(t)+r(t)f(x(φ(t)))=0. Motivated by the work of Kiguradze (1992), the existence and asymptotic properties of nonoscillatory solutions are investigated in case when the differential operator ℒx=x‴+q(t)x′ is oscillatory.

Variability of the oceanographic structure in the Adriaticb Sea and the its relation to climate change: the activity of ISMAR-CNR. Over the last few decades, ISMAR-CNR carried out several oceanographic studies in the Adriatic sea using research vessels, buoys, moored instrumentations and satellite remote sensing for earth exploration and climate change interpretation. The present paper describe the activities of ISMAR-CNR finalized to the answering of key scientific questions and defines the drivers for sea-level rise, eutrophication, hypoxia, and mucilage. In particular, the importance of long term research for spatial and temporal observations of semienclosed marine basins as a key environment for the earth system as a whole is highlited.