An Overview of Antibiotics as Emerging Contaminants: Occurrence in Bivalves as Biomonitoring Organisms

Antibiotics are used for therapeutic and prophylactic purposes in both human and veterinary medicine and as growth promoting agents in farms and aquaculture. They can accumulate in environmental matrices and in the food chain, causing adverse effects in humans and animals including the development of antibiotic resistance. This review aims to update and discuss the available data on antibiotic residues, using bivalves as biomonitoring organisms. The current research indicates that antibiotics’ presence in bivalves has been investigated along European, American and Asian coasts, with the majority of studies reported for the last. Several classes of antibiotics have been detected, with a higher frequency of detection reported for macrolides, sulfonamides and quinolones. The highest concentration was instead reported for tetracyclines in bivalves collected in the North Adriatic Sea. Only oxytetracycline levels detected in this latter site exceeded the maximum residual limit established by the competent authorities. Moreover, the risk that can be derived from bivalve consumption, calculated considering the highest concentrations of antibiotics residues reported in the analyzed studies, is actually negligible. Nevertheless, further supervisions are needed in order to preserve the environment from antibiotic pollution, prevent the development of antimicrobial resistance and reduce the health risk derived from seafood consumption.

Factors Influencing Habitat Selection of Three Cryptobenthic Clingfish Species in the Shallow North Adriatic Sea

Cryptobenthic fishes were often overlooked in the past due to their cryptic lifestyle, so knowledge of their ecology is still incomplete. One of the most poorly studied taxa of fishes in the Mediterranean Sea is clingfish. In this paper we examine the habitat preferences of three clingfish species (Lepadogaster lepadogaster, L. candolii, and Apletodon incognitus) occurring in the Gulf of Trieste (Northern Adriatic). The results show that all three species have a cryptic lifestyle and are well-segregated based on their depth distribution and macro- and microhabitat preferences. L. lepadogaster inhabits shallow waters of the lower mediolittoral and upper infralittoral, where it occurs on rocky bottoms under stones. L. candolii similarly occurs in the rocky infralittoral under stones, but below the lower distribution limit of L. lepadogaster, and in seagrass meadows, where it occupies empty seashells. Such hiding places in seagrass meadows are also occupied by A. incognitus, which mostly occurs below the lower distribution limit of L. candolii. Despite the overlap of depth and macrohabitat, the probability of individuals of two species encountering each other or competing in the same habitat is low when the depth range is combined with the microhabitat preferences of these species.

A robust fuzzy logic-based model for predicting the critical total drawdown in sand production in oil and gas wells

Sand management is essential for enhancing the production in oil and gas reservoirs. The critical total drawdown (CTD) is used as a reliable indicator of the onset of sand production; hence, its accurate prediction is very important. There are many published CTD prediction correlations in literature. However, the accuracy of most of these models is questionable. Therefore, further improvement in CTD prediction is needed for more effective and successful sand control. This article presents a robust and accurate fuzzy logic (FL) model for predicting the CTD. Literature on 23 wells of the North Adriatic Sea was used to develop the model. The used data were split into 70% training sets and 30% testing sets. Trend analysis was conducted to verify that the developed model follows the correct physical behavior trends of the input parameters. Some statistical analyses were performed to check the model’s reliability and accuracy as compared to the published correlations. The results demonstrated that the proposed FL model substantially outperforms the current published correlations and shows higher prediction accuracy. These results were verified using the highest correlation coefficient, the lowest average absolute percent relative error (AAPRE), the lowest maximum error (max. AAPRE), the lowest standard deviation (SD), and the lowest root mean square error (RMSE). Results showed that the lowest AAPRE is 8.6%, whereas the highest correlation coefficient is 0.9947. These values of AAPRE (<10%) indicate that the FL model could predicts the CTD more accurately than other published models (>20% AAPRE). Moreover, further analysis indicated the robustness of the FL model, because it follows the trends of all physical parameters affecting the CTD.

Aspects of Reproductive Biology of the European Hake (Merluccius merluccius) in the Northern and Central Adriatic Sea (GSA 17-Central Mediterranean Sea)

The study focused on the macroscopic, histological, and biometric analysis of European hake females in GSA 17 (Central-North Adriatic Sea). From 2013 to 2015, 976 females were collected and analyzed monthly. Though females in spawning conditions were found during the whole year, the trend of GSI showed a peak of the reproductive season from April to July in 2014 and 2015. HSI and Kn reached the highest values in September, after the spawning peaks. In 2013, the trend of these indices did not highlight an evident peak, probably due to an adverse event that occurred in the previous winter in the Adriatic shelf. The length at first maturity (L50) was estimated by macroscopic and histological approaches, resulting in 30.81 cm for the macroscopical length and 33.73 cm for the histological length; both values are higher than the current catching legal size. For the first time in this area, batch and relative fecundity were estimated. Relative fecundity was similar to the Mediterranean and the Atlantic stocks, whereas batch fecundity values were lower compared to other fishing grounds. Overall, the analysis of reproductive parameters plays a fundamental role in the sustainable management of this resource in an area as overfished as the Central-North Adriatic Sea.

Cost-benefit analysis of coastal flood defence measures in the North Adriatic Sea

The combined effect of global sea level rise and local subsidence phenomena poses a major threat to coastal settlements. Flooding events are expected to grow in frequency and magnitude, increasing the potential economic losses and costs of adaptation. In Italy, a large share of the population and economic activities are located along the coast of the peninsula, although risk of inundation is not uniformly distributed. The low-lying coastal plain of Northeast Italy is the most sensitive to relative sea level changes. Over the last half a century, the entire north-eastern Italian coast has experienced a significant rise in relative sea level, the main component of which was land subsidence. In the forthcoming decades, sea level rise is expected to become the first driver of coastal inundation hazard. We propose an assessment of flood hazard and risk linked with extreme sea level scenarios, both under historical conditions and sea level rise projections at 2050 and 2100. We run a hydrodynamic inundation model on two pilot sites located in the North Adriatic Sea along the Emilia-Romagna coast: Rimini and Cesenatico. Here, we compare alternative risk scenarios accounting for the effect of planned and hypothetical seaside renovation projects against the historical baseline. We apply a flood damage model developed for Italy to estimate the potential economic damage linked to flood scenarios and we calculate the change in expected annual damage according to changes in the relative sea level. Finally, damage reduction benefits are evaluated by means of cost-benefit analysis. Results suggest an overall profitability of the investigated projects over time, with increasing benefits due to increased probability of intense flooding in the next future.

Phenology of Anemonia viridis and Exaiptasia diaphana (Cnidaria: Anthozoa) from marine temperate ecosystems

Population dynamics in lower metazoans are strongly regulated by environmental factors. The running climate crisis could affect regularity of life strategies; therefore, studying life cycles and reproductive patterns of benthic species may provide key information on effects of environmental changes in temperate seas. The North Adriatic Sea is a peculiar basin due to high food availability and high fluctuations of physical parameters. Here, cnidarians are one of the most abundant taxa and sea anemones are the largest representatives. Aim of this study is to assess the life history and the reproductive biology of two potential species models: the sea anemones: Anemonia viridis and Exaiptasia diaphana. The present research is the first quantitative study on the variations in abundance and reproductive biology of the two species. We reported new insights about abundance fluctuations throughout the year and about the gametogenesis of the two sea anemones. In particular, data on spermatogenesis of A. viridis from the Mediterranean Sea were supplied for the first time.

A Virtual Geostationary Ocean Colour Sensor to characterise the river-sea interaction over the North Adriatic Sea.

&lt;p&gt;Inherent optical properties (IOPs) and concentrations of the sea water components are key quantities in supporting the monitoring of the water quality and the study of the ecosystem functioning. In coastal waters, those quantities have a large spatial and temporal variability, due to river discharges and meteo-marine conditions, such as wind, wave and current, and their interaction with shallow water bathymetry. This short term variability can be adequately captured only using Geostationary Ocean Colour (OC) satellites, absent over the European seas.&lt;/p&gt;&lt;p&gt;In this study, to compensate the lack of an OC geostationary sensor over the North Adriatic Sea (NAS), the Virtual Geostationary Ocean Colour Sensor (VGOCS) dataset has been used. VGOCS contains data from several OC polar satellites, making available multiple images a day of the NAS, approaching the temporal resolution of a geostationary sensor.&lt;/p&gt;&lt;p&gt;Generally, data from different satellite sensors are characterized by different uncertainty sources and consequently, looking at two satellite images, it is not easy to ascertain how much of the observed differences are due to real processes. In the VGOCS dataset, the inter-sensor differences are reduced, as the satellite data were adjusted with a multi-linear regression algorithm based on in situ reflectance acquired in the gulf of Venice. Consequently, the use of the adjusted spectra as input in the retrieval of the IOPs and the concentrations allows performing a reliable analysis of the short-time bio-optical variability of the basin.&lt;/p&gt;&lt;p&gt;In this work, we demonstrate the suitability of VGOCS to better characterise the river-sea interaction and to understand the influence of the river forcing on the short time variability of IOPs and concentrations in the coastal areas. This variability will be analysed for different case studies characterised by a different regime of river discharges, using meteorological, hydrological, and oceanographic fields as ancillary variables. This new approach and the availability of this new set of data represent an opportunity for interdisciplinary studies, in support to and interacting also with modelling implementations in river-sea areas.&lt;/p&gt;