Animal Forest Mortality: Following the Consequences of a Gorgonian Coral Loss on a Mediterranean Coralligenous Assemblage

In this work, the consequences of a local gorgonian coral mortality on the whole coralligenous assemblage were studied. A Before/After-Control/Impact sampling design was used: the structure of the coralligenous assemblage was compared before and after the gorgonian mortality event at the mortality site and two control sites. At the mortality site, a relevant decrease in alpha and beta diversity occurred, with a shift from a stratified assemblage characterized by gorgonians and other invertebrates to an assemblage dominated by algal turfs; conversely, neither significant variations of the structure nor decrease in biodiversity were observed at the control sites. The assemblage shift involved the main taxa in different times: in autumn 2018, a large proportion of the plexaurid coral Paramuricea clavata died, but no significant changes were observed in the structure of the remaining assemblage. Then, in autumn 2019, algal turfs increased significantly and, one year later, the abundance of the gorgonian Eunicella cavolini and bryozoans collapsed. Although the mechanisms of the assemblage shift following gorgonian loss will remain uncertain and a cause-effect relationship cannot be derived, results suggest the need for detecting signs of gorgonian forests stress in monitoring programs, which should be considered early indicators of their condition. in the coralligenous monitoring programs for detecting any sign of gorgonian forests stress which should be considered an early indicator of the assemblage condition

Multiple non-species-specific pathogens possibly triggered the mass mortality in Pinna nobilis

The fan mussel, Pinna nobilis, represents the largest bivalve endemic to the Mediterranean Sea. Since 2016, dramatic mass mortality of this species has been observed in several areas. The first surveys suggested that Haplosporidium pinnae (currently considered species-specific) was the main etiological agent, but recent studies have indicated that a multifactorial disease may be responsible for this phenomenon. In this study, we performed molecular diagnostic analyses on P. nobilis, P. rudis, and bivalve heterologous host species from the island of Sardinia to shed further light on the pathogens involved in the mass mortality. The results support the occurrence of a multifactorial disease and that Mycobacterium spp. and H. pinnae are not necessarily associated with the illness. Indeed, our analyses revealed that H. pinnae is not species-specific for P. nobilis, as it was present in other bivalves at least three years before the mass mortality began, and species of Mycobacterium were also found in healthy individuals of P. nobilis and P. rudis. We also detected the species Rhodococcus erythropolis, representing the first report in fan mussels of a bacterium other than Mycobacterium spp. and Vibrio spp. These results depict a complicated scenario, further demonstrating how the P. nobilis mass mortality event is far from being fully understoo

Multiple indices on different habitats and descriptors provide consistent assessments of environmental quality in a marine protected area

In the last decades, climate change and human pressures have increasingly and dramatically impacted the ocean worldwide, calling for urgent actions to safeguard coastal marine ecosystems. The European Commission, in particular, has set ambitious targets for member states with two major directives, the Water Framework Directive (WFD) and the Marine Strategy Framework Directive (MSFD), both designed to protect the marine environment in EU waters. Diverse biotic indices have accordingly been developed to assess water and habitat quality. The WFD adopts four Biological Quality Elements (BQEs), whereas the MSFD recommends a set of eleven qualitative descriptors. The borderline between water quality and habitat quality is hard to trace and so far most assessments have involved the use of a few indices and were mainly related to a single BQE or qualitative descriptor. In this study, thanks to the availability of a large dataset encompassing a wide array of descriptors, we compared the performance of 11 biotic indices relative to three habitats/biotic components (reefs, seagrass, and fish) of the Marine Protected Area (MPA) of Capo Carbonara (SE Sardinia, Italy). The aim was to assess whether the indices were consistent in defining the environmental status in the MPA investigated. We used the graphical approach RESQUE (REsilience and QUality of Ecosystem), which enabled us to obtain a single and comprehensive measure of the status of the environment by integrating several metrics. This approach was applied here to different habitats for the first time. All indices were consistent with each other in confirming the good status of Capo Carbonara MPA. The use of RESQUE provided insights to interpret the differences between water quality, defined according to the WFD, and habitat quality, defined according to the MSFD. Differences between the two EU directives, in terms of either requirements or goals, have long been discussed but the present study highlights for the first time that they are congruent in their assessment of the environmental status of marine ecosystems

Acute Delta Hepatitis in Italy spanning three decades (1991–2019): Evidence for the effectiveness of the hepatitis B vaccination campaign

Updated incidence data of acute Delta virus hepatitis (HDV) are lacking worldwide. Our aim was to evaluate incidence of and risk factors for acute HDV in Italy after the introduction of the compulsory vaccination against hepatitis B virus (HBV) in 1991. Data were obtained from the National Surveillance System of acute viral hepatitis (SEIEVA). Independent predictors of HDV were assessed by logistic-regression analysis. The incidence of acute HDV per 1-million population declined from 3.2 cases in 1987 to 0.04 in 2019, parallel to that of acute HBV per 100,000 from 10.0 to 0.39 cases during the same period. The median age of cases increased from 27 years in the decade 1991-1999 to 44 years in the decade 2010-2019 (p < .001). Over the same period, the male/female ratio decreased from 3.8 to 2.1, the proportion of coinfections increased from 55% to 75% (p = .003) and that of HBsAg positive acute hepatitis tested for by IgM anti-HDV linearly decreased from 50.1% to 34.1% (p < .001). People born abroad accounted for 24.6% of cases in 2004-2010 and 32.1% in 2011-2019. In the period 2010-2019, risky sexual behaviour (O.R. 4.2; 95%CI: 1.4-12.8) was the sole independent predictor of acute HDV; conversely intravenous drug use was no longer associated (O.R. 1.25; 95%CI: 0.15-10.22) with this. In conclusion, HBV vaccination was an effective measure to control acute HDV. Intravenous drug use is no longer an efficient mode of HDV spread. Testing for IgM-anti HDV is a grey area requiring alert. Acute HDV in foreigners should be monitored in the years to come

High strain rate behaviour in tension of steel B500A reinforcing bar

In reinforced concrete structures under severe dynamic loading, as impact and blast, both concrete and reinforcing bars are subjected to high strain-rates. While the dynamic tensile behaviour of concrete is the subject of many researches, the behaviour of the reinforcing steel under high strain rate has been not completely considered yet. Such behaviour is of capital importance in the structural assessment under the abovementioned loading conditions. This is the reason why an experimental program on rebar, stirrup and wire steels under high strain rate in tension is running at the DynaMat Laboratory. In this study the effect of high strain rate on the mechanical properties of B500A steel reinforcing bars in tension has been analysed. The steel of three different bars having diameter of 6, 8 and 10mm have been investigated. The experiments have been carried out by means of a Split Hopkinson Tensile Bar at 250, 500 and 1000s−1. Finally the parameters of the well-known Johnson-Cook and Cowper-Symonds materials models have been obtained

Experimental investigation on the response of UHP(FR)C at high stress-rates under compression

Understanding the dynamic response of Ultra-High Performance Fibre-Reinforced Concrete has important implications for engineering applications, including protective structures and critical infrastructures. It is wellknown that the loading rate affects both material failure mechanism and mechanical properties such as strengths and absorbed energy. Moreover, materials properties are influenced by stress confinement, which usually occurs in a real structure. The aim of this preliminary experimental campaign was to analyse the behaviour of the dynamic response of UHPFRC and its matrix under compression considering a pre-compression state of 56.5 MPa (about 1/3 of the failure stress). Compression at high stress rate (1.5 TPa/s) were carried out on cylindrical specimens with diameter of 30mm and three different heights of 30, 45 and 60 mm, respectively. An increment of strength and fracture time has been observed while increasing of the length of the specimen and a slight reduction of both quantities with the introduction of fibres for the longer specimens. The experimental results are analysed and discussed with the aim to better understand the mechanical behaviour of UHPFRC materials in case of dynamic event under service loading conditions and to study the size-effect on the material response

Biodegradation of polycyclic aromatic hydrocarbons by pleurotus sajor-caju

Polycyclic aromatic hydrocarbons (PAHs) are considered priority pollutants because they have potentially dangerous effects on the environment and human health. Bioremediation has recently become attractive to restore polluted sites, because it is not expensive and fulfils the most important properties required by the current regulations. In this work the capability of a white-rot fungi, Pleurotus sajor-caju, was assessed for degradation of pyrene and chrysene. The main objective was to investigate the effects of pollutant concentration on the mycelium growth and find the conditions that can enhance the microorganism tolerance when exposed to pyrene and chrysene. The tests carried out in Petri dishes showed that chrysene inhibited mycelium growth, whereas pyrene was well tolerated. Experiments in liquid medium evidenced that the mycelium was able to degrade pyrene with a removal efficienty greater than 90%

Dynamic behaviour of an earthen material under different impact loading conditions

The dynamic behaviour of earthen materials reinforced with natural fibres is little studied although earth buildings are often built in seismic areas. In this paper the dynamic behaviour of an earthen material reinforced with hemp fibres under different impact loadings has been experimentally investigated. The dynamic response of the material in 3-point bending was investigated through an instrumented dropweight device, while the response in tension and in compression was investigated through a modified Hopkinson bar device. Typical impact response curves for tension, compression and bending impact tests have been obtained. The favourable effect of fibres in dissipating fracture energy under impact loads has been observed in all these types of test

Dynamic behaviour of an earthen material under different impact loading conditions

The dynamic behaviour of earthen materials reinforced with natural fibres is little studied although earth buildings are often built in seismic areas. In this paper the dynamic behaviour of an earthen material reinforced with hemp fibres under different impact loadings has been experimentally investigated. The dynamic response of the material in 3-point bending was investigated through an instrumented dropweight device, while the response in tension and in compression was investigated through a modified Hopkinson bar device. Typical impact response curves for tension, compression and bending impact tests have been obtained. The favourable effect of fibres in dissipating fracture energy under impact loads has been observed in all these types of test