Resilience assessment in complex natural systems.

Ecological resilience is the capability of an ecosystem to maintain the same structure and function and avoid crossing catastrophic tipping points (i.e. undergoing irreversible regime shifts). While fundamental for management, concrete ways to estimate and interpret resilience in real ecosystems are still lacking. Here, we develop an empirical approach to estimate resilience based on the stochastic cusp model derived from catastrophe theory. The cusp model models tipping points derived from a cusp bifurcation. We extend cusp in order to identify the presence of stable and unstable states in complex natural systems. Our Cusp Resilience Assessment (CUSPRA) has three characteristics: (i) it provides estimates on how likely a system is to cross a tipping point (in the form of a cusp bifurcation) characterized by hysteresis, (ii) it assesses resilience in relation to multiple external drivers and (iii) it produces straightforward results for ecosystem-based management. We validate our approach using simulated data and demonstrate its application using empirical time series of an Atlantic cod population and marine ecosystems in the North Sea and the Mediterranean Sea. We show that Cusp Resilience Assessment is a powerful method to empirically estimate resilience in support of a sustainable management of our constantly adapting ecosystems under global climate change.

Living under natural conditions of ocean acidification entails energy expenditure and oxidative stress in a mussel species.

We investigated the health conditions of the Mediterranean mussel Mytilus galloprovincialis recruited in the CO2 vents system of Castello Aragonese at Ischia Island (Mediterranean Sea). Individuals of M. galloprovincialis were sampled in three sites along the pH gradient (8.10, 7.7 and up to <7.4). Untargeted metabolomics and biochemical endpoints related to energetic metabolism, oxidative stress/damage, neurotoxicity and immune defense were analyzed. Corrosion of the valves occurred at low pH. A separation of the metabolome was observed along the pH gradient. Metabolites belonging to amino acids, nucleosides, lipids and organic osmolytes were significantly reduced in the organisms from the most acidified sites. The content of reactive oxygen species and the activity of glutathione peroxidase were reduced in organisms from the acidified sites compared to ambient pH, and no oxidative damage was induced. Overall results suggested the presence of an energy cost underpinning long-term survival in acidified conditions for this species.

Assessing the economic value of Posidonia oceanica (L.) at Tremiti Islands (Mediterranean Sea): An ecosystem condition-based approach.

In the context of limiting global warming, the seagrass Posidonia oceanica (L.) gained the centrality of several international climate change mitigation projects being the most effective carbon storage sink among Mediterranean seagrasses. To assess and monitor the change of environmental conditions and economic values of natural resources, the present study moves from the insights of the System of Environmental-Economic Accounting - Ecosystem Accounting to assess the economic value of the carbon sequestration and storage capacity of the Mediterranean-endemic seagrass P. oceanica at the Tremiti Islands Marine Protected Area. The economic value is compared across: i. the reference study by Pergent-Martini et al.; ii. the ecological condition-based approach; and iii. the unit value transfer. Based on the obtained outcomes, an ecosystem-based approach would prevent biases in the accounting of the ecosystem-service provision capacity of P. oceanica and help the policy maker to implement adequate public investment policies to mitigate its overall degradation.

Distribution, ecological, and health risk assessment of trace elements in the surface seawater along the littoral of Tangier Bay (Southwestern Mediterranean Sea).

In the current study, an environmental assessment of surface seawater in Tangier Bay was conducted by analyzing physicochemical parameters and trace elements, such as As, Cr, Zn, Cd, Pb, and Cu. The results showed mean concentrations (µg/l) of 22.50 for As, 0.46 for Cr, 8.57 for Zn, 15.41 for Cd, 0.23 for Pb, and 1.83 for Cu. While most trace elements met the guidelines, elevated levels of Cd raised concerns about long-term exposure. Pollution indices, including the contamination factor, degree of contamination, and water quality index, indicate the impact of human activities, dividing sites into arsenic-cadmium contamination, wastewater influence, and low pollution levels. Statistical methods, such as ANOVA, revealed no significant differences in trace element levels across the bay. PCA and HCA revealed that Cr, Cu, and Zn originated from common anthropogenic sources, whereas Pb and Cd originated from distinct sources. As indicates that natural geological processes influence its origin.

Assessment of Ecosystem Services Provided by Macrophytes in Southern Baltic and Southern Mediterranean Coastal Lagoons.

The ecological importance of macrophytes is well known and reflected in nature protection law, for example, as a key biological quality element. However, the socio-economic role, such as the impact of macrophyte presence on recreational activities, is often overlooked. The purpose of this study was to assess the human benefits (or ecosystem services) provided by macrophytes. We developed a list of 25 macrophyte ecosystem services and 79 assessment indicators based on expert knowledge and literature data. First, hypothetical scenarios of coastal lagoons were developed to assess the impact of different ecological states (i.e., macrophyte coverage) and management measures (i.e., fisheries) on the ecosystem service provision. Scenario assessments were carried out by stakeholder workshops and literature search. Second, the ecosystem service potential of submerged and emergent macrophyte habitats were assessed by macrophyte experts and literature data. Results showed that cultural services are most important in terms of the overall actual provision of ecosystem services (scenario assessment) but also showing highest potential of the hypothetical ecosystem service provision (habitat assessment). Highest overall potential is shown for reeds and tall forb communities (83 out of maximum 125), followed by seagrass beds (71) and seaweed communities (61). Our ecosystem service assessment approaches (i.e., scenario and habitat-based) using socio-cultural data (i.e., stakeholders and experts-based) and biophysical data (i.e., indicators-based) can serve as supportive tools for coastal management and policy implementation visualizing the benefits of macrophytes to humans.

Paraffin waxes in the North-Western Mediterranean Sea: A comprehensive assessment in the Pelagos Sanctuary, a Specially Protected Area of Mediterranean Importance.

Paraffin waxes are widely recognized as emerging marine pollutants, even their classification by the recent monitoring programs and the knowledge of their occurrence, and sources of contamination in marine ecosystems are poorly defined and reported. Wax presence and distribution have been evaluated in different environmental compartments in the Pelagos Sanctuary (Mediterranean Sea) floating on the sea surface and stranded on beaches, focussing on their characterization, accumulation areas and pollution inputs. More than 2500 yellow paraffin residues were detected and analysed in the study area showing a prevailing dimension smaller than 5 mm. The Genoa Canyon and the waters facing Gorgona Island resulted in the more polluted areas representing two distinct hotspots of wax accumulation potentially related to the high density of tanker vessels sailing to and from the harbour of Genova and Livorno. Higher concentrations of beached particles were found along the Tuscan coast (11 items/100 m) and on Pianosa Island (110 items/m2). This study gives valuable insights into paraffin wax pollution in the Pelagos Sanctuary, emphasizing the need for harmonized monitoring and detection methods to elucidate the potential impacts on marine organisms. Moreover, mitigating actions are crucial to prevent and curb the waxes pollution of marine ecosystems.

Towards a sustainable fisher-dolphin coexistence: Understanding depredation, assessing economic damage and evaluating management options.

Finding solutions for a sustainable coexistence between wildlife and humans is considered among the most challenging environmental management issues for scientists, conservationists, managers, and stockholders world-wide. Depredation by the common bottlenose dolphin (Tursiops truncatus) on small scale fisheries has increased in the recent years, leading to a growing conflict in many areas of the Mediterranean Sea and pressing for urgent management solutions. This study aims at developing a management framework for a sustainable coexistence between fishers and dolphins in Sardinia (Mediterranean Sea). Relying on the combination of different approaches (field study, literature review and Multi Criteria Decision Analysis), the scientific evidence necessary for understanding dolphin depredation were updated and improved, the related economic damage was calculated, and different management options were identified and evaluated by several stakeholder groups to support the decision-making process. Averaging for all investigated net types (gillnet and trammel net), a depredation frequency of 53% was found, the highest values ever found in both Sardinia and many other Mediterranean sites. Depredation probability was influenced by different factors, such as net type, fishing operation duration, depth of the fishing site and period. The estimated economic damage due to depredation ranges on average between 6492 and 11,925 euro per year and depends on the type of fishing net. The results from the field study, the literature review and the stakeholder involvement allowed us to define the most plausible and shared management options, identifying a framework for assessing and managing the conflict between fishers and dolphins for the creation of a more sustainable vision for the future.

Assessment of interactive acoustic deterrent devices set on trammel nets to reduce dolphin-fishery interactions in the Northern Tyrrhenian Sea.

Dolphin-fishery interaction is a worldwide issue affecting dolphins through bycatch and fishers through catch or gear damages. Concerning the Mediterranean Sea, problematic interactions mainly occur between common bottlenose dolphin and small-scale fisheries. Acoustic Deterrent Devices such as pingers, are one of the most widespread measures used in attempts to face this issue. Therefore, the efficiency of interactive pingers (DiD01) in protecting the trammel nets from dolphin interactions was assessed in the Northern Tyrrhenian Sea. From March to October 2021, a total of 139 fishing trials using nets with pingers (TEST) and without pingers (CTRL), respectively n = 97 and n = 42, were carried out. Non-parametric statistic of the Catch per Unit Effort, comparing control and test nets, was not significantly different (p > 0.05) using catches weights (CPUEW) while it was significant (p < 0.01) considering the number of individuals (CPUEN). Moreover, richness and relative abundance of species resulted statistically higher in test nets (p < 0.05). This finding suggests that the absence of dolphin in the neighbourhood of fishing areas thanks to the use of pingers increases the diversity of target species. Catch damages caused by dolphins were statistically higher in nets without pinger than in nets with pinger (p < 0.05). No dolphin bycatch was recorded during fishing operations.

Trace metals and macrominerals in common seaweeds in the Marchica (a restored lagoon, Mediterranean Sea): Nutritional value and health risk assessment.

This study investigated the contents of macrominerals (Na, K, Ca, Mg and P) and essential trace metals (Fe, Mn, Cu, Zn and Se) in four species of seaweeds (Gracilaria sp., Alsidium corallinum, Caulerpa prolifera, and Chaetomorpha sp.) from Marchica Lagoon. The contents of macrominerals with mean values (% dw) can be sequenced in this descending order, [Ca > Mg > Na > K > P] for Caulerpa prolifera, and the decreasing sequence [K > Ca > Mg > P > Na] for Chaetomorpha sp. In red seaweeds, Gracilaria sp. and Alsidiumcorallinum followed these orders: [K > Ca > Na > Mg > P] and [K > Na > Ca > Mg > P] respectively. The essential trace metals mean values (mg kg-1) followed the decreasing order [Fe > Mn > Zn > Cu > Se] for Alsidiumcorallinum, Chaetomorpha sp. and Gracilaria sp., and the following order [Fe > Mn > Zn > Se > Cu] for Caulerpa prolifera. Based on the calculated recommended dietary allowance (RDA), targeted hazard quotient (THQ) and the hazard index (HI), the studied seaweeds did not pose any health risk for human consumption.

Radiation risk assessment of coastal biota from a quasi-Fukushima hypothetical accident in the Mediterranean Sea.

The occurrence of the February 6, 2023, earthquake in Turkey was the idea of this research to define a Fukushima-like accident scenario in the Akkuyu nuclear reactor and investigate its radiation effects on the coastal organisms of the Mediterranean Sea. The concentration rate (CR), activity concentration in organisms, internal dose, external dose, and total dose rate were estimated using the ERICA Tool from 137Cs, 134Cs and 131I radionuclides. The minimum and maximum radiocesium CR were calculated at 0.063 Bq kg-1 fresh weight (f.w)/Bq kg-1 soil and 4.042 Bq kg-1 (f.w)/Bq kg-1 soil dry weight (d.w). Where this value for 131I ranged from 0.005 to 0.295 Bq kg-1 (f.w)/Bq kg-1 soil. For mammals-large and arthropods, we calculated the significant internal and external dose rates. All of the estimated dose rates were higher than the ICRP's derived consideration reference levels (10 µGy h-1).

Oocyte dynamics for Atlantic bluefin tuna (Thunnus thynnus) in the southern Gulf of Mexico: A comparative assessment of Mediterranean spawners using two stereological methods.

Although most research focused on the northern Gulf of Mexico for western Atlantic bluefin tuna, the histological records of reproductive activity of this species in the southern Gulf of Mexico (Mexican waters) have been presented for the first time. This work is the first to study oocyte dynamics in Atlantic bluefin tuna caught in the southern Gulf of Mexico by assessing and comparing them with Mediterranean stock (BFT-E) through stereology using two different methods. Regardless of Atlantic bluefin tuna females returning to their respective spawning grounds at different months in the southern Gulf of Mexico and the Mediterranean, both stocks arrived reproductively inactive and remained in these zones during periods of similar length; they were reproductively active until March for the southern Gulf of Mexico and May for the Mediterranean females. The comparison of the size structure between the two stocks examined using kernel density estimators demonstrated a quite remarkable difference in mean fork lengths between stocks. The ovarian oocyte density, that is, the number of oocytes per gram of ovary, for each gonad stage predicted using the Weibel and Gomez and oocyte packing density (OPD) methods did not significantly differ between stocks and showed that advanced vitellogenic oocytes from spawning-capable females are an appropriate indicator to estimate potential fecundity, presenting values of c. 1273 and ~1355 eggs per gram for the southern Gulf of Mexico and Mediterranean females, respectively. Females caught in Mexican waters (southern Gulf of Mexico) were larger than those caught in the Mediterranean; however, it was demonstrated that the length and weight of females did not affect ovarian oocyte density production. In addition, densities estimated for each gonad stage using W&G and OPD methods did not differ between stocks and presented equal patterns in their oocyte dynamics. These findings contribute to a better understanding of the reproductive biology of Atlantic bluefin tuna, especially in the southern Gulf of Mexico, due to the lack of information regarding this zone, and may allow to support strategies for proper assessment, management, and conservation.

Modelling CO2 budget of mussel farms across the Mediterranean Sea.

The role of bivalve aquaculture as a carbon sink is highly debated, without a general consensus on the components to include in the budget. This study proposes to estimate the terms of the budget using a scope-for-growth-based model. The model was applied at 12 Mediterranean sites, with environmental forcings provided by operational oceanography data spanning over 12 years. Mussels were found to be slight sinks, with a limited variability across sites, if all components of the budget, i.e. accumulation in soft tissue, emissions associated with calcification and respiration, are included. The differences found among stations concerning the calcification and soft tissue contributions to the budget were found to be related to site-specific productivity and water chemistry parameters. This led to the identification of a set of meta-models, which could be used for relating the budget to local conditions, at a screening level, rendering them useful for optimal site selection.

Improvement in the Post-Processing of Wave Buoy Data Driven by the Needs of a National Coast and Sea Monitoring Agency.

Technological development in terms of the power requirement for data acquisition and processing opens new perspectives in the field of environmental monitoring. Near real-time data flow about the sea condition and a possible direct interface with applications and services devoted to marine weather networks would have a significant impact on several aspects, such as, for example, safety and efficiency. In this scenario, the needs of buoy networks have been analyzed, and the estimation of directional wave spectra from buoys' data has been deeply investigated. Two methods have been implemented, namely the truncated Fourier series and the weighted truncated Fourier series, and they have been tested by both simulated and real experimental data, representative of typical Mediterranean Sea conditions. From simulation, the second method proved to be more efficient. From the application to real case studies, it emerged that it works effectively in real conditions, as confirmed by parallel meteorological observations. The estimation of the main propagation direction was possible with a small uncertainty of a few degrees, yet the method exhibits a limited directional resolution, which suggests the need for undertaking further studies, briefly addressed in the conclusions.

Abnormal fluoride distribution, human health risk assessment, predicted no-effect concentration (PNEC) and environmental hazards in an Egyptian lake connected to the Mediterranean Sea.

Fluoride can affect the metabolism and physiological functioning of humans and aquatic organisms like any hazardous substance when it exceeds its permissible limits and PNEC values. The fluoride content of the lake water and sediment samples collected from different locations was determined to assess its risks to humans and its ecological toxicity in Lake Burullus. Statistical analyses show that the proximity of the supplying drains had an impact on the fluoride content. Fluoride ingestion and skin contact in lake water and sediment during swimming for child, female and male were evaluated at 95, 90, and 50%. The values of hazard quotient (HQ) and total hazard quotient (THQ) for children, females and males were less than one, reflecting that exposure to fluoride through ingestion and skin-to-skin contact while swimming poses no risks to human health. PNEC values for fluoride in lake water and sediment were estimated using the equilibrium partitioning method (EPM). The ecological risk assessment of fluoride for acute and chronic toxicity was performed for the three trophic levels based on the PNEC, the half-maximal effective concentration (EC50), the median lethal dose (LC50), the no-observed effect concentration (NOEC), and the 5% lethal concentration (EC05). The risk quotient (RQ), mixture risk characterization ratios (RCRmix), relative contribution (RC), toxic unit (TU), and sum of toxic units (STU) were estimated. The acute and chronic RCRmix(STU) and RCRmix(MEC/PNEC) produced similar values for the three trophic levels in lake water and sediment, indicating that invertebrates are the most sensitive species to fluoride. These results of evaluating the environmental risks of fluoride in lake water and sediments reflected its significant impact on aquatic organisms living in the lake area in the long term.

A multi-criteria assessment of the implementation of innovative technologies to achieve different levels of microplastics and macroplastics reduction.

This paper proposes and applies a multicriteria decision analysis framework tailored to assess measures for reducing the concentration of microplastics and macroplastics in seas, by implementing ground-breaking clean-up technologies and addressing different types of pollutant sources. Environmental, socio-economic and financial impacts are considered to provide a ranking of these measures for better-informed decision making. The data required to evaluate the performance of the technologies in different locations and scales are analyzed to understand the consequences of the different measures in terms of plastic pathways and sites, and the amounts accumulated, using innovative simulation models. The framework is applied to the Mediterranean Sea, providing insights for designing measures to respond to the challenges of cleaning seas and fulfill the EU marine strategy. The results for the best ranked alternatives show that dealing with microplastics is much more expensive (by one order of magnitude) than dealing with macroplastics.

First baseline assessment of seafloor litter on Italian coralligenous assemblages (Mediterranean Sea) in accordance with the European Marine Strategy Framework Directive.

A monitoring programme for coralligenous assemblages was carried out in Italy for implementation of the Marine Strategy Framework Directive (MSFD), aiming to characterise the coralligenous' environmental status and litter distribution. A standardised monitoring protocol, based on ROV-imaging, has been applied; this paper analyses the data obtained during the first MSFD cycle (2015-2019). Ninety-five areas were monitored at depths ranging between 14 and 199 m in the three subregions bordering Italy. Overall, 4316 macrolitter items were recorded. The median litter density was 2 items 100 m-2 (range: 0-120 items 100 m-2), but significant subregional differences emerged in litter quantities and composition. Fishery-related litter (mainly lines and ropes) was the most common type (86 %), affecting vulnerable coralligenous reefs. A first baseline is proposed for assessing achievement toward Good Environmental Status and evaluation of the efficacy of the Italian MSFD measures aiming to eliminate the negative effects of marine litter on vulnerable reefs.

Integrated approach for marine litter pollution assessment in the southern Tyrrhenian Sea: Information from bottom-trawl fishing and plastic ingestion in deep-sea fish.

Marine litter pollution threatens marine ecosystems and biodiversity conservation, particularly on seafloors where all anthropogenic waste naturally sinks. In this study, we provide new information on the composition, density and origin of seafloor macrolitter as well as on plastic ingestion in deep-sea fish from bottom-trawling by-catch in the southern Tyrrhenian Sea. Plastic constituted the highest fraction of litter in terms of density (64 %) and weight (32 %) and was also retrieved in the gastrointestinal traits of Chlorophthalmus agassizi, Coelorhynchus coelorhynchus and Hoplosthethus mediterraneus. FT-IR spectroscopy analysis on the seafloor macrolitter and the ingested plastics revealed the presence of artificial polymers including PE, PET/polyester, PA widely used for food packaging, plastic bags and several common products, especially Single Use Plastic (SUP). These results underline how poor waste management schemes or their incorrect application strongly contribute to marine litter accumulation on seafloors and plastic ingestion in deep-sea fish.

Techno-economic analysis of an offshore wind farm on the eastern Mediterranean Sea coast.

Turkey has rapidly become one of the top markets for onshore wind energy with a 10 GW onshore wind power installation, a significant accomplishment for the nation. It means that Turkey's wind energy capacity has more than tenfold increase in the last 10 years. Despite the fact that Turkey has no offshore wind farms, research has indicated a significant and untapped energy potential. This work provides a comprehensive techno-economic analysis of the Samandag Offshore Wind Farm (OWF) project in Turkey. To undertake an economic feasibility study under different Feed-in Tariffs (FiT) and discount rates, a discounted cash flow economic model is utilized. This study takes into consideration the economic indicators utilized in decision-making processes from the perspective of an OWF investor. The planned OWF project is shown to be economically viable only provided specific techno-economic prerequisites are satisfied. Samandag City has a lower levelized cost of energy (LCOE), which is roughly $69.97/MWh, according to the findings. However, the findings show that the net present value (NPV) is very sensitive to discount rates and FiT. The goal of this research is to contribute scientifically to the development of offshore wind energy in Turkey.

Preliminary assessment of persistent organic pollutants (POPs) in tissues of Risso's dolphin (Grampus griseus) specimens stranded along the Italian coasts.

Ecotoxicological and pathological research on Grampus griseus (Cuvier, 1812) (Risso's dolphins) is scarce both globally and in the Mediterranean Sea. This species has been classified as "Vulnerable" by the International Union for Conservation of Nature (IUCN) in the Mediterranean Sea. To evaluate the presence of "persistent organic pollutants" (POPs), especially organochlorine compounds (OCs), in the animals, chemical analyses were performed on tissues and organs of Risso's dolphin stranded along the Italian coasts between 1998 and 2021. Toxic contaminants such as hexachlorobenzene (HCB), polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane and its metabolites (DDTs) were examined in the blubber, liver, muscle, and brain of 20 animals, and data was correlated with sex, age, and stranding locations.

Economic losses related to the reduction of Posidonia ecosystem services in the Gulf of Gabes (Southern Mediterranean Sea).

In the early XXth century, the Gulf of Gabes in SE Tunisia used to host the most extended Posidonia oceanica seagrass beds in the Mediterranean basin and was a highly productive hotspot of benthic species. Since the 70's, >500 million t of wet toxic phosphogypsum discharges from a fertilizer industrial complex have led to the gradual loss of ∼90 % of its initial surface. This drastic shrinkage is accompanied by significant value losses originated from the direct and indirect-use services of which the most important ones are small scale fisheries and carbon storage function. Using market valuations of a number of services we estimate economic losses at 105 million € in 2014 (∼915€/ha), i.e., around 115 % of the added value of the gabesian fertilizer factories for the same year. Value losses should increase in the near future in relation with the COP26 agreements which boosted the open carbon credit market. Without actions to reduce negative production externalities caused by the fertilizer industry in the Gulf of Gabes it would not be possible to recover Posidonia ecosystems in this region leading to further economic, ecologic, and cultural losses.