Monitoring extreme meteo-marine events in the Mediterranean area using the microseism (Medicane Apollo case study)

Microseism is the continuous background seismic signal caused by the interaction between the atmosphere, the hydrosphere and the solid Earth. Several studies have dealt with the relationship between microseisms and the tropical cyclones, but none focused on the small-scale tropical cyclones that occur in the Mediterranean Sea, called Medicanes. In this work, we analysed the Medicane Apollo which impacted the eastern part of Sicily during the period 25 October–5 November 2021 causing heavy rainfall, strong wind gusts and violent sea waves. We investigated the microseism accompanying this extreme Mediterranean weather event, and its relationship with the sea state retrieved from hindcast maps and wave buoys. The spectral and amplitude analyses showed the space–time variation of the microseism amplitude. In addition, we tracked the position of Apollo during the time using two different methods: (i) a grid search method; (ii) an array analysis. We obtained a good match between the real position of Apollo and the location constraint by both methods. This work shows that it is possible to extract information on Medicanes from microseisms for both research and monitoring purposes.peer-reviewe

Microseism and medicane Apollo : a new approach to investigate the Mediterranean extreme weather events

Microseism is the most continuous and ubiquitous seismic signal on the Earth and is caused by the interaction between the atmosphere, the hydrosphere and the Solid Earth. In literature, there are several studies that deal with the relationship between microseism and cyclonic activity considering in particular hurricanes, tropical cyclones and typhoons. However, the relationships between microseism and the small-scale tropical cyclones that occur in the Mediterranean Sea, called Medicanes, have never been analysed. For this reason, we considered the Medicane Apollo, which developed in the Ionian Sea and impacted the eastern part of Sicily during the period 25th October to 5th November 2021 causing heavy rainfall (> 400 mm/48h), strong wind gusts (104 km/h) and violent sea waves (significant wave height > 3.5 m). Furthermore, the heavy rainfall induced by the presence of Apollo, caused damage to infrastructure and agriculture forcing the Sicilian regional government to declare a state of emergency for 32 municipalities (in the provinces of Catania, Messina, Siracusa and Ragusa) that were mostly affected by the Medicane Apollo.peer-reviewe

Seascape characterization of a Mediterranean vermetid reef: a structural complexity assessment

In the Mediterranean Sea, vermetid reefs can modify coastal seascapes forming platforms in the intertidal zone of rocky coasts. With their three-dimensional and seaward-expanding structure, these bioconstructions support high biodiversity levels and provide important ecological functions and ecosystem services. In this study, we perform a first structural characterization of a vermetid reef seascape (hereafter, vermetid reefscape) and quantitatively assess the degree of their contribution to the structural complexity of the coastal seascape. Aerial images of a vermetid reef coast were acquired in the Marine Protected Area of Capo Gallo-Isola delle Femmine (Southern Tyrrhenian Sea) by means of unmanned aerial vehicle technology. In the seascape, the outer reef, platform, and coast classes were identified and digitized in GIS environment. The resulting vermetid reefscape was analysed by means of FRAGSTATS software using metrics belonging to the “area-edge”, “shape”, and “aggregation” categories. To quantitatively assess the structural complexity, the edge density, area-weighted perimeter area ratio, and landscape shape index metrics were applied to the seascapes with and without the vermetid reefs to simulate a sea level rise scenario. In addition, the effect of their presence in terms of coast length (i.e., total edge) was statistically tested using the Wilcoxon signed rank test. The outer reef had the highest total edge value (5,785.6 m) and, at the same time, the lowest class area (1,040 m2). It was also the patchiest, and the most fragmented and geometrically complex class in the seascape. Overall, the bioconstruction positively contributed to the structural complexity of the seascape with higher values of coastal area (12%), edge density (139%), area-weighted perimeter-area ratio (90%), and landscape shape index (66%). The Wilcoxon test revealed a statistically significant effect of the vermetid reefs presence on the coastal total edge (z = 3.9, p < 0.005), with a large effect size (r = 0.74). The results showed an overall higher structural complexity of the vermetid reefscape, indicating that its loss would lead to a significantly less complex seascape, entailing detrimental effects on the supported biodiversity levels and the valuable ecosystem services provided

The scientific research on Natural Capital: A bibliometric network analysis

Natural capital can be defined as the stock of natural resources generating a "natural income" in terms of valuable flows of different types of ecosystem goods and services. According to "strong sustainability", natural capital is irreplaceable with manufactured capital and it ensures a life support system vital for human well-being. In this study, the global scientific literature on natural capital was explored by performing a bibliometric network analysis. The investigation of the networks of authors, countries, journals, and keywords allowed a comprehensive overview of the scientific literature on natural capital. Results showed an increase in the attention given to the topic of natural capital worldwide. The combined use of social network analysis and bibliometrics proved to be a promising approach for exploring the scientific literature by applying systems thinking in bibliometric science

Modeling matter and energy flows in marine ecosystems using emergy and eco-exergy methods to account for natural capital value

The identification of principles explaining the development of ecosystems has been a major target of systems ecology and ecological modelling. Among these principles, the thermodynamic goal functions (GFs) named emergy and eco-exergy are recognised as methods unfolding the role of matter and energy flows in the functioning of ecological systems. The biophysical assessment of natural capital stocks is based on the evaluation of matter and energy flows invested by nature for their generation. In this paper, the emergy and eco-exergy methods were used to account for the natural capital value of two Mediterranean Marine Protected Areas (MPAs) located in Southern Italy. In particular, the assessment focused on four main habitats: 1) sciaphilic hard bottom (coralligenous bioconstruction), 2) photophilic hard bottom, 3) soft bottom, and 4) Posidonia oceanica seagrass bed. The emergy method allowed the assessment of natural capital in terms of direct and indirect solar energy flows invested for its generation, while the eco-exergy method accounted for the chemical energy stored in organic matter and the genetic information embodied in biomass stocks. The sciaphilic hard bottom showed a high emergy density value in the two MPAs (2.06∙1012 and 7.22∙1011 sej m−2), confirming the high convergence of input resource flows in the formation of this habitat. This high value reflects the effort of nature in the formation of this habitat and therefore it suggests the need for its consideration in conservation strategies. Instead, Posidonia oceanica seagrass bed showed the highest value of eco-exergy density in both MPAs (3.56∙106 and 3.54∙106 kJ m−2). The eco-exergy results were influenced by two main factors: 1) the large biomass density of Posidonia oceanica, and 2) the high ß value of Posidonia oceanica reflecting its evolutionary history that involved the acquisition of key adaptations for the successful colonization of marine environments. The integration between emergy and eco-exergy methods resulted in a useful approach to account for different nature values based on a biophysical perspective. Such a perspective could complement economic evaluations based on market criteria, thus supporting decision making processes oriented to the sustainable management of marine resources

Integrating natural capital assessment and marine spatial planning: A case study in the Mediterranean sea

Marine and coastal ecosystems are among the most productive environments in the world and their stocks of natural capital offer a bundle of vital ecosystem services. Anthropogenic pressure seriously threatens health and long-term sustainability of marine environments. For these reasons, integrated approaches capable of combining ecological and socio-economic aspects are needed to achieve nature conservation and sustainability targets. In this study, the value of natural capital of the Egadi Islands Marine Protected Area (EI-MPA) was assessed through a biophysical and trophodynamic environmental accounting model. The emergy value of both autotrophic and heterotrophic natural capital stocks was calculated for the main habitats of the EI-MPA. Eventually, the emergy value of natural capital was converted into monetary units to better communicate its importance to local managers and policy-makers. The total value of natural capital in the EI-MPA resulted in 1.12·1021sej, equivalent to about 1.17 billion of euros. In addition, using Marxan software, the results of the environmental accounting were integrated with spatial data on main human uses. This integration took into account the trade-offs between conservation measures and human exploitation by means of two different scenarios, with and without considering human uses in the EI-MPA. The comparison between the scenarios highlighted the importance of taking into account human activities in marine spatial planning (MSP), allowing the identification of key areas for natural capital conservation. In conclusion, this study showed the importance of integrating environmental accounting with conservation planning to support effective strategies for ecological protection and sustainable management of human activities. The results of this study represent a first benchmark useful to explore alternative nature conservation strategies in the EI-MPA, and, more in general, in Mediterranean MPAs

The scientific research on ecosystem services: A bibliometric analysis

The scientific research on ecosystem services (ES) has grown substantially over the past ten years, making more evident the vital role played by natural ecosystems in support of human economy and well-being. Several studies showed that biodiversity represents a fundamental part of the Earth's life support system. Biodiversity considerably affects ecosystem functioning while contributing to the provision of different types of ES. The increasing ecological awareness of scientists, citizens, and policy makers on the importance of natural capital stocks and ES flows boosted nature conservation strategies and the development of more environmentally friendly production processes. In this study, we explored the global scientific literature on ES over the last thirty years. The software VOSviewer was used to create maps based on network data of scientific publications displaying relationships among scientific journals, researchers, and countries. Specific keywords were finally used to explore the co-occurrence of different terms connected to the research on ES. Results show that the Millennium Ecosystem Assessment had a major impact on the scientific literature dealing with the ES concept. The top country researching on ES was USA, while the top journal was Ecological Economics. In terms of co-occurrence, the top keywords were "biodiversity", "management", "conservation", and "climate change". This study identified the main research areas characterizing the scientific literature on ES. Social network analysis and maps based on network data make possible the application of systems thinking in bibliometric science. This type of analysis allows for the investigation of research development in specific fields of science, capturing the interdisciplinarity of research topics crossing the boundary of specific disciplines, as it is the case of ES

Unravelling the Relationship Between Microseisms and Spatial Distribution of Sea Wave Height by Statistical and Machine Learning Approaches

Global warming is making extreme wave events more intense and frequent. Hence, the importance of monitoring the sea state for marine risk assessment and mitigation is increasing day-by-day. In this work, we exploit the ubiquitous seismic noise generated by energy transfer from the ocean to the solid earth (called microseisms) to infer the sea wave height data provided by hindcast maps. To this aim, we use a combined approach based on statistical analysis and machine learning. In particular, a random forest model shows very promising results in the spatial and temporal reconstruction of sea wave height by microseisms. The observed dependence of input importance from the distance sea grid cell-seismic station suggests how the reliable monitoring of the sea state in a wide area by microseisms needs data recorded by dense networks, comprising stations evenly distributed along the coastlines