ABSTRACT1. Mass mortality events are becoming more common all over the world, both in tropical and temperate seas. An extensive mortality occurred in the Mediterranean Sea in 1999, affecting many benthic species, mainly sponges and gorgonians.2. The recovery of a population of the sea fan Paramuricea clavata, for a period of 3 yr, from 1999 to 2002, was studied by both line transects and fixed frames. The average size of the colonies decreased, indicating a size-dependent mortality episode, but their density, as a result of successful recruitment, was not altered after 3 yr.3. P. clavata showed three recovery patterns: (i) sexual reproduction, (ii) coenenchyme regeneration and (iii) fragmentation of affected branches. Moreover, the growth rates of small colonies varied in the different years. The sex ratio of the population was also altered, with females being more affected than males; the population studied showed a significant male bias (3.3:1, n ¼ 150), varying greatly from the typical sex ratio (1:1) previously recorded in the same population before the mass mortality event.

Mesophotic habitats, hosting benthic assemblages totally unknown and unexpected in the early 2000s, are attracting an increasing interest from scientists. Realizing that many long living and habitat forming species are playing a unique pocket of biodiversity in the frame of climate crisis, it is important to recognize the potential of the mesophotic zone in conservation strategies. The mesophotic zone is characterized by environmental factors generally more stable than the shallow counterpart; therefore, it represents a refuge habitat to preserve species that, in shallow waters, may be involved in bleaching events, massive mortalities or other pathologies generally triggered by thermal anomalies. The definition of the mesophotic zone in the temperate seas is confused, creating possible misunderstandings and problems not only from a scientific point of view but also in communication and outreach strategies. Here, we review the scientific literature to build the best definition possible based on the maximum consensus coming from papers analysis. Moreover, the key roles of mesophotic habitats, including ecosystem engineers as animal forests, have been schematized to enhance the perception of the potential risks we are running in case of damage or loss of these habitats.

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The hydroid assemblage of the Siladen Island coral reef (North Sulawesi, Indonesia) is made up of 107 species belonging to 51 genera and 28 families. The study of their spatial distribution has identified three different zones which are well-characterized: (1) the reef flat, where hydroids are mainly represented by cryptic species living in the shady crevices of the corals, epibiontic on sponges or sea grasses; (2) the edge of the reef characterized by hydroids growing mainly on the shady side of the corals, with the exception of the tufts of the large colonies of the stinging zooxanthellateAglaophenia cupressina; and (3) the vertical reef, where hydroids reach their maximum diversity and abundance and are often involved in symbiotic relationships.The number of hydroid species shows a seasonal trend with a summer minimum (July–September) and a winter maximum (November–February). The strong correlation between these variations and the abundance of rainfall suggests that food availability, strictly related to the seasonal amount of rain, represents the main abiotic factor triggering the hydroid species richness and the abundance of this tropical assemblage.

Paramuricea clavata (Cnidaria, Octocorallia) is an important ecosystem engineer of coralligenous assemblages increasingly threatened by anthropogenic activities and climate changes. As climate warming is predicted to continue in the coming years it is important to hypothesize future scenarios. Here we tested the influence of gorgonian colonies on sedimentation rates and vagile fauna trends, comparing sediments collected by traps inside and outside a gorgonian garden, in a coralligenous community of the Western Ligurian Sea, at 32 m depth, over a period of 1 year. The results indicated that sea fans created a sort of homeostatic effect on the surrounding habitat. We found evidence that where gorgonian colonies were present, the monthly fluctuations of sediments rate were lower than outside a garden. Gorgonian colonies also influenced the distribution of the associated vagile fauna; these organisms were generally more abundant inside than outside the garden. The data collected in this work appear to confirm the role of P. clavata as an ecosystem engineer, affecting biomass and variability of the surrounding habitat at both spatial and temporal scales.

During the last few decades, Mediterranean epibenthic assemblages have been involved in mass mortality events, in which sea fans were one of the most threatened groups. Explants of the most common Mediterranean gorgonians (Paramuricea clavata, Eunicella cavolinii, E. singularis, and E. verrucosa, 40 explants from each species) were transplanted in the field in order to evaluate the response to transplantation, survival and growth rate of the cuttings during an annual cycle, from February 2003 to March 2004. Colonies of each species overcame transplantation stress and during the first three months they showed a mean survival rate of 98% and an average positive growth rate of 7.65%. In the summer season 2003, during the heatwave that affected the Mediterranean basin, the experimental cuttings suffered, showing a mean negative growth rate and a reduction of survival. At the end of the stress event, P. clavata revealed the worst recovery while all Eunicella species showed a good ability to recover. In particular, E. singularis evidenced the highest resilience among the species. The transplant method described here could be employed to try to recover sea fan populations in the precoralligenous and coralligenous communities in possible future projects of restocking, where anthropic activities (anchoring and/or fishing) and global warming are deeply compromising their survival. Moreover, a species-specific capability to recover was identified after the stress event concomitant to the increase of the sea temperature.

Exposure to quartz particles induces a pathological process named silicosis. Alveolar macrophages initiate the disease through their activation, which is the origin of the later dysfunctions. Ascorbic acid is known to selectively dissolve the quartz surface. During the reaction, ascorbic acid progressively disappears and hydroxyl radicals are generated from the quartz surface. These observations may be relevant to mammalian quartz toxicity, as substantial amounts of ascorbic acid are present in the lung epithelium. We studied the inflammatory response of the murine macrophage cell line RAW 264.7 incubated with ascorbic acid‐treated quartz, through the expression and activity of the enzyme cyclo‐oxygenase‐2 (COX‐2). COX‐2 expression and prostaglandin secretion were enhanced in cells incubated with ascorbic acid‐treated quartz. In contrast, no changes were observed in cells incubated with Aerosil OX50, an amorphous form of silica. Quantification of COX‐2 mRNA showed a threefold increase in cells incubated with ascorbic acid‐treated quartz compared with controls. The transcription factors, NF‐κB, pCREB and AP‐1, were all implicated in the increased inflammatory response. Reactive oxygen species (H2O2 and OH•) were involved in COX‐2 expression in this experimental model. Parallel experiments performed on rat alveolar macrophages from bronchoalveolar lavage confirmed the enhanced COX‐2 expression and activity in the cells incubated with ascorbic acid‐treated quartz compared with untreated quartz. In conclusion, the selective interaction with, and modification of, quartz particles by ascorbic acid may be a crucial event determining the inflammatory response of macrophages, which may subsequently develop into acute inflammation, eventually leading to the chronic pulmonary disease silicosis.

Abstract:We developed a rapid, practical and non-toxic salting-out method for the extraction of DNA from marine organisms, and tested it on two representative species of Porifera and Cnidaria, both living in association with symbiotic zooxanthellae. We tested the efficiency of the protocol by comparing the output of the method for fresh tissue, frozen tissue and tissue stored in ethanol. It proved to be effective for extracting DNA in the case of the methods of preservation considered here, and for obtaining quantities of DNA comparable to those obtained via the traditional approach. The DNA from both species was of good quality. The DNA obtained was amplified by PCR using specific primers for the large ribosomal subunit, allowing the identification of the presence of both the host and symbiont genomes.