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Savalia savaglia is an ecosystem engineer listed as Near-Threatened by the IUCN, even though effective management and proper monitoring efforts to assess its distribution is still lacking. The record of large, long-established colonies can indicate the occurrence of areas with limited human local pressure. These areas may be considered as proxies for the creation of baselines of reference useful to design restoration strategies. The aim of this work was to update the distribution of S. savaglia Mediterranean populations to develop an Ecological Niche Model, highlighting potential areas for future monitoring programs. Occurrence data were collected and harmonized into a single dataset using the scientific literature and validated observations to feed a presence-only MaxEnt model, obtaining a basin-level potential distribution of the species. The results of our study can support decision-makers in marine spatial planning measures including the preservation of mesophotic environments and prioritizing areas for conservation., (Copyright © 2022. Published by Elsevier Ltd.)

Global warming is causing the increase in intensity and frequency of heatwaves, which are often associated with mass mortality events of marine organisms from shallow and mesophotic rocky habitats, including gorgonians and other sessile organisms. We investigated the microbiome responses of the gorgonians Paramuricea clavata, Eunicella cavolini, and the red coral Corallium rubrum to the episodic temperature anomalies detected in the North Western Mediterranean, during August 2011. Although the investigated corals showed no signs of visible necrosis, the abundance of associated Bacteria and Archaea increased with increasing seawater temperature, suggesting their temperature-dependent proliferation. Coral microbiomes were highly sensitive to thermal anomaly amplitude and exhibited increased bacterial diversity to greater thermal shifts. This effect was explained by the decline of dominant bacterial members and the increase of new, rare and opportunistic taxa, including pathogens, revealing a direct effect of heatwave-induced alteration of the microbiomes and not a secondary consequence of coral necrosis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

Microplastics are recognised as a potential global threat to marine ecosystems, but the biological mechanisms determining their impact on marine life are still largely unknown. Here, we investigated the effects of microplastics on the red coral, a long-lived habitat-forming organism belonging to the Corallium genus, which is present at almost all latitudes from shallow-water to deep-sea habitats. When exposed to microplastics, corals preferentially ingest polypropylene, with multiple biological effects, from feeding impairment to mucus production and altered gene expression. Microplastics can alter the coral microbiome directly and indirectly by causing tissue abrasions that allow the proliferation of opportunistic bacteria. These multiple effects suggest that microplastics at the concentrations present in some marine areas and predicted for most oceans in the coming decades, can ultimately cause coral death. Other habitat-forming suspension-feeding species are likely subjected to similar impacts, which may act synergistically with climate-driven events primarily responsible for mass mortalities.

We investigated possible synergic effects on coral reefs of the local land reclamation activities in the Himmafushi Island (North Malè atoll, Maldives) and the global bleaching event that affected the Maldives in 2016. A BACI (Before-After Control-Impact) sampling design was adopted to contrast effects of dredging activities before and after the occurrence of both dredging and bleaching. The Reef Check protocol, a standardised and worldwide survey method, was applied to collect data through underwater visual surveys on corals, macro-zoobenthos, and fish communities. The bleaching in 2016 hit all the reefs investigated, but only in the reefs around Himmafushi (i.e., the impact sites) the live hard coral reduced significantly its cover and the sand deposited on reefs showed a fourfold increase. Substrate indicators (i.e., coral community and abiotic components) turned out to be more effective than macro-zoobenthos and fish in this short-term environmental impact study., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Thanks to several European directives and conventions there is a general increase of awareness regarding the key ecological role of coralligenous habitats in the Mediterranean Sea, addressing several research projects to standardize protocols for the description of its integrity. Here we surveyed 13 stations along the Italian coasts of the Western Mediterranean Sea, using video-transects technique, comparing the biological structure of coralligenous assemblages and testing the importance of their three-dimensional complexity as a proxy to define their health conditions. We considered the diversity of taxa, fishing impacts and the entity of damage on gorgonian's choenenchyme due to thermal stress, to evidence a gradient in the coralligenous health conditions. Here we developed a method to evaluate coralligenous complexity, selecting categories of taxa particularly sensitive to multiple stressors, named Structural Descriptors to describe the three-dimensional structure of the bioconcretions and to assess a unique Index of 3D - Structural Complexity., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

In lower metazoans, the aggregative properties of dissociated cells leading to in vitro stable multicellular aggregates have furnished a remarkable experimental material to carry out investigations in various research fields. One of the main expectations is to find good models for the study in vitro of the first steps of biomineralization processes. In this study, we examined five common Mediterranean gorgonians (Paramuricea clavata, Corallium rubrum, Eunicella singularis, Eunicella cavolinii, and Eunicella verrucosa) using mechanical cell aggregate production techniques. In particular, we investigated the conditions of aggregate formation, their number and survival in experimental conditions, the DNA synthesizing activity using 5'-bromo-2'-deoxyuridine (BrdU) tests, and the response to calcein addition and observed the secretion of newly formed sclerites. The BrdU tests showed that cell proliferation depends on the size of aggregates and on the presence/absence of symbiotic zooxanthellae. With epifluorescent and confocal imaging from calcein addition assays, we observed the presence of calcium ions within cells, a possible clue for prediction of sclerite formation or calcium deposition. The species-specific efficiency in production of cell aggregates is correlated to the size of polyps, showing that the higher density of polyps and their diameter correspond to higher production of cell aggregates. Regarding the long-term maintenance, we obtained the best results from E. singularis, which formed multicellular aggregates of 0.245 mm ± 0.086 mm in size and maintained symbiotic association with zooxanthellae throughout the experimental run. Formation of sclerites within aggregates opens a wide field of investigation on biomineralization, since de novo sclerites were observed around 30 d after the beginning of the experiment.

Mediterranean gorgonian forests are threatened by several human activities and are affected by climatic anomalies that have led to mass mortality events in recent decades. The ecological role of these habitats and the possible consequence of their loss are poorly understood. Effects of gorgonians on the recruitment of epibenthic organisms were investigated by manipulating presence of gorgonians on experimental panels at 24 m depth, for Eunicella cavolinii, and at 40 m depth, for Paramuricea clavata, at two sites: Tavolara Island (Tyrrhenian Sea) and Portofino Promontory (Ligurian Sea). After 4 months, the most abundant taxa on the panels were encrusting green algae, erect red algae and crustose coralline algae at 24 m depth and encrusting brown algae and erect red algae at 40 m depth. Assemblages on the panels were significantly affected by the presence of the gorgonians, although effects varied across sites and between gorgonian species. Species diversity and evenness were lower on panels with gorgonian branches. Growth of erect algae and recruitment of serpulid polychaetes were also affected by the presence of the gorgonians, primarily at Tavolara. Crustose coralline algae and erect sponges were more abundant on E. cavolinii panels at 24 m depth, while encrusting bryozoans were more abundant on P. clavata panels at 40 m depth. Effects of gorgonians on recruited assemblages could be due to microscale modification of hydrodynamics and sediment deposition rate, or by a shading effect reducing light intensity. Gorgonians may also intercept settling propagules, compete for food with the filter-feeders and/or for space by producing allelochemicals. Presence of gorgonians mainly limits the growth of erect algae and enhances the abundance of encrusting algae and sessile invertebrates. Therefore, the gorgonian disappearances may cause a shift from assemblages characterised by crustose coralline algae to filamentous algae assemblages, decreasing complexity and resilience of coralligenous bioconstructions.

Mass mortality events of benthic invertebrates in the Mediterranean Sea are becoming an increasing concern with catastrophic effects on the coastal marine environment. Sea surface temperature anomalies leading to physiological stress, starvation and microbial infections were identified as major factors triggering animal mortality. However the highest occurrence of mortality episodes in particular geographic areas and occasionally in low temperature deep environments suggest that other factors play a role as well. We conducted a comparative analysis of bacterial communities associated with the purple gorgonian Paramuricea clavata, one of the most affected species, collected at different geographic locations and depth, showing contrasting levels of anthropogenic disturbance and health status. Using massive parallel 16SrDNA gene pyrosequencing we showed that the bacterial community associated with healthy P. clavata in pristine locations was dominated by a single genus Endozoicomonas within the order Oceanospirillales which represented ∼90% of the overall bacterial community. P. clavata samples collected in human impacted areas and during disease events had higher bacterial diversity and abundance of disease-related bacteria, such as vibrios, than samples collected in pristine locations whilst showed a reduced dominance of Endozoicomonas spp. In contrast, bacterial symbionts exhibited remarkable stability in P. clavata collected both at euphotic and mesophotic depths in pristine locations suggesting that fluctuations in environmental parameters such as temperature have limited effect in structuring the bacterial holobiont. Interestingly the coral pathogen Vibrio coralliilyticus was not found on diseased corals collected during a deep mortality episode suggesting that neither temperature anomalies nor recognized microbial pathogens are solely sufficient to explain for the events. Overall our data suggest that anthropogenic influence may play a significant role in determining the coral health status by affecting the composition of the associated microbial community. Environmental stressful events and microbial infections may thus be superimposed to compromise immunity and trigger mortality outbreaks.

Sponges are characterised by high levels of phenotypic plasticity, thus allowing the same species to live in different habitats by taking different shapes. Here we describe 28 sponge species associated with the octocorals Carijoa riisei, Paratelesto rosea and Alertigorgia hoeksemai in Indonesia, Hawai'i and Vietnam, including four species that are new to science (Chondropsis subtilis, Hymedesmia (Hymedesmia) spinata, Hymedesmia (Stylopus) perlucida, Mycale (Aegogropila) furcata). Moreover, a large proportion of the described sponge species (21.4%) represent new records for the studied areas (Indonesia and Hawai'i). In total, we have studied 47 colonies of C. riisei associated with 24 sponge species, 5 colonies of P. rosea associated with 4 species and one colony of A. hoeksemai associated with one sponge species. Collectively, these examples of associations highlight the importance of epibiosis as a biodiversity enhancing process.

The red coral Corallium rubrum is a habitat-forming species with a prominent and structural role in mesophotic habitats, which sustains biodiversity hotspots. This precious coral is threatened by both over-exploitation and temperature driven mass mortality events. We report here that biocalcification, growth rates and polyps' (feeding) activity of Corallium rubrum are significantly reduced at pCO2 scenarios predicted for the end of this century (0.2 pH decrease). Since C. rubrum is a long-living species (>200 years), our results suggest that ocean acidification predicted for 2100 will significantly increases the risk of extinction of present populations. Given the functional role of these corals in the mesophotic zone, we predict that ocean acidification might have cascading effects on the functioning of these habitats worldwide.

Chemical analysis of the Indonesian soft coral Sinularia sp. (order Alcyonacea, family Alcyoniidae) afforded a known glucosylcerebroside of the sarcoehrenoside-type and sinularioside (2), a new naturally triacetylated glycolipid containing two α-D-arabinopyranosyl residues and a myristyl alcohol unit. Their complete stereostructures were solved by interpretation of MS and NMR data along with CD analysis of degradation products. Sinularioside proved to moderately inhibit LPS-induced NO release, providing interesting clues into the poorly understood structure-activity relationships for anti-inflammatory glycolipids., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Chemical investigation of the Indonesian soft coral Sinularia sp. resulted in the isolation of three known (1, 2 and 7) and five new (3-6 and 8) sterols, characterized by either 24-methylcholestane or gorgostane skeletons. The stereostructures of the new compounds have been elucidated by application of HR-MS and 2D NMR techniques. The isolated steroids have been evaluated for their interaction with the farnesoid X-activated receptor (FXR) and some of them, including the new compound 3 and gorgosterol (7), showed a consistent antagonistic activity, potentially useful for the treatment of cholestasis. The FXR antagonistic activity of gorgosterol (7) was also supported by gene expression experiments. Our results represent the first evaluation of soft coral steroids for interaction with nuclear receptors and qualify gorgosterol (7) as a new chemotype of FXR antagonist., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Mass mortality events of benthic invertebrates in the temperate north-western (NW) Mediterranean Sea have been observed in recent seasons. A 16 month in situ study in the Ligurian Sea (NW Mediterranean Sea) demonstrated that the occurrence of Paramuricea clavata mortality episodes were concomitant to a condition of prolonged high sea surface temperatures, low chlorophyll concentrations and the presence of culturable Vibrio spp. in seawater. The occurrence of Vibrio spp. at the seasonal scale was correlated with temperature; with few vibrios retrieved on specific media when the temperature dropped below 18 degrees C and a sharp increase of vibrios abundance (up to 3.4 x 10(4) MPN l(-1)) when the temperature was greater than or equal to 22 degrees C. Phylogenetic and phenotypic analysis of Vibrio isolates associated with healthy and diseased P. clavata colonies collected during a mortality episode showed that these bacteria were significantly more abundant in diseased than in healthy corals and were related to the V. harveyi, V. splendidus and V. coralliilyticus groups, the latter only identified in diseased organisms. Inoculation of bacterial isolates from these groups onto healthy P. clavata in aquaria caused disease signs and death in a range of Vibrio concentrations, temperature values and trophic conditions consistent with those recorded in the field. It is concluded that Vibrio infections may act as an additional triggering mechanism of mass mortality events in the coastal Mediterranean Sea and that their occurrence is climate-linked. Predicted global warming leading to long-lasting hot summer periods together with stratification resulting in energetic constraints represent a major threat to the survival of benthic invertebrates in the temperate NW Mediterranean Sea due to potential disease outbreak associated with Vibrio pathogens.

Although the biometric investigation of the cnidome represents an essential diagnostic feature to successfully identify cnidarian species, further efforts are needed to fully characterize eventual differences. Important model actiniarians, such Anemonia viridis and Aiptasia spp., are commonly used for scientific purposes; however, their identification is often difficult, and the description of their cnidome is, therefore, essential. To contribute to this necessity, specimens of Anemonia viridis and Aiptasia couchii from the North Adriatic Sea were collected to acquire data (i.e. length, width, size range, length/width ratio) about cnidae from different tissues (i.e. column, tentacles, actinopharynx, mesenteries, and acrorhagi/acontia). Four types of cnidae were observed in each species. A. viridis shows microbasic b-mastigophores, microbasic p-mastigophores, holotrichous isorhizas, and spirocysts, whereas A. couchii harbored basitrichs, microbasic p-mastigophore, microbasic p-amastigophore and spirocysts. Molecular and phylogenetic analyses were also performed using three mitochondrial markers to confirm the correct classification of the specimens here analysed. [ABSTRACT FROM AUTHOR]