This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
2021 International Workshop on Metrology for the Sea; Learning to Measure Sea Health Parameters (MetroSea), 2021
The precious red coral, Corallium rubrum, and the yellow gorgonian, Eunicella cavolini, have been... more The precious red coral, Corallium rubrum, and the yellow gorgonian, Eunicella cavolini, have been frequently reported as co-occurring species in the deep Mediterranean Sea. However, knowledge regarding spatial distribution of the two species in the deep sea is still fragmented, as well as potential drivers of their co-occurrence. This study aims to provide data on the status of deep-dwelling red coral populations, which are now the main target of commercial harvesting, study the demography of the yellow gorgonian in the deep sea, and finally analysing their variability when co-occur. Both species exhibited the highest population density at deeper depths and the presence of an inverse relationship between population density and colony height. We found a high percentage (40% on average) of red coral harvestable colonies (> 10 mm basal diameter), as well as of living colonies (77% as average). Our study evidenced that most of co-occurring colonies were found below 130 m depth. Red coral density did not significantly vary with the presence of E. cavolini, whereas the yellow gorgonian showed significant higher density when co-occur with red coral, even if with lower height. Distance-based linear modelling (DistLM) revealed that red coral density significantly influenced the presence of the yellow gorgonian, emphasizing the need for proper conservation strategies of red coral populations in order to preserve habitat complexity and associated diversity.
In the last decades, the scientific community has developed many methods and approaches for the a... more In the last decades, the scientific community has developed many methods and approaches for the assessment of surface waters quality status and the relative impacts of anthropogenic pressures including, among the others, municipal and industrial wastewater treatment plants, agriculture, animal farming and many other land uses. According to the Water Framework Directive (WFD; 2000/60/EC), each EU Member State has been committed to identifying River Basin Districts, in which, ideally, every water body within European boundaries should have been included. As a contribution to the quality assessment of the Sardinian River Basin District, in the framework of the project “Hydraulic and environmental modelling for the gap analysis and the identification of programmes of measures aimed to satisfy the environmental quality objectives” funded by the Regione Sardegna, we applied a simplified version of the AQUATOX model, developed for investigating its feasibility and validity in case of missi...
Since rising temperature (T) will enhance biochemical reactions and coastal marine sediments are ... more Since rising temperature (T) will enhance biochemical reactions and coastal marine sediments are hotspots of carbon cycling, marine heatwaves’ (MHWs’) intensification caused by climate change will affect coastal biogeochemistry. We investigated the effects of MHWs on sediment organic matter (OM) in a nearshore locality (NW Sardinia, Mediterranean Sea) receiving an artificial warm water plume generating T anomalies of 1.5–5.0 °C. Sediments were collected before and after 3 and 11 weeks from the initial plume release. Both MHWs influenced sedimentary OM quantity, composition, and degradation rates, with major effects associated with the highest T anomaly after 3 weeks. Both MHWs enhanced sedimentary OM contents, with larger effects associated with the highest T anomaly. Phytopigment contents increased in the short term but dropped to initial levels after 11 weeks, suggesting the occurrence of thermal adaptation or stress of microphytobenthos. In the longer term we observed a decrease ...
2021 International Workshop on Metrology for the Sea; Learning to Measure Sea Health Parameters (MetroSea)
Marine animal forests are important mesophotic habitats threatened by an increasing number of nat... more Marine animal forests are important mesophotic habitats threatened by an increasing number of natural and human pressures. Although several international agreements aim to protect these vulnerable ecosystems, the Environmental Status of most of these benthic animal-structured habitats remains unknown. Based on ROV footage, we evaluated the Environmental Status of 5 black corals forests in the center of the Western Mediterranean Sea, through the Mesophotic Assemblages Conservation Status (MACS) Index. The MACS index combines two independent indices: the Index of Status of the benthic communities, analyzing conspicuous species diversity, basal layer and canopy composition; the Index of Impact, analyzing siltation level, canopy condition and marine litter occurrence. The five investigated sites are characterized by the presence of two Antipatharians, Antipathella subpinnata and Leiopathes glaberrima, dwelling in different environmental conditions. Four sites showed high and good values of the Index of Status, and only one site showed a moderate status. Regarding the Impact Index, four sites were classified with low values, except one showed a very low value. Overall, four black forests were classified in a Good and one in a Very High Environmental Status. Assessing the Environmental Status is the first step needed to monitor these essential habitats’ health over time and improve the current frameworks for their conservation and protection, such as the Marine Strategy Framework Directive
Corallium rubrum and Eunicella cavolini are two octocorals, reported as co-occurring species in t... more Corallium rubrum and Eunicella cavolini are two octocorals, reported as co-occurring species in the deep rocky habitats of the Mediterranean Sea with a high hydrodynamic and moderate eutrophication. Their spatial distribution and demography in the deep sea are mainly affected by temperature and direct and indirect anthropogenic activities; however, knowledge of the factors that potentially influence their co-existence is scarce. This paper provides novel data on the distribution and demography of these two species, at depths between 50 and 290 m in the Western Mediterranean Sea, providing insights on their co-occurrence. Both species exhibited the highest population density at deeper sites (>150 m), showing an inverse size–density relation. Density values ranged from 0.03 colonies m−2 to 32 and 80 col. m−2 for yellow gorgonian and red coral, respectively. The two species co-occurred in 13% of the total frames examined, mostly dwelling between 120 and 160 m depth. Distance-based l...
River ecosystems are characterised by a naturally high level of hydrodynamic perturbations which ... more River ecosystems are characterised by a naturally high level of hydrodynamic perturbations which create aquatic-terrestrial habitats indispensable for many species, as well as for the human beings' welfare. Environmental degradation and habitat loss caused by increasing anthropogenic pressures and global change affect freshwater aquatic ecosystems worldwide and have caused changes in water flow regimes and channels morphologies. These, in turn, decreased the natural flow capacity and reduced habitat availability, thus causing severe degradation of rivers' ecological integrity. The ecological flow (e-flow) is commonly intended as the quantity, timing, duration, frequency and quality of water flows required to sustain freshwater, estuarine and near‐shore ecosystems and the human livelihoods and well‐being. Maintaining the e-flow represents a potential tool for restoring and managing river ecosystems, to preserve the autochthonous living communities, along with environmental se...
XXIII Congress of the Italian Association of Oceannography and Limnology, Functioning, alteration... more XXIII Congress of the Italian Association of Oceannography and Limnology, Functioning, alteration and restoration of aquatic ecosystems, 26-29 September 2017, Cagliari, Sardinia, Italy.-- XXIII Congresso della Associazione Italiana di Oceanologia e Limnologia - XXIII Congress of the Italian Association of Oceannography and Limnology, Funzionamento, alterazioni e recupero degli ecosistemi acquatici
2018 Ocean Sciences Meeting, 11-16 February, in Portland, OregonBottom trawling is a major driver... more 2018 Ocean Sciences Meeting, 11-16 February, in Portland, OregonBottom trawling is a major driver of sedimentary dynamics in the deep sea, resuspending surface sediments and eroding the seafloor. Although the impacts of trawling on deep-sea sediment properties and the resulting impairment of the ecosystem functioning have been previously documented, its repercussions on the bioavailability of organic matter still need to be fully addressed. To provide insighits on this, biochemical composition of organic matter (proteins, lipids, carbohydrates, and phytopigments) along with sediment dry bulk density, grain size, and 210Pb concentrations were analyzed in triplicate sediment cores retrieved in trawled and untrawled sites from the Gulf of Castellammare, Sicily (Mediterranean Sea), during the EU Eurofleets-2 ISLAND (ExplorIng SiciLian CAnyoN Dynamics). The trawled site was severely eroded, as shown by the high dry bulk density and depleted excess 210Pb concentrations, whereas the excess 210Pb profile at the untrawled site revealed a 6 cm thick surface mixed layer derived from bioturbation overlaying softer sediments that had accumulated at an average rate of 0.15 cm yr-1. Overall, organic matter contents in the trawled site were 14-37% lower than those in the untrawled one. However, bioavailable organic matter (lipids, proteins, and phytopigments) concentrations in the uppermost layer were comparable in both trawled and untrawled sites, likely due to similar inputs of pelagic organic matter prior to the sampling period. Phytopigment concentrations decreased with depth along the cores at both sites, but at a ca. 20% higher rate in the trawled areas. This result suggests that persistent sediment resuspension and erosion due to trawling can modify food value of surficial sediments for the benthos more rapidly than biological consumption or sediment bioturbation. Then, we hypothesize that the biota in persistently trawled sediments may be more dependent upon the input from the overlaying water layers than that in untrawled sitesPeer Reviewe
Timing and rates of release of particulate organic matter (POM) beneath the Antarctic sea ice dur... more Timing and rates of release of particulate organic matter (POM) beneath the Antarctic sea ice during the melting season are relatively unknown. To shed light on this topic, we investigated: i) quantity and biochemical composition of POM released below annual sea ice in Terra Nova Bay (TNB, Ross Sea, Antarctica) through sediment traps deployed at 10- and 30-m depth; ii) the abundance and taxonomic composition of phytoplankton; iii) the abundance and biochemical composition of two zooplankton species, namely the pteropods Clione limacina antarctica and Limacina helicina antarctica. Overall, our results show that in late spring-early summer in TNB the melting of annual sea ice determines a rapid release of particles into the underlying water column, and that those particles are transported downward at the rate of hours to days. POM fluxes were dominated by lipids, which probably resulted from zooplankton grazing activity on sea-ice algae and faecal pellets that were released into the w...
Marine litter is an ever-increasing problem that demands immediate reduction plans and mitigation... more Marine litter is an ever-increasing problem that demands immediate reduction plans and mitigation actions that should act synergically to efficiently meet ambitious goals. Since the seafloor has been recognized as the major sink for marine debris, the study of litter accumulation dynamics represents a fundamental tool to evaluate future removal actions. We analysed a 7 years (2013-2019) standardized data series collected along Sardinian fishing grounds through MEDiterranean International Trawl Survey, for which estimates of density and weight of seafloor macro-litter were calculated over 707 hauls. Results show the absence of any temporal trend in seafloor macro-litter density and weight, but rather indicate a spatial and bathymetric segregation of different litter categories. Our data showed how different sources and physical features of macro-litter items (i.e., plastic and fishing gears, rubber, glass, metal and textile) led to spatially segregated accumulation hotspots. These hotspots often occurred at shallower depths and closer to coastlines, representing spots where future litter removal action could be prioritized. We also point out here how the identification of seafloor macro-litter hotspots using aggregated data that include plastic items could indeed hide the identification of hotspots of other less abundant but yet detrimental macro-litter categories accumulated in the marine environment.
Mediterranean red coral Corallium rubrum is considered the most precious coral worldwide. Harvest... more Mediterranean red coral Corallium rubrum is considered the most precious coral worldwide. Harvesting activities are performed by licensed scuba divers and managed through the recent pan-Mediterranean management plan issued by General Fisheries Commission for the Mediterranean (GFCM) along with measures locally enacted, imposing limits on licenses, harvesting season, minimum depth of dive, and size. The use of Remotely Operated Vehicles (ROVs) is prohibited, with the only exception being for scientific purposes. Despite measures already in force, the implementation of additional management tools has been recently recommended. This article reports results from the first monitoring campaign on C. rubrum harvesting based on ROVs for seabed exploration and Onboard Scientific Observers (OSOs), carried out from 2012 to 2015 along the coast of Sardinia (Mediterranean Sea-Western basin). More than 450 dives were monitored, confirming how ROV's support eases the scouting of exploitable banks, leading to increases in catches. OSOs reported the collection of colonies below the minimum reference size and catches/dive above limits. Onboard observers collected data also on colony diameter, which is crucial for the estimation of population size structure and exploitation status. OSOs proved to be valid tools in providing additional and reliable information on red coral harvesting, thus deserving to be included among mandatory measures for the sustainable exploitation of red coral in the Mediterranean Sea.
Microplastics (MPs) are ubiquitous contaminants of the marine environment, and the deep seafloor ... more Microplastics (MPs) are ubiquitous contaminants of the marine environment, and the deep seafloor is their ultimate sink compartment. Manipulative and field experiments provided evidence of the ingestion of MPs by deep-sea fauna, but knowledge of MPs' fate once ingested still remains scant. We provide evidence of MP partial retention and fragmentation mediated by digestion activity of a Norwegian langoustine, a good bioindicator for MP contamination of the deep sea. We report here that MPs in the intestines were more abundant and significantly smaller (up to 1 order of magnitude in surface) than those in the stomachs. Our results show that the stomach can act as a size-bottleneck for ingested MPs, enhancing the retention of larger particles within the stomach and promoting fragmentation into smaller plastic debris, which is then released in the intestine. Our results provide evidence that the langoustine is responsible for the fragmentation of MPs already accumulated in sediments through its scavenging activity and digestion. These findings highlight the existence of a new peculiar kind of "secondary" MPs, introduced in the environment by biological activities, which could represent a significant pathway of plastic degradation in a secluded and stable environment such as the deep sea.
Over the last decades, Global Climate Change (GCC) caused increase in seawater temperature, which... more Over the last decades, Global Climate Change (GCC) caused increase in seawater temperature, which have shown to be detrimental for Mediterranean red coral populations (Corallium rubrum). Recent researches described how responses to temperature increase can differ depending on location and previous stress history; however, investigations throughout a wide bathymetric range on the thermo-tolerance of specimens sharing the same thermally stable environment are still lacking. In order to test if C. rubrum colonies dwelling below the thermocline threshold have an intrinsic different sensitivity to thermal stress, corals at different depths (32 m and 100 m) were collected, kept in aquaria, and their responses to stress analysed in lab experiments. Oxygen consumption and necrosis dynamics were estimated at different temperature regimes (14°C; 21°C and 25°C). Shallow water samples showed a significant lower oxygen consumption and coenosarc necrosis at all temperatures, revealing a potential...
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
2021 International Workshop on Metrology for the Sea; Learning to Measure Sea Health Parameters (MetroSea), 2021
The precious red coral, Corallium rubrum, and the yellow gorgonian, Eunicella cavolini, have been... more The precious red coral, Corallium rubrum, and the yellow gorgonian, Eunicella cavolini, have been frequently reported as co-occurring species in the deep Mediterranean Sea. However, knowledge regarding spatial distribution of the two species in the deep sea is still fragmented, as well as potential drivers of their co-occurrence. This study aims to provide data on the status of deep-dwelling red coral populations, which are now the main target of commercial harvesting, study the demography of the yellow gorgonian in the deep sea, and finally analysing their variability when co-occur. Both species exhibited the highest population density at deeper depths and the presence of an inverse relationship between population density and colony height. We found a high percentage (40% on average) of red coral harvestable colonies (> 10 mm basal diameter), as well as of living colonies (77% as average). Our study evidenced that most of co-occurring colonies were found below 130 m depth. Red coral density did not significantly vary with the presence of E. cavolini, whereas the yellow gorgonian showed significant higher density when co-occur with red coral, even if with lower height. Distance-based linear modelling (DistLM) revealed that red coral density significantly influenced the presence of the yellow gorgonian, emphasizing the need for proper conservation strategies of red coral populations in order to preserve habitat complexity and associated diversity.
In the last decades, the scientific community has developed many methods and approaches for the a... more In the last decades, the scientific community has developed many methods and approaches for the assessment of surface waters quality status and the relative impacts of anthropogenic pressures including, among the others, municipal and industrial wastewater treatment plants, agriculture, animal farming and many other land uses. According to the Water Framework Directive (WFD; 2000/60/EC), each EU Member State has been committed to identifying River Basin Districts, in which, ideally, every water body within European boundaries should have been included. As a contribution to the quality assessment of the Sardinian River Basin District, in the framework of the project “Hydraulic and environmental modelling for the gap analysis and the identification of programmes of measures aimed to satisfy the environmental quality objectives” funded by the Regione Sardegna, we applied a simplified version of the AQUATOX model, developed for investigating its feasibility and validity in case of missi...
Since rising temperature (T) will enhance biochemical reactions and coastal marine sediments are ... more Since rising temperature (T) will enhance biochemical reactions and coastal marine sediments are hotspots of carbon cycling, marine heatwaves’ (MHWs’) intensification caused by climate change will affect coastal biogeochemistry. We investigated the effects of MHWs on sediment organic matter (OM) in a nearshore locality (NW Sardinia, Mediterranean Sea) receiving an artificial warm water plume generating T anomalies of 1.5–5.0 °C. Sediments were collected before and after 3 and 11 weeks from the initial plume release. Both MHWs influenced sedimentary OM quantity, composition, and degradation rates, with major effects associated with the highest T anomaly after 3 weeks. Both MHWs enhanced sedimentary OM contents, with larger effects associated with the highest T anomaly. Phytopigment contents increased in the short term but dropped to initial levels after 11 weeks, suggesting the occurrence of thermal adaptation or stress of microphytobenthos. In the longer term we observed a decrease ...
2021 International Workshop on Metrology for the Sea; Learning to Measure Sea Health Parameters (MetroSea)
Marine animal forests are important mesophotic habitats threatened by an increasing number of nat... more Marine animal forests are important mesophotic habitats threatened by an increasing number of natural and human pressures. Although several international agreements aim to protect these vulnerable ecosystems, the Environmental Status of most of these benthic animal-structured habitats remains unknown. Based on ROV footage, we evaluated the Environmental Status of 5 black corals forests in the center of the Western Mediterranean Sea, through the Mesophotic Assemblages Conservation Status (MACS) Index. The MACS index combines two independent indices: the Index of Status of the benthic communities, analyzing conspicuous species diversity, basal layer and canopy composition; the Index of Impact, analyzing siltation level, canopy condition and marine litter occurrence. The five investigated sites are characterized by the presence of two Antipatharians, Antipathella subpinnata and Leiopathes glaberrima, dwelling in different environmental conditions. Four sites showed high and good values of the Index of Status, and only one site showed a moderate status. Regarding the Impact Index, four sites were classified with low values, except one showed a very low value. Overall, four black forests were classified in a Good and one in a Very High Environmental Status. Assessing the Environmental Status is the first step needed to monitor these essential habitats’ health over time and improve the current frameworks for their conservation and protection, such as the Marine Strategy Framework Directive
Corallium rubrum and Eunicella cavolini are two octocorals, reported as co-occurring species in t... more Corallium rubrum and Eunicella cavolini are two octocorals, reported as co-occurring species in the deep rocky habitats of the Mediterranean Sea with a high hydrodynamic and moderate eutrophication. Their spatial distribution and demography in the deep sea are mainly affected by temperature and direct and indirect anthropogenic activities; however, knowledge of the factors that potentially influence their co-existence is scarce. This paper provides novel data on the distribution and demography of these two species, at depths between 50 and 290 m in the Western Mediterranean Sea, providing insights on their co-occurrence. Both species exhibited the highest population density at deeper sites (>150 m), showing an inverse size–density relation. Density values ranged from 0.03 colonies m−2 to 32 and 80 col. m−2 for yellow gorgonian and red coral, respectively. The two species co-occurred in 13% of the total frames examined, mostly dwelling between 120 and 160 m depth. Distance-based l...
River ecosystems are characterised by a naturally high level of hydrodynamic perturbations which ... more River ecosystems are characterised by a naturally high level of hydrodynamic perturbations which create aquatic-terrestrial habitats indispensable for many species, as well as for the human beings' welfare. Environmental degradation and habitat loss caused by increasing anthropogenic pressures and global change affect freshwater aquatic ecosystems worldwide and have caused changes in water flow regimes and channels morphologies. These, in turn, decreased the natural flow capacity and reduced habitat availability, thus causing severe degradation of rivers' ecological integrity. The ecological flow (e-flow) is commonly intended as the quantity, timing, duration, frequency and quality of water flows required to sustain freshwater, estuarine and near‐shore ecosystems and the human livelihoods and well‐being. Maintaining the e-flow represents a potential tool for restoring and managing river ecosystems, to preserve the autochthonous living communities, along with environmental se...
XXIII Congress of the Italian Association of Oceannography and Limnology, Functioning, alteration... more XXIII Congress of the Italian Association of Oceannography and Limnology, Functioning, alteration and restoration of aquatic ecosystems, 26-29 September 2017, Cagliari, Sardinia, Italy.-- XXIII Congresso della Associazione Italiana di Oceanologia e Limnologia - XXIII Congress of the Italian Association of Oceannography and Limnology, Funzionamento, alterazioni e recupero degli ecosistemi acquatici
2018 Ocean Sciences Meeting, 11-16 February, in Portland, OregonBottom trawling is a major driver... more 2018 Ocean Sciences Meeting, 11-16 February, in Portland, OregonBottom trawling is a major driver of sedimentary dynamics in the deep sea, resuspending surface sediments and eroding the seafloor. Although the impacts of trawling on deep-sea sediment properties and the resulting impairment of the ecosystem functioning have been previously documented, its repercussions on the bioavailability of organic matter still need to be fully addressed. To provide insighits on this, biochemical composition of organic matter (proteins, lipids, carbohydrates, and phytopigments) along with sediment dry bulk density, grain size, and 210Pb concentrations were analyzed in triplicate sediment cores retrieved in trawled and untrawled sites from the Gulf of Castellammare, Sicily (Mediterranean Sea), during the EU Eurofleets-2 ISLAND (ExplorIng SiciLian CAnyoN Dynamics). The trawled site was severely eroded, as shown by the high dry bulk density and depleted excess 210Pb concentrations, whereas the excess 210Pb profile at the untrawled site revealed a 6 cm thick surface mixed layer derived from bioturbation overlaying softer sediments that had accumulated at an average rate of 0.15 cm yr-1. Overall, organic matter contents in the trawled site were 14-37% lower than those in the untrawled one. However, bioavailable organic matter (lipids, proteins, and phytopigments) concentrations in the uppermost layer were comparable in both trawled and untrawled sites, likely due to similar inputs of pelagic organic matter prior to the sampling period. Phytopigment concentrations decreased with depth along the cores at both sites, but at a ca. 20% higher rate in the trawled areas. This result suggests that persistent sediment resuspension and erosion due to trawling can modify food value of surficial sediments for the benthos more rapidly than biological consumption or sediment bioturbation. Then, we hypothesize that the biota in persistently trawled sediments may be more dependent upon the input from the overlaying water layers than that in untrawled sitesPeer Reviewe
Timing and rates of release of particulate organic matter (POM) beneath the Antarctic sea ice dur... more Timing and rates of release of particulate organic matter (POM) beneath the Antarctic sea ice during the melting season are relatively unknown. To shed light on this topic, we investigated: i) quantity and biochemical composition of POM released below annual sea ice in Terra Nova Bay (TNB, Ross Sea, Antarctica) through sediment traps deployed at 10- and 30-m depth; ii) the abundance and taxonomic composition of phytoplankton; iii) the abundance and biochemical composition of two zooplankton species, namely the pteropods Clione limacina antarctica and Limacina helicina antarctica. Overall, our results show that in late spring-early summer in TNB the melting of annual sea ice determines a rapid release of particles into the underlying water column, and that those particles are transported downward at the rate of hours to days. POM fluxes were dominated by lipids, which probably resulted from zooplankton grazing activity on sea-ice algae and faecal pellets that were released into the w...
Marine litter is an ever-increasing problem that demands immediate reduction plans and mitigation... more Marine litter is an ever-increasing problem that demands immediate reduction plans and mitigation actions that should act synergically to efficiently meet ambitious goals. Since the seafloor has been recognized as the major sink for marine debris, the study of litter accumulation dynamics represents a fundamental tool to evaluate future removal actions. We analysed a 7 years (2013-2019) standardized data series collected along Sardinian fishing grounds through MEDiterranean International Trawl Survey, for which estimates of density and weight of seafloor macro-litter were calculated over 707 hauls. Results show the absence of any temporal trend in seafloor macro-litter density and weight, but rather indicate a spatial and bathymetric segregation of different litter categories. Our data showed how different sources and physical features of macro-litter items (i.e., plastic and fishing gears, rubber, glass, metal and textile) led to spatially segregated accumulation hotspots. These hotspots often occurred at shallower depths and closer to coastlines, representing spots where future litter removal action could be prioritized. We also point out here how the identification of seafloor macro-litter hotspots using aggregated data that include plastic items could indeed hide the identification of hotspots of other less abundant but yet detrimental macro-litter categories accumulated in the marine environment.
Mediterranean red coral Corallium rubrum is considered the most precious coral worldwide. Harvest... more Mediterranean red coral Corallium rubrum is considered the most precious coral worldwide. Harvesting activities are performed by licensed scuba divers and managed through the recent pan-Mediterranean management plan issued by General Fisheries Commission for the Mediterranean (GFCM) along with measures locally enacted, imposing limits on licenses, harvesting season, minimum depth of dive, and size. The use of Remotely Operated Vehicles (ROVs) is prohibited, with the only exception being for scientific purposes. Despite measures already in force, the implementation of additional management tools has been recently recommended. This article reports results from the first monitoring campaign on C. rubrum harvesting based on ROVs for seabed exploration and Onboard Scientific Observers (OSOs), carried out from 2012 to 2015 along the coast of Sardinia (Mediterranean Sea-Western basin). More than 450 dives were monitored, confirming how ROV's support eases the scouting of exploitable banks, leading to increases in catches. OSOs reported the collection of colonies below the minimum reference size and catches/dive above limits. Onboard observers collected data also on colony diameter, which is crucial for the estimation of population size structure and exploitation status. OSOs proved to be valid tools in providing additional and reliable information on red coral harvesting, thus deserving to be included among mandatory measures for the sustainable exploitation of red coral in the Mediterranean Sea.
Microplastics (MPs) are ubiquitous contaminants of the marine environment, and the deep seafloor ... more Microplastics (MPs) are ubiquitous contaminants of the marine environment, and the deep seafloor is their ultimate sink compartment. Manipulative and field experiments provided evidence of the ingestion of MPs by deep-sea fauna, but knowledge of MPs' fate once ingested still remains scant. We provide evidence of MP partial retention and fragmentation mediated by digestion activity of a Norwegian langoustine, a good bioindicator for MP contamination of the deep sea. We report here that MPs in the intestines were more abundant and significantly smaller (up to 1 order of magnitude in surface) than those in the stomachs. Our results show that the stomach can act as a size-bottleneck for ingested MPs, enhancing the retention of larger particles within the stomach and promoting fragmentation into smaller plastic debris, which is then released in the intestine. Our results provide evidence that the langoustine is responsible for the fragmentation of MPs already accumulated in sediments through its scavenging activity and digestion. These findings highlight the existence of a new peculiar kind of "secondary" MPs, introduced in the environment by biological activities, which could represent a significant pathway of plastic degradation in a secluded and stable environment such as the deep sea.
Over the last decades, Global Climate Change (GCC) caused increase in seawater temperature, which... more Over the last decades, Global Climate Change (GCC) caused increase in seawater temperature, which have shown to be detrimental for Mediterranean red coral populations (Corallium rubrum). Recent researches described how responses to temperature increase can differ depending on location and previous stress history; however, investigations throughout a wide bathymetric range on the thermo-tolerance of specimens sharing the same thermally stable environment are still lacking. In order to test if C. rubrum colonies dwelling below the thermocline threshold have an intrinsic different sensitivity to thermal stress, corals at different depths (32 m and 100 m) were collected, kept in aquaria, and their responses to stress analysed in lab experiments. Oxygen consumption and necrosis dynamics were estimated at different temperature regimes (14°C; 21°C and 25°C). Shallow water samples showed a significant lower oxygen consumption and coenosarc necrosis at all temperatures, revealing a potential...
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