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Background. Ceriantharia is a subclass of the phylum Cnidaria, which comprises tube- dwelling marine invertebrates. This subclass is composed of three families, including Arachnactidae, with two known genera. Currently, the genus Arachnanthus has five valid species recorded from Australia, the Mediterranean Sea and both the Southern and Northern Pacific Ocean. However, at the moment, there is no record of organisms of this family from the South Atlantic Ocean. Besides that, the life cycle of any species of the genus Arachnanthus is known. The present study describes a new species of the genus Arachnanthus and its life cycle, based on specimens from Uruguay and South of Brazil. Methods. Larvae were collected by plankton net in Rio Grande--Brazil and the development and external morphology of these specimens were observed in the laboratory during two years, and subsequently described. Additionally, nine adult ceriantharians correspondent to the larvae from Rio Grande were collected in Uruguay and their external and internal anatomies, and cnidome were described. Results. Arachnanthus errans sp. nov. exhibited a free-swimming, short-lived cerinula larvae that spent short-time on the plankton. The larva developed into small and translucent polyps with a short actinopharynx, one pair of mesenteries attached to a siphonoglyph, and a medium first pair of metamesenteries. Further, the adult polyp displayed an unprecedented locomotion behavior in Ceriantharia that is first reported here, it can crawl under and in between the sediment. [ABSTRACT FROM AUTHOR]

As far as the knowledge of the seabed is concerned, both for safe navigation and for scientific research, 3D models, particularly digital bathymetric models (DBMs), are nowadays of fundamental importance. This work aimed to evaluate the quality of DBMs according to the interpolation methods applied to obtain grid format 3D surfaces from scattered sample points. Other complementary factors affecting DBM vertical accuracy, such as seabed morphological complexity and surveyed points sampling density, were also analyzed by using a factorial ANOVA experimental design. The experiments were performed on a multibeam dataset provided by the Italian Navy Hydrographic Institute (IIM) with an original resolution of 1 m × 1 m grid spacing, covering a surface of 0.24 km2. Six different sectors comprising different seabed morphologies were investigated. Eight sampling densities were randomly extracted from every sector, each with four repetitions. Finally, four different interpolation methods were tested, including: radial basis multiquadric function (RBMF), ordinary kriging (OK), universal kriging (UK) and Gaussian Markov random fields (GMRF). The results demonstrated that both RBMF and OK produced very accurate DBM in areas characterized by low levels of seabed ruggedness at sampling densities of only 0.0128 points/m2 (equivalent grid spacing of 8.84 m). In contrast, a higher density of 0.1024 points/m2 (3.13 m grid spacing) was required to produce accurate DBM in areas with more complex seabed topography. On the other hand, UK and GMRF were strongly influenced by morphology and sampling density, yielding higher vertical random errors and more prone to slightly overestimate seabed depths. In addition, sampling density and morphology were the factors that most influenced the vertical accuracy of the interpolated DBM. In this sense, the highly statistically significant influence of the interaction between sampling density and morphology on the vertical accuracy of the interpolated DBM confirms the need to perform a preliminary analysis of seabed morphological complexity in order to increase, if necessary, the number of surveyed points in cases of complex morphologies. [ABSTRACT FROM AUTHOR]

Emerging evidence of rhodolith bed complexity and heterogeneity poses a challenge to monitoring strategies and questions about the role of abiotic factors in controlling the observed morphostructural diversity. Mollusk thanatocoenoses quickly respond to environmental conditions, expressing fidelity to biocoenosis and representing, thus, a useful ecological/paleoecological tool to unravel this heterogeneity. In this research, we studied three distinct rhodolith beds from the Tyrrhenian Sea (Italy), in a range between 40 and 100 m of water depth, together with their mollusk thanatocoenoses, sediment size, and oceanographic conditions. The beds are all heterogeneous and rarely correspond to a specific rhodolith morphotype and shape. On the contrary, the study of the associated thanatocoenoses led to distinguish at least five different assemblages within the known variability of the Coastal detritic (DC) association. DC and deep mud (VP) mollusk species dominate hanatocoenosis A, which is associated with mixed sediment and a low hydrodynamic regime. Thanatocoenosis B corresponds to an assemblage in which DC species mixed with species of adjacent vegetated bottoms in sandy sediment with a medium hydrodynamic. Thanatocoenosis C includes species related to muddy coastal detritic (DE) and offshore detritic (DL) associated with sand and a variable proportion of praline and branch morphotypes. Thanatocoenoses D and E include a wide range of detritic species (DE DC, DL) together with VP and coralligenous (C), associated with exclusive praline and gravelly sand (Thanat. D), or a mixed proportion of branch and praline and mixed sediment (Thanat. E). Our results demonstrate that the study of mollusk thanatocoenoses provides insights into the diversity within and among heterogeneous rhodolith beds. Moreover, rhodoliths, as part of the sediment, create microhabitats suitable for a wide range of mollusk species that contribute to the formation of complex thanatocoenoses. [ABSTRACT FROM AUTHOR]

Nudibranchs have a mostly carnivorous diet, and they prey on a wide variety of other animal taxa. Many species, mainly belonging to the Cladobranchia suborder, feed on cnidarians, including member of the class Hydrozoa. Several hydrozoan species display a symbiotic lifestyle, being associated with other benthic invertebrates, including for instance bryozoans, corals, octocorals, and sponges. In our knowledge, no record of nudibranch predation on symbiotic hydrozoans has been reported so far, possibly thanks to the protective action by the host towards its symbiotic hydrozoan. Here, we show the unexpected case of a nudibranch belonging to the recently described species Sakuraeolis marhe (Fernández-Simón and Moles, 2023) feeding on Zanclea sp. 2, a hydrozoan associated with the cheilostome bryozoan Celleporaria sp. This trophic association is confirmed by the presence and storage of the nematocysts into the nudibranch cnidosacs. Moreover, the nudibranch appears to selectively store mostly a single type of nematocyst, that is large size stenotele. The observation here reported represents the first well-documented record of a nudibranch feeding on a symbiotic hydrozoan and the first confirmed case of predation on Zanclea polyps. Moreover, we provide additional genetic information and the first description of the internal anatomy of S. marhe. [ABSTRACT FROM AUTHOR]

Eudendrium capillaroides Schuchert, 2008 has not been reported since its original description. The new and abundant material found in Ceuta, southern coast of the Strait of Gibraltar, allows us to refine the morphological diagnosis of this species. Eudendrium capillaroides is characterized by small monosiphonic colonies, a dense ring at the base of the hydranth, and it seems to have a preference for growing on other hydroids. Male gonophores on atrophied polyps, two-chambered (occasionally one chamber), and female gonophores on reduced polyps in the initial stages of development but hydrants later completely atrophied. Nematocysts are heterotrichous microbasic euryteles of two size classes, a larger size densely distributed in a band on the hydrant body basally and a smaller size abundant mainly on the tentacles. Furthermore, we carried out molecular analyses to assess the status of E. capillaroides and its most similar congener E. capillare within the genus Eudendrium. The use of few morphological characters or incomplete descriptions may thus lead to an incorrect wide distribution of a nominal species that actually represents a species complex. This can particularly be the case in less conspicuous species, such as many hydroids, where the degree of diversity might be underestimated. The accurate description of tiny, inconspicuous and/or cryptic species is important in order to better estimate global marine diversity as well as to understand marine communities and the relationships between their components. [ABSTRACT FROM AUTHOR]

The sub-fossil red coral deposits of Sciacca (Sicily Channel) have attracted scientific attention for nearly 150 years. Their origin and formation have been long questioned and investigated, given the fact that they represent one of the most intriguing geobiological events ever to occur in the Mediterranean basin. Less attention was given to the paleo-community associated with the sub-fossil coral. Radiocarbon age determinations, in particular, were provided only for red coral, neglecting the possibility of understanding which species were simultaneously present in the coralline paleo-community and which was their role. The study of cemented coral rubble pieces revealed that Corallium rubrum covered the largest time interval (more than 3000 years) and was contemporary to many secondary epibionts over two millennia and to Madrepora oculata for about 500 years; this last finding suggested that an uncommon co-dominance between the two structuring species occurred in the nearby living communities. The lack of Fe–Mg deposits on the cemented coral rubbles coupled with the low bioerosion rate of the red coral skeletons by the demosponge Siphonodictyon coralliirubri (assessed through the analysis of the erosive paleo-scars) suggested that the deposits met with a rapid sediment cover-up. Moreover, for the first time, the analysis of a piece of cemented coral rubble of sub-fossil red coral coming from Sardinian waters confirmed that, albeit to a lesser extent, the conditions favouring the preservation of dead corals can occur also in different localities far from Sciacca. [ABSTRACT FROM AUTHOR]

Sea-bottom sampling at bathyal depths off the Apulian margin (southwestern Adriatic Sea) recovered shelly biogenic sediments rich in mollusk remains. Noteworthy is the occurrence in such taphocoenoses of loose chiton valves, rarely reported in these environments. We identified four species of Polyplacophora, Leptochiton asellus (Gmelin, 1791), Belknapchiton alveolus (M. Sars MS, Lovén, 1846), Hanleya hanleyi (Bean in Thorpe, 1844), and the new species Leptochiton antondohrni. L. asellus (Gmelin, 1791) and B. alveolus are primarily of North Atlantic (boreo-celtic) affinity and thus considered to belong to last Pleistocene glacial assemblages, whose presence in the study area has long been ascertained. The same could be true for the valves of H. hanleyi and, possibly, Leptochiton antondohrni n. sp. Finally, we updated the list of mollusks found thus far in the deep-sea taphocoenoses of this area, including new records of North Atlantic-type taxa considered at present extinct in the Mediterranean basin. [ABSTRACT FROM AUTHOR]

The paper estimates the tidal distances between the components of wide binary stars (BS) in the Pleiades. We used data on the parameters of the Pleiades cluster and wide BSs in the Pleiades, obtained earlier from the Gaia DR2 data. Two models of a cluster are considered in the form of a gravitating sphere, homogeneous and inhomogeneous in density. Using the integrals of angular momentum and energy of the motion of the centers of mass of the BSs, two elliptical orbits and two open "rosette-like" trajectories of the centers of mass of the BSs relative to the center of mass of the three-body system (the BS components and the cluster) are constructed. For three bodies in a coordinate system nonuniformly rotating relative to their center of mass with the origin at the center of mass of the BS the equations of motion are written. For the model of a homogeneous cluster, a formula is obtained for the value for a BS moving along an elliptical orbit. The integrals of angular momentum and energy of motion of the components of the BS and three bodies of the system are obtained. The sizes of the area under the surface of zero velocities (SZV) of the BS components along the axes of the coordinate system with the origin in the center of mass of the BS are estimated. It is shown that in the model of a homogeneous cluster, the sizes of the area under the SZV of the BS components in the pericenters of the considered orbits are smaller than in the apocenters, and on the inner and outer parts of the BS orbits there are restrictions on the size of the area under the SZV of the BS components that differ in number and magnitude. For the model of an inhomogeneous cluster, an equation is obtained for the quantity for the BS moving along the "rosette" trajectory relative to the center of mass of three bodies. The quantities are numerically determined for the BS at different points of two such trajectories. With the help of the energy integral of the motion of three bodies, the sizes of the area under the SZV of the BS components are determined. With an increase in the distance of the center of mass of the BS from the center of mass of three bodies in the model of an inhomogeneous cluster, an increase in the size of the area under the SZV of the BS components was noted, as well as the existence of more complex restrictions on the size of this area than in a homogeneous cluster. Mutual distances between the components of wide BSs in the Pleiades are between the maximum and minimum values of for BSs on "rosette" trajectories. The increase in with the distances of the BS components from the center of the cluster is mainly due to the motion of the BS along its trajectories in the Pleiades. Other applications of the integral for estimating the BS parameters in the Pleiades are also considered. [ABSTRACT FROM AUTHOR]

Background: Hydrothermal vents, cold seeps, pockmarks and seamounts are widely distributed on the ocean floor. Over the last fifty years, the knowledge about these volcanic-associated marine ecosystems has notably increased, yet available information is still limited, scattered, and unsuitable to support decision-making processes for the conservation and management of the marine environment. Methods: Here we searched the Scopus database and the platform Web of Science to collect the scientific information available for these ecosystems in the Mediterranean Sea. The collected literature and the bio-geographic and population variables extracted are provided into a systematic map as an online tool that includes an updated database searchable through a user-friendly R-shiny app. Results: The 433 literature items with almost one thousand observations provided evidence of more than 100 different volcanic-associated marine ecosystem sites, mostly distributed in the shallow waters of the Mediterranean Sea. Less than 30% of these sites are currently included in protected or regulated areas. The updated database available in the R-shiny app is a tool that could guide the implementation of more effective protection measures for volcanic-associated marine ecosystems in the Mediterranean Sea within existing management instruments under the EU Habitats Directive. Moreover, the information provided in this study could aid policymakers in defining the priorities for the future protection measures needed to achieve the targets of the UN Agenda 2030. [ABSTRACT FROM AUTHOR]

To better understand the depositional constraints on the fingerprint characteristics of methane isotopes, we present a set of carbon/hydrogen isotopic data for CH4, CO2, pore water, carbonate, and total organic carbon along a 70‐m sedimentary core. The sedimentary facies (Units I, II, and III from upper to bottom) suggested depositional environments of the present estuary, shallow marine, and floodplain‐estuary. Calculations suggested that around 86% of methane was produced through the CO2 reduction pathway. In this pathway, the hydrogen in CH4 is from ambient water, while the carbon is from dissolved inorganic carbon. Correspondingly, our study showed that the values of δDCH4 displayed similar trends with those of δDH2O and Cl− concentrations along the depth profiles. The low δDCH4 below 44.5 m corresponded to low δDH2O and low salinity during the cold and low‐sea‐level period. The values of δ13CCH4 generally synchronously changed with those of δ13CCO2. The variation trends of δ13CCH4 and δ13CCO2 were the same with δ13Ccarbonate from 10 to 70 m depth but decoupled above 10 m. The values of δ13CCH4 in Units II and III were correlated with the δ13Ccarbonates, which is related to the sedimentary processes. But decoupling of low values of δ13CCH4 and δ13CCO2 from δ13Ccarbonates in Unit I may be related to preferential microbial consumption of labile compounds with light carbon isotopic compositions, such as lipids. In short, the variations of δ13CCH4 and δDCH4 were largely related to the sedimentary process, which controlled the isotopic compositions of both water and carbonate. Plain Language Summary: As an important greenhouse gas, methane (CH4) contributes more to global warming than the same mole's carbon dioxide (CO2). The methane isotopic composition is widely used to trace sources. Coastal sediments, recording the rise and stabilization of the global sea level since the Last Glacial Maximum, host enormous volumes of CH4. Of interest is whether the depositional process could impact methane isotopic signatures, adding uncertainty to the traceability. We conducted analyses including C/H isotopic data of CH4, CO2, porewater, carbonates, and total organic carbon along a 70‐m sedimentary core from Hangzhou Bay, China. Calculations suggested that about 86% of methane was produced through the CO2 reduction pathway. In this pathway, the hydrogen in CH4 is derived from ambient water, while the carbon is from CO2, which was isotopically in equilibrium with carbonate. Our results suggested that sedimentary processes are the primary abiotic factors affecting the variations of the stable carbon and hydrogen isotopic compositions of biogenic CH4 from coastal sediment. Key Points: Higher than 80% of biogenic methane along the sediment core was produced through the CO2 reduction pathwayC and H of biogenic CH4 from ambient CO2 and H2 are isotopically in equilibrium with ambient carbonate and water, respectivelyThe sedimentary process is one of the primary abiotic factors affecting the variations of δ13CCH4 and δDCH4 from coastal sediment [ABSTRACT FROM AUTHOR]

A forest of the black coral Antipathella subpinnata was found from 52 to 80 m depth in three different sites at Tremiti Islands Marine Protected Area (MPA; Mediterranean Sea), with two of them hosting a monospecific forest on horizontal and vertical substrates. Colonies of A. subpinnata showed a mean density between 0.22 ± 0.03 and 2.40 ± 0.26 colonies m -2 (maximum local values of 2.4-7.2 colonies m -2 ). The link between the local distribution of A. subpinnata and the main oceanographic features confirmed the fundamental role of the currents in shaping the distribution of the species in presence of hard substrata. This black coral forest represents the only one known thus far in the Adriatic Sea, but it could be linked with other unseen forests all over the Mediterranean Sea. The associated megafauna highlights the importance of these forests as habitat for species of both conservation and commercial importance but, at the same time, makes such habitat a target for fishing practices, as many lost fishing gears were found within the coral forest. The enlargement of the MPA borders and the enforcement of controls in the area of the A. subpinnata forest is urgently needed for the proper conservation of this protected species.

Seascape mapping is critical to understanding ecosystem services and managing areas with potential for fishing, power generation, mining, and tourism. Despite advances in marine geophysics, the necessary equipment to make underwater cartography can be expensive and requires a certain degree of specialization. In areas with scarce data, ethnomapping can be used for the elaboration or complementation of marine cartography. In addition, it provides information about the nature, concepts, phenomena, and nomenclatures attributed by the local population. The aim of this study was to integrate the knowledge of artisanal fishermen from NE Brazil into the mapping of seascapes, validating the obtained cartography with scientific sampling. Focus groups were used to promote an open discussion of local users' knowledge about seascapes and their importance for local fisheries. After analyzing, it was possible to correlate the products of participatory mapping with the scientific data available in the literature, resulting in the seascape ethnomap. Nine seascapes relevant to subsistence fisheries were identified. The mapping of seascapes and fauna captured by indigenous fishermen was similar to that produced from preexisting geology, geomorphology, and fishing data. This validated the methodological protocol and the importance of the participation of local populations in coastal conservation and management activities. [ABSTRACT FROM AUTHOR]

The precious red coral (Corallium rubrum L.) represents one of the most fascinating marine species of the Mediterranean Sea. Several samples, including red coral together with its accompanying species, were found in the zoological collection of the Italian pioneer biologist Lazzaro Spallanzani (1729–1799), collected in the Messina Strait during his voyage in Sicily (1788). The study of these samples allowed the inclusion of numerous additional species in the traditional red coral facies as the large oyster Neopycnodonte cochlear, the giant barnacle Pachylasma giganteum, the mesophotic scleractinian Caryophyllia (Caryophyllia) cyathus. These specimens proved to be very useful in describing the diversity of the paleo-community including red coral, shedding light on its formation processes. In particular, some specimens are composed of red coral rubble consolidated and cemented with other carbonatic remains Probably, these peculiar specimens have a similar origin to those of the Sciacca Banks already known from the Sicily Channel. In fact, the two areas are prone to intense seismic activity that periodically causes mass mortalities of red coral from nearby rocky reliefs and the formation of biogenic detritus, while the resulting chemical environment of the water and the sediments allows the consolidation of the carbonatic remains. [ABSTRACT FROM AUTHOR]

Pennatulaceans (Octocorallia: Pennatulacea) are among the most dominant octocoral species living in soft bottom communities. Some of them are cosmopolitan and have been recorded in all seas and oceans of the world, from shallow waters up to about 6260 m deep. In the present study, we try to find answers to questions about the biogeographical distribution of sea pens including most recently described species. We also evaluate the diversity and faunistic affinities among pennatulaceans of the world’s oceans, and determine the degree of faunistic isolation of the Mediterranean Sea from the Atlantic. Finally, we return to the old debate about the hypothetical oldest diversification center of sea pen lineages. [ABSTRACT FROM AUTHOR]

Distribution and occurrence data of the sea fan Leptogorgia sarmentosa (Esper, 1791) in the Mediterranean Sea were updated thanks to new photographic surveys, highlighting the presence of the species off NE Sardinia and, in particular, in the Tavolara-Punta Coda Cavallo Marine Protected Area (TPCCMPA). The estimated average distance among colonies strongly suggests that they are not able to sexually reproduce and that they probably can be considered a sterile pseudo-population supported by inputs of larvae from the Italian mainland coast towards Sardinia. The putative conveyor belt for larval input to this area is a small permanent gyre (the North-Tyrrhenian Gyre) counterclockwise moving from the Italian to the Sardinian coasts. In TPCCMPA, the growth of one colony settled at 30 m depth was investigated across 7 years (2016–2022). The morphometric parameters indicated a linear development of the colony, in terms of branch development and 3D complexity estimated through the fractal dimension. The observed growth rates were not regular but were reached through a highly variable positive and negative oscillation. A significant correlation was obtained between growth rate and average Autumn and Winter water temperature, suggesting that somatic growth occurs in these periods. In the context of long-lasting elevated seawater temperatures and local damage linked to fishing activities, L. sarmentosa was confirmed to be a resilient species compared with other erect seascape components, like other gorgonians and sponges. [ABSTRACT FROM AUTHOR]

The understanding of human anatomy has been an endeavour spanning thousands of years from the Egyptians and Greeks in antiquity to the present day. Scholars and scientists have overcome great barriers to discover the inner workings and complexities of the human body, from personal challenges and prejudices to obstacles placed by society. Our present understanding of anatomy has accumulated over centuries, and progressive generations of physicians have contributed to the ever‐growing evidence‐based knowledge. This article explores the contributions made by Vesalius and his contemporaries in the first half of the sixteenth century. These enlightened scholars advanced anatomical knowledge and, perhaps more importantly, the scientific method, directly impacting the mindset and methodologies of future anatomists. Individuals such as Berengario da Carpi and Gabriele Falloppio produced bodies of work during their lifetime that were not only important in disputing the teachings of Galen of Pergamon, which had been accepted as almost unquestionable truths for a thousand years, but also instrumental in developing a new generation of scientists. The anatomists of the late renaissance were unable to resolve many of the factual inaccuracies of Galenic teaching but provided the groundwork for scientific thinking which future generations of anatomists benefited greatly from. The principles of documenting what is observed and establishing a methodical approach to question discrepancies in experiments would go on to influence physicians such as Harvey and Malpighi to investigate and draw correct conclusions in their research and ultimately advance our understanding of human anatomy to what it is today. [ABSTRACT FROM AUTHOR]

Hyperspectral image (HSI) classification has recently been successfully explored by using deep learning (DL) methods. However, DL models rely heavily on a large number of labeled samples, which are laborious to obtain. Therefore, finding a way to efficiently embed DL models in limited labeled samples is a hot topic in the field of HSI classification. In this paper, an active learning-based siamese network (ALSN) is proposed to solve the limited labeled samples problem in HSI classification. First, we designed a dual learning-based siamese network (DLSN), which consists of a contrastive learning module and a classification module. Secondly, in view of the problem that active learning is difficult to effectively sample under the extremely limited labeling cost, we proposed an adversarial uncertainty-based active learning (AUAL) method to query valuable samples, and to promote DLSN to learn a more complete feature distribution by fine-tuning. Finally, an active learning architecture, based on inter-class uncertainty (ICUAL), is proposed to construct a lightweight sample pair training set, fully extracting the inter-class information of sample pairs and improving classification accuracy. Experiments on three generic HSI datasets strongly demonstrated the effectiveness of ALSN for HSI classification, with performance improvements over other related DL methods. [ABSTRACT FROM AUTHOR]

The underwater hyperspectral imager enables the detection and identification of targets on the seafloor by collecting high-resolution spectral images. The distance between the hyperspectral imager and the targets cannot be consistent in real operation by factors such as motion and fluctuating terrain, resulting in unfocused images and negative effects on the identification. In this paper, we developed a novel integrated underwater hyperspectral imaging system for deep sea surveys and proposed an autofocus strategy based on liquid lens focusing transfer. The calibration tests provided a clear focus result for hyperspectral transects and a global spectral resolution of less than 7 nm in spectral range from 400 to 800 nm. The prototype was used to obtain spectrum and image information of manganese nodules and four other rocks in a laboratory environment. The classification of the five kinds of minerals was successfully realized by using a support vector machine. We tested the UHI prototype in the deep sea and observed a Psychropotidae specimen on the sediment from the in situ hyperspectral images. The results show that the prototype developed here can accurately and stably obtain hyperspectral data and has potential applications for in situ deep-sea exploration. [ABSTRACT FROM AUTHOR]

Mesopelagic fishes are an important element of marine food webs, a huge, still mostly untapped food resource and great contributors to the biological carbon pump, whose future under climate change scenarios is unknown. The shrinking of commercial fishes within decades has been an alarming observation, but its causes remain contended. Here, we investigate the effect of warming climate on mesopelagic fish size in the eastern Mediterranean Sea during a glacial–interglacial–glacial transition of the Middle Pleistocene (marine isotope stages 20–18; 814–712 kyr B.P.), which included a 4°C increase in global seawater temperature. Our results based on fossil otoliths show that the median size of lanternfishes, one of the most abundant groups of mesopelagic fishes in fossil and modern assemblages, declined by approximately 35% with climate warming at the community level. However, individual mesopelagic species showed different and often opposing trends in size across the studied time interval, suggesting that climate warming in the interglacial resulted in an ecological shift toward increased relative abundance of smaller sized mesopelagic fishes due to geographical and/or bathymetric distribution range shifts, and the size-dependent effects of warming. [ABSTRACT FROM AUTHOR]

Copyright of Italian Journal of Nursing (IJN) / Giornale Italiano di Infermieristica is the property of Collegio IPASVI MI-LO-MB - Ordine Professioni Infermieristiche MI-LO-MB and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ancient hydrocarbon-seep sites known as "Calcari a Lucina" are common in Miocene strata of northern Italy and typically consist of carbonate deposits dominated by large lucinid, bathymodiolin, and vesicomyid bivalves. Here we report two new sites found in Upper Miocene strata at Monte Mauro near Brisighella in the Emilia-Romagna province. One is unusual by being embedded in unconsolidated siltstone without any carbonate, but yet, consisting of the typical, seep-restricted bivalves Bathymodiolus moroniae and Archivesica aharoni vesicomyid clams and bathymodiolin mussels. The second deposit is dominated by the lucinid Megaxinus bellardianus, which has never been reported from a Miocene seep deposit in this region, despite being common in coeval siliciclastic sediments nearby. This species emphasizes biogeographic relationships between Upper Miocene seep faunas in the Mediterranean region and the tropic Indo-West Pacific Ocean. [ABSTRACT FROM AUTHOR]

Copyright of Journal of King Abdulaziz University: Marine Sciences is the property of King Abdulaziz University, Scientific Publishing Centre and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Rhodolith seabeds are 'ecosystem engineers' composed of free-living calcareous red macroalgae, which create extensive marine habitats. This study addressed how depth influenced the structure (size and morphology) of rhodoliths and the abundance of associated floral and faunal epibionts across the Eastern Atlantic Ocean. Sampling was carried out at two sites within five regions (Brittany, Galicia, Madeira, Gran Canaria, and Principe Island), from temperate to tropical, covering a latitudinal gradient of 47°, in three depth strata (shallow, intermediate and deep), according to the rhodolith bathymetrical range in each region. Depth typically affected the rhodolith size at all regions; the largest nodules were found in the intermediate and deep strata, while rhodolith sphericity was larger at the shallow depth strata. Higher biomasses of attached macroalgae (epiphytes) were observed at depths where rhodoliths were larger. The abundance of epifauna was variable across regions and depth strata. In general, the occurrence, structure, and abundance of the associated biota across rhodolith habitats were affected by depth, with local variability (i.e., sites within regions) often displaying a more significant influence than the regional (large-scale) variation. Overall, this study showed that the rhodolith morphology and associated epibionts (flora and fauna) were mostly affected by depth, irrespective of latitude. [ABSTRACT FROM AUTHOR]

The Mediterranean Sea hosts a great Nudibranchia diversity and has proved to be particularly intriguing in the case of the family Onchidorididae, a group of dorid nudibranchs that lately increased its diversity with the addition of one recently described Mediterranean species. The Onchidorididae family has a troubled systematic history to date, characterized by uncertainties and genera that are considered valid or not, according to the different authors. This confused taxonomy reflects the lack of a broad and comprehensive view on the phylogenetic relationships occurring between Onchidorididae members, an incorrect interpretation of the diagnostic morphological characters, and a poor knowledge of important biological aspects characterizing the different genera included in the family. To shed some light on the systematics of Onchidorididae, an integrative taxonomic revision was carried out involving morphological, ecological, and molecular analyses on an updated dataset. Mediterranean specimens and species were added to the dataset of the already known Onchidorididae and a new species from the Adriatic Sea (Central Mediterranean Sea) is described here. Furthermore, historical controversies are clarified due to the discovery of new important synapomorphies useful to define genera belonging to the Onchidorididae family and to describe a new genus. Finally, the taxonomic status of all the known Onchidorididae species is investigated and discussed, filling the gap of knowledge on neglected species. [ABSTRACT FROM AUTHOR]

A biodiversity survey on three corallivorous snails (Mollusca: Gastropoda) was performed at 28 sites around the island of Bonaire to assess their distribution patterns and associated host corals. The snails and their hosts were identified and counted in three depth zones: 5–10, 10–20, and 20–30 m. The snails were Coralliophila galea and C. salebrosa (Muricidae: Coralliophilinae), and Cyphoma gibbosum (Ovulidae: Simniinae). All three species were widespread around the island without apparent interspecific geographical variation. Coralliophila galea was found exclusively on scleractinian corals, Coralliophila salebrosa almost exclusively on octocorals, and Cyphoma gibbosum only on octocorals. Coralliophila salebrosa showed more dietary overlap with Cyphoma gibbosum than with Coralliophila galea. Coralliophila galea was the most commonly encountered species with the largest number of host species. Owing to its hosts distribution, this species also showed a greater maximum depth and a wider bathymetrical range than the other two snails. The other two snails were shallower and their depth ranges did not differ significantly. Host-coral size did not seem to have influence on the number of snails per host. Coral damage caused by the snails was visible but appeared to be low, causing no mortality in Bonaire, which suggests that the relation with their hosts is more parasitic than predatory. Because these three corallivores have occasionally been reported to occur as outbreaks in other Caribbean localities and may act as vectors in the dispersal of coral diseases, it is recommended that future studies should focus on their population dynamics. [ABSTRACT FROM AUTHOR]

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We present a very high-resolution bathy-morphological map of the offshore sector around the Scoglio d’Affrica islet (northern Tyrrhenian Sea, Italy). The study area covers a sector of 45 km2, between 3 and 85 m depth. Its central part, i.e. the apex of the Ridge, is characterised by a flat or gently sloping seafloor, where three mud volcanoes, and 250 pockmarks are recognised. Differently, the western and eastern Ridge flanks are steeper and characterised by 60 quasi-rectilinear escarpments and small ridges, more than 20 morphological highs, and elongated channels occasionally floored by bedforms. The seafloor shallower than 40 m is covered by Posidonia oceanica, forming compact and continuous or fragmented meadows intermingled with sandy patches. The main map represents the bathy-morphological setting of the area, which is largely affected by fluid seepage, providing insights for habitat mapping and preliminary marine geohazard assessment due to the violent gas outburst from mud volcanoes. [ABSTRACT FROM AUTHOR]

According to the most recent scenarios, sea level is expected to keep rising during the next decades because of global warming. In this context, coastal areas are highly vulnerable to marine and climate-related processes, such as erosion and inundation. Such processes are expected to cause shoreline retreat and local morphological variations with consequent loss in natural ecosystems, exploitable coastal land, and significant socio-economic impacts. This paper aims at outlining future scenarios of potential coastal inundation along the NE coastal sector of the Island of Gozo (Malta). The study assessed expected coastline positions for the investigated coastal stretch by analysing high-resolution topographic data coupled with sea level projections for the years 2050 and 2100, accounting also for the contribution of storm surges. Results are expected to sensitize local authorities and communities about potential threats derived from sea level rise that could affect coastal areas in the near future. [ABSTRACT FROM AUTHOR]

This study aims to provide information on the site fidelity, residency patterns and the social structures of bottlenose dolphins occurring in the Gulf of Taranto in order to supply effective indications supporting the future management and conservation measures of the species. Out of 141 photo-identified individuals about 76% were re-sighted from 2 up to 31 times. The site fidelity analysis of photo-identified individuals highlighted the occurrence of 20 seasonal residents, 62 visitors and 59 transient individuals that were included in a local population in which emigration and reimmigration events occurred, as suggested by the residency-pattern analysis. The association pattern, performed using SOCPROG 2.9, highlighted a relatively low mean value of the overall half-weight association index (0.11 ± 0.04). However, the test for the null hypothesis of 'random association' was rejected and the temporal analysis made with SLAR suggested the presence of both extremely fluid and stable associations between individuals, describing a fission fusion social structure with a certain degree of social organization. Moreover, the cluster and social network analysis showed two geographically and socially segregated units. Thus, more investigations are needed and the development of a specific conservation plan for bottlenose dolphins in the whole area is required. [ABSTRACT FROM AUTHOR]

Habitat mapping, physical characteristics and benthic community of a rhodolith bed in the Pelagie Islands (Strait of Sicily, Mediterranean Sea) were studied through Multi–Beam Echo–Sounder (MBES), Remotely Operated Vehicle (ROV) and grab samples. The geomorphological analysis revealed an articulated and wide rhodolith bed; video inspections highlighted a bed with high coverage, few sandy patches and with a prevalence of the boxwork morphotype. A total of 207 taxa with 876 specimens were identified, and Polychaeta was the dominant taxon. Linguimaera caesaris, a Lessepsian benthic amphipod, was recorded in all sampling sites, and its presence represents an input to deepen the benthic assemblage research on the rhodolith bed. In terms of morphotype composition, dead/live ratio and species variability, the bed variability indicated a good status of health, although trawling signs were detected through ROV videos. The present study broadens the knowledge on Mediterranean rhodolith beds and supports the importance of survey and monitoring activities for the conservation and management of this important habitat. [ABSTRACT FROM AUTHOR]

Electrical Resistivity Tomography (ERT) is a robust and well-consolidated method largely applied in near-surface geophysics. Nevertheless, the mapping of the spatial resistivity patterns of the subsurface at a depth greater than 1 km was performed in just a few cases by the ERT method, called deep ERT (DERT). Since, in many cases, the term DERT was adopted with ambiguity for geoelectrical explorations varying in depth within a range of 0–500 m, the main goal of this review is to clearly define the DERT method, identifying a threshold value in the investigation depth. The study focuses both on the purely methodological aspects (e.g., geoelectrical data processing in low noise-to-signal ratio conditions; tomographic algorithms for data inversion) and on the technological features (e.g., sensor layouts, multi-array systems), envisaging the future directions of the research activity, especially that based on machine learning, for improving the geoelectrical data processing and interpretation. The results of the more significant papers published on this topic in the last 20 years are analyzed and discussed. [ABSTRACT FROM AUTHOR]

Porifera are considered key components of benthic communities, being typical inhabitants of both shallow and deep waters, from the mesolittoral to the bathyal zone. Although sponges are one of the most common organisms in Western Mediterranean ecosystems, in many areas the knowledge on this taxon is still very limited. In the current study, we aim to analyse and compare the sponge communities characterising the hard bottoms of two islands, Montecristo and Giglio, belonging to the Tuscan Archipelago National Park (TANP, Italy), in relation to a bathymetric gradient. A total of 340 samples were collected, 13 orders and 48 species (46 Demospongiae and 2 Calcarea) identified, with Chondrosia reniformis representing the most recorded species, being found at all sites at almost all depths. Depth was the only significant factor in the observed pattern, while the sponge community is shared between the two Islands. In addition, our data were analysed together with data available in the literature on sponges of the Tuscan Archipelago, to assess the sampling effort. Among all the Islands of the Archipelago, Giglio and Montecristo showed the higher mean species diversity. Nonetheless, the sampling effort resulted not sufficient for each Island and future studies targeting Porifera are needed. Our work is the first summarising the sponge diversity of the entire Tuscan Archipelago, and one of the few focussing entirely on the sponge fauna. These results provide new important information on the area of the TANP, aimed to become a future Marine Protected Area, adding new records, and highlighting the high diversity of a poorly known area. [ABSTRACT FROM AUTHOR]

The occurrence, relative abundance and bathymetric distribution of the deep Mediterranean heterobranch fauna were evaluated as a result of an extensive visual census down to 1825 m depth, carried out along the western Italian coasts, covering a latitudinal range of about 600 nautical miles. Observations were conducted using Remotely Operated Vehicles (ROVs) in 551 sites, focusing on the deepest part of the continental shelf, the shelf edge and the upper bathyal zone. The analysis of over 508 hours of video footage and more than 27,000 high-resolution photographs allowed to explore about 594,000 m2 of rocky outcrops and nearby soft seafloors in four main coastal areas (Ligurian Sea, north-central Tyrrhenian Sea, southern Tyrrhenian Sea, and Sicily Channel) and twelve offshore seamounts. Thirty-six species of heterobranchs, for a total of 559 records, were identified. Sixteen were only sporadically spotted (< 1% of the total observations), while three (Paraflabellina ischitana, Tritoniidae nd and Peltodoris atromaculata) contributed each for more than 10% of the records. An extension of the known Mediterranean bathymetric distribution was reported for 80% of the observed species, with many typically shallow-water taxa being also found in mesophotic environments (40–200 m). The observed marked decrease in diversity and abundance suggested that Mediterranean heterobranchs are mainly a coastal benthic group. From the geographical point of view, the heterobranch fauna present in the Ligurian Sea appeared significantly different from that observed in the Tyrrhenian Sea and the Sicily Channel, and this latitudinal pattern was discussed. Particular attention was given to single out the bathymetric distribution of the food sources of the most frequently observed species, supporting stenophagy as a limiting factor for their colonisation of the deep sea. [ABSTRACT FROM AUTHOR]

The mesophotic zone is a relatively poorly studied area of the Mediterranean Sea, drawing great interest by the scientific community in the last years. This zone represents a connection between the shallow water and the deep-sea communities, in which photophilic framework builders (e.g. coralline red algae) are gradually replaced by heterotrophic ones, such as ahermatypic corals and the bivalve Neopycnodonte cochlear. In this habitat the framework-forming organisms produce a hard substrate with a high topographic complexity, hosting a great biodiversity of secondary structuring taxa like bryozoans. During a survey on coralligenous banks in the mesophotic zone in c. 60 m depth off Gallipoli (southern Apulia), epibiotic aggregations of N. cochlear were found on the fans of the hexacoral Savalia savaglia. In the present paper the diversity of cheilostomatid bryozoans hosted by these bivalve aggregations is described and compared with published information on similar nearby habitats. A total of 48 taxa were found, six of which are newly described: Crassimarginatella matildae sp. nov., Micropora biopesiula sp. nov., Haplopoma celeste sp. nov., Schizomavella (Schizomavella) cerranoi sp. nov., Schizomavella (Calvetomavella) biancae sp. nov., and Schizoporella adelaide sp. nov. The species richness known from the southern Apulian shelf at this depth (47 species) is hereby raised to 83 cheilostomatid bryozoans. Moreover, only 12 species are shared with the other localities studied previously, while 36 are restricted to Gallipoli, supporting the hypothesis of a high rate of exclusivity among Apulian sites in terms of species composition. The differences in faunal composition, and particularly the presence of several new species discovered at Gallipoli, show once more that our knowledge of the bryozoan fauna in certain Mediterranean habitats is still incomplete and warrants further studies. [ABSTRACT FROM AUTHOR]

The bamboo coral Isidella elongata is a forest-forming alcyonacean that dwells on deep-sea soft bottoms and is presently found in the Otranto Channel (Southern Adriatic Sea). In this study, we explored the spatial distribution and the demographic structure of the I. elongata facies (IF) over time, along with the diversity of IF-associated fauna in the southern Adriatic Sea, by using a time-series data of 9 years (2012–2020) from the Mediterranean International Bottom Trawl Survey (MEDITS). The spatial distribution of I. elongata was confronted with the fishing effort in the study area over time. This facies showed a constant spatial extent but a decreasing biomass over time. Changes in the basal diameter distribution of the colonies were also observed, with a significant decrease in the sizes from 2014 to 2020. These results suggest an increasing fishery-related impact from a developing deep-sea fishery occurring in the study area. The bamboo coral in the study area represents a hotspot of biodiversity in the context of the bathyal environment. A fisheries-restricted area was recently proposed in the context of the General Fisheries Commission for the Mediterranean at the Otranto Channel to help the conservation of I. elongata in the southern Adriatic Sea. [ABSTRACT FROM AUTHOR]

This study provides a detailed reconstruction of cold-water coral mound build-up within the East Melilla Coral Province (southeastern Alboran Sea), more precisely at the northern part of Brittlestar Ridge I, over the last 300 kyr. The multiproxy investigation of core MD13-3462G reveals that mound build-up took place during both interglacial and glacial periods at average aggradation rates ranging between 1 and 10 cm kyr -1. These observations imply that corals never thrived but rather developed under stressful environmental conditions. Maximum aggradation rates of 18 cm kyr -1 are recorded during the last glacial period, hence providing the first evidence of coral mound development during this time period in the western Mediterranean. The planktonic (Globigerina bulloides) and benthic (Lobatula lobatula) δ18 O records from core MD13-3462G show typical interglacial–glacial variations during the last two interglacial–glacial cycles. This is in contrast with δ18 O records generally recovered from coral mounds and highlights that the northern part of Brittlestar Ridge I experienced reduced albeit relatively continuous accretion. High abundances of infaunal benthic foraminifera (Bulimina marginata, Bulimina striata, and Uvigerina mediterranea) suggest that weak seafloor oxygenation associated with important terrestrial organic matter input characterized interglacial periods, whilst the dominance of large epibenthic species (Discanomalina coronata and Lobatula lobatula) and Miliolids is probably linked to stronger Levantine Intermediate Water circulation and fresher organic matter input during glacial periods. In addition, the computed tomography (CT) quantification of macrofaunal remains shows that the bryozoan Buskea dichotoma is present throughout the entire 300 kyr of mound build-up history, with the exception of MIS 5, and is possibly a key contributor to mound development during glacial periods. The comparison of our observations to other long-term coral mound records demonstrates that western and central Mediterranean coral mounds do not show concurrent build-up over interglacial–glacial cycles, implying that their development may be driven by regional and local environmental forcing. [ABSTRACT FROM AUTHOR]

Understanding the impacts of microplastics on living organisms in aquatic habitats is one of the hottest research topics worldwide. Despite increased attention, investigating microplastics in underwater environments remains a problematic task, due to the ubiquitous occurrence of microplastic, its multiple modes of interactions with the biota, and to the diversity of the synthetic organic polymers composing microplastics in the field. Several studies on microplastics focused on marine invertebrates, but to date, the benthic sea slugs (Mollusca, Gastropoda, Heterobranchia) were not yet investigated. Sea slugs are known to live on the organisms on which they feed on or to snack while gliding over the sea floor, but also as users of exogenous molecules or materials not only for nutrition. Therefore, they may represent a potential biological model to explore new modes of transformation and/or management of plastic, so far considered to be a non-biodegradable polymer. In this study we analysed the stomachal content of Bursatella leachii, an aplysiid heterobranch living in the Mar Piccolo, a highly polluted coastal basin near Taranto, in the northern part of the Ionian Sea. Microplastics were found in the stomachs of all the six sampled specimens, and SEM/EDX analyses were carried out to characterize the plastic debris. The SEM images and EDX spectra gathered here should be regarded as a baseline reference database for future investigations on marine Heterobranchia and their interactions with microplastics. [ABSTRACT FROM AUTHOR]

Carbonate skeletal remains are altered and disintegrate at yearly to decadal scales in present‐day shallow‐marine environments with intense bioerosion and dissolution. Present‐day brachiopod death assemblages are invariably characterized by poor preservation on continental shelves, and abundant articulated shells of brachiopods with complete brachidia are thus not expected to be preserved if not rapidly buried. However, such preservation is paradoxically observed in shallow‐water Palaeozoic and Mesozoic brachiopod assemblages. Here, we show that a bathyal death assemblage time‐averaged to several millennia (Adriatic Sea) consists of sediment‐filled articulated shells of Gryphus vitreus with complete brachidia. Post‐mortem age distributions indicate that disintegration half‐lives exceed several centuries (c. 500–1700 years). The high frequency of articulated but centuries‐old shells (>50%) and the fitting of taphonomic models to post‐mortem ages indicate that disarticulation half‐life is unusually long (c. 200 years). Rapid sediment filling of shells: (1) inhibited disarticulation, loop fragmentation and colonization by coelobites; and (2) induced precipitation of ferromanganese oxides at redox fronts within shells. Sediment‐filled articulated shells, however, still resided at the sediment–water interface as indicated by encrusters and sponges that infested them after death. Sediment‐filled shells disintegrated through bioerosion and physical wear when residence in the taphonomically active zone exceeded c. 2000 years. We suggest that the articulation paradox is driven by the Mesozoic Marine Revolution (MMR) that escalated predation, bioturbation and organic matter recycling, all intensifying shell disintegration. A scenario with slow disarticulation in bathyal environments may have lead to preservation of articulated shells in shallow‐water assemblages prior to the MMR. [ABSTRACT FROM AUTHOR]

Seamounts are globally important and essential ecosystems for supporting and maintaining marine biodiversity. In the Mallorca Channel, three prominent seamounts are present: Ausias March, Ses Olives and Emile Baudot. Currently, this area is being evaluated for inclusion in the Natura 2000 network. For this objective three surveys were conducted in the seamounts of the Mallorca Channel during July 2018 and July 2020. Samples of macro-invertebrates obtained in the deep sea revealed a rich fauna of Mollusca (68 species belonging to 40 families). New Mollusca occurrences included: four species of Gastropoda: Colus jeffreysianus, Cantrainea peloritana, Fusiturris similis, Gymnobela abyssorum, and seven species of Bivalvia: Pododesmus squama, Allogramma formosa, Asperarca nodulosa, Cetomya neaeroides, Spondylus gussonii, Haliris granulata and Policordia gemma. Where possible, the identification of these species was confirmed using the DNA barcoding method (sequencing of the cytochrome c oxidase subunit I). This study contributes towards filling the gap in knowledge of deep-sea mollusc fauna of the north-western Mediterranean. [ABSTRACT FROM AUTHOR]

We report 35 molluscan species from Late Miocene cold-seep carbonates from the Amlang Formation in the Ilocos-Central Luzon Basin in Luzon Island, Philippines, collected in a large quarry in the province of Pangasinan. The 19 bivalve species are largely representatives of chemosymbiotic families; the six new species are the nuculid Acila (Truncacila) interferencia sp. nov., the mytilid Bathymodiolus labayugensis sp. nov., the thyasirid Conchocele pangasinanensis sp. nov., the lucinid Megaxinus gorrospei sp. nov., the vesicomyid Pliocardia ballesterosi sp. nov., and Sisonia frijellanae gen. et sp. nov., of uncertain taxonomic affinity. The 16 gastropods include one species restricted to seep deposits, the neritid species Thalassonerita hagai sp. nov.; the buccinid Enigmaticolus semisulcata represents the first fossil record of its genus. Biogeographically, the Pangasinan seep fauna shows several links to Neogene seep faunas in other tropical/subtropical areas, namely the Mediterranean and Caribbean regions. In contrast, shared taxa with nearby but extratropical Japan are few, as are shared taxa with Miocene seep deposits in New Zealand. [ABSTRACT FROM AUTHOR]

Evaluation of the impact of climatic changes on the composition of fish assemblages requires quantitative measures that can be compared across space and time. In this respect, the mean temperature of the catch (MTC) approach has been proven to be a very useful tool for monitoring the effect of climate change on fisheries catch. Lack of baseline data and deep-time analogues, however, prevent a more comprehensive evaluation. In this study, we explore the applicability of the mean temperature approach to fossil fish faunas by using otolith assemblage data from the eastern Mediterranean and the northern Adriatic coastal environments corresponding to the last 8000 years (Holocene) and the interval 2.58–1.80 Ma B. P. (Early Pleistocene). The calculated mean temperatures of the otolith assemblage (MTO) range from 13.5 to 17.3 °C. This case study shows that the MTO can successfully capture compositional shifts in marine fish faunas based on variations in their climatic affinity driven by regional climate differences. However, the index is sensitive to methodological choices and thus requires standardized sampling. Even though theoretical and methodological issues prevent direct comparisons between MTO and MTC values, the MTO offers a useful quantitative proxy for reconstructing spatial and temporal trends in the biogeographic affinity of fossil otolith assemblages. [ABSTRACT FROM AUTHOR]

Why don't people care about the deep sea? was a question addressed in a 2020 Food for Thought article in this journal. That article delivered an extensive critique of misleading statements, poorly structured analogies, and common misconceptions to challenge the largely negative or unnecessarily sensationalist narrative when the deep sea is communicated to the public. The overarching sentiment of that article has been countered by a Comment in which it is argued that people do in fact care about the deep sea. However, this counter argument is based on very little to do with the deep sea but rather a corpus of studies relating mostly to cold water corals and people's willingness to pay for their conservation and restoration in the event of impending or recent destruction. We do not feel that the Comment addresses the same problem as discussed in the original article. Here, we explain that the seeming differences of opinion about whether people care about the deep sea are based on two things: the title of the article commented on (not its content) and how the original article, and the Comment on it, define the deep sea. [ABSTRACT FROM AUTHOR]

This paper aims to study the application of hyperspectral technology in the classification of deep-sea manganese nodules. Considering the spectral spatial variation of hyperspectral images, the difficulty of label acquisition, and the inability to guarantee stable illumination in deep-sea environments. This paper proposes a local binary pattern manifold superpixel-based fuzzy clustering method (LMSLIC-FCM). Firstly, we introduce a uniform local binary pattern (ULBP) to design a superpixel algorithm (LMSLIC) that is insensitive to illumination and has texture perception. Secondly, the weighted feature and the mean feature are fused as the representative features of superpixels. Finally, it is fused with fuzzy clustering method (FCM) to obtain a superpixel-based clustering algorithm LMSLIC-FCM. To verify the feasibility of LMSLIC-FCM on deep-sea manganese nodule data, the experiments were conducted on three different types of manganese nodule data. The average identification rate of LMSLIC-FCM reached 83.8%, and the average true positive rate reached 93.3%, which was preferable to the previous algorithms. Therefore, LMSLIC-FCM is effective in the classification of manganese nodules. [ABSTRACT FROM AUTHOR]

Over recent decades, many Mediterranean and Ponto-Caspian aquatic invertebrate species have dispersed northwards and established as non-native species in colder regions. We hypothesized that these species have cold-tolerant traits, which facilitate dispersal into colder climates. Thanks to these traits, Southern European aquatic species are able to cross biogeographic boundaries. We downloaded the list of all alien invertebrate species that were fully aquatic (i.e. lacking terrestrial adults) from the GRIIS database and picked out those Mediterranean and Ponto-Caspian species that have undergone northwards range expansion. We identified traits that may facilitate dispersal to colder climates including the following: small size; capacity for behavioural thermoregulation; feeding habit (omnivorous, filter-feeders, food generalists); quiescence and dormancy (or diapause); freezing avoidance (presence of cryoprotectants); tolerance to low temperatures or eurythermicity; active dispersal; and enhanced reproduction. We statistically tested the null hypotheses that Mediterranean and Ponto-Caspian alien aquatic invertebrate species that dispersed into the north have all of these traits. We used contingency tables populated with raw frequency data with χ2—tests and assessed statistical significance at α of 0.05. We identified 95 Mediterranean and Ponto-Caspian alien aquatic invertebrate species that have shown northwards range extension, 10 (10%) of which were of Mediterranean origin and 85 (90%) of Ponto-Caspian origin. We found that this northwards dispersal from Southern Europe is mainly limited to a few following groups of aquatic invertebrates: small crustaceans, molluscs, cnidarians and annelids. Ability to go to diapause, hibernation or resting period, temperature tolerance and small size were the traits most commonly shared by these organisms. We conclude that Mediterranean and Ponto-Caspian aquatic invertebrate species showing northwards range expansion have cold-tolerant strategies. The traits analysed can favour the establishment of the species. [ABSTRACT FROM AUTHOR]

Fouling control coatings (FCCs) are used to prevent the accumulation of marine biofouling on, e.g., ship hulls, which causes increased fuel consumption and the global spread of non-indigenous species. The standards for performance evaluations of FCCs rely on visual inspections, which induce a degree of subjectivity. The use of RGB images for objective evaluations has already received interest from several authors, but the limited acquired information restricts detailed analyses class-wise. This study demonstrates that hyperspectral imaging (HSI) expands the specificity of biofouling assessments of FCCs by capturing distinguishing spectral features. We developed a staring-type hyperspectral imager using a liquid crystal tunable filter as the wavelength selective element. A novel light-emitting diode illumination system with high and uniform irradiance was designed to compensate for the low-filter transmittance. A spectral library was created from reflectance-calibrated optical signatures of representative biofouling species and coated panels. We trained a neural network on the annotated library to assign a class to each pixel. The model was evaluated on an artificially generated target, and global accuracy of 95% was estimated. The classifier was tested on coated panels (exposed at the CoaST Maritime Test Centre) with visible intergrown biofouling. The segmentation results were used to determine the coverage percentage per class. Although a detailed taxonomic description might be complex due to spectral similarities among groups, these results demonstrate the feasibility of HSI for repeatable and quantifiable biofouling detection on coated surfaces. [ABSTRACT FROM AUTHOR]

The family Cocculinidae (Gastropoda: Cocculinida) consists of small, usually colourless benthic limpets living primarily at depths below 100 m, and on decaying plant or animal remains. These habitats are difficult to sample and the knowledge about Cocculinidae species diversity, biogeography, ecology and evolution is therefore poor. To explore the species diversity of the Cocculinidae, we examined 499 specimens collected from 196 sites, mainly explored during expeditions of the 'Tropical Deep-Sea Benthos' programme in the Indo-West Pacific (IWP). To propose a species hypotheses, we used an integrated approach to taxonomy in which we combined DNA-based methods, with morphological, geographical and ecological considerations. To classify the species hypotheses into genera, we used a combination of one mitochondrial and two nuclear gene fragments to reconstruct a phylogenetic tree. We then used six morphological characters to diagnose the identified genera. Our results revealed an exceptionally high diversity of IWP Cocculinidae, with 51 species hypotheses that were mostly not assigned to available species names. We also discovered a previously unknown type of copulatory structure in the group. At a higher taxonomic level, we identified ten main clades in the family. Although six of them matched existing genera, four others should be regarded as new genera awaiting formal description. [ABSTRACT FROM AUTHOR]

Mesophotic reefs are poorly known worldwide despite their great ecological relevance and management importance for coral reef conservation strategies. To aid in filling this gap, we conducted a pioneering, large-scale survey, covering a total of around 315 miles in length, in the largest Brazilian coastal Marine Protected Area (MPA) Costa dos Corais. From the digital bathymetry model (30 to 50 m depth) generated by a multibeam echo sounder, we selected areas of greater geomorphological diversity for a detailed investigative expedition of mesophotic ecosystems. Various sampling techniques were used: single-beam echo sounders for detailing the relief, a remotely operated underwater vehicle (ROV) for habitat type investigation, baited remote underwater video (BRUV) for collecting images of the fish community, and scuba diving to perform transects describing the benthic and fish community. We analyzed reef environments from 20 to 68 m deep. As a result, we present the mapping and geomorphological characterization of two compartments of mesophotic reefs at 21–45 m depth and an image library of mesophotic ecosystems with the species description and indications of whether it is a new record in the region. Biodiversity data were collected covering eight species of sponges, with greater abundance for Ircinia spp., Aplysina spp., and Xestospongia muta; eight from corals, mainly Siderastrea spp. And Montastrea cavernosa; and 68 species of reef fish, with the Labridae family (including Scarinae—11 species) being the richest. Our results demonstrate the importance of mesophotic reefs for MPA Costa dos Corais reef biodiversity and, with that, the need to protect these areas through the application of local conservation strategies, such as the creation of "no-take zones". [ABSTRACT FROM AUTHOR]

Compared to their fossil counterparts, living brachiopods are investigated far less often, due to their occurrence in remote environments such as dark caves or deep environments. Due to the scarcity of studies targeting in situ brachiopods' populations, large-scale information on their distribution and ecological preferences is still lacking, especially on hardgrounds. The extensive employment of remotely operated vehicles (ROVs), however, has opened up the chance to better explore this taxon's diversity and ecology in the mesophotic and bathyal zones. The analysis of over 600 h of video footage collected from 624 sites, from 40 m to 1825 m, located along the Ligurian and Tyrrhenian coasts of Italy and the Sicily Channel, allowed for a large-scale investigation. The four identified species, Novocrania anomala, Gryphus vitreus, Megerlia truncata and Terebratulina retusa, emerged as common macrofaunal components of the explored habitats, especially between 150 m and 250 m, with high occurrences in the northern areas, especially on offshore seamounts. All species can form dense aggregations of individuals, with M. truncata showing the densest populations on steep rocky terraces (up to 773 individuals m−2). Except for G. vitreus, the only species also recorded on soft bottoms, the others were found exclusively on hardgrounds, with N. anomala showing a peculiar ability to exploit anthropogenic substrates such as terracotta amphorae. No stable species-specific associations were noted, even if numerous species were frequently observed together. Although brachiopods do not show the conspicuous tridimensionality of large filter-feeders, their substrate occupancy and their role in pelagic–benthic processes support their importance in deep-sea Mediterranean ecosystems. [ABSTRACT FROM AUTHOR]