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Coralligenous (C) includes calcareous build-ups of biogenic origin, characterised by the association of calcareous algae and several invertebrates. This habitat is one of the most important at the Mediterranean scale; it is a hot-spot of biodiversity thriving from shallow waters down to the limit of the mesophotic zone. The Italian project “CRESCIBLUREEF - Grown in the blue: new technologies for the knowledge and conservation of the Mediterranean reefs” aims at studying peculiar C outcrops found along a depth gradient offshore Marzamemi village (SE Sicily). During the first project expedition (June 2021), we performed a Multibeam Echosounder (MBES) survey of the target area by using a R2Sonic 2022 system. A new 17 km2 high-resolution morpho-bathymetric map was realised, which interpretation led to the identification and classification of five major habitats, including different C morphotypes. C habitat in the form of banks was found mainly distributed between 30 and 35 m of water depth (w.d.). This investigation allowed us to observe and quantify the overall C distribution along a depth gradient spanning between 20 and 100 m of w.d., giving us a broad-scale perspective of its extension at the seafloor. A third marine survey (September 2021) was focused on collecting video and still images by using a Sony α Alpha 7ii reflex coupled with the Easydive Leo3 Wi housing and the Easydive illumination system Smart Sea - Gold Plus 7000 Lumen, through scuba diving. Data collection was performed over selected areas suitable for the application of underwater photogrammetry, taking into account the presence of C build-ups (as confirmed by the interpretation of the MBES dataset) and the operational depth (i.e.: no more than 35 m of w.d.). Data collected by adopting this technique and processed using Structure-from-Motion (SfM) algorithms allowed us to get more information at the community level of such complex habitats, coupling the seafloor scale with the smaller scale obtained by direct observations. In this work, our intention is to improve the understanding of the geospatial context of Coralligenous distribution and extent from a multiscale perspective. Specifically, we want to show how eco-geomorphological indexes calculated using the high-resolution outputs of the C photogrammetry (3D meshes, DTMs, and orthomosaics) may be used to perform resolute investigations of such habitat on a broader scale, by considering their spatial distribution extrapolated from the MBES data.

Crustose coralline algae (CCA) form Coralligenous build-ups, which are ranked among the most important ecosystems in the Mediterranean shelf. Their skeletal framework hosts a variety of epi- and infaunal communities, which compete for space, contributing to the reef growth, or weaken the structure throughout bio-erosive activities. Investigating the relationship between the algal framework and these hosted communities is of extreme importance for ecological and palaeoecological purposes and monitoring goals. In this frame, the Italian project “CRESCIBLUREEF - Grown in the blue: new technologies for the knowledge and conservation of the Mediterranean reefs”, is aimed at investigating coralligenous reefs present in the area off the Marzamemi village (South-East Sicily). Two build-ups have been collected: the first one at 37 m depth, from an area rich in coralligenous cover, and the second one at 36 m depth, from a submarine channel with sparsely distributed build-ups. We present here two new investigative techniques, so far seldom applied for the characterization of the Coralligenous. The first approach involved the quantification of the surficial cover, with the use of an image analysis software, both before and after the removal of their ephemeral canopy of unmineralized organisms.These models were then analysed using Object-Based Image Analysis (OBIA) algorithms that allowed the quantification of the surficial cover. Moreover, the analysis allowed the identification and categorisation of the organisms and materials on the external part of the build-ups, confirming the primary role of CCA as the major component of the samples. Afterwards, a Computed-Tomography (CT) scan was used - for the first time with Coralligenous - to reconstruct the inner structure of the build-ups and, together with radiocarbon dating, to infer the build-ups age and growth rate. CT analysis divided the framework into four main categories based on their density (Low, Medium, High and Ultra High). The structure’s cavities, either primary or developed through taphonomic processes, have been measured as porosity. The overall highly-resolved analysis points to a complex and nonlinear growth of the build-ups. The understanding of the structural density, porosity, growth rate, and surficial cover of the build-ups is shedding some light on the Coralligenous inception and growth.

Coralligenous (C) is a type of Open Frame Reef, characterized by a variable association of calcareous red algae and macroinvertebrates. It is distributed across the Mediterranean shelf below the deepest seagrass meadows and down to the mesophotic zone, with different facies. The Italian project FISR “CRESCIBLUREEF” provided an extraordinary opportunity to explore the development of the Mediterranean C, from inception to present-day morphology and distribution off the SE coasts of Sicily. The spatial extension of C hybrid banks and discrete reliefs over the studied Sicilian shelf controls the hydrodynamics at the seafloor, the habitat biodiversity, and the related carbonate production at the shelf scale. The analyzed C samples, collected at about 36 m depth, had a columnar shape, were Holocene in age, and their development significantly modified the seafloor geomorphology. Our observations confirmed that most of the framework was built by calcareous red algae with an important contribution by bryozoans, with serpulids, molluscs, and rare corals as accompanying components of the sessile macroscopic fauna.The framework was highly porous, with a primary porosity derived from the growth, shape and structure of the skeletal components of both builders and dwellers, and an important secondary porosity derived from bioerosion and other early taphonomic processes involving both skeletonised and soft-bodied organisms, like sponges. During the entire process of framework growth and development, sponges played an important role as mineralization mediators of the autochthonous micrite fraction, which contributes significantly to the framework consolidation. Detrital micrite, rich in fine skeletal remains, is trapped in the primary and secondary cavities and represents an archive for the study of the organisms which are not directly involved in the framework building.

Calcareous red algae have calcified cell walls constituted by high-Mg calcite or aragonite (Morse et al., 2006). They are considered suitable paleoclimate archives due to their worldwide distribution and their longevity through indeterminate growth (Kamenos et al., 2008). Boron isotopes (δ11B) measured in their calcified thallus are considered a pH proxy (Hemming and Hanson, 1992). In seawater, boron occurs as boric acid and borate ion. Both species are enriched in 11B as pH increases, with boric acid characterized by an enrichment factor of 27‰ compared to borate. The boron isotope proxy theory states that borate is exclusively incorporated in the mineral lattice (Hemming and Hanson, 1992). Therefore, if we measure δ11B in carbonates, we can derive the seawater pH at the time of precipitation. Literature data on δ11B in calcareous red algae are sparse, and the mechanisms of boron incorporation are still poorly known (Piazza et al., 2022). We tested the boron isotope-pH proxy on calcareous red algae grown at 1 m depth close to CO2 seeps off the coasts of Ischia (Italy), and Methana (Greece), which are both characterized by a broad range of natural pH in seawater (from 6.80 ± 0.43 to 8.08 ± 0.07 units). Environmental data characterizing the seawater during the algal growth were extracted from CMEMS products (Marine Copernicus Service Information), or provided by literature. The δ11B values in the algae (δ11Balgae) analysed by Multi Collector Inductively-Coupled Plasma Mass Spectrometry ranged from 22.23‰ to 26.59‰, calibrated over a range of δ11B in aqueous borate (δ11Bborate) extending from 12.68‰ to 18.05‰. A crystallographic control over boron incorporation was shown by the difference in the isotopic composition of carbonate polymorphs, with Mg-calcite enriched in 11B compared to aragonite. Values of δ11Balgae higher than δ11Bborate could be attributed to the up-regulation of the calcifying fluid pH exerted by the algae. We proposed a multi-specific calibration using literature data of boron isotopes in cultured coralline algae combined with our new data on wild-grown specimens, widening the range of pH considered for δ11B calibrations so far. The proposed calibration is particularly useful when experimental calibration is not possible, such as in the fossil record and in the case of ambiguous identifications.ReferencesHemming N. G. & Hanson G. N. 1992. Boron isotopic composition and concentration in modern marine carbonates. Geochim. Cosmochim. Acta, 56, 537-543.Kamenos N. A., Cusack M. & Moore P. G. 2008. Coralline algae are global paleothermometers with bi-weekly resolution. Geochim. Cosmochim. Acta, 72, 771-779.Morse J. W., Andersson A. J. & Mackenzie F. T. 2006. Initial responses of carbonate-rich shelf sediments to rising atmospheric pCO2 and ‘‘ocean acidification’’: role of high Mg-calcites. Geochim. Cosmochim. Acta, 70, 5814-5830.Piazza G., Bracchi V. A., Langone A., Meroni A. N. & Basso D. 2022. Growth rate rather than temperature affects the B / Ca ratio in the calcareous red alga Lithothamnion corallioides. Biogeosciences, 19, 1047-1065.

The West‐Svalbard continental slope represents one of the northernmost gas hydrate provinces in the world. It is located on the western Svalbard margin in the eastern Fram Strait at ~79°N, north of the Knipovich Ridge and Molloy transform fault, situated on a hot and relatively young oceanic crust. The project Advancing Knowledge of Methane in the Arctic (AKMA), funded by the Norwegian Research Council, explores Arctic methane sources, processes, ecosystems and geological history in part of this province. During a dedicated research expedition (CAGE21-1-AKMA) a spectacular pinnacle-like structure has been identified at 914 m of water depth in the area of the north Kniponich Ridge, during the exploration by remotely operated vehicle. The structure is located at the base of a small-scale escarpment, typified by the presence of carbonate slabs. It is more than 1 m in height, has a diameter of at least 50 cm, and appears isolated on a flat seafloor with muddy-dominated heterogeneous sediment. From the video, the structure was apparently composed of dead bivalves cemented in a substrate of finer particles. Many bivalves were still articulated and with their valves closed, although no sign of living bivalves could be detected. Living regular echinoids, one large crinoid, several sponges and a few soft corals colonized the surface at the time of observation. Small samples have been collected from the surface of this fossil bivalve pinnacle. These samples supported the video-based interpretation of a fossil structure composed of cemented and carbonate-encrusted dead valves, among which the most abundant and the largest specimens belong to Thyasira cf capitanea, both juvenile and adult. The valves, either articulated or disarticulated, are often cemented by a white thick (3 mm) authigenic carbonate crust that binds together the mollusk shells, but also encrusts some of them internally. This means that these crusts continued to grow also after the death of the mollusks, when some of the valves were open. Additional interesting benthic fauna recognized in the cement includes small gastropods and foraminifers. The genus Thyasira has already been described as a typically chemosymbiotic group of species and as such, it has been reported from active cold seeps in the Arctic, as well as in other geographic areas and in the geologic record. We interpret the pinnacle as fossil evidence of a site of past methane emission, possibly exhumed by recent erosional or gravity-driven resedimentation processes.

Coralligenous (C) includes calcareous build-ups of biogenic origin, formed since the Holocene transgression. Peculiar columnar-shaped C outcrops were documented offshore Marzamemi village (SE Sicily, Ionian Sea), although the actual extension and distribution were not assessed. Project ‘CRESCIBLUREEF’ produced a new, 17 km2 high-resolution bathymetric map, leading to good knowledge about their extent in this area. C bioconstructions are largely distributed along two depth ranges 36–42 m and 86–102 m water depth. By coupling the documented uplift rate in this region and the Holocene sea-level curve, we were able to interpret the distribution of C outcrops over terraces. However, additional investigation is required to understand: (1) the role of the inherited continental shelf landscape, in creating a favorable substrate for the settlement and growth of C habitats during the Holocene, and (2) the extent to which C bioconstructions can impact the evolution of present-day continental shelf landforms and landscapes.

Coralligenous (C) bioconstructions include calcareous build-ups of biogenic origin that typify selected regions of the Mediterranean Sea. These peculiar habitats thrive from shallow waters (15-20 m of water depth (w.d.) up to the limit of the mesophotic zone, and they formed since the Holocene transgression. They are from few to tens of meters large, displaying variable lateral continuity and thickness. Peculiar C outcrops are present offshore Marzamemi (southeastern Sicily, Ionian Sea). Their extension and distribution across the shelf were investigated within the project CRESCIBLUREEF - Grown in the blue: new technologies for knowledge and conservation of Mediterranean reefs. We produced a new 17 km2 high-resolution bathymetric map using a R2-Sonic 2022 system, ground-truthed by ROV video inspections. From a geomorphological point of view, the shelf is typified by four distinct marine terraces. Climate change and tectonic uplift are the dominant forcing mechanisms responsible for the formation of long and narrow terraced landforms in a variety of geomorphic settings; and marine terraces are largely used to reconstruct the Quaternary glacial and interglacial climates. The coupling of documented uplift rate in this region (ca. 0.2 mm/yr since the Tyrrhenian time) and the evidence reported in literature for late Quaternary relative sea-level curves shows a good correlation between the distribution of C outcrops and local, short stasis of sea level transgression periods, culminated with the rapid Flandrian transgression. C outcrops are mainly spread over the first and last terraces at two specific depth ranges: from 36 to 42 m of w.d., and from 86 to 102 m of w.d., respectively. Settlement and growth were mainly favored by a low sedimentation regime. Indeed, lowstand stages were likely characterized by erosional forces. This is particularly noticeable in the middle of our study area, where we have a paleo-incision typified by peculiar erosional features we were able to map. The role of the inherited continental shelf landscape in creating favorable substrate for the settlement and growth of C during the Holocene is here investigated.

Field-based classes in geological sciences are crucial components of geoscience education and research. Owing to the COVID-19 pandemic, such activities became problematic due to limitations such as travel restrictions and lockdown periods: this motivated the geoeducational community to tailor new ways to engage people in field activities. As a result, we adopted Immersive Virtual Reality as a tool to involve students, academics, and the lay public in field exploration, thus making geological exploration accessible also to people affected by permanent or temporary motor disabilities. In particular, we evaluated how users perceive the usefulness of this approach as applied to Earth Science learning and teaching, through nine outreach events, where a total of 459 participants were involved, with different ages and cultural backgrounds. The participants explored, in an immersive mode, four geological landscapes, defined as virtual geological environments, which have been reconstructed by cutting-edge, unmanned aerial system-based photogrammetry techniques. They include: Santorini (Greece), the North Volcanic Zone (Iceland), and Mt. Etna (Italy). After the exploration, each participant filled in an anonymous questionnaire. The results show that the majority would be willing to repeat the experience, and, most importantly, the majority of the students and Earth Science academics who took part in the navigation confirmed the usefulness of this technique for geo-education purposes. Our approach can be considered as a groundbreaking tool and an innovative democratic way to access information and experiences, as well as to promote inclusivity and accessibility in geo-education, while reducing travel costs, saving time, and decreasing the carbon footprint. This work has been carried out in the framework of the following projects: i) ACPR15T4_ 00098 “Agreement between the University of Milan Bicocca and the Cometa Consortium for the experimentation of cutting-edge interactive technologies for the improvement of science teaching and dissemination” of Italian Ministry of Education, University and Research (ARGO3D - https://argo3d.unimib.it/); ii) Erasmus+ Key Action 2 2017-1-UK01-KA203- 036719 “3DTeLC – Bringing the 3D-world into the classroom: a new approach to Teaching, Learning and Communicating the science of geohazards in terrestrial and marine environments” (http://3dtelc.lmv.uca.fr/; https://www.3dtelc.com/); iii) 2018 EGU Public Engagement Grants (https://www.egu.eu/outreach/peg/).

This paper analyses and describes the benthic foraminiferal associations within the Pleistocene deposits of the Stirone River (Emilia-Romagna, Italy), with the purpose of testing foraminifera as Indirect Palaeo-Seagrass Indicators (IPSIs). Our analyses focused on two different biofacies: a Thalassinoides biofacies, characterised by an oligotypic biotic assemblage and a Pinna biofacies representing an infralittoral soft bottom colonised by marine phanerogams and characterized by high biodiversity. To strengthen the analyses, we have compared the Stirone foraminiferal association with the one of Fauglia (Tuscany, Italy), in which a well-preserved, early Pleistocene, fossil Posidonia meadow, is present. The aim of this work is to provide qualitative and quantitative parameters that can be used to recognize past vegetated environments, where fossil seagrass are no longer present. Considering the influence of ecological constraints and diagenetic processes on the foraminiferal assemblages, several indexes such as the IndexEP, the modified FORAM index (FI’), the “long vs. short life-span index” (ILS), and the K/REXT (keeled/rounded morphotypes) have been calculated and a morphotype-based analysis has been provided. Among the tested indexes, the latter proved to be the most reliable IPSI, in association with the presence of morphotype A*, permanently attached, encrusting foraminifera and the abundance of Rosalinidae.

Recent advances on the mechanism and pattern of calcification in coralline algae led to contradictory conclusions. The evidence of a biologically controlled calcification process, resulting in distinctive patterns at the scale of family, was observed. However, the coralline calcification process has been also interpreted as biologically induced because of the dependency of its elemental composition on environmental variables. To clarify the matter, five collections of Lithothamnion corallioides from the Atlantic Ocean and the Mediterranean Sea, across a wide depth range (12–66 m), have been analyzed for morphology, anatomy and cell wall crystal patterns in both perithallial and epithallial cells to detect possible ultrastructural changes. L. corallioides shows the alternation of tiers of short-squared and long-ovoid/rectangular cells along the perithallus, forming a typical banding. The perithallial cell length decreases according to water depth and growth rate, whereas the diameter remains constant. Our observations confirm that both epithallial and perithallial cells show primary (PW) and secondary (SW) calcite walls. Rectangular tiles, with the long axis parallel to the cell membrane forming a multi-layered structure, characterize the PW. Flattened squared bricks characterize the SW, with roundish outlines enveloping the cell and showing a zigzag and cross orientation. Long and short cells have different thicknesses of PW and SW, increasing in short cells. Epithallial cells are one to three flared cells with the same shape of the PW and SW crystals. Despite the diverse seafloor environments and the variable L. corallioides growth rate, the cell walls maintain a consistent ultrastructural pattern with unaffected crystal shape and arrangement. A comparison with two congeneric species, L. minervae and L. valens, showed similar ultrastructural patterns in the SW but evident differences in the PW crystal shape. Our observations point to a biologically control rather than an induction of the calcification process in coralline algae and suggest a possible new morphological diagnostic tool for species identification, with relevant importance for paleontological applications. Finally, secondary calcite, in the form of dogtooth crystals that fill the cell lumen, has been observed. It represents a form of early alteration in living collections which can have implications in the reliability of climate and paleoclimate studies based on geochemical techniques.

Climate change and tectonic uplift are the dominant forcing mechanisms responsible for the formation of long and narrow terraced landforms in a variety of geomorphic settings, and marine terraces are largely used to reconstruct the Quaternary glacial and interglacial climates. Along the Mediterranean coast, a considerable number of popular scientific articles have acknowledged a range of marine terraces in the form of low-relief surfaces resulting from the combined effects of tectonic uplift and eustatic sea-level fluctuations, as relevant geomorphological indicators of past sea-level high-stands. With the exception of a few recent studies on the significance of submarine depositional terraces (SDT), submerged terraced landforms have been less investigated. By integrating different marine and terrestrial datasets, our work brings together and re-examines numerous terraced landforms that typify the Cilento Promontory and its offshore region. In this area, studies since the 1960s have allowed the recognition of well-defined Middle to Upper Pleistocene marine terraces on land, while only a few studies have investigated the occurrences of late Pleistocene SDT. Furthermore, to date, no studies have consistently integrated findings. For our work, we correlated major evidence of emerged and submarine terraced landforms in order to support an improved understanding of the tectono-geomorphological evolution of the Cilento Promontory and to further clarify the geomorphological significance of submerged terraces.

The B/Ca ratio in calcareous marine species is informative of past seawater CO32- concentrations, but scarce data exist on B/Ca in coralline algae. Recent studies suggest influences of temperature and growth rates on B/Ca, the effect of which could be critical for the reconstructions of surface ocean pH and atmospheric pCO2. In this paper, we present the first laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses of Mg, Sr, Li, and B in the coralline alga Lithothamnion corallioides collected from different geographic settings and depths across the Mediterranean Sea and in the Atlantic Ocean. We produced the first data on putative temperature proxies (Mg/Ca, Li/Ca, Sr/Ca, Mg/Li) and B/Ca in a coralline algal species grown in different basins from across the photic zone (12, 40, 45, and 66 m depth). We tested the B/Ca correlation with temperature proxies and growth rates in order to evaluate their possible effect on B incorporation. Our results suggested a growth rate influence on B/Ca, which was evident in the sample with the lowest growth rate of 0.10 mm yr−1 (Pontian Isl., Italy; 66 m depth) and in Elba (Italy; 45 m depth), where the algal growth rate was the highest (0.14 mm yr−1). At these two sites, the measured B/Ca was the lowest at 462.8 ± 49.2 µmol mol−1 and the highest at 757.7 ± 75.5 µmol mol−1, respectively. A positive correlation between B/Ca and temperature proxies was found only in the shallowest sample from Morlaix (Atlantic coast of France; 12 m depth), where the amplitude of temperature variation (ΔT) was the highest (8.9 ∘C). Still, fluctuations in B/Ca did not mirror yearly seasonal temperature oscillations as for Mg/Ca, Li/Ca, and Sr/Ca. We concluded that growth rates, triggered by the different ΔT and light availability across depth, affect the B incorporation in L. corallioides.

Whale sharks are known to aggregate in coastal areas. In the South Ari Marine Protected Area (Maldives) a aggregation, mostly represented by young males with a high level of residency, has been described in the literature. Despite the worldwide interest in the natural resources of the Maldives, this population is increasingly subjected to anthropogenic pressure and major concern regards the flourishing tourist industry. In this study, data collected by the Maldives Whale Shark Research Programme between 2014 and 2017 have been used to detect both temporal and spatial patterns of occurrence. Favourable environmental conditions to visually detect whale sharks have been defined for the studied area. Accordingly, a total of 1077 shark encounters have been analysed in this study. Environmental conditions (i.e. sea surface temperature, monsoon occurrence) have been used to detect possible factors affecting the spatial and temporal variability of Rhincodon typus aggregations. A two-way ANOVA has been performed to detect temporal trends in animal occurrence, sea surface temperature pattern and to investigate the sea bottom depth variability during encounters. Significant differences in the monthly occurrence of whale sharks within the same year and among different years have been detected. Similar patterns have been observed for environmental parameters such as sea surface temperature and depth. A different spatial distribution has also been detected as a function of the Indian Monsoon reversal (north-eastern and south-western) affecting the area. During the northeast monsoon period, whale sharks appeared to concentrate in a smaller longitudinal range closer to the western-central part of the MPA, where deeper water conditions occur due to the proximity of a deep depression (submarine canyon). Results from this study provide new pieces of information for the implementation of dedicated management actions to protect the whale sharks population inhabiting the South Ari Marine Protected Area.

In the Mediterranean Sea, crustose coralline algae form endemic algal reefs known as Coralligenous (C) build-ups. The high degree of complexity that C can reach through time creates notable environmental heterogeneity making C a major hotspot of biodiversity for the Mediterranean basin. C build-up can variably modify the submarine environment by affecting the evolution of submerged landforms, although its role is still far from being systematically defined. Our work proposes a new, ad-hoc semi-automated, GIS-based methodology to map the distribution of C build-ups in shallow coastal waters using high-resolution bathymetric data, collected on a sector of the southern Apulian continental shelf (Southern Adriatic Sea, Italy). Our results quantitatively define the 3D distribution of C in terms of area and volume, estimating more than 103,000 build-ups, covering an area of roughly 305,200 m2, for a total volume of 315,700 m3. Our work firstly combines acoustic survey techniques and geomorphometric analysis to develop innovative approaches for eco-geomorphological studies. The obtained results can contribute to a better definition of the ocean carbon budget, and to the monitoring of local anthropogenic impacts (e.g., bottom trawling damage) and global changes, like ocean warming and acidification. These can affect the structural complexity and total volume of carbonate deposits characterizing the Mediterranean benthic environment.

Lepidocyclinids are one of the most common group of Cenozoic large benthic foraminifera and, thanks to their clear evolutionary patterns, they are extensively used in biostratigraphy. They originated during the Eocene in the American region and then spread eastward, reaching a worldwide distribution in the Oligocene. This paper investigates the southernmost population of lepidocyclinids ever found along the Pacific coast of South America, located in the lower part of the Paracas Formation (Los Choros Member) of the East Pisco Basin of Peru. The examined Los Choros strata are composed of mixed siliciclastic-bioclastic coarse-grained deposits. The skeletal assemblage is dominated by large benthic foraminifera and mollusks with subordinate echinoids and barnacles, suggesting a deposition in a shallow, tropical, shelf environment with a moderate nutrient supply. The large benthic foraminiferal assemblage is largely dominated by Lepidocyclina rdouvillei. This species is extremely primitive, exhibiting ancestral characters such as a straight wall separating the protoconch and deuteroconch, very large principal auxiliary chambers and a poorly organized equatorial plane. The presence of common and primitive L. rdouvillei, supported by the associated occurrence of Polylepidina, suggests an age comprised between 43.6 Ma and 40.5 Ma for the Los Choros Member in the study area. This range is confirmed by nannofossil assemblages that indicate an age between 42.37 Ma and 40.34 Ma for the base of the overlying Yumaque Member of the Paracas Formation. These results highlight the potential of lepidocyclinids for biostratigraphy and paleoenvironmental reconstructions in South America.

In this work, we present preliminary results of the first application in the Mediterranean Sea of a hyperspectral camera, a device commonly used for satellite or airborne remote sensing, adapted for the underwater environment. The spectral analysis was carried out on hyperspectral images acquired in two different environmental settings in the southern Adriatic Sea. This new technology shows high potentialities of application for benthic habitat mapping and monitoring.

Hyperspectral imagers enable the collection of high-resolution spectral images exploitable for the supervised classification of habitats and objects of interest (OOI). Although this is a well-established technology for the study of subaerial environments, Ecotone AS has developed an underwater hyperspectral imager (UHI) system to explore the properties of the seafloor. The aim of the project is to evaluate the potential of this instrument for mapping and monitoring benthic habitats in shallow and deep-water environments. For the first time, we tested this system at two sites in the Southern Adriatic Sea (Mediterranean Sea): the cold-water coral (CWC) habitat in the Bari Canyon and the Coralligenous habitat off Brindisi. We created a spectral library for each site, considering the different substrates and the main OOI reaching, where possible, the lower taxonomic rank. We applied the spectral angle mapper (SAM) supervised classification to map the areal extent of the Coralligenous and to recognize the major CWC habitat-formers. Despite some technical problems, the first results demonstrate the suitability of the UHI camera for habitat mapping and seabed monitoring, through the achievement of quantifiable and repeatable classifications.

In the Mediterranean, build-ups (created by coralline algae, Cladocora caespitosa, deep-water corals, vermetids, polychaetes and bacteria) and rhodolith beds are important hot-spots of biodiversity. Being severely threatened by anthropogenic impact and climate change, they have been included in international directives on environmental protection. This work wants to support the ongoing research on modern bioconstructions by providing further data on the long-term effects of environmental factors on these habitats. Our results are based on the analysis of the existing literature on the outcropping Quaternary successions of the Adriatic and Ionian coasts of peninsular Italy. The existing reports of build-ups and rhodalgal carbonates have been summarized in an homogeneous data-set and then studied to highlight distribution patterns in space and time. The analyses consistently outlined the importance of sedimentation rate in controlling the general distribution of build-ups and rhodalgal carbonates. The majority of the reports is concentrated south of the Gargano, where the sediment-load of the rivers is small. The majority of the reports is related to coralline algae, suggesting that they were the main carbonate producers during the period. C. caespitosa general distribution is mainly controlled by temperature, with most of the occurrences dating back to the warm periods of the late Ionian and of the Tarantian. Large build-ups of Cladocora are restricted to embayments and gulfs well-protected against storm waves. The distribution of the outcrops of deep-water corals is biased by the geological setting. A remarkable uplift is necessary to bring these corals from their original deep-water setting to elevated areas onshore. Consequently, most of the outcrops are in Southern Calabria which is characterized by a strong Quaternary uplift. Chemosynthetic build-ups, intertidal bioconstructions (made by vermetids, polychaetes or coralline algae), as well as stromatolites, are rare in the study area., Rivista Italiana di Paleontologia e Stratigrafia (Research In Paleontology and Stratigraphy), V. 124, N. 2 (2018)

Sea floor mapping along the Apulia continental shelf (Italy) verified the abundance of autochthonous red algae build-ups, mapped as coralligenous habitats (CHs), in a water depth range of 5-100 m. In general, CHs were found to develop three dimensional structures, with a rigid framework and to represent an important geomorpho-logical and sedimentological element on the Mediterranean shelf. Here, we provide the first geomorphological description of CHs (thus poorly categorized) using acoustic data obtained from Side Scan Sonar (SSS) and MultiBeam (MB) echosounder surveys, ground-truthed using a ROV and underwater camera. In SSS mosaics, CHs generally yielded intermediate to high backscatter in response to a rigid cavernous framework. According to the various shapes and the lateral continuity that coralligenous build-ups displayed in explored locations, two distinct textures were determined to be present. Various geomorphological expressions of CHs were noted within our dataset and in images obtained from MB bathymetry. We determined that coralligenous build-ups are typically represented by positive-relief structures that vary from isolated blocks (randomly scattered on a generally flat mobile soft bottom) to a field of blocks (adjacent or even coalescent), and/to ridge with several metres of lateral continuity. In most cases, CHs occurred on flat mobile soft bottom, thus representing an example of coralligenous de plateau. Our results characterize for the first time the CHs through seafloor mapping techniques, which demonstrated to represent an instrumental tool for their geomorphological characterization.

Coralligenous has a relevant role in submarine landscape formation and demise through geological times, producing various morphotypes on the seafloor. Several terms are used to define coralligenous morphotypes, but their application through different geological and environmental settings still remains inconsistent. Through a systematic analysis of seafloor acoustic remote data (multibeam, side scan sonar and subbottom profiler) along Apulia continental shelf, ground-truthed by video observations and direct sampling, we detected a number of coralligenous morpho-acoustic facies as 0.2 up to 4 m topographic reliefs with steep flanks and a rigid inhomogeneous biogenic framework, characterized by medium to strong SSS backscatter and a variable plan-view geometry. The observed pattern led to the identification of coralligenous meso- and macrohabitat in which the biogenic frameworks (i.e. coralligenous) prevail as sole biocommunity on the seafloor or are associated with other type of habitats: (i) coralligenous sensu stricto, (ii) coralligenous and detritic bottom, (iii) coralligenous and muddy bottom, (iv) coralligenous and Posidonia meadow. Finally we improve the geomorphological definition of bank, proposing this new descriptive rigorous categorization for coralligenous morphotypes on sub-horizontal substrate: 1) tabular bank, 2) discrete relief, and 3) hybrid bank.

The Upper Pleistocene deposits of Capo Colonna marine terrace (Calabria, southern Italy) contain a volumetrically important record of red algal facies developed during a transgressive–regressive cycle, well-expressed along a nearshore–offshore transect. This setting presents an ideal opportunity for the acquisition and interpretation of paleoecological information on coralline-dominated deposits and their response to relative sea level changes. The Capo Colonna deposits include rigid build-ups, rhodolith accumulations, and a maerl bed. The build-ups, identified as a fossil example of the present day Mediterranean coralligenous, are primarily formed by Mesophyllum alternans and, subordinately, by Lithophyllum stictaeformae , Titanoderma pustulatum and Lithothamnion sp., rarely alternating with encrusting bryozoans. Fruticose praline rhodoliths occur in a packstone bed, up to 160 cm thick, 2 to 5 cm in size and composed of Lithothamnion sp., Mesophyllum sp., and rare T. pustulatum . The maerl bed is about 60 cm thick and laterally continuous for several tens of meters, and consists of interlocked unattached red algal branches of the species Lithothamnion corallioides , Phymatolithon sp., Lithophyllum sp., and Lithothamnion sp. The lateral distribution along the shelf profile of different red algal facies was influenced by transgressive–regressive trends. While praline rhodoliths and the maerl bed developed on mobile substrates mostly during the early highstand, respectively at intermediate and distal shelf sectors, the Mesophyllum -dominated coralligenous build-ups continued to grow for most of the regressive phase, progressively occupying all the preserved paleoshelf profile during sea level fall and resulting in a characteristic ecological vertical succession of crustose algae facies in the distal segment of the transect. Differences in substrate types determined variability in the coralligenous morphologies, with dome to mushroom shapes starting from discontinuous blocks of a basal conglomerate, and WE elongated platforms developing from a hardground and from rhodolith beds. Eventually, the development of red algal deposits became in itself the dominant control on substrate type. The red algae rich deposits of Capo Colonna marine terrace not only suggest a relationship between available substrate and geomorphological expression of the coralligenous build-ups, but also provide a framework for the paleoecological interpretation of other Neogene and Quaternary rhodalgal deposits from the Mediterranean region.

The protocols available for sampling and monitoring shallow subtidal rhodolith beds (RBs) are inadequate for the deep Mediterranean analogues, and need calibration in order to attain comparable results. After reviewing the present knowledge of the specificities of Mediterranean RBs, and in the framework of the ongoing international effort for their conservation, a two-step approach is suggested for their definition, identification, delimitation, description, and monitoring. Regional mapping should be improved, and RBs should be identified and delimited as those areas of the sea floor with >10% cover of live rhodoliths over a minimum surface of 500 m2, on 1:10000 scale. More detailed scales (at least 1:1000) should be used for monitoring selected RBs, in order to detect significant changes through time. Beside location and areal extent, the description of RBs should include the occurrence of macroscopic sedimentary structures of the sea floor, thickness of live cover, mean percentage cover of live thalli and surface live/dead ratio, cover of dominant morphologies of rhodoliths (simplified on a ternary diagram), and volumetrically important calcareous algal species. For the purpose of assessment of the ecological status and the evaluation of human-induced impacts, quantitative data about community composition are required. The comparative assessment of ecological status and the identification of RBs of high conservation value for special protection should consider the natural geographic and seasonal/annual variability of RBs. Copyright © 2015 John Wiley & Sons, Ltd.

Coralligenous is the most volumetrically significant type of autochthonous carbonate build-up in the Mediterranean, but its range of morphological variability at the macroscale, and potential link with environmental factors have not been fully documented. Well-preserved examples of coralligenous are exposed in shallow marine carbonate deposits from the Upper Pleistocene Le Castella marine terrace (Southern Italy). The coralligenous build-ups occur in the lower part of an unconformity-bounded, transgressive-regressive sequence. They show high structural and morphological heterogeneity in terms of framework type and build-up size, over a distance of several hundred meters. In northern exposures, coralligenous forms banks up to 4 m high, with a dense, coralline-dominated framework, laterally adjacent to paleo-channels devoid of build-ups and filled by coeval infra-circalittoral biogenic packstone. To the south, build-ups are smaller (up to 1.8 m high), with an open algal framework and local predominance of the coral Cladocora caespitosa as primary framework builder. At both locations, the most important framework-building coralline species is Mesophyllum philippii ; Titanoderma pustulatum also occurs. Analysis of sedimentary structures, paleo-topographic indicators, faunal composition of associated mollusk assemblages, and predominance of M. philippii suggest the algal builds-ups grew within a shallow-water, possibly infralittoral setting, competing for space with other biocoenoses. Suitable substrate availability in the form of conglomerate blocks or shell accumulations was the primary factor controlling the inception and spatial distribution of coralligenous. Differences in hydrodynamism and water turbidity determined variability in size and internal composition between the northern and southern locations. To the south, abundant supply of fine suspended sediment resulted in smaller build-ups with more open framework, the growth of which was terminated abruptly by sediment burial. Eventually, relative sea level fall during regression prevented further growth of the coralligenous even in the northern area. This study contributes to a better understanding of the relationship between coralligenous morphology and environmental factors, highlighting the role of suitable substrate availability, turbidity, and sediment burial in influencing spatial and temporal variability of coralligenous assemblages.

Four 1:15,000 maps for the coastal area of Mar Piccolo (Taranto, southern Italy) are presented. The study area is a small, sheltered shallow marine basin of about 20 km2, located north of Taranto town. It contains some submarine, karstic freshwater springs (citri) that have determined the development of intensive aquaculture in the past. Now, the Mar Piccolo is a highly polluted area due to the presence of both military and industrial navy docks and various heavy industries located in proximal areas: (i) the ILVA steel plant in Taranto, the largest in Europe; (ii) the ENI oil refinery and (iii) the CEMENTIR, the largest cement and concrete plant in southern Italy. Many studies show that water and sediments are contaminated (heavy metals, isopropyl alcohol, polychlorinated biphenyl [PCB], etc.), and various remediation projects are now in preparation. In this study, we analyze the physical characteristics of the Mar Piccolo environment by producing several maps: a geological map; a geomorphological map; a bathy-morphological map and a map of the thickness of surficial sediment. All these maps are original products focused on the realization of a reliable geological picture for the Mar Piccolo area. They represent the first steps toward the detailed knowledge of the Mar Piccolo physical environment, which we consider to be a fundamental requirement for developing the most appropriate remediation techniques.

The Mar Piccolo Basin is a coastal brackish marine ecosystem located along the northern coast of the Gulf of Taranto (Southern Italy). Despite the ecological relevance of the area (Site of Community Importance IT9130004, Regional Reserve ‘Palude La Vela’ EUAP1189), the entire basin is subjected to intensive human usage. The main activities include extensive mussel farming, important industrial activities, a military harbor and densely populated shores. The goal of our study was to spatially quantify human pressure within the basin and its relationship with biocoenoses. A broad set of data was integrated including acoustic remote data (obtained using a multibeam echosounder and side scan sonar devices), direct observations obtained by SCUBA diving and from a trawled camera, an orthophoto and ESRI® Imagery Basemap. At least eight categories of anthropogenic infrastructure and marks of past and present-day human activities were identified within the Mar Piccolo Basin water column and on the seafloor. These included line farms, pole farms, breeding frame structures, anchoring scars, excavations, buoys, wrecks and undefined traces. Each category was mapped and described using morphometric characterization. The integration of all available data allowed the production of an original map providing the Mar Piccolo seafloor disturbance by anthropogenic impact and an updated distribution of benthic communities, showing their spatial relation. Through the production of a specific thematic map, our work provides the first quantitative assessment of the extent and density of the identified human impact in order to evaluate seafloor integrity.

This contribution discusses current carbonate deposition in the channel between the Ponza and Palmarola islands and along the western coast of Palmarola, focusing on the quantitatife contribution of biogenic carbonate and in particular on the production and accumulation of carbonates by coralline algae. Seventeen out of 150 grab samples have been selected as representative of the main sedimentary features facies of the seafloor between 30 and 100 m of water depth (wd). They were analyzed using XRD and EDTA titration. Thin sections of the same samples were made to identify their biogenic components and to quantify the contribution of calcareous algae to the total sediment. Maximum carbonate production takes place between 40 and 70 m wd, with the percentage of carbonates ranging between 83.1 and 95.7%. of the total. Multidimensional statistical analyses found two different carbonate facies: the coralline algae facies (CA) occupies 38 km 2 between 30 and 70 m wd, and the carbonate matrix facies (CM) covers 24 km 2 between 70 and 100 m wd. An estimate of the current contribution of algal carbonates to seafloor sediments is about 80% in the CA facies and 15% in the CM facies. The accumulation of total carbonate sediments in the uppermost 2 cm interval of the CA facies is calculated to be 20 566 g m -2 and the fraction of coralline carbonate in the superficial 2-cm layer of the CM facies is calculated as 16 452 g m -2. The production rate of the mean 7% live coralline covers ranges between 7.91 and 31.64 g m -2 yr -1. © Publications Scientifiques du Muséum national d'Histoire naturelle, Paris.

On the continental shelf off the Ciento peninsula (eastern Tyrrhenian Sea) the occurrence of more than 13 km(2) of maerl beds was documented through acoustic surveys. Swath bathymetric data along with a dense grid of chirp-sonar profiles were acquired over more than 180 km(2). The maerl facies was characterized on the basis of the components analysis of 32 grab samples collected at selected sites. Mapped maerl-beds are predominant on submerged terraces located at variable water depth (wd) between 42 and 52 m. This preferred distribution on submerged terraces is probably associated with relatively vigorous bottom currents generated by local circulation that hinders the deposition of terrigenous sediments. Calcareous red algae result to be the most important producers of carbonates from 40 down to 60 m wd. We calculated the coralline carbonate accumulation from the percentage cover of coralline algae (thin section mapping) x 1 cm-thick layer of sediment x measured coralline density. The total coralline cover (living plus dead) in the Cilento area is 13.96 km(2), with a total 316 800 tons of algal carbonate in the surface 1 cm layer, that correspond to 20 430 g m(-2). Living maerl is recorded at a depth of 47 m, with a live coralline cover of about 40% over a minimum area of about 1.2 km(2). This live maerl has a thickness of about 1 cm and is composed mainly of unattached branches of Lithothamnion corallioides (P.L.Crouan & H.M.Crouan) P.L.Crouan & H.M.Crouan, 1867. The molluscan association of the maerl bed is dominated by characteristic species of the Coastal Detritic Biocoenosis. The production of carbonate by living coralline algae has been calculated as weight of live corallines in 1 cm-thick layer x 100 y(-1) x total area(-1) and corresponds to 90.8 g m(-2) y(-1).

Persististrombus latus (GMELIN, 1791) (=Strombus bubonius LAMARCK, 1822), is the most iconic representative of the “Senegalese fauna”, a fossil assemblage of tropical water organisms thought to have colonized the Mediterranean Sea during the last interglacial. As such, P. latus has become an important stratigraphic marker of Marine Isotope Stage (MIS) 5.5, allowing the correlation of raised coastal deposits used in studies of sea level variations and tectonic uplift. P. latus is found in shallow marine sediments of Tyrrhenian age (~124 ka) in several localities of the Italian peninsula. However, despite intensive surveying through the years, the late Pleistocene marine terraces of the Crotone peninsula, which preserve an extensive volume of fossiliferous deposits attributed to MIS 5, have yielded very few specimens of P. latus. This paper reports the finding of several new specimens of P. latus near Isola di Capo Rizzuto, in deposits that had been independently assigned to MIS 5.5, and two specimens from the Capo Colonna terrace, which is thought to correlate with MIS 5.3 or 5.1. The Crotone peninsula, therefore, represents one of the few localities in Italy where multiple stratigraphically distinct P. latus-bearing units can be observed.

Ongoing microbialite formation is described at two previously unreported sites in southern Sinai, Egypt. Samples were collected in the peritidal tropical environment of Nabq Bay and Hidden Bay (southern Sinai, Egypt). Field observations and sample analyses show evidence of both sediment trapping and biostabilization in bacterial mucilaginous sheaths and microbially induced mineralization, producing a suite of increasingly lithified material: from agglomerated, consolidated sand to lithified crusts and oncoids. Thin-sections show evidence of bacteria (cyanobacteria and sulphate-reducing bacteria) among the constituent grains in the form of gelatinous filaments (green and red sheaths), and microalgal colonies along the outer edge, accompanied by a very high grade of clast alteration. The alternation of planar to irregular dark, superposed layers, and clastic layers is visible at the surface and/or inside some crusts. Widespread filaments of Schizothrix among grains have been identified, as well as extracellular polymeric substances (EPS), sheaths stabilizing particles, and calcareous tubular encrustations around cyanobacteria filaments. Carbonate precipitates include diffuse micrite, microcrystals of high-Mg calcite precipitating in the EPS matrix, and acicular aragonite as isopachous rims around grains. Cementation is accompanied by partial dissolution and progressive alteration of original grain boundaries. We describe four microbialite categories on the basis of their macroscopic morphology combined with different texture and lithification grade. The occurrence of the southern Sinai microbialites is explained by the interplay of local sedimentary dynamics and accommodation space in a peritidal tropical environment undergoing large temperature and salinity variations.

During a research fieldtrip in the Crotone peninsula - an area characterized by a flight of well developed Pleistocene marine terraces - a level rich of in situ Persististrombus latus GMELIN 1791 (= Strombus bubonius LAMARCK 1822) has been discovered in a quarry south of Isola di Capo Rizzuto (Calabria, southern Italy) at ~ 46 m above sea level. P. latus is a shallow warm-water marine gastropod belonging to the Strombidae family. Presently, it lives along the tropical coasts of Africa but entered the Mediterranean through the Gibraltar Strait in the late Pleistocene as part of the socalled Senegalese fauna. P. latus found as fossil in the Mediterranean is commonly considered a marker of Marine Isotope Stage (MIS) 5.5. This is the first documented record of a level containing multiple specimens of in situ P. latus in the Crotone terraces, allowing direct correlation to the Tyrrhenian Stage or MIS 5.5. The bio-calcarenite and associated P. latus specimens have been collected in order to petrographically analyze the sediment and describe the benthic association