Benthic foraminifers and siliceous sponge spicules assemblages in the Quaternary rhodolith rich sediments from Pontine Archipelago shelf

The bottom samples (Quaternary in age) of two cores (CS1 and Caro1) collected at 60 and 122 m water depth in the marine area near Ponza Island (Pontine Archipelago, Tyrrhenian Sea) are investigated. In particular, benthic foraminifers and siliceous sponge spicules are considered. The coralline red algae (pralines, boxworks and unattached branches) are abundant in both samples and, particularly, in the CS1 bottom as well as the benthic foraminifers. The siliceous sponge spicules also are very diversified and abundant in the CS1 bottom sample, while in the Caro1 bottom they are rare and fragmented. Benthic foraminiferal assemblage of two samples is dominated by Asterigerinata mamilla and Lobatula lobatula, typical epiphytic species but also able to live on circalittoral detrital seafloors, adapting to an epifaunal lifestyle. Based on these data the bottom of the studied cores represents the upper circalittoral zone, within the present-day depth limit distribution of coralline red algae in the Pontine Archipelago (shallower than 100 m water depth)

Benthic foraminiferal assemblages and rhodolith facies evolution in post-LGM sediments from the Pontine Archipelago shelf (Central Tyrrhenian Sea, Italy)

The seabed of the Pontine Archipelago (Tyrrhenian Sea) insular shelf is peculiar as it is characterized by a mixed siliciclastic–carbonate sedimentation. In order to reconstruct the Late Quaternary paleoenvironmental evolution of the Pontine Archipelago, this study investigates the succession of facies recorded by two sediment cores. For this purpose, benthic foraminifera and rhodoliths assemblages were considered. The two cores (post-Last Glacial Maximum in age) were collected at 60 (CS1) and 122 m (Caro1) depth on the insular shelf off Ponza Island. The paleontological data were compared with seismo-stratigraphic and lithological evidence. The cores show a deepening succession, with a transition from a basal rhodolith-rich biodetritic coarse sand to the surface coralline-barren silty sand. This transition is more evident along core Caro1 (from the bottom to the top), collected at a deeper water depth than CS1. In support of this evidence, along Caro1 was recorded a fairly constant increase in the amount of planktonic foraminiferal and a marked change in benthic foraminiferal assemblages (from Asterigerinata mamilla and Lobatula lobatula assemblage to Cassidulina carinata assemblage). Interestingly, the dating of the Caro1 bottom allowed us to extend to more than 13,000 years BP the rhodolith record in the Pontine Archipelago, indicating the possible presence of an active carbonate factory at that time

New discoveries at Woolsey Mound, MC118, northern Gulf of Mexico

Woolsey Mound, a 1km-diameter carbonate-gas hydrate complex in the northern Gulf of Mexico, is the site of the Gulf’s only seafloor monitoring station-observatory in its only research reserve, Mississippi Canyon 118. Active venting, outcropping hydrate, and a thriving chemosynthetic community recommend the site for study. Since 2005, the Gulf of Mexico Hydrates Research Consortium has been conducting multidisciplinary studies to 1. Characterize the site, 2. Establish a facility for real-time monitoring-observing of gas hydrates in a natural setting, 3. Study the effects of gas hydrates on seafloor stability, 4. Establish fluid migration routes and estimates of fluid-flux at the site, 5. Establish the interrelationships between the organisms at the vent site and the association-dissociation of hydrates. A variety of novel geological, geophysical, geochemical and biological studies has been designed and conducted, some in survey mode, others in monitoring mode. Geophysical studies involving merging multiple seismic data acquisition systems accompanied by the application of custom processing techniques verify communication of surface features with deep structures. Supporting geological data derive from innovative recovery techniques. Geochemical sensors, used experimentally in survey mode, including aboard an AUV, double as monitoring devices. A suite of pore-fluid sampling devices has returned data that capture change at the site in daily increments; using only noise as an energy source, hydrophones have returned daily fluctuations in physical properties. Ever-expanding capabilities of a custom-ROV have been determined by research needs. Processing of new as well as conventional data via unconventional means has resulted in the discovery of new features…..vents, faults, benthic fauna…..and modification of others including pockmarks, hydrate outcrops, vent activity, and water-column chemical plumes. Though real-time monitoring awaits communications and power link to land, periodic data-collection reveals a carbonate-hydrate mound, part of an immensely complex hydrocarbon system

Geohazard features of the north-western Sicily and Pantelleria

9 pages, 3 figures, supplemental material https://doi.org/10.1080/17445647.2024.2342931.-- Data availability statement: Department of Earth and Marine Science of the University of Palermo for institutional purposes, so their access will be available by contacting the reference people (attilio.sulliunipa.it) upon reasonable requestWe present maps of geohazard features identified across north-western Sicily and Pantelleria in the framework of the Magic project (MArine Geohazard along Italian Coasts), which involved Italian marine geological researchers in 2007-2013. These seafloor features were recognized using high-resolution bathymetry data and rely on the morphological expression of the seafloor and shallow sub-surface processes. The north-western Sicily is a complex continental margin, affected by morphodynamic, depositional, and tectonic processes. The Egadi offshore is controlled by fault escarpments and alternating retreating and progradational processes. Ustica and Pantelleria submerged edifices show the effect of volcanic activity. The Ustica seafloor is interested in volcanic, tectonic, and gravitational instability processes, while the Pantelleria offshore underwent erosive-depositional processes and the effect of bottom currents. Two levels of interpretation are represented: the physiographic domain at a scale of 1:250.000 and the morphological units and morpho-bathymetric elements at a 1:100.000 scaleThe Magic Project has been funded by the Italian Civil Protection Department. [...] With the institutional support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S)Peer reviewe

Black Coral Distribution in the Italian Seas: A Review

Antipatharian corals are important structural and complex members of benthic communities inhabiting the Italian seafloor. In this study, the distribution of black corals in Italy is reported and mapped for the first time. This review has permitted the identification of occurrences of such vulnerable marine ecosystems along the Italian coasts in a bathymetric range of 42 m to 790 m. Black corals appear to be most conspicuous and widely distributed in the mesophotic zone (from around 60 to 300 m depth), with a major occurrence on the rocky bottom and shoals. This review also highlights that these communities suffer direct damage from anthropogenic impacts (fishing activity and lost garbage). Finally, this study provides evidence that the reported Italian submarine sites associated with the occurrence of black corals probably represent only a small portion of their real distribution. This finding urges the need to increase monitoring efforts to support the protection and the conservation of these pristine species assemblages

INFLUENCE OF FLUID EMISSIONS ON SHALLOW-WATER BENTHIC HABITATS OF THE PONTINE ARCHIPELAGO (TYRRHENIAN SEA, ITALY)

An active fluid emission area located off the eastern coast of Zannone Island (western Pontine Archipelago) has been studied in order to investigate benthic assemblages related to vent-activity. The fluid escape feature is a giant depression (about 0.5 km2) located on the outer shelf, between 110 and130 m water depth. Evidences of active emissions were detected by ROV observations and sediment sampling, whereas integration of high-resolution multibeam bathymetry, backscatter and ground-truth data allowed us to characterize and identify different seafloor types (e.g., lithified seafloor and sandy sediment). Moreover, the analysis of ROV videos and grab samples allowed the definition of the benthic assemblages (micro and megafauna) living within the vent-areas and in the nearby seafloor. This study shows results from the first integrated analysis of the morpho-acoustic, sedimentological and biological characteristics of the northern sector of the Zannone giant depression, highlighting great differences between vent and non-vent seafloor areas. In vent areas, the seafloor is characterized by high morphological complexity and peculiar benthic habitats strongly controlled by dissolution processes, indicating “extreme” conditions due to active fluid emissions

The response of benthic meiofauna to hydrothermal emissions in the Pontine Archipelago, Tyrrhenian Sea (central Mediterranean Basin)

Recent investigations highlighted the occurrence of a giant depression related to hydrothermal activity off the Pontine Archipelago (central Mediterranean Sea, Italy). The new record of a giant seeping depression (Zannone Giant Pockmark, ZGP) in shallow-water provides the opportunity to study fluid vent impact on meiobenthic communities. The micropaleontological analyses on living (Rose Bengal stained) and dead assemblages recorded inside and outside the Zannone Giant Pockmark, allow to highlight changes in the structure and composition of the foraminiferal community that suggest variations of fluid emissions in different sectors of the study area. Inside the ZGP, under the direct influence of venting activity, a very peculiar living foraminiferal assemblage is found. It consists of agglutinated species (Spiculosiphon oceana, Jaculella acuta, Deuterammina rotaliformis) never found or very rare in the Mediterranean Sea. On the contrary dead assemblage testifies the changes on foraminiferal assemblages under carbonate dissolution process. Outside the pockmark in the nearby area of ZGP, the integrated meiofaunal and geochemical data suggest a transitional condition between vent influenced sedimentation and the typical carbonate sedimentation recorded in the rest of the Pontine Archipelago. In particular a possible spread of the venting activity in the northern and southern sectors of the study area, towards the edge of the Zannone insular shelf, is inferred. The impact of fluid emissions on foraminiferal assemblages can be summarized in the following observations: reduced biodiversity, increase of agglutinated species with predominant siliceous component in the test structure, limited distribution of living specimens inside the sediment, disappearance of porcelaneous taxa and presence of carbonate loss tests. As the result, the venting activity is likely to be the main environmental driver on the meiofaunal distribution. We also report, at the emission sites in the Pontine Archipelago, the presence of agglutinated species such as Spiculosiphon oceana, Jaculella acuta, Deuterammina rotaliformis, never found earlier in the Mediterranean Sea

Gas related features offshore the western Pontine Islands (Tyrrhenian Sea)

Several seafloor depressions have been found on the seafloor around the Western Pontine Archipelago (Palmarola, Ponza and Zannone Islands) located around 30 km away from the Latium coast. By the integration of different geophysical data have been possible to identify specific gas related structures as little pockmarks and large depressions located both on the continental shelf and upper slope. The large depressions are located few kilometers away from the Zannone Island at depths between 105 and 140 m. They have an average surface of 0.25 km2 and are 10 m deep compared to the surrounding seafloor. Other gas related features have been found in the north-western sector of Palmarola Island (depth between 60 and 90 m), in the southern sector of Ponza Island (depth between 130 and 140 m) and in the northern sector of the archipelago (depth between 200 and 400 m). Video observations (by Remotely Operated Vehicle) acquired across the depressions placed offshore the Zannone Island, were use