Characterization of an undocumented CO2 hydrothermal vent system in the Mediterranean Sea: Implications for ocean acidification forecasting.

A previously undocumented shallow water hydrothermal field from Sicily (Southern Tyrrhenian Sea, Italy) is here described, based on a multidisciplinary investigation. The field, covering an area of nearly 8000 m2 and a depth from the surface to -5 m, was explored in June 2021 to characterise the main physico-chemical features of the water column, describe the bottom topography and features, and identify the main megabenthic and nektonic species. Twenty sites were investigated to characterise the carbonate system. Values of pH ranged between 7.84 and 8.04, ΩCa between 3.68 and 5.24 and ΩAr from 2.41 to 3.44. Geochemical analyses of hydrothermal gases revealed a dominance of CO2 (98.1%) together with small amounts of oxygen and reactive gases. Helium isotope ratios (R/Ra = 2.51) and δ13CCO2 suggest an inorganic origin of hydrothermal degassing of CO2 and the ascent of heat and deep-seated magmatic fluids to the surface. Visual census of fishes and megabenthos (mainly sessile organisms) allowed the identification of 64 species, four of which are protected by the SPA/BIO Protocol and two by the International Union for Conservation of Nature. The macroalgae Halopteris scoparia and Jania rubens and the sponge Sarcotragus sp. were the dominant taxa in the area, while among fishes Coris julis and Chromis chromis were the most abundant species. This preliminary investigation of San Giorgio vent field suggests that the site could be of interest and suitable for future experimental studies of ocean acidification.

Pleural drainage vs video-assisted thoracoscopic debridement in children affected by pleural empyema.

BACKGROUND: Both thoracic drainage and video-assisted thoracic surgery (VATS) are available treatment for pleural empyema in pediatric patients. MATERIALS AND METHODS: This retrospective multicenter study includes pediatric patients affected by pleural empyema treated from 2004 to 2021 at two Italian centers. Patients were divided in G1 (traditional approach) and G2 (VATS). Demographic and recovery data, laboratory tests, imaging, surgical findings, post-operative management and follow-up were analyzed. RESULTS: 70 patients with a mean age of 4.8 years were included; 12 (17.1%) in G1 and 58 (82.9%) in G2. Median surgical time was 45 min in G1, 90 in G2 (p < 0.05). Mean duration of thoracic drainage was 7.3 days in G1, 6.2 in G2 (p > 0.05). Patients became afebrile after a mean of 6.4 days G1, 3.9 in G2 (p < 0.05). Mean duration of antibiotic therapy was 27.8 days in G1, 25 in G2 (p < 0.05). Mean duration of postoperative hospital stay was 16 days in G1, 12.1 in G2 (p < 0.05). There were 4 cases (33.3%) of postoperative complications in G1, 17 (29.3%) in G2 (p > 0.05). 2 (16.7%) patients of G1 needed a redosurgery with VATS, 1 (1.7%) in G2. CONCLUSIONS: VATS is an effective and safe procedure in treatment of Pleural Empyema in children: it is associated to reduction of chest tube drainage, duration of fever, hospital stay, time of antibiotic therapy and recurrence rate.

Modern Iron Ooids of Hydrothermal Origin as a Proxy for Ancient Deposits.

We constrained the origin and genetic environment of modern iron ooids (sand-sized grains with a core and external cortex of concentric laminae) providing new tools for the interpretation of their fossil counterparts as well as the analogous particles discovered on Mars. Here, we report an exceptional, unique finding of a still active deposit of submillimetric iron ooids, under formation at the seabed at a depth of 80 m over an area characterized by intense hydrothermal activity off Panarea, a volcanic island north of Sicily (Italy). An integrated analysis, carried out by X-ray Powder Diffraction, Environmental Scanning Electron Microscopy, X-ray Fluorescence and Raman spectroscopy reveals that Panarea ooids are deposited at the seafloor as concentric laminae of primary goethite around existing nuclei. The process is rapid, and driven by hydrothermal fluids as iron source. A sub-spherical, laminated structure resulted from constant agitation and by degassing of CO2-dominated fluids through seafloor sediments. Our investigations point the hydrothermal processes as responsible for the generation of the Panarea ooids, which are neither diagenetic nor reworked. The presence of ooids at the seawater-sediments interface, in fact, highlights how their development and growth is still ongoing. The proposed results show a new process responsible for ooids formation and gain a new insight into the genesis of iron ooids deposits that are distributed at global scale in both modern and past sediments.

Exceptional discovery of a shallow-water hydrothermal site in the SW area of Basiluzzo islet (Aeolian archipelago, South Tyrrhenian Sea): An environment to preserve.

The geological, biological and geochemical features of a particular field of hydrothermal vents, discovered in the Panarea Volcanic Complex during a research survey carried out in 2015, are described for the first time. The site, located at 70-80 m depth off the South-western coast of the islet of Basiluzzo, was named Smoking Land for the presence of a large number of wide and high active chimneys and was characterized in terms of dissolved benthic fluxes, associated macrofauna and megafauna communities and preliminary mineralogy and geochemistry of chimney structures. On the whole field, a total of 39 chimneys, different in size and shape, were closely observed and described; 14 of them showed emission of low temperature hydrothermal fluids of marine origin characterized by acidified chemical conditions. The CTD and benthic chamber measurements highlighted that the Smoking Land is able to form a sea water bottom layer characterized by variable acidity and high DIC and trace elements concentrations; these characteristics weaken moving away from the chimney mouths. The SEM-EDS analysis of the collected solid samples revealed a chimney structure principally composed by amorphous and low crystalline Fe-oxyhydroxides of hydrothermal origins. The ROV explorations revealed a wide coverage of red algae (Peyssonnelia spp.) colonized by the green algae Flabiella petiolata and by suspension feeders, mainly sponges, but also bryozoans, and tubicolous polychaetes. Although novent-exclusive species were identified, the benthic communities found in association to the chimneys included more taxa than those observed in the surrounding no-vent rocky areas. These first findings evidence a submarine dynamic habitat where geological, chemical and biological processes are intimately connected, making the Smoking Land an important site in terms of marine heritage that should be safeguarded and protected.

Assessment of the origin and geothermal potential of the thermal waters by hydro-isotope geochemistry: Eskisehir province, Turkey.

The thermal fluids vented over Eskisehir province have been investigated for their origin and to estimate the geothermal potential of the area. Thermal waters as well as bubbling and dissolved gases were collected and analysed for their chemical and isotopic features. Their isotopic composition varies in the range from -11.5 to -7.7 ‰ for δ18O, -84 and -57 ‰ for δ2H, and 0-7.2 TU for tritium. The gases (bubbling and dissolved) are mostly N2-dominated with a significant amount of CO2. The helium isotopic ratios are in the range of 0.2-0.66 R/Rac, indicate remarkable mantle-He contribution ranging between 2 and 10 % in the whole study area. Considering the estimated geothermal gradient about three times higher than the normal gradient, and the reservoir temperatures estimated to be between 50 and 100 °C using quartz and chalcedony geothermometers, a circulation model was built where possible mixing with shallow waters cool down the uprising geothermal fluids.

Changes in prokaryotic community composition accompanying a pronounced temperature shift of a shallow marine thermal brine pool (Panarea Island, Italy).

Hot Lake is a recently described thermal brine pool off Panarea Island (Eolian Islands, Italy) where emitted fluids are highly saline and rich in CO2 and H2S. The prokaryotic community composition in surface sediment samples was analyzed by high-throughput Illumina sequencing targeting the V3 region of the 16S rRNA at two time points that differed mainly with respect to temperature conditions, high-temperature (94 °C, HT09) and low-temperature (28.5 °C, LT10). Bacterial richness and diversity were greater than those of Archaea under both temperature conditions. In contrast to Bacteria, diversity and evenness of Archaea greatly increased at LT10. While the phylogenetic analysis indicated the presence of members mostly affiliated with the same taxonomic groups, their relative abundances differed from HT09 to LT10, resulting in different bacterial and archaeal assemblages. Both HT09 and LT10 were dominated by members of the Epsilonproteobacteria. Within this subphylum, bacteria of the genus Sulfurimonas were most frequently detected at HT09, while Arcobacter prevailed at LT10. The abundance of other dominant taxonomic groups (≥1 % of Illumina reads) also correlated with temperature conditions. Members assigned to hyperthermophilic Euryarchaeota (Thermococci) or to thermophilic (Caldiserica) and thermoresistant (Firmicutes) bacterial taxa were dominant at HT09, while those related to non-thermophilic Bacteroidetes, Fusobacteria and Actinobacteria were dominant at LT10. Several, probably photosynthetic, members of the Alphaproteobacteria, Chlorobi, Cyanobacteria and Chloroflexi were recovered under both temperature conditions. The co-occurrence of photosynthetic and chemolithotrophic microorganisms represents a unique feature of shallow vents such as Hot Lake.

Bacterial and archaeal populations at two shallow hydrothermal vents off Panarea Island (Eolian Islands, Italy).

The aim of this study was to investigate the microbial community thriving at two shallow hydrothermal vents off Panarea Island (Italy). Physico-chemical characteristics of thermal waters were examined in order to establish the effect of the vents on biodiversity of both Bacteria and Archaea. Water and adjacent sediment samples were collected at different times from two vents, characterised by different depth and temperature, and analysed to evaluate total microbial abundances, sulphur-oxidising and thermophilic aerobic bacteria. Total microbial abundances were on average of the order of 10(5) cells ml(-1), expressed as picoplanktonic size fraction. Picophytoplanktonic cells accounted for 0.77-3.83% of the total picoplanktonic cells. The contribution of bacterial and archaeal taxa to prokaryotic community diversity was investigated by PCR-DGGE fingerprinting method. The number of bands derived from bacterial DNA was highest in the DGGE profiles of water sample from the warmest and deepest site (site 2). In contrast, archaeal richness was highest in the water of the coldest and shallowest site (site 1). Sulphur-oxidising bacteria were detected by both culture-dependent and -independent methods. The primary production at the shallow hydrothermal system of Panarea is supported by a complex microbial community composed by phototrophs and chemolithotrophs.

Successful thoracoscopic resection of pulmonary metastasis less than 1 cm in size utilizing preoperative CT-guided wire localization.

Preoperative computer tomography (CT) guidance localization utilizing a percutaneous guidewire before thoracoscopic resection is safe and beneficial in children with pulmonary nodules less than 1 cm in size or located deep in the pleural surface. This paper describes a successful thoracoscopic resection of a little subpleural pulmonary metastasis of a Wilm's tumor in a 5-year-old child utilizing preoperative CT-guided wire localization of the lesion. The thoracoscopic procedure was performed with the use of two ports, the nodule was easily localized,and the pulmonary wedge resection was made by the use of an endo-GIA linear stapling device after guidewire removal. The operating time was 45 minutes and the chest tube was removed after 48 hours. The postoperative course was uneventful, and the child was discharged on postoperative day 5. This technique allows the surgeon to resect little pulmonary nodules, avoiding the need of more invasive procedures as standard thoracotomy without adjunctive morbidity and with good cosmetic results.

Congenital bilateral mid-ureteral stricture: a unique case.

Congenital mid-ureteral stenosis is a very rare entity which typically occurs on one side. This condition is usually misdiagnosed as hydronephrosis or megaureter, and only after surgery is the correct diagnosis made. We report the case of a bilateral mid-ureteral stenosis. No other cases of bilateral strictures have been found in the literature.