Fig 1.
Map of the Panarea Volcanic Complex showing the investigated area (red rectangle). Bathymetries from ISMAR, reprinted from [24] under a CC BY license, with permission from ISMAR-CNR, original copyright 2013.
Fig 2.
Map of the investigated area reporting the tracks covered during the ROV survey. The black tracks covered the Smoking land; the white tracks covered the no-vent surrounding area.
Fig 3.
High-resolution swath bathymetry maps.
A) map of the whole investigated area, SW of Basiluzzo Islet. The black dots indicate the benthic chamber stations; B) map of the Smoking Land hydrothermal field (WGS84, UTM33, cell size 20x20 cm, vertical exaggeration 3X). The black triangles indicate the location of the sampled chimneys, while the black square indicates the location of the chimney reconstructed based on HD video-images.
Fig 4.
Three-dimensional model of the Smoking Land (WGS84, UTM 33, cell size 0.5 m).
A) vertical exaggeration 2x; B) vertical exaggeration 3x.
Fig 5.
Images of a reconstructed chimneys located in the Smoking Land (38°39’30”N, 15°6’3”E; Fig 3: RC).
A) Reconstruction of the chimney performed on HD video-image. B) underwater image of anterior side; C) underwater image of the posterior site of the summit of the chimney showing a wide yellowish deposit and the emission of bubbles. Scale bars: 20 cm for foreground.
Fig 6.
Underwater images of the chimneys located in the Smoking Land sampled during the 2015 research survey.
(A) chimney VA; (B-C) chimney SF; (D-F) chimney GB. Scale bars: 20 cm for foreground.
Table 1.
List of identified taxa and number of video segments in which each taxon was observed associated to chimneys of Smoking Land with and without evidences of fluid emissions and to the surrounding rocky no-vent area.
Fig 7.
Underwater pictures of the Smoking Land vent fauna.
(A) some colonies of Reteporella grimaldii and group of polychaetes Sabellidae on a chimney with active emissions of bubble plumes; (B) coverage of the red encrusting coralline algae Peyssonnelia spp. together with R. grimaldii and the green algae Flabellia petiolata; (C) emission mouth surrounded by F. petiolata and encrusting sponges (cfr. Haplosclerida and cfr. Haliclona sp.); (D-E) macrobenthic and fish community typically found to be associated with the investigated chimneys; (F) accumulation of volcanic rocks encrusted by red algae and colonized by some specimens of Myriapora truncata, Stylocidaris affinis and Caryophyllia sp. in the no-vent area North-West of the vents field. Scale bars: 20 cm for foreground.
Fig 8.
Correspondence analysis (CA) for area.
Ordination diagram for the first two canonical axes of the correspondence analyses using species n. of observation data per area (E, chimneys with emission; NE, chimneys without emission; NV, no-vent area). Species codes as in Table 1.
Fig 9.
Physico-chemical parameters recorded by the EXO2 Sonde in the Smoking Land area.
A) pH; B) Temperature; C) Dissolved Oxygen; D) Oxidation-Reduction Potential; E) Turbidity; F) Salinity.
Table 2.
Results of physicochemical parameter analyses carried out on board by the CTD probe in water samples collected in the hydrothermal water flux coming out of the GB and SF chimneys.
Table 3.
Dissolved benthic fluxes measured by the benthic chamber in the Smoking Land and in no-vent areas.
pH has been shown both as flux of H+ and as variations of pH units per square meter per day during the measurements.
Fig 10.
Benthic chamber measured parameters in BC3 site.
Temperature and salinity recorded in the Benthic Chamber in the BC3 site located close to the Smoking Land.
Fig 11.
Scanning electron microscopy images of textures of the analyzed hydrothermal chimneys.
(A-B) chimney GB; (C-D) chimney VA; (E-F) chimney SF.
Table 4.
SEM-EDS representative data (% wt) of the analyzed chimneys samples.
Table 5.
XRF data of major oxides (% wt) and trace elements (ppm) of the analyzed samples.