Chiara Tessarolo

Seafloor integrity of the Mar Piccolo Basin (Southern Italy): quantifying anthropogenic impact

ABSTRACT 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.

Geology of Mar Piccolo, Taranto (southern Italy): the physical basis for remediation of a polluted marine area

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.

Geomorphology of the Vlora Gulf Seafloor: Results from Multibeam and High-Resolution Seismic Data

Abstract The present work reports the main results obtained from recent seafloor-mapping activities carried out offshore from south-western Albania. The area explored consists of two distinctive physiographic units: the Vlora Gulf (which is bounded to the west by the Karaburun Peninsula) and the upper continental slope offshore from the western side of the Karaburun Peninsula. Along these areas, 500 km2 of multibeam echo–sounder coverage, about 2500 km of chirp-sonar data, and 200 km2 of side-scan sonar mosaic (100–500 kHz) were acquired. This new acoustic data set was collected by two different oceanographic expeditions, which were carried out in the framework of the Centro Internazionale di Scienze del Mare (CISM) project (supported by Interreg III Italia–Albania), which focused on studying, through a multidisciplinary approach, the geological setting and the ecosystem conditions of a poorly investigated area of the Adriatic Sea, such as the Vlora Gulf. The investigated area incorporates water depths measurements from 5 m down to 57 m, whereas the offshore margin of the Karaburun Peninsula has been investigated down to 900 m water depth. The acquired high-resolution multibeam bathymetry, combined with the described chirp-sonar echo-types, documents how the recent evolution of the Vlora Gulf is strictly dependent on complex, sedimentary dynamics established in this area. Here, the Vjose River is the dominant source of sediment for the continental shelf. We provided evidences that the (Vjose River) sediment distribution is under the control of a complex, local circulation pattern that is defined by the peculiar regional shape of the gulf which is tectonically controlled. The tectonic control on the present-day, sedimentary processes is also evident offshore from the Karaburun Peninsula, along the upper slope, where important resedimentation processes have been recognized and are related to the recent geodynamic evolution of the margin.

Life on the edge: active microbial communities in the Kryos MgCl 2 -brine basin at very low water activity

The Kryos Basin is a deep-sea hypersaline anoxic basin (DHAB) located in the Eastern Mediterranean Sea (34.98°N 22.04°E). It is filled with brine of re-dissolved Messinian evaporites and is nearly saturated with MgCl2-equivalents, which makes this habitat extremely challenging for life. The strong density difference between the anoxic brine and the overlying oxic Mediterranean seawater impedes mixing, giving rise to a narrow chemocline. Here, we investigate the microbial community structure and activities across the seawater–brine interface using a combined biogeochemical, next-generation sequencing, and lipid biomarker approach. Within the interface, we detected fatty acids that were distinctly 13C-enriched when compared to other fatty acids. These likely originated from sulfide-oxidizing bacteria that fix carbon via the reverse tricarboxylic acid cycle. In the lower part of the interface, we also measured elevated rates of methane oxidation, probably mediated by aerobic methanotrophs under micro-oxic conditions. Sulfate reduction rates increased across the interface and were highest within the brine, providing first evidence that sulfate reducers (likely Desulfovermiculus and Desulfobacula) thrive in the Kryos Basin at a water activity of only ~0.4 Aw. Our results demonstrate that a highly specialized microbial community in the Kryos Basin has adapted to the poly-extreme conditions of a DHAB with nearly saturated MgCl2 brine, extending the known environmental range where microbial life can persist.