The Anthropogenic Footprint of Physical Harm on the Seabed of Augusta Bay (Western Ionian Sea); A Geophysical Investigation

Abstract

Augusta Bay is an embayment of the Hyblean sector in south-eastern Sicily (Southern Italy) that faces the Ionian Sea and includes the Rada di Augusta, a wide littoral sector sheltered by breakwaters, which hosts intense harbor activities. Rada di Augusta and the adjacent Priolo embayment were listed in the National Remediation Plan (NRP) by the Italian Ministry of Environment, as they have suffered major anthropic impacts over the last seventy years. Indeed, extensive petrochemical and industrial activities, military and commercial maritime traffic, as well as agriculture and fishery activities, have resulted in a highly complex combination of impacts on the marine environment and seafloor. In this paper, we investigate the extent of human-driven physical impacts on the continental shelf, offshore of Rada di Augusta, by means of Multibeam echosounder, Side-Scan Sonar and Chirp Sonar profilers, as well as direct seabed samplings. At least seven categories of anthropogenic footprints, i.e. anchor grooves and scars, excavations, trawl marks, targets, dumping trails, isolated dumping and dumping cumuli, mark the recent human activities at the seafloor. The practice of dredge spoil disposal, possibly protracted for decades during the last century, has altered the seafloor morphology of the central continental shelf, by forming an up-to-9 m-thick hummocky deposit, with acoustic features noticeably different from those of any other shelf lithosome originated by natural processes. All available data were reported in an original thematic map of the seafloor features, offering an unprecedented opportunity to unravel sediment facies distribution and localization of anthropogenic disturbance. Finally, the shelf area was ranked, based on the coexistence of multiple stressors from human-driven physical harm, thus providing a semi-quantitative analysis of environmental damage classification in the area.

Circular structures on the seabed: differentiating between natural and anthropogenic origins—Examples from the Southwestern Baltic Sea

“…Repetitive dumping of coarser material likely determines the string pattern. Similar linear arrangements of irregular high reflectivity patches have been observed in SSS images at the Point Gray dumpsite in Canada (Hart, 1992;Mosher et al, 1997;Sullivan et al, 2006) and in southeastern Sicily (Budillon et al, 2022). They are linear or curvilinear successions of high backscatter patches caused by dumping material on fine-grained seafloor from a mobile barge.…”

“…Also, as a result of the ship moving forward or drifting, "string of pearls"-like features form on the seafloor (Mosher et al, 1997;Blondel, 2009). The seafloor relief character of these structures may be influenced by the speed of ship movement, the amount and type of material dumped, and post-depositional dispersion processes (Budillon et al, 2022).…”

Conceptos Básicos de la Ciencia del Sonido en el Mar

“…Los sonidos generados por las actividades humanas constituyen una parte importante del fondo acústico oceánico total [96,97] y se utiliza para muchos fines valiosos, como la comunicación, la navegación, defensa, investigación, la exploración y la pesca. Sin embargo, algunos sonidos son solo un subproducto de otra actividad, como el ruido generado por los buques y por las actividades industriales en alta mar, incluidas las perforaciones y la producción de petróleo.…”

A new multi-resolution bathymetric dataset of the Gulf of Naples (Italy) from complementary multi-beam echosounders

“…Among the European Seas, the Mediterranean Sea is a hotspot of biodiversity, hosting more than 7.5% of global biodiversity (Bianchi and Morri, 2000) with a high percentage of endemic species (Myers et al, 2000) and unique ecosystems. However, the basin is recognized to be "under siege" due to the historical and still ongoing impacts from multiple stressors such as littering and dumping, trawling, ghost fishing, seaborne traffic and modification of the seafloor (Coll et al, 2012;Puig et al, 2012;Madricardo et al, 2017Madricardo et al, , 2019Canals et al, 2021;Budillon et al, 2022;Pellegrini et al, 2023;Trincardi et al, 2023). This is particularly evident in the Gulf of Naples, a densely populated coastal region stretching along 385 km on the eastern Tyrrhenian Sea, which represents an important tourist destination including the Gulf Islands (Capri, Ischia and Procida), Sorrento Peninsula, Vesuvius National Park, Phlegraean Fields and archaeological sites of Pompeii, Herculaneum, Pozzuoli and Cuma.…”