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Submarine canyons are known as one of the seafloor morphological features where living cold-water coral (CWC) communities develop in the Mediterranean Sea. We investigated the CWC community of the two westernmost submarine canyons of the Gulf of Lions canyon system: the Cap de Creus Canyon (CCC) and Lacaze Duthiers Canyon (LDC). Coral associations have been studied through video material recorded by means of a manned submersible and a remotely operated vehicle. Video transects have been conducted and analyzed in order to obtain information on (1) coral bathymetric distribution and density patterns, (2) size structure of coral populations, and (3) coral colony orientation with respect to the substrate. Madrepora oculata was the most abundant CWC in both canyons, while Lophelia pertusa and Dendrophyllia cornigera mostly occurred as isolated colonies or in small patches. An important exception was detected in a vertical cliff in LDC where a large Lophelia pertusa framework was documented. This is the first record of such an extended L. pertusa framework in the Mediterranean Sea. In both canyons coral populations were dominated by medium and large colonies, but the frequent presence of small-sized colonies also indicate active recruitment. The predominant coral orientation with respect to the substrate (90° and 135°) is probably driven by the current regime as well as by the sediment load transported by the current flows. In general no clear differences were observed between the CWC populations from CCC and LDC, despite large differences in particulate matter between canyons. [ABSTRACT FROM AUTHOR]

Recently acquired swath-bathymetry data and high-resolution seismic reflection profiles offshore Adra (Almería, Spain) reveal the surficial expression of a NW--SE trending 20 km-long fault, which we termed the Adra Fault. Seismic imaging across the structure depicts a subvertical fault reaching the seafloor surface and slightly dipping to the NE showing an along-axis structural variability. Our new data suggest normal displacement of the uppermost units with probably a lateral component. Radiocarbon dating of a gravity core located in the area indicates that seafloor sediments are of Holocene age, suggesting present-day tectonic activity. The NE Alboran Sea area is characterized by significant low-magnitude earthquakes and by historical records of moderate magnitude, such as the Mw = 6.1 1910 Adra Earthquake. The location, dimension and kinematics of the Adra Fault agree with the fault solution and magnitude of the 1910 Adra Earthquake, whose moment tensor analysis indicates normal-dextral motion. The fault seismic parameters indicate that the Adra Fault is a potential source of large magnitude (Mw ≤ 6.5) earthquakes, which represents an unreported [ABSTRACT FROM AUTHOR]

Abstract: The Cap de Creus and the Palamós submarine canyon heads were instrumented during two consecutive winters to study their respective role in the dynamics of the sediment transport on the north-western Mediterranean Sea. Several events of dense shelf-water cascading (DSWC) were identified simultaneously at both canyons and compared between them. DSWC events were characterized by abrupt drops of temperature, increases of current speeds, and peaks of high suspended-sediment concentrations (SSC). Concentrations up to 170mg l−1 were recorded in both studied winters at the Cap de Creus Canyon coinciding with the first DSWC event of the winter concurrent with an eastern storm. Overall, the amount of sediment transported during the DSWC events was one order of magnitude greater at the Cap de Creus Canyon than at the Palamós Canyon. Results from this study have identified for the first time the presence of DSWC events also in the Palamós Canyon head, south of the Gulf of Lions (GoL), and corroborated previous findings that the Cap de Creus Canyon is the main pathway for DSWC and the associated sediment transport from the GoL down to the deeper regions of the north-western Mediterranean. [Copyright &y& Elsevier]