Seamount evolution related to tectonics and influence on recent sedimentary systems

Investigate the Spanish Continental Shelf West Off Canary Island

NA

Geological study of Cadiz Gulf

Study new migration areas and release points of methane and hydrated gasses in the continental platform of the gulf of Cádiz and their origins. Research seabed structures around the gulf of Cádiz.

Evaluate transport of water salinity, temperature, carbon and other variables of the greenhouse

The NUREIEV2 cruise targets the main objective of testing the hypothesis that sea storms are the main trigger for the transfer of matter and energy, including pollutants and litter, from the coastal to the deep ocean in the SE of Spain (36º20’N to 37º36’N and 2º40’W to 0º40’W). A dedicated strategy was performed during the NUREIEV2 cruise to achieve the objective including: 1) the collection of sediment cores (multicores) in the vicinity of the mine tailings deposit near the Portman Bay 2) the recovery and redeployment of mooring lines with automated sediment traps and currentmeters to monitor particle fluxes (including pollutants released from the mine tailings deposit) and near bottom oceanographic parameters (current speed and directions, temperature, transmissivity), 3) the profiling of the water column (by means of a CTD) to study physico-chemical characteristics of the water column, 4) the collection of floating debris including microplastics from surface waters 5) and the high resolution swath mapping and TOPAS profiling to investigate seafloor features.

The main target of the NUREIEVA-MAR-1 campaign is twofold. On the one hand, it aims to establish the geometry and the three-dimensional internal structure of the deposit of mineral discharges submerged in front of the Bay of Portmán and, on the other hand, it intends to verify the data obtained by obtaining witnesses from the deposit. During the campaign, a high resolution multibeam bathymetric cartography and a high density mesh of TOPAS PS18 parametric probe profiles will be carried out, and sediment tokens will be obtained by gravity or piston core grabs of the longest length possible, as well as by means of multicorer, box corer and dredge Van Veen for the upper part of the deposit. In addition, the discharge of dissolved metals from the deposit emerged at sea will be quantified using CTD profiles and sampling with hydrographic bottles. Floating microplastics will also be sampled.

The leg 1 of the NUREIEV 3 oceanographic cruise took place from 22 to 30 April 2016. The area of work has located on the continental margin of the SE of Iberian Peninsula, off the coast of Murcia and Almeria, with reference coordinates from 36º20'N to 37º36'N and 2º40'W to 0º40'W. The tasks performed consisted of: • Bathymetric mapping with multibeam echosounder for seabed mapping, from inner shelf to upper slope (50 to 1500 m depth). • Geophysical works with TOPAS, very high resolution seismic profiles, to characterize the sedimentary cover of the study area. • Recovery of 5 mooring lines, instrumented for the continuous monitoring of the hydrological (water masses) and sediment (particle fluxes) dynamics from the last cruise in September 2015. Each mooring line is composed by one current meter for measuring temperature, turbidity, velocity and direction of currents and one sediment trap for sampling sinking particles. In addition, each mooring is equipped with an acoustic release for recovery and with suitable buoyancy. Monitoring with instrumented mooring lines has covered an annual cycle, in two phases of 6 months each one. • CTD profiling and water sampling. Profiles have been made in each of the submarine canyons monitored for measuring physical and chemical variables of water column (temperature, salinity, turbidity, oxygen concentration and chlorophyll) and calibration of instruments of mooring lines. • Performing surface sampling of floating microplastics by neuston net. • Sampling of surface sediments by multicorer.

ISLAND is a research cruise that will address the above issues through the following 3 specific objectives: a) To explore how the NW Sicilian canyons evolved during the Late Quaternary (differences in style, frequencies and intensity of sedimentary flows, possible differences in forcing mechanisms) and to assess which canyon(s) is/are more “active” in the present-day conditions and why. b) To establish whether canyons displaying different morphologies and controlled by different processes may be characterized by differences in the spatial distribution and variability of benthic biomass and biodiversity (are the most active canyons always the most biodiverse?). c) To explore the role of bottom trawling fishery in shaping the morphology and governing the presentday dynamics of submarine canyons and eventually assess its impact in altering canyon biodiversity (is trawling activity affecting the natural canyon seascapes and sedimentary dynamics, inducing a change in biodiversity?).