Seafloor deformation related to Quaternary tectonics in the Majorca Channel, Balearic Promontory (Western Mediterranean)

El análisis morfotectónico del sector central del Promontorio Balear, entre las islas de Ibiza y Mallorca, mediante batimetría multihaz y perfiles sísmicos de muy alta resolución ha permitido diferenciar varios rasgos morfológicos relacionados con la tectónica a dos escalas. Los elementos de gran escala, de dirección NE-SO, son: i) el escarpe Émile Baudot; ii) el monte submarino Émile Baudot, y iii) la alineación de montes submarinos Ausiàs March y Ses Olives. Los elementos de pequeña escala son: i) dos elevaciones longitudinales (ENE-OSO); ii) escarpes rectilíneos (NO-SE a NE-SO); iii) depresiones tectónicas (NNE SSO a NE-SO); y iv) alineaciones rectilíneas de pockmarks (NO-SE a NNE-SSO). Los elementos de mayor tamaño responden a la configuración estructural neógeno-cuaternaria. El escarpe Émile Baudot limita el Promontorio Balear y la cuenca oceánica del Mediterráneo Occidental. La alineación de montes submarinos Ausiàs March y Ses Olives está generada por una fase extensional, y el monte submarino Émile Baudot forma parte de una alineación volcánica NO-SE asociada a la Zona de Fractura de Ibiza. Los elementos de pequeña escala están relacionados con estructuras tectónicas activas que deforman las unidades sedimentarias del Cuaternario y el fondo marino. Las elevaciones longitudinales están generadas por pliegues anticlinales, mientras que el resto de estructuras están asociadas a la actividad de fallas normales de buzamiento alto.A morphotectonic analysis has been carried out between the islands of Ibiza and Majorca in the central sector of the Balearic Promontory using multibeam bathymetry and very high-resolution seismic profiles. Several morphological features related to tectonics at two different scales have been differentiated. The large-scale features have a NE-SW direction, they are: i) the Émile Baudot Escarpment; ii) the Émile Baudot seamount, and iii) the Ausiàs March and Ses Olives seamounts alignment. The differentiated small-scale elements are i) two longitudinal elevations (ENE-WSW); ii) rectilinear scarps (NW-SE to NE-SW); iii) tectonic depressions limited by one or two scarps (NNE-SSW to NE-SW), and iv) rectilinear pockmarks alignments (NW-SE to NNE-SSW). The largest elements respond to the Neogene-Quaternary structural configuration. The Émile Baudot escarpment is the limit between the Balearic Promontory and the Western Mediterranean oceanic basin. The alignment of the Ausiàs March and Ses Olives seamounts respond to the last extensional phase, and the Émile Baudot seamount forms part of a NW-SE volcanic alignment that could be associated with the Ibiza Fracture Zone. The smaller elements are related to active tectonic structures that deform Quaternary sedimentary units and the seafloor. The longitudinal elevations correspond to anticlinal folds, while the rest of the structures are associated to the activity of near vertical normal faults.En prens

Morphosedimentary characterization of the Capbreton submarine canyon system, Bay of Biscay (Cantabrian Sea)

Various studies have been carried out to the declaration of new marine protected areas for their importance for habitats, according to the Natura 2000 Network. One of these sites is a sector of the Capbreton Submarine Canyon System, located in front of the Basque Country coast, in the Bay of Biscay (North Atlantic). During the Intemares_CapBreton 0619 and 0620 surveys; bathymetric, backscatter, high-resolution parametric data and samples of sediments, rocks and benthic communities from the seabed were acquired. The study was completed by recording video transects with the underwater vehicle ROTV Politolana from the IEO. The processing and analysis of the geophysical information has allowed obtaining a detailed bathymetry grid of 10 × 10 m, from which the first morphosedimentary characterization of the system of tributary canyons to the E-W trending main canyon and its interfluves has been made. One of the main features of this canyon system is the presence of a large pockmark field on adjacent platforms between canyons, located between 500 and 1000 m water depth. Within this field, pockmarks are shown as circular to elliptical depressions, most likely related to gas rich-fluid emissions to the subsurface.Versión del edito

Informe de distribución espacial de características geomorfológicas y sedimentarias del sector meridional del LIC ESZZ15002 Espacio marino del oriente y sur de Lanzarote-Fuerteventura

En este informe se presenta una caracterización morfosedimentaria y estructural del margen sur de Fuerteventura, nueva y ampliada, que ha supuesto un beneficio para el estudio de las características morfológicas y de los hábitats bentónicos del margen sur de Fuerteventura. Para ello se ha realizado el reprocesado de los datos batimétricos y de reflectividad disponibles en la zona, que ha permitido mejorar su resolución y calidad, y ampliar de manera considerable la zona de estudio en relación a la estudiada en el proyecto anterior LIFE+INDEMARES. Los datos batimétricos se han interpretado junto con los registros de sonda paramétrica de alta resolución y los datos sedimentológicos (granulometría, mineralogía, contenido en materia orgánica y carbonatos) y petrológicos (tipo de roca) de muestras del fondo marino obtenidas durante en el proyecto LIFE+INDEMARES. Entre los tipos morfológicos cartografiados en la zona abundan los rasgos estructurales y erosivos, pero también existen rasgos deposicionales y biogénicos a lo largo de toda el área de estudio. Además se han identificado varios conos volcánicos situados a lo largo del talud. Las muestras de sedimento recuperadas se sitúan preferentemente en el techo del Banco de Amanay y en la zona de El Banquete, corresponden, fundamentalmente, a sedimentos gruesos de tipo arena-arena gravosa y en menor medida arena fangosa, con alto contenido en carbonato. Por su parte, dentro del material rocoso predominan las rocas volcánicas, principalmente los basaltos olivínicos, y las rocas carbonatadas ferruginosas. Entre las principales carencias identificadas, que podrían ser consideradas como una actividad futura para la mejora del conocimiento de la zona, destaca la ausencia de (1) una malla apropiada de registros de sonda paramétrica, ya que los existentes se centran en el techo del Banco de Amanay y en El Banquete, dejando las zonas profundas sin estudiar; y (2) una distribución adecuada de los muestreos de sedimento, ya que como en el punto anterior, las muestras recuperadas se limitan, fundamentalmente al techo del Banco de Amanay y El Banquete, dejando muchas áreas sin explorar. Esta escasez de muestras no permite un calibrado suficientemente correcto de los datos de reflectividad que son clave en la realización de modelos de predicción de hábitat.This report presents a new and expanded morphosedimentary and structural characterization of the southern margin of Fuerteventura. The multibeam data (bathymetry and backscatter) available in the study area have been reprocessed, and high resolution parametric profiles, sedimentological (grain size, mineralogy, organic matter, and carbonate content) and petrological (type of rock) data have been integrated to achieve a more complete approach. The reprocessing of bathymetric data has substantially improved the resolution and quality of the data, and the addition of data from previous projects (ZEE project) has allowed to extend the study area. All this new information provides a benefit to the study of the morphological characteristics and the benthic habitats from the south of Fuerteventura area. Among the morphological types mapped in the study area, structural and erosive features are frequent, but depositional and biogenic features also appear in the whole area. Moreover, several volcanic cones have been mapped along the slope. Sediment samples retrieved at the study area, mostly located at the top of the Amanay Bank and El Banquete, correspond to coarse sediments as sand-gravelly sand and, in a lesser extent, with muddy sand of high carbonate content. The analysis from the rock samples indicates the presence of both volcanic (mainly olivine basalts) and carbonate (ferruginous) rocks. We identify two shortcomings in this study: (1) the absence of a suitable grid of high resolution sub-bottom profiles, since the available records are limited to the top of Amanay Bank and El Banquete area and, (2) the absence of a spatially more homogeneous and intensive grid for surficial sediment samples; this makes impossible to obtain a good calibration between the sediment samples and the backscatter data. For these reasons, we strongly recommend future activities to improve the knowledge of the area with a more detailed geophysical and sedimentological study, which will result in better habitat prediction models.Fondos LIFE, Comisión Europea. Fundación Biodiversidad. LIFE IP-PAF INTEMARE

Recovery Signals of Rhodoliths Beds since Bottom Trawling Ban in the SCI Menorca Channel (Western Mediterranean)

One of the objectives of the LIFE IP INTEMARES project is to assess the impact of bottom trawling on the vulnerable benthic habitats of the circalittoral bottoms of the Menorca Channel (western Mediterranean), designated a Site of Community Importance (SCI) within the Natura 2000 network. The present study compares the epibenthic communities of four areas, subjected to different bottom trawl fishing intensity levels. The assignment of fishing effort levels was based on the fishing effort distribution in the area calculated from Vessel Monitoring System (VMS) data and the existence of two Fishing Protected Zones in the Menorca Channel. Biological samples were collected from 39 beam trawl stations, sampled during a scientific survey on April 2019. We compare the diversity, composition, and density of the epibenthic flora and fauna, together with the rhodoliths coverage and the morphology of the main species of rhodoliths of four areas subjected to different levels of bottom trawl fishing effort, including one that has never been impacted by trawling. Our results have shown negative impacts of bottom trawling on rhodoliths beds and the first signals of their recovery in areas recently closed to this fishery, which indicate that this is an effective measure for the conservation of this habitat of special interest and must be included in the management plan required to declare the Menorca Channel as a Special Area of Conservation.En prens

Improving Scientific Knowledge of Mallorca Channel Seamounts (Western Mediterranean) within the Framework of Natura 2000 Network

The scientific exploration of Mallorca Channel seamounts (western Mediterranean) is improving the knowledge of the Ses Olives (SO), Ausias March (AM), and Emile Baudot (EB) seamounts for their inclusion in the Natura 2000 network. The aims are to map and characterize benthic species and habitats by means of a geological and biological multidisciplinary approach: high-resolution acoustics, sediment and rock dredges, beam trawl, bottom trawl, and underwater imagery. Among the seamounts, 15 different morphological features were differentiated, highlighting the presence of 4000 pockmarks, which are seafloor rounded depressions indicators of focused fluid flow escapes, usually gas and/or water, from beneath the seabed sediments. So far, a total of 547 species or taxa have been inventoried, with sponges, fishes, mollusks, and crustaceans the most diverse groups including new taxa and new geographical records. Up to 29 categories of benthic habitats have been found, highlighting those included in the Habitats Directive: maërl beds on the summits of AM and EB, pockmarks around the seamounts and coral reefs in their rocky escarpments as well as fields of Isidella elongata on sedimentary bathyal bottoms. Trawling is the main demersal fishery developed around SO and AM, which are targeted to deep water crustaceans: Parapenaeus longirostris, Nephrops norvegicus, and Aristeus antennatus. This study provides scientific information for the proposal of the Mallorca Channel seamounts as a Site of Community Importance and for its final declaration as a Special Area of Conservation

Twenty years of ground-based NDACC FTIR spectrometry at Izaña Observatory - overview and long-term comparison to other techniques

High-resolution Fourier transform infrared (FTIR) solar observations are particularly relevant for climate studies, as they allow atmospheric gaseous composition and multiple climate processes to be monitored in detail. In this context, the present paper provides an overview of 20 years of FTIR measurements taken in the framework of the NDACC (Network for the Detection of Atmospheric Composition Change) from 1999 to 2018 at the subtropical Izaña Observatory (IZO, Spain). Firstly, long-term instrumental performance is comprehensively assessed, corroborating the temporal stability and reliable instrumental characterization of the two FTIR spectrometers installed at IZO since 1999. Then, the time series of all trace gases contributing to NDACC at IZO are presented (i.e. C2H6, CH4, ClONO2, CO, HCl, HCN, H2CO, HF, HNO3, N2O, NO2, NO, O3, carbonyl sulfide (OCS), and water vapour isotopologues H162O, H182O, and HD16O), reviewing the major accomplishments drawn from these observations. In order to examine the quality and long-term consistency of the IZO FTIR observations, a comparison of those NDACC products for which other high-quality measurement techniques are available at IZO has been performed (i.e. CH4, CO, H2O, NO2, N2O, and O3). This quality assessment was carried out on different timescales to examine what temporal signals are captured by the FTIR records, and to what extent. After 20 years of operation, the IZO NDACC FTIR observations have been found to be very consistent and reliable over time, demonstrating great potential for climate research. Long-term NDACC FTIR data sets, such as IZO, are indispensable tools for the investigation of atmospheric composition trends, multi-year phenomena, and complex climate feedback processes, as well as for the validation of past and present space-based missions and chemistry climate models.The Izaña FTIR station has been supported by the German Bundesministerium für Wirtschaft und Energie (BMWi) via DLRunder grants 50EE1711A and by the Helmholtz Society via the research program ATMO. In addition, this research was funded by the European Research Council under FP7/(2007-2013)/ERC Grant agreement nº 256961 (project MUSICA), by the Deutsche Forschungsgemeinschaft for the project MOTIV (GeschaFTIRzeichen SCHN 1126/2-1), by the Ministerio de Economía y Competitividad from Spain through the projects CGL2012-37505 (project NOVIA) and CGL2016-80688-P (project INMENSE), and by EUMETSAT under its Fellowship Programme (project VALIASI)