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International audience; Connectivity between spawning grounds and recruitment areas of marine fish species drives population structure and dynamics, and may be affected by climate-induced changes in oceanographic processes. We analysed the variability in recruitment success of larvae to estuarine nursery areas along the Iberian Atlantic coast of four fish species with distinct spawning grounds and periods (Solea solea, Solea senegalensis, Platichthys flesus and Dicentrarchus labrax). Concomitantly, we explored the variations in connectivity patterns between "cold" and "warm" year archetypes. We used a three-dimensional Lagrangian transport particle-tracking model integrating time series of velocity, temperature and salinity fields archived from the Regional Ocean Modelling System. We simulated individual larval dispersal, over extended spawning periods, from multiple coastal spawning areas to estuarine recruitment areas over 20 years (1989-2008). Overall, high inter-and intra-annual variation were found for all species. Nonetheless, highest overall average recruitment estimates were obtained for S. solea and D. labrax (with 7.3% and 5.7% of the particles released in spawning areas reaching a recruitment area, respectively) compared to S. senegalensis and P. flesus (3.4% and 1.7%, respectively). Recruitment estimates were overall higher at earlier spawning dates but peak values occurred at later spawning events. Regarding spawning origin, particles that recruited to the northern part of the Iberian coast were mainly from southern source areas. For estuarine systems located in southern Portugal, the relative contributions of northern and southern coastal spawning areas were more balanced, or with a preponderance of northern spawning areas (namely for S. senegalensis and D. labrax). Recruitment was higher in "warm" years compared to "cold" years, except for P. flesus for which nil recruitment was registered in the southern Iberian coast during "warm" years. Larvae also travelled farther in "warm" years compared to "cold" years. Ultimately, understanding how oceanographic conditions govern larval recruitment to estuarine nursery areas is pivotal to forecast the potential impacts of climate change on species with segregated life histories, and will underpin long term management and safeguarding of estuarine nursery role.

Effective sustainable management of marine fisheries requires that assessed management units (that is, fish stocks) correspond to biological populations. This issue has long been discussed in the context of Atlantic bluefin tuna (ABFT, Thunnus thynnus) management, which currently considers two unmixed stocks but does not take into account how individuals born in each of the two main spawning grounds (Gulf of Mexico and Mediterranean Sea) mix in feeding aggregations throughout the Atlantic Ocean. Using thousands of genome-wide molecular markers obtained from larvae and young of the year collected at the species’ main spawning grounds, we provide what is, to the best of our knowledge, the first direct genetic evidence for “natal homing” in ABFT. This has facilitated the development of an accurate, cost-effective, and non-invasive tool for tracing the genetic origin of ABFT that allows for the assignment of catches to their population of origin, which is crucial for ensuring that ABFT management is based on biologically meaningful stock units rather than simply on catch location., Sí

The Ecopath food web model that describes the Portuguese continental shelf ecosystem was fitted to available time series to investigate the ecosystem dynamics and decline of the Portuguese sardine stock. Our results showed that the Portuguese continental shelf ecosystem model is a good predictor of biomass and catch time series trends for many species. Moreover, our results suggested that the main factors that drove the ecosystem dynamics were trophic interactions, fishing and environmental forcing (sea surface temperature). The same drivers were important in explaining sardine decline among which the largest contribution was observed when incorporating sea surface temperature forcing on adult sardine, followed by fishing. Moreover, sardine eggs predators (i.e., chub mackerel, horse mackerel and bogue) were emphasised as the most important among trophic interactions in explaining sardine trend between 1986 and 2017. Furthermore, a flow control hypothesis test, showed that model parametrization allows explaining sardine behaviour through wasp-waist control mechanism, characteristic for upwelling systems. This study represents an important step forward in understanding the changes that occurred in the Portuguese continental shelf ecosystem and provides helpful insights to explain Portuguese sardine decline., SI

International audience; There has been growing interest in recent years in the use of homogeneously reprocessed ground-based GNSS, VLBI, and DORIS measurements for climate applications. Existing datasets are reviewed and the sensitivity of tropospheric estimates to the processing details is discussed. The uncertainty in the derived IWV estimates and linear trends is around 1 kg m−2 RMS and ± 0.3 kg m−2 per decade, respectively. Standardized methods for ZTD outlier detection and IWV conversion are proposed. The homogeneity of final time series is limited however by changes in the stations equipment and environment. Various homogenization algorithms have been evaluated based on a synthetic benchmark dataset. The uncertainty of trends estimated from the homogenized times series is estimated to ±0.5 kg m−2 per decade. Reprocessed GNSS IWV data are analysed along with satellites data, reanalyses and global and regional climate model simulations. A selection of global and regional reprocessed GNSS datasets and ERA-interim reanalysis are made available through the GOP-TropDB tropospheric database and online service. A new tropo SINEX format, providing new features and simplifications, was developed and it is going to be adopted by all the IAG services.

The subduction of seamounts and ridge features at convergent plate boundaries plays an important role in the deformation of the overriding plate and influences geochemical cycling and associated biological processes. Active serpentinization of forearc mantle and serpentinite mud volcanism on the Mariana forearc (between the trench and active volcanic arc) provides windows on subduction processes. Here, we present (1) the first observation of an extensive exposure of an undeformed Cretaceous seamount currently being subducted at the Mariana Trench inner slope; (2) vertical deformation of the forearc region related to subduction of Pacific Plate seamounts and thickened crust; (3) recovered Ocean Drilling Program and International Ocean Discovery Program cores of serpentinite mudflows that confirm exhumation of various Pacific Plate lithologies, including subducted reef limestone; (4) petrologic, geochemical and paleontological data from the cores that show that Pacific Plate seamount exhumation covers greater spatial and temporal extents; (5) the inference that microbial communities associated with serpentinite mud volcanism may also be exhumed from the subducted plate seafloor and/or seamounts; and (6) the implications for effects of these processes with regard to evolution of life. This article is part of a discussion meeting issue ‘Serpentine in the Earth system’.

International audience; The Earth surface thermal infrared (TIR) radiation shows conspicuously an anisotropic behavior just like the bidirectional reflectance of visible and near infrared spectral domains. The importance of thermal radiation directionality (TRD) is being more and more widely recognized in the applications because of the magnitude of the effects generated. The effects of TRD were originally evidenced through experiments in 1962, showing that two sensors simultaneously measuring temperature of the same scene may get significantly different values when the viewing geometry is different. Such effect limits inter-comparison of measurement datasets and land surface temperature (LST) products acquired at different view angles, while raising the question of measurement reliability when used to characterize land surface processes. These early experiments fostered the development of modeling approaches to quantify TRD with the aim of developing a correction for Earth surface TIR radiation. Initiatives for pushing the analysis of TIR data through modeling have been lasted since 1970s. They were initially aimed at mimicking the observed TIR radiance with consideration of canopy structure, component emissivities and temperatures, and Earth surface energy exchange processes. Presently, observing the Earth surface TRD effect is still a challenging task because the TIR status changes rapidly. Firstly, a brief theoretical background and the basic radiative transfer equation are presented. Then, this paper reviews the historical development and current status of observing TRD in the laboratory, in-situ, from airborne and space-borne platforms. Accordingly, the TRD model development, including radiative transfer models, geometric models, hybrid models, 3D models, and parametric models are reviewed for surfaces of water, ice and sea, snow, barren lands, vegetation and urban landscapes, respectively. Next, we introduce three potential applications, including normalizing the LST products, estimating the hemispheric upward longwave radiation using multi-angular TIR observations and separating surface component temperatures. Finally, we give hints and directions for future research work. The last section summarizes the study and stresses three main conclusions.

The contamination of marine ecosystems by contaminants of emerging concern such as personal care products or per- and polyfluoroalkyl substances is of increasing concern. This work assessed the concentrations of selected contaminants of emerging concern in water and sediment of European aquaculture areas, to evaluate their co-variation with legacy contaminants (polycyclic aromatic hydrocarbons) and faecal biomarkers, and estimate the risks associated with their occurrence. The 9 study sites were selected in 7 European countries to be representative of the aquaculture activities of their region: 4 sites in the Atlantic Ocean and 5 in the Mediterranean Sea. Musks, UV filters, preservatives, per- and polyfluoroalkyl substances and polycyclic aromatic hydrocarbons were detected in at least one of the sites with regional differences. While personal care products appear to be the main component of the water contamination, polycyclic aromatic hydrocarbons were mostly found in sediments. As expected, generally higher levels of personal care products were found in sewage impacted sites, urbanised coasts and estuaries. The risk assessment for water and sediment revealed a potential risk for the local aquatic environment from contaminants of both legacy and emerging concern, with a significant contribution of the UV filter octocrylene. Despite marginal contributions of per- and polyfluoroalkyl substances to the total concentrations, PFOS (perfluorooctane sulfonate) aqueous concentrations combined to its low ecotoxicity thresholds produced significant hazard quotients indicating a potential risk to the ecosystems., This study was financially supported by the SEA-on-a-CHIP project, funded from European Union Seventh Framework Programme (FP7-OCEAN-2013) under grant agreement No. 614168. Antonio Marques is supported through the FCT Investigator program (IF).

Proponents of artificial reef (AR) deployment are often motivated by the usefulness of such structures. The usefulness of ARs is related to their capability of providing ecosystem services/additional functions. We present two distinct Portuguese AR case studies: (1) The Nazaré reef off the central coast of Portugal and (2) the Oura reef off the Algarve coast. Semi-structured interviews were conducted with local fishermen in the fishing towns of Nazaré and Quarteira pre-and post-AR deployment. The main focus of the interviews was to understand fishermen's perception of AR usefulness (or lack thereof) in terms of nine ecosystem services/additional functions potentially provided by the ARs. We tested the null hypothesis that ARs do not provide additional ecosystem services/additional functions. When queried pre-AR deployment, fishermen indicated that ARs are most likely to provide three ecosystem services: "habitat and refuge," "biodiversity preservation" and "food production." Fishermen had similar perceptions post-deployment. For the Nazaré reef, fishermen tended to have a positive or neutral perception of ecosystem services/additional functions being provided by ARs. For the Oura reef, fishermen tended to have a mostly neutral perception of AR ecosystem services; however, there were also some positive and other negative perceptions. It was difficult for stakeholders to conceptualize some of the ecosystem services/additional functions provided by ARs prior to actively using them. As a result, some stakeholders changed their perception of the ecosystem services/additional functions after using the structures. These results indicate that stakeholders likely need to perceive ARs as useful in order for them to provide their support for AR installation. Likewise, their support is often needed to justify the use of public funds to install ARs, therefore making it imperative for resource managers to undertake similar interviews with fishermen when considering the use of ARs in other areas. MARE program, within the project "Implantacao e estudo integrado de sistemas recifais" PROMAR program "Elaboracao de estudos de caracterizacao do estado de colonizacao e impacto socioeconomico do recife artificial da Nazare" - 02-PE/2011/GJ info:eu-repo/semantics/publishedVersion

Little is known about the fractionation of Li isotopes during formation of biogenic carbonates, which form the most promising geological archives of past seawater composition. Here we investigated the Li isotope composition (delta Li-7) and Li/Ca ratios of organisms that are abundant in the Phanerozoic record: mollusks (mostly bivalves), echinoderms, and brachiopods. The measured samples include (i) modern calcite and aragonite shells from various species and natural environments (13 mollusk samples, 5 brachiopods and 3 echinoderms), and (ii) shells from mollusks grown under controlled conditions at various temperatures. When possible, the mollusk shell ultrastructure was micro-sampled in order to assess intra-shell heterogeneity. In this paper, we systematically characterize the influence of mineralogy, temperature, and biological processes on the delta Li-7 and Li/Ca of these shells and compare with published data for other taxa (foraminifera and corals). Aragonitic mollusks have the lowest delta Li-7, ranging from +16 to +22%, echinoderms have constant delta Li-7 of about +24%, brachiopods have delta Li-7 of +25 to +28%, and finally calcitic mollusks have the largest range and highest delta Li-7 values, ranging from +25% to +40%. Measured brachiopods have similar delta Li-7 compared to inorganic calcite precipitated from seawater (delta Li-7 of +27 to +29%), indicating minimum influence of vital effects, as also observed for other isotope systems and making them a potentially viable proxy of past seawater composition. Calcitic mollusks, on the contrary, are not a good archive for seawater paleo-delta Li-7 because many samples have significantly higher delta Li-7 values than inorganic calcite and display large interspecies variability, which suggests large vital effects. In addition, we observe very large intra-shell variability, in particular for mixed calcite-aragonite shells (over 20% variability), but also in mono-mineralic shells (up to 12% variability). Aragonitic bivalves have less variable delta Li-7 (7% variability) compared to calcitic mollusks, but with significantly lower delta Li-7 compared to inorganic aragonite, indicating the existence of vital effects. Bivalves grown at various temperatures show that temperature has only a minor influence on fractionation of Li isotopes during shell precipitation. Interestingly, we observe a strong correlation (R-2 = 0.83) between the Li/Mg ratio in bivalve Mytilus edulis and temperature, with potential implications for paleo-temperature reconstructions. Finally, we observe a negative correlation between the delta Li-7 and both the Li/Ca and Mg/Ca ratio of calcite mollusks, which we relate to biomineralization processes. To explain this correlation, we propose preferential removal of 6 Li from the calcification site of calcite mollusks by physiological processes corresponding to the regulation of the amount of Mg in the calcifying medium. We calculate that up to 80% of the initial Li within the calcification site is removed by this process, leading to high delta Li-7 and low Li/Ca in some calcite mollusk specimens. Collectively, these results suggest that Mg (and thus [Li]) is strongly biologically controlled within the calcifying medium of calcite mollusks. Overall, the results of this study show that brachiopods are likely to be suitable targets for future work on the determination of paleo-seawater Li isotope composition-an emerging proxy for past weathering and hydrothermal processes.

International audience; A wide range of environmental applications require the monitoring of land surface temperature (LST) at frequent intervals and fine spatial resolutions, but these conditions are not offered nowadays by the available space sensors. To overcome these shortcomings, LST downscaling methods have been developed to derive higher resolution LST from the available satellite data. This research concerns the application of a data assimilation (DA) downscaling approach, the genetic particle smoother (GPS), to disaggregate Meteosat 8 LST time series (3 km × 5 km) at finer spatial resolutions. The methodology was applied over the Crau-Camargue region in Southeastern France for seven months in 2009. The evaluation of the downscaled LSTs has been performed at a moderate resolution using a set of coincident clear-sky MODIS LST images from Aqua and Terra platforms (1 km × 1 km) and at a higher resolution using Landsat 7 data (60 m × 60 m). The performance of the downscaling has been assessed in terms of reduction of the biases and the root mean square errors (RMSE) compared to prior model-simulated LSTs. The results showed that GPS allows downscaling the Meteosat LST product from 3 × 5 km2 to 1 × 1 km2 scales with a RMSE less than 2.7 K. Finer scale downscaling at Landsat 7 resolution showed larger errors (RMSE around 5 K) explained by land cover errors and inter-calibration issues between sensors. Further methodology improvements are finally suggested

9 páginas, 4 tablas, 9 figuras, To better understand sources and transport of particulate material in the NW Iberian coastal upwelling system, a mooring line dotted with an automated PPS 4/3 sediment trap was deployed off Cape Silleiro at the base of the photic zone. The samples were collected from November 2008 through June 2012 over sampling periods of 4-12 days. Our study represents the first automated sediment trap database for the NW Iberian margin. The magnitude and composition of the settling material showed strong seasonal variability with the highest fluxes during the poleward and winter mixing periods (averages of 12.9±9.6 g m−2 d−1 and 5.6±5.6 g m−2 d−1 respectively), and comparatively lower fluxes (3.6±4.1 g m−2 d−1) for the upwelling season. Intensive deposition events registered during poleward and winter mixing periods were dominated by the lithogenic fraction (80±3%). They were associated to high energy wave-driven resuspension processes, due to the occurrence of south-westerly storms, and intense riverine inputs of terrestrial material from Minho and Douro rivers. On the other hand, during the spring - summer upwelling season, the share of biogenic compounds (organic matter, calcium carbonate (CaCO3), biogenic silica (bSiO2)) to downward fluxes was higher, reflecting an increase in pelagic sedimentation due to the seasonal intensification of primary production and negligible river inputs and wave-driven resuspended material. Otherwise, the large variations of biogenic settling particles were mainly modulated by upwelling intensity, which by means of upwelling filaments ultimately controlled the offshore transport of the organic carbon fixed by primary producers towards the adjacent ocean. Based on the average downward flux of organic carbon (212 mg C m−2 d−1) and considering an average primary production of 1013 mg C m−2 d−1 from literature, we estimated that about 21% of the fixed carbon is vertically exported during the upwelling season, This study was sponsored by CAIBEX (CTM2007-66408-C02-01/MAR) and REIMAGE (CTM2011–30155–C03–03) projects funded by the Spanish Government, EXCAPA project (10MDS402013PR) supported by Xunta de Galicia, the EU FEDER funded projects RAIA (INTERREG 2009/2011; 0313/RAIA/E) and RAIA.co (INTERREG 2011/2013; 052/RAIA.co/1E) and the CALIBERIA project (PTDC/MAR/102045/2008) financed by Fundaçao para a Ciència e a Tecnologia (FCT-Portugal). D.Z. was funded by a postdoctoral fellowship (Plan I2C) from Xunta de Galicia (Spain)

IODP 339 Site U1385 ("Shackleton site", e.g. Hodell et al., 2013a), from the SW Iberian margin, offers the opportunity to study marine microfossil population dynamics by comparing several past interglacials and to test natural shifts of species that occurred across these warm periods, in a subtropical context. Here, more specifically, we present results obtained for the dinoflagellate cyst (dinocyst) population integrated at a regional scale thanks to the addition of data from proximal sites from southern Iberian margin. When possible, observations made using the dinocyst bio-indicator are compared to additional proxies from the same records in order to test the synchronicity of the marine biota response. Pollen data available for some of the compiled marine sequences also offer the opportunity to directly compare marine biota with terrestrial ecosystem responses. This spatio-temporal compilation reveals that, over the last 800 ka, surface waters around Iberia were tightly coupled to (rapid) climate changes and were characterised by coherent dinocyst assemblage patterns, highlighting a permanent connection between Atlantic and Mediterranean waters as evidenced through a continuous exchange of dinocyst populations. Some index species well illustrate the evolution of the regional hydrographic context along time, as for instance Spiniferites and Impagidinium species, together with Lingulodinium machaerophorum, Bitectatodinium tepikiense and heterotrophic brown cysts. They constitute key bio-indicators in context of natural environmental shifts at long and short timescales. info:eu-repo/semantics/publishedVersion

Review article.-- 20 pages, 18 figures, The Gibraltar arc, spans a complex portion of the Africa–Eurasia plate boundary marked by slow oblique convergence and intermediate and deep focus seismicity. The seemingly contradictory observations of a young extensional marine basin surrounded by an arcuate fold-and-thrust belt, have led to competing geodynamic models (delamination and subduction). Geophysical data acquired in the past decade provide a test for these models and support a narrow east-dipping, subduction zone. Seismic refraction studies indicate oceanic crust below the western Gulf of Cadiz. Tomography of the upper mantle reveals a steep, east-dipping high P-wave velocity body, beneath Gibraltar. The anisotropic mantle fabric from SKS splitting shows arc-parallel “fast directions”, consistent with toroidal flow around a narrow, westward retreating subducting slab. The accompanying WSW advance of the Rif–Betic mountain belt has constructed a thick pile of deformed sediments, an accretionary wedge, characterized by west-vergent thrust anticlines. Bathymetric swath‐mapping images an asymmetric embayment at the deformation front where a 2 km high basement ridge has collided. Subduction has slowed significantly since 5 Ma, but deformation of recent sediments and abundant mud volcanoes suggest ongoing activity in the accretionary wedge. Three possible origins for this deformation are discussed; gravitational spreading, overall NW–SE convergence between Africa and Iberia and finally a WSW tectonic push from slow, but ongoing roll-back subduction. In the absence of arc volcanism and shallow dipping thrust type earthquakes, evidence in favor of present-day subduction can only be indirect and remains the object of debate. Continued activity of the subduction offers a possible explanation for great (M > 8.5) earthquakes known to affect the area, like the famous 1755 Great Lisbon earthquake. Recent GPS studies show SW motion of stations in N Morocco at velocities of 3–6 mm/yr indicating the presence of an independent block, a “Rif–Betic–Alboran” microplate, situated between Iberia and Africa, Much of this work was funded by the EU FP6 project NEAREST. The Nearest-Seis survey was funded by the complementary action #CGL2006-27098-E/BTE of the Spanish MICINN. We thank the Captains and crews of the vessels involved in the acquisition of all of this new data, and without whose efforts, this wealth of new data could never have been acquired. We also thank many other Spanish, Portuguese, German and Dutch colleagues who have contributed significantly to the collective efforts to advance our understanding of the tectonics in this complex region. J.C. Duarte acknowledges support from the Australian Research Council through Discovery Grant DP110103387. P.R. and F.R. acknowledge support from the projects TOPOMED — “Plate re-organization in the western Mediterranean: lithospheric causes and topographic consequences”, and SWIMGLO (refs. TOPOEUROPE/0001/2007 and SWIMGLO — PTDC/MAR/100522/2008)

International audience; Quantitative and qualitative analyses of planktonic foraminiferal assemblages from 134 core-top sediment samples collected along the western Iberian margin were used to assess the latitudinal and longitudinal changes in surface water conditions and to calibrate a Sea Surface Temperature (SST) transfer function for this seasonal coastal upwelling region. Q-mode factor analysis performed on relative abundances yielded three factors that explain 96% of the total variance: factor 1 (50%) is exclusively defined by Globigerina bulloides, the most abundant and widespread species, and reflects the modern seasonal (May to September) coastal upwelling areas; factor 2 (32%) is dominated by Neogloboquadrina pachyderma (dextral) and Globorotalia inflata and seems to be associated with the Portugal Current, the descending branch of the North Atlantic Drift; factor 3 (14%) is defined by the tropical–sub-tropical species Globigerinoides ruber (white), Globigerinoides trilobus trilobus, and G. inflata and mirrors the influence of the winter-time eastern branch of the Azores Current. In conjunction with satellite-derived SST for summer and winter seasons integrated over an 18year period the regional foraminiferal data set is used to calibrate a SST transfer function using Imbrie & Kipp, MAT and SIMMAXndw techniques. Similar predicted errors (RMSEP), correlation coefficients, and residuals' deviation from SST estimated for both techniques were observed for both seasons. All techniques appear to underestimate SST off the southern Iberia margin, an area mainly occupied by warm waters where upwelling occurs only occasionally, and overestimate SST on the northern part of the west coast of the Iberia margin, where cold waters are present nearly all year round. The comparison of these regional calibrations with former Atlantic and North Atlantic calibrations for two cores, one of which is influenced by upwelling, reveals that the regional one attests more robust paleo-SSTs than for the other approaches.

The existing land data assimilation projects (NLDAS, GLDAS, ELDAS) do not include interactive vegetation land surface models, which limits the use of remote sensing data. The analysed variable in LDAS is soil moisture, only, and there is a need to account for vegetation biomass to monitor the biosphere vegetation-atmosphere CO2 exchange. The geoland Integrated Project (2004-2007) co-funded by the European Commission, aims at addressing European and global environment issues, based on the use of remote sensing data. The carbon observatory of geoland, hereinafter referred to as "geoland/Carbon", provides a pre-operational global carbon accounting system, dealing with the impact of weather and climate variability on ecosystems fluxes and carbon stocks, on daily to seasonal and inter-annual time scales. The solution chosen in geoland/Carbon is to merge the LDAS approach and the interactive vegetation models, by making two communities work together: the meteorologists involved in ELDAS and the carbon modellers. In particular, we investigate the relationship between weather and climate variability and terrestrial CO2 fluxes. The integration of in situ meteorological measurements and different satellite remote sensing sources of information are made by using assimilation techniques. In order to integrate the existing approaches and to deliver an assessment based on independent modelling results, two land surface models are used: 1) an operational scheme (ECMWF) used in numerical weather forecast models, modified to describe an interactive vegetation (based on ISBA-A-gs, Meteo-France); 2) a carbon-water-energy land surface scheme, fitted with carbon dynamics in biomass and soil pools, and with ecosystem dynamics (LSCE). The assimilation system can be run at the global scale with both carbon models. The assimilated output fields are checked against global observations of different nature, such as eddy covariance networks, long term ecological time series (e.g. IGBP transects), forest and soil carbon inventories, or satellite products that were not used at first in the assimilation procedure. At the end of this project, ECMWF is able to propose a single near-operational system based on components of the two approaches

International audience; We thank Marques for his Comment (Marques, 2014) on our paper (Duarte et al., 2013) about subduction initiation at the southwest Iberia margin (SIM). Here we demonstrate that his comments are based on wrong premises: (1) Marques ignores a fundamental premise of the setting of the stud-ied area: the evidence for two tectonic driving mechanisms: the Gibral-tar subduction and the oblique Nubia-Iberia convergence. Compressive stresses may arise from (a) an imbalance in horizontal forces due to partial slab breakoff and/or a decrease in the subduction rate; (b) expulsion of the Alboran block; (c) torques at the SIM; and (d) pull of the oceanic corridor toward Gibraltar, resisted by the adjacent northern oceanic segment (Gor-ringe area) being dragged against a relatively immobile Iberia. (2) It is widely accepted that the Gibraltar arc formed due to subduc-tion rollback. Evidence includes: 1) tomography showing a high-velocity east-dipping body up to the 660 discontinuity; 2) deep seismic events (>600 km); 3) the presence of a 15-km-thick accretionary wedge rooting in an east-dipping décollement); 4) mud volcanism in the foreland; 5) active thrusting in the wedge; 6) GPS data showing a westward-moving Alboran plate; 7) the existence of an oceanic corridor in the foreland; 8) existence of an extensional back-arc region; 9) calc-alkaline arc volcanism; and 10) pressure-temperature-time paths of high-grade metamorphic rocks in the Betics. The existence of subduction beneath Gibraltar was highly disputed in the past, but in the past decade the debate has shifted from "is there subduction in Gibraltar?" to whether the subduction is still active or not. In Duarte et al. (2013) we discuss both possibilities. (3) Lithospheric-scale structures cannot be directly deduced from crustal seismics. This is a limitation of the method, and not evidence that the structures are too small to be lithospheric. Complementary methods need to be used, such as earthquake hypocenters. In the studied area, the seismic-ity is concentrated at ~40–60 km depth, with focal mechanisms showing reverse faulting and NW-SE shortening (Geissler et al., 2010). Hence, it is reasonable to infer that the compressive structures root into the mantle. (4) We referred the 1969 and 1755 earthquakes because their high magnitudes (~8–9 M w) are characteristic of convergent zones. And even though the location of the 1755 quake is uncertain, the source of the 1969 quake lies 50 km southeast of the Gorringe, in the fl at abyssal plain. The fault plane solution indicates conjugate ~N60°-striking 45°-dipping planes with a reverse motion. Fukao (1973) favored the southern conjugate based on the distribution of the aftershocks, but at the time there was a large uncertainty in their location. No major northwest-dipping structures exist in this area. In our map, we show a set of southeast-dipping thrusts that seem to be connected and could have generated the 1969 quake. When Fu-kao published his paper, the Gorringe root was interpreted as a northwest-dipping megathrusts, with "consumption of oceanic lithosphere" (Purdy, 1975, p. 973). In the models of Purdy (1975) and McKenzie (1977), the African plate was subducting beneath Eurasia (the subduction zone was part of the east-west Azores-Gibraltar plate boundary) and what we pro-pose is the nucleation and northward propagation of a new (convergent) plate boundary along the SIM. (5) The main idea of our paper is that the interference between the Gibraltar subduction zone and the Azores-Gibraltar Fault Zone can seed the reactivation of the SIM. Calculation of the forces involved in this process is complex and beyond the classical 2-D evaluation of buoyancy versus ridge push forces used for spontaneous subduction initiation. Three-dimensional modeling (analog/numerical) would be necessary to understand the forces involved in such case of induced initiation. Two-dimensional models of spontaneous initiation are inadequate to quantitatively gauge subduction initiation along the SIM. Nevertheless, estimation of the Gibraltar slab pull force and the force required to break a passive margin are provided. (6) Marques states "subduction in northern Iberia is overlooked … . By doing so, the evaluation of the force balance along the SIM is fl awed." The northern Iberia incipient accretionary wedge formed due to the clos-ing of the Tethys, and has been inactive since the Burdigalian (ca. 20 Ma). Thus it is irrelevant to the present-day force balance. Marques further ar-gues "overthrusting in northern Iberia could take up all the Nubia-Iberia convergence … , which makes it critical in the evaluation of the force balance in Iberia." At present, this is not the case. The observations show that shortening is being accommodated at the SIM. Marques' main arguments are: (1) lack of "relevant data"; (2) absence of "use [of] critical model results that would constrain their [our] hypothe-sis of subduction initiation"; and (3) overlooking "relevant literature." But Marques fails to explain exactly what relevant data are missing, especially when a new tectonic map was presented to sustain our hypothesis. The second point is based on the wrong premise that 2-D models of spontane-ous subduction initiation can be used to constrain this case of induced initiation, whereas a 3-D approach would be required. Consequently the claim that we "overlooked relevant literature" is mostly unfounded.