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Pascual A.,CSIC - Mediterranean Institute for Advanced Studies | Ruiz S.,CSIC - Mediterranean Institute for Advanced Studies | Olita A.,CNR Institute for Coastal Marine Environment | Troupin C.,Balearic Islands Coastal Observing and Forecasting System SOCIB | And 11 more authors.
Frontiers in Marine Science | Year: 2017

The challenges associated with meso- and submesoscale variability (between 1 and 100 km) require high-resolution observations and integrated approaches. Here we describe a major oceanographic experiment designed to capture the intense but transient vertical motions in an area characterized by strong fronts. Finescale processes were studied in the eastern Alboran Sea (Western Mediterranean) about 400 km east of the Strait of Gibraltar, a relatively sparsely sampled area. In-situ systems were coordinated with satellite data and numerical simulations to provide a full description of the physical and biogeochemical variability. Hydrographic data confirmed the presence of an intense salinity front formed by the confluence of Atlantic Waters, entering from Gibraltar, with the local Mediterranean waters. The drifters coherently followed the northeastern limb of an anticyclonic gyre. Near real time data from acoustic current meter data profiler showed consistent patterns with currents of up to 1m/s in the southern part of the sampled domain. High-resolution glider data revealed submesoscale structures with tongues of chlorophyll-a and oxygen associated with the frontal zone. Numerical results show large vertical excursions of tracers that could explain the subducted tongues and filaments captured by ocean gliders. A unique aspect of AlborEx is the combination of high-resolution synoptic measurements of vessel-based measurements, autonomous sampling, remote sensing and modeling, enabling the evaluation of the underlying mechanisms responsible for the observed distributions and biogeochemical patchiness. The main findings point to the importance of fine-scale processes enhancing the vertical exchanges between the upper ocean and the ocean interior. © 2017 Pascual, Ruiz, Olita, Troupin, Claret, Casas, Mourre, Poulain, Tovar-Sanchez, Capet,Mason, Allen,Mahadevan and Tintoré.


Sanchez-Roman A.,CSIC - Mediterranean Institute for Advanced Studies | Ruiz S.,CSIC - Mediterranean Institute for Advanced Studies | Pascual A.,CSIC - Mediterranean Institute for Advanced Studies | Mourre B.,Balearic Islands Coastal Observing and Forecasting System SOCIB | Guinehut S.,Collecte Localisation Satellites CLS
Ocean Science | Year: 2017

In this work a simplified observing system simulation experiment (OSSE) approach is used to investigate which Argo design sampling in the Mediterranean Sea would be necessary to properly capture the mesoscale dynamics in this basin. The monitoring of the mesoscale features is not an initial objective of the Argo network. However, it is an interesting question from the perspective of future network extensions in order to improve the ocean state estimates. The true field used to conduct the OSSEs is provided by a specific altimetry-gridded merged product for the Mediterranean Sea. Synthetic observations were obtained by sub-sampling this Nature Run according to different configurations of the ARGO network. The observation errors required to perform the OSSEs were obtained through the comparison of sea level anomalies (SLAs) from altimetry and dynamic height anomalies (DHAs) computed from the real in situ Argo network. This analysis also contributes to validate satellite SLAs with an increased confidence. The simulation experiments show that a configuration similar to the current Argo array in the Mediterranean (with a spatial resolution of 2°× 2°) is only able to recover the large-scale signals of the basin. Increasing the spatial resolution to nearly 75km× 75km, allows the capture of most of the mesoscale signal in the basin and to retrieve the SLA field with a RMSE of 3cm for spatial scales larger than 150km, similar to those presently captured by the altimetry. This would represent a theoretical reduction of 40% of the actual RMSE. Such a high-resolution Argo array composed of around 450 floats, cycling every 10 days, is expected to increase the actual network cost by approximately a factor of 6. © 2017 The Author(s).


Reglero P.,Spanish Institute of Oceanography | Santos M.,Tecnalia | Balbin R.,Spanish Institute of Oceanography | Laiz-Carrion R.,Spanish Institute of Oceanography | And 4 more authors.
Deep-Sea Research Part II: Topical Studies in Oceanography | Year: 2017

Tuna spawning habitats are traditionally characterized using data sets of larvae or gonads from mature adults and concurrent environmental variables. Data on egg distributions have never previously been used since molecular analyses are mandatory to identify tuna eggs to species level. However, in this study we use molecularly derived egg distribution data, in addition to larval data, to characterize hydrographic and biological drivers of the spatial distribution of eggs and larvae of bluefin Thunnus thynnus and albacore tuna Thunnus alalunga in the Balearic Sea, a main spawning area of these species in the Mediterranean. The effects of the hydrography, characterized by salinity, temperature and geostrophic velocity, on the spatial distributions of the eggs and larvae are investigated. Three biological variables are used to describe the productivity in the area: chlorophyll a in the mixed layer, chlorophyll a in the deep chlorophyll maximum and mesozooplankton biomass in the mixed layer. Our results point to the importance of salinity fronts and temperatures above a minimum threshold in shaping the egg and larval distribution of both species. The spatial distribution of the biotic variables was very scattered, and they did not emerge as significant variables in the presence-absence models. However, they became significant when modeling egg and larval abundances. The lack of correlation between the three biotic variables challenges the use of chlorophyll a to describe trophic scenarios for the larvae and suggests that the spatial distribution of resources is not persistent in time. The different patterns in relation to biotic variables across species and stages found in this and other studies indicate a still elusive understanding of the link between trophic levels involving tuna early larval stages. Our ability to improve short-term forecasting and long-term predictions of climate effects on the egg and larval distributions is discussed based on the consistency of the environmentally driven spatial patterns for the two species. © 2017 Elsevier Ltd.


Diedrich A.,Balearic Islands Coastal Observing and Forecasting System SOCIB | Upham P.,University of Manchester | Levidow L.,Open University Milton Keynes | van den Hove S.,Median SCP | van den Hove S.,Autonomous University of Barcelona
Environmental Science and Policy | Year: 2011

Recent EU policy has linked research agendas with societal challenges, which has resulted in an increased emphasis on the need for exchange of knowledge between research and non-research actors, especially civil society organisations. Concurrent with this, has been a call for democratic accountability of research agendas and science that addresses Grand Societal Challenges. The challenge of environmental sustainability features strongly in these discussions with an emphasis on global warming, the tightening of energy, water and food supplies, and the overarching goal of achieving an 'eco-efficient economy'. However, this challenge can be defined in various ways, with different definitions orienting towards different solutions many of which we argue may be contradictory to the goal of environmental sustainability. In this commentary we illustrate how dominant research agendas are often orientated towards the partisan agendas of influential stakeholders, favouring myopic technological fixes and marginalising other civil society actors and critical insights from social science. Our main recommendations include a more dominant role for social sciences, involving civil society more actively in research agenda setting, increased communication, information sharing and capacity building, and increased interdisciplinarity. © 2011 Elsevier Ltd.


Troupin C.,CSIC - Mediterranean Institute for Advanced Studies | Pascual A.,CSIC - Mediterranean Institute for Advanced Studies | Valladeau G.,Collecte Localisation Satellites CLS | Pujol I.,Collecte Localisation Satellites CLS | And 6 more authors.
Advances in Space Research | Year: 2015

Satellite altimetry measurements from SARAL-AltiKa are analysed in the coastal ocean using the results of the G-AltiKa mission (1-5 August 2013), which combined altimeter, HF radar and glider data coincident with the satellite track, south-west of Ibiza Island, in the Western Mediterranean Sea. The absolute dynamic topography, computed from 1 Hz and 40 Hz altimetry data, and the dynamic height, computed from glider temperature and salinity, both exhibited a weak signal with amplitudes of order 2 cm. The resulting geostrophic and HF radar velocities along the track depicted a north-westward coastal current with a maximal velocity larger than 20 cm s-1. This demonstrates that the AltiKa altimeter is able to resolve SLA signals of more than 2 cm, and gradients in those signals over several tens of kilometres. After filtering, the 40 Hz data depicted a signal consistent with the other platforms, up to a distance of order 10 km from the coast. © 2014 COSPAR. Published by Elsevier Ltd. All rights reserved.


Pascual A.,CSIC - Mediterranean Institute for Advanced Studies | Lana A.,CSIC - Mediterranean Institute for Advanced Studies | Troupin C.,Balearic Islands Coastal Observing and Forecasting System SOCIB | Ruiz S.,CSIC - Mediterranean Institute for Advanced Studies | And 3 more authors.
Marine Geodesy | Year: 2015

We present an initial assessment of SARAL/AltiKa data in the coastal band. The study focuses on the Ibiza Channel where the north-south water exchanges play a key role in controlling the circulation variability in the western Mediterranean. In this area, the track 16 of SARAL/AltiKa intercepts the domain covered by a coastal high-frequency (HF) radar system, which provides surface currents with a range up to 60 km. We evaluate the performance of the SARAL/AltiKa Ssalto/Duacs delayed-time along-track products compared to the HF radar surface velocity fields. SARAL/AltiKa data are retrieved at a distance of only 7 km from the coast, putting in evidence the emerging capabilities of the new altimeter. The derived velocities resolved the general features of the seasonal mesoscale variability with reasonable agreement with HF radar fields (significant correlations of 0.54). However, some discrepancies appear, which might be caused by instrumental hardware radar errors, ageostrophic velocities as well as inaccurate corrections and editing in the altimeter data. Root mean square (rms) differences between the estimated SARAL/AltiKa and the HF radar velocities are about 13 cm/s. These results are consistent with recent studies in other parts of the ocean applying similar approaches to Topex/Poseidon and Jason-1 missions and using coastal altimeter corrections. © 2015, Copyright © Taylor & Francis Group, LLC.


Alvarez-Berastegui D.,Balearic Islands Coastal Observing and Forecasting System SOCIB | Hidalgo M.,Spanish Institute of Oceanography | Tugores M.P.,Spanish Institute of Oceanography | Reglero P.,Spanish Institute of Oceanography | And 11 more authors.
ICES Journal of Marine Science | Year: 2016

The ecology of highly migratory marine species is tightly linked to dynamic oceanographic processes occurring in the pelagic environment. Developing and applying techniques to characterize the spatio-temporal variability of these processes using operational oceanographic data is a challenge for management and conservation. Here we evaluate the possibility of modelling and predicting spawning habitats of Atlantic bluefin tuna in the Western Mediterranean, using pelagic seascape metrics specifically designed to capture the dynamic processes affecting the spawning ecology this species. The different seascape metrics applied were processed from operational oceanographic data products providing information about the temporal and spatial variability of sea surface temperature, kinetic energy and chlorophyll a. Spawning locations were identified using larval abundances sampled in the Balearic Sea, one of the main reproductive areas for this species in the Mediterranean Sea. Results confirm the high dependence of bluefin tuna spawning ecology on mesoscale oceanographic processes while providing spawning habitat maps as a tool for bluefin tuna assessment and management, based on operational oceanographic data. Finally, we discuss the coming challenges that operational fisheries oceanography and pelagic seascape ecology face to become fully implemented as predictive tools. © 2016 International Council for the Exploration of the Sea 2016. All rights reserved.


Alvarez-Berastegui D.,Balearic Islands Coastal Observing and Forecasting System SOCIB | Ciannelli L.,Oregon State University | Aparicio-Gonzalez A.,Spanish Institute of Oceanography | Reglero P.,Spanish Institute of Oceanography | And 5 more authors.
PLoS ONE | Year: 2014

Seascape ecology is an emerging discipline focused on understanding how features of the marine habitat influence the spatial distribution of marine species. However, there is still a gap in the development of concepts and techniques for its application in the marine pelagic realm, where there are no clear boundaries delimitating habitats. Here we demonstrate that pelagic seascape metrics defined as a combination of hydrographic variables and their spatial gradients calculated at an appropriate spatial scale, improve our ability to model pelagic fish distribution. We apply the analysis to study the spawning locations of two tuna species: Atlantic bluefin and bullet tuna. These two species represent a gradient in life history strategies. Bluefin tuna has a large body size and is a long-distant migrant, while bullet tuna has a small body size and lives year-round in coastal waters within the Mediterranean Sea. The results show that the models performance incorporating the proposed seascape metrics increases significantly when compared with models that do not consider these metrics. This improvement is more important for Atlantic bluefin, whose spawning ecology is dependent on the local oceanographic scenario, than it is for bullet tuna, which is less influenced by the hydrographic conditions. Our study advances our understanding of how species perceive their habitat and confirms that the spatial scale at which the seascape metrics provide information is related to the spawning ecology and life history strategy of each species. © 2014 Alvarez-Berastegui et al.


PubMed | University of the Balearic Islands, Balearic Islands Coastal Observing and Forecasting System SOCIB, Oregon State University and Spanish Institute of Oceanography
Type: Journal Article | Journal: PloS one | Year: 2014

Seascape ecology is an emerging discipline focused on understanding how features of the marine habitat influence the spatial distribution of marine species. However, there is still a gap in the development of concepts and techniques for its application in the marine pelagic realm, where there are no clear boundaries delimitating habitats. Here we demonstrate that pelagic seascape metrics defined as a combination of hydrographic variables and their spatial gradients calculated at an appropriate spatial scale, improve our ability to model pelagic fish distribution. We apply the analysis to study the spawning locations of two tuna species: Atlantic bluefin and bullet tuna. These two species represent a gradient in life history strategies. Bluefin tuna has a large body size and is a long-distant migrant, while bullet tuna has a small body size and lives year-round in coastal waters within the Mediterranean Sea. The results show that the models performance incorporating the proposed seascape metrics increases significantly when compared with models that do not consider these metrics. This improvement is more important for Atlantic bluefin, whose spawning ecology is dependent on the local oceanographic scenario, than it is for bullet tuna, which is less influenced by the hydrographic conditions. Our study advances our understanding of how species perceive their habitat and confirms that the spatial scale at which the seascape metrics provide information is related to the spawning ecology and life history strategy of each species.

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