This study investigates the influence of sea ice on eutrophication in the Baltic Sea ecosystem by comparing simulations from 1953 to 2017, with ice and without ice cover. We assessed the impact from ice cover by using eutrophication indicators defined by the Marine Strategy Framework Directive (MSFD), the Dia/Dino index and the newly proposed Trophic Transfer Index (TTI). Five out of six indicators suggest a negative impact of sea ice on the eutrophication status of the Baltic Sea, with a marked increase in ice impact observed in the early 1970s, followed by a decline in the late 1980s.
View Article and Find Full Text PDFWorldwide, governments are implementing strategies to combat marine litter. However, their effectiveness is largely unknown because we lack tools to systematically monitor marine litter over broad spatio-temporal scales. Metre-sized aggregations of floating debris generated by sea-surface convergence lines have been reported as a reliable target for detection from satellites.
View Article and Find Full Text PDFIn the Western Mediterranean Sea, forage fishes have changed in abundance, body condition, growth, reproduction, and distribution in the last decades. Different hypotheses have been proposed to explain these changes, including increase in fishing mortality; changes in environmental conditions affecting species fitness, and planktonic productivity and quality; recovery of top predators; and increase in competitors. We investigated the main drivers and changes of the pelagic ecosystem and their effects using an ecosystem-based modelling approach.
View Article and Find Full Text PDFCumulative pressures are rapidly expanding in the Mediterranean Sea with consequences for marine biodiversity and marine resources, and the services they provide. Policy makers urge for a marine ecosystem assessment of the region in space and time. This study evaluates how the whole Mediterranean food web may have responded to historical changes in the climate, environment and fisheries, through the use of an ecosystem modelling over a long time span (decades) at high spatial resolution (8 × 8 km), to inform regional and sub-regional management.
View Article and Find Full Text PDFIntroduction And Objectives: Surgical aortic valve replacement (SAVR) can modify the natural history of severe aortic stenosis (SAS). However, compared with the general population, these patients have a loss of life expectancy. The life expectancy of patients who undergo SAVR due to low-gradient SAS with preserved left ventricular ejection fraction (LVEF) is unknown.
View Article and Find Full Text PDFMar Pollut Bull
February 2022
Plastic litter pollution is one of the major concerns for the health of marine ecosystems worldwide. This pervasive form of pollution affects all oceans and seas and it's interacting with multiple levels of the marine food webs. In the European context, several pieces of legislation try to fight against this pervasive and ubiquitous form of pollution.
View Article and Find Full Text PDFEnviron Model Softw
November 2021
Marine Ecosystem Models (MEMs) provide a deeper understanding of marine ecosystem dynamics. The United Nations Decade of Ocean Science for Sustainable Development has highlighted the need to deploy these complex mechanistic spatial-temporal models to engage policy makers and society into dialogues towards sustainably managed oceans. From our shared perspective, MEMs remain underutilized because they still lack formal validation, calibration, and uncertainty quantifications that undermines their credibility and uptake in policy arenas.
View Article and Find Full Text PDFIntroduction And Objectives: In young patients with severe aortic stenosis, it is unknown whether their life expectancy restored after aortic valve replacement (AVR) is unknown.
Methods: We analyzed all patients aged between 50 and 65 years who underwent isolated AVR in 27 Spanish centers during an 18-year period. We compared observed and expected survival at 15 years of follow-up.
Objectives: Some researchers have observed an increased number of deaths during the follow-up of young patients who undergo aortic valve replacement due to severe aortic stenosis, suggesting that this procedure does not restore their life expectancy. Our goal was to confirm these findings and explore sex-based differences.
Methods: All patients between 50 and 65 years of age who underwent isolated aortic valve replacement in 27 Spanish centres during an 18-year period were included.
The relative abundance of nitrate (N) over phosphate (P) measured as a molar ratio (N:P) is typically considered to determine the macronutrient limiting marine primary production. In low-complexity biogeochemical models, a simple threshold value is usually applied based on the canonical Redfield ratio (N:P = 16). However, the N:P ratio is not constant in many oceanic areas, especially marginal, semi-enclosed seas, such as the Mediterranean basin.
View Article and Find Full Text PDFObjectives: The decision about whether to use a biological or a mechanical prosthesis for aortic valve replacement remains controversial in patients between 50 and 65 years of age and has yet to be addressed in a Mediterranean population. This research aimed to analyse long-term survival and major morbidity rates (30-day mortality, stroke, any prosthetic reoperation and major bleeding) within this population.
Methods: Our multicentre observational retrospective study included all subjects aged 50-65 years who had a primary isolated aortic valve replacement due to severe aortic stenosis at 7 public hospitals from Andalusia (Spain) between 2000 and 2015.
Deep water convection (DC) in winter is one of the major processes driving open-ocean primary productivity in the Northwestern Mediterranean Sea. DC is highly variable in time, depending on the specific conditions (stratification, circulation and ocean-atmosphere interactions) of each specific winter. This variability also drives the interannual oscillations of open-ocean primary productivity in this important region for many commercially-important fish species.
View Article and Find Full Text PDFWe evaluate the changes on the hydrological (temperature and salinity) and biogeochemical (phytoplankton biomass) characteristics of the Mediterranean Sea induced by freshwater flow modifications under two different scenarios for the end of the 21st century. An ensemble of four regional climate model realizations using different global circulation models at the boundary and different emission scenarios are used to force a single ocean model for the Mediterranean Sea. Freshwater flow is modified according to the simulated changes in the precipitation rates for the different rivers' catchment regions.
View Article and Find Full Text PDFThe Mediterranean Sea has been defined "under siege" because of intense pressures from multiple human activities; yet there is still insufficient information on the cumulative impact of these stressors on the ecosystem and its resources. We evaluate how the historical (1950-2011) trends of various ecosystems groups/species have been impacted by changes in primary productivity (PP) combined with fishing pressure. We investigate the whole Mediterranean Sea using a food web modelling approach.
View Article and Find Full Text PDFMediterranean ecosystems support important processes and functions that bring direct benefits to human society. Yet, marine ecosystem services are usually overlooked due to the challenges in identifying and quantifying them. This paper proposes the application of several biophysical and ecosystem modelling approaches to assess spatially and temporally the sustainable use and supply of selected marine ecosystem services.
View Article and Find Full Text PDFWe use a newly developed technique that is based on the information flow concept to investigate the causal structure between the global radiative forcing and the annual global mean surface temperature anomalies (GMTA) since 1850. Our study unambiguously shows one-way causality between the total Greenhouse Gases and GMTA. Specifically, it is confirmed that the former, especially CO2, are the main causal drivers of the recent warming.
View Article and Find Full Text PDFGlobal Biogeochem Cycles
August 2014
Unlabelled: The temporal dynamics of biogeochemical variables derived from a coupled 3-D model of the Mediterranean Sea are evaluated for the last 50 years (1960-2010) against independent data on fisheries catch per unit effort (CPUE) for the same time period. Concordant patterns are found in the time series of all of the biological variables (from the model and from fisheries statistics), with low values at the beginning of the series, a later increase, with maximum levels reached at the end of the 1990s, and a posterior stabilization. Spectral analysis of the annual biological time series reveals coincident low-frequency signals in all of them.
View Article and Find Full Text PDFBuoyancy-induced unstable boundary currents and the accompanying retrograde density fronts are often the sites of pronounced mesoscale activity, ageostrophic frontal processes, and associated high biological production in marginal seas. Biophysical model simulations of the Catalano-Balearic Sea (Western Mediterranean) illustrated that the unstable and nonlinear southward frontal boundary current along the Spanish coast resulted in a strain-driven frontogenesis mechanism. High upwelling velocities of up to 80 m d(-1) injected nutrients into the photic layer and promoted enhanced production on the less dense, onshore side of the front characterized by negative relative vorticity.
View Article and Find Full Text PDFA three dimensional biophysical model was employed to illustrate the biological impacts of a meandering frontal jet, in terms of efficiency and persistency of the autotrophic frontal production, in marginal and semi-enclosed seas. We used the Alboran Sea of the Western Mediterranean as a case study. Here, a frontal jet with a width of 15-20 km, characterized by the relatively low density Atlantic water mass, flows eastward within the upper 100 m as a marked meandering current around the western and the eastern anticyclonic gyres prior to its attachment to the North African shelf/slope topography of the Algerian basin.
View Article and Find Full Text PDFGlobal surface temperature has been increasing since the beginning of the 20th century but with a highly variable warming rate, and the alternation of rapid warming periods with 'hiatus' decades is a constant throughout the series. The superimposition of a secular warming trend with natural multidecadal variability is the most accepted explanation for such a pattern. Since the start of the 21st century, the surface global mean temperature has not risen at the same rate as the top-of-atmosphere radiative energy input or greenhouse gas emissions, provoking scientific and social interest in determining the causes of this apparent discrepancy.
View Article and Find Full Text PDFDiatoms, a major component of the large-sized phytoplankton, are able to produce and release polyunsaturated aldehydes after cell disruption (potential PUAs or pPUA). These organisms are dominant in the large phytoplankton fraction (>10 µm) in the Strait of Gibraltar, the only connection between the Mediterranean Sea and the Atlantic Ocean. In this area, the hydrodynamics exerts a strong control on the composition and physiological state of the phytoplankton.
View Article and Find Full Text PDFAim: To identify prescription drugs involved in falsified prescriptions in community pharmacies in 6 European countries.
Methods: A cross-sectional survey among 2,105 community pharmacies in Belgium, France, Italy, the Netherlands, Spain and Sweden was carried out to collect all suspect prescription forms. For each reported drug, the number of reported falsified prescriptions per thousand inhabitants was estimated.
During the past two decades, Mediterranean waters have been warming at a rather high rate resulting in scientific and social concern. This warming trend is observed in satellite data, field data and model simulations, and affects both surface and deep waters throughout the Mediterranean basin. However, the warming rate is regionally different and seems to change with time, which has led to the question of what causes underlie the observed trends.
View Article and Find Full Text PDFThe Strait of Gibraltar replenishes the Mediterranean with Atlantic waters through an intense eastward current known as the Atlantic Jet (AJ). The AJ fertilizes the southwestern Mediterranean and is considered to be the ultimate factor responsible for the comparatively high fish production of this region. Here, we perform an analysis of the available historical catches and catch per unit effort (CPUE), together with a long series of surface currents, kinetic energy and chlorophyll concentration.
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