Contrasting drivers and trends of ocean acidification in the subarctic Atlantic.

The processes of warming, anthropogenic CO2 (Canth) accumulation, decreasing pHT (increasing [H+]T; concentration in total scale) and calcium carbonate saturation in the subarctic zone of the North Atlantic are unequivocal in the time-series measurements of the Iceland (IS-TS, 1985-2003) and Irminger Sea (IRM-TS, 1983-2013) stations. Both stations show high rates of Canth accumulation with different rates of warming, salinification and stratification linked to regional circulation and dynamics. At the IS-TS, advected and stratified waters of Arctic origin drive a strong increase in [H+]T, in the surface layer, which is nearly halved in the deep layer (44.7 ± 3.6 and 25.5 ± 1.0 pmol kg-1 yr-1, respectively). In contrast, the weak stratification at the IRM-TS allows warming, salinification and Canth uptake to reach the deep layer. The acidification trends are even stronger in the deep layer than in the surface layer (44.2 ± 1.0 pmol kg-1 yr-1 and 32.6 ± 3.4 pmol kg-1 yr-1 of [H+]T, respectively). The driver analysis detects that warming contributes up to 50% to the increase in [H+]T at the IRM-TS but has a small positive effect on calcium carbonate saturation. The Canth increase is the main driver of the observed acidification, but it is partially dampened by the northward advection of water with a relatively low natural CO2 content.

Anthropogenic CO2 and ocean acidification in Argentine Basin Water Masses over almost five decades of observations.

The chemical conditions of the Argentine Basin (western South Atlantic Ocean) water masses are evaluated with measurements from eleven hydrographic cruises to detect and quantify anthropogenic and natural stressors in the ocean carbon system. The database covers almost half-century (1972-2019), a time-span where the mean annual atmospheric carbon dioxide concentration (CO2atm) increased from 325 to 408 ppm of volume (ppm). This increase of atmospheric CO2 (83 ppm, the 64% of the total anthropogenic signal in the atmosphere) leads to an increase in anthropogenic carbon (Cant) across all the water column and the consequent ocean acidification: a decrease in excess carbonate that is unequivocal in the upper (South Atlantic Central Water, SACW) and intermediate water masses (Sub Antarctic Mode Water, SAMW and Antarctic Intermediate Water, AAIW). For each additional ppm in CO2atm the water masses SACW, SAMW and AAIW lose excess carbonate at a rate of 0.39 ± 0.04, 0.47 ± 0.05 and 0.23 ± 0.03 µmol·kg-1·ppm-1 respectively. Modal and intermediate water masses in the Argentine Basin are very sensitive to carbon increases due low buffering capacity. The large rate of AAIW acidification is the synergic effect of carbon uptake combined with deoxygenation and increased remineralization of organic matter. If CO2 emissions follows the path of business-as-usual emissions (SSP 5.85), SACW would become undersaturated with respect to aragonite at the end of the century. The undersaturation in AAIW is virtually unavoidable.

The Northeast Atlantic is running out of excess carbonate in the horizon of cold-water corals communities.

The oceanic uptake of atmospheric carbon dioxide (CO2) emitted by human activities alters the seawater carbonate system. Here, the chemical status of the Northeast Atlantic is examined by means of a high-quality database of carbon variables based on the GO-SHIP A25 section (1997-2018). The increase of atmospheric CO2 leads to an increase in ocean anthropogenic carbon (Cant) and a decrease in carbonate that is unequivocal in the upper and mid-layers (0-2,500 m depth). In the mid-layer, the carbonate content in the Northeast Atlantic is maintained by the interplay between the northward spreading of recently conveyed Mediterranean Water with excess of carbonate and the arrival of subpolar-origin waters close to carbonate undersaturation. In this study we show a progression to undersaturation with respect to aragonite that could compromise the conservation of the habitats and ecosystem services developed by benthic marine calcifiers inhabiting that depth-range, such as the cold-water corals (CWC) communities. For each additional ppm in atmospheric pCO2 the waters surrounding CWC communities lose carbonate at a rate of - 0.17 ± 0.02 µmol kg-1 ppm-1. The accomplishment of global climate policies to limit global warming below 1.5-2 â„ƒ will avoid the exhaustion of excess carbonate in the Northeast Atlantic.

Meridional overturning circulation conveys fast acidification to the deep Atlantic Ocean.

Since the Industrial Revolution, the North Atlantic Ocean has been accumulating anthropogenic carbon dioxide (CO2) and experiencing ocean acidification, that is, an increase in the concentration of hydrogen ions (a reduction in pH) and a reduction in the concentration of carbonate ions. The latter causes the 'aragonite saturation horizon'-below which waters are undersaturated with respect to a particular calcium carbonate, aragonite-to move to shallower depths (to shoal), exposing corals to corrosive waters. Here we use a database analysis to show that the present rate of supply of acidified waters to the deep Atlantic could cause the aragonite saturation horizon to shoal by 1,000-1,700 metres in the subpolar North Atlantic within the next three decades. We find that, during 1991-2016, a decrease in the concentration of carbonate ions in the Irminger Sea caused the aragonite saturation horizon to shoal by about 10-15 metres per year, and the volume of aragonite-saturated waters to reduce concomitantly. Our determination of the transport of the excess of carbonate over aragonite saturation (xc[CO32-])-an indicator of the availability of aragonite to organisms-by the Atlantic meridional overturning circulation shows that the present-day transport of carbonate ions towards the deep ocean is about 44 per cent lower than it was in preindustrial times. We infer that a doubling of atmospheric anthropogenic CO2 levels-which could occur within three decades according to a 'business-as-usual scenario' for climate change-could reduce the transport of xc[CO32-] by 64-79 per cent of that in preindustrial times, which could severely endanger cold-water coral habitats. The Atlantic meridional overturning circulation would also export this acidified deep water southwards, spreading corrosive waters to the world ocean.

Dissolved Organic Carbon in the North Atlantic Meridional Overturning Circulation.

The quantitative role of the Atlantic Meridional Overturning Circulation (AMOC) in dissolved organic carbon (DOC) export is evaluated by combining DOC measurements with observed water mass transports. In the eastern subpolar North Atlantic, both upper and lower limbs of the AMOC transport high-DOC waters. Deep water formation that connects the two limbs of the AMOC results in a high downward export of non-refractory DOC (197 Tg-C·yr(-1)). Subsequent remineralization in the lower limb of the AMOC, between subpolar and subtropical latitudes, consumes 72% of the DOC exported by the whole Atlantic Ocean. The contribution of DOC to the carbon sequestration in the North Atlantic Ocean (62 Tg-C·yr(-1)) is considerable and represents almost a third of the atmospheric CO2 uptake in the region.

Prevalencia de hipertensión arterial en la población de San Javier, Misiones / Prevalence of hypertension in the town of San Javier, Misiones

Hasta la actualidad, no existen en nuestro país estudios que utilizando criterios estrictos para el diagnóstico de hipertensión arterial (HTA) hayan determinado la prevalencia de esta patología en este grupo de población. Como parte de un proyecto de atención médica primaria realizado en el departamento de San Javier, provincia de Misiones, se efectuó un estudio de corte transversal retrospectivo con el objetivo de determinar la prevalencia de HTA, respetando los criterios que establece el consenso de HTA de 2013 de la Sociedad Argentina de Cardiología (SAC) para su diagnóstico. Material y método: Se incluyó la totalidad de la población ˃ 18 años (n=12.468). Para ello fueron consultadas las historias clínicas (HC) de la totalidad de la población, las cuales fueron registradas por médicos, enfermeros y promotores de salud capacitados, utilizando esfingomanómetros calibrados. Se consideró HTA cuando el promedio de dos determinaciones de la PA en dos oportunidades distintas fue ≥ 140 mmHg de presión arterial sistólica (PAS) y/o ≥ 90 mmHg de presión arterial diastólica (PAD), según criterios de la SAC. Se realizó además electrocardiograma de 12 derivaciones en búsqueda de lesión de órgano blanco. Resultados: La PAS promedio de la población general fue 130 mmHg, y la PAD fue 84 mmHg. La prevalencia global de HTA fue 31% (PAS de 148 ± 14 mmHg y una PAD de 99 ± 12 mmHg) con una edad promedio de 48,5 años. De los pacientes con diagnóstico de HTA, el 31% tuvo hipertensión arterial diastólica, el 14% tuvo hipertensión arterial sistólica, y el 55% (n=2143) presentaron ambos valores de HTA aumentados. La prevalencia de HTA en varones fue 29%, edad promedio 52 años, PAS 143 mmHg y PAD 101 mmHg. En mujeres 71%, edad promedio 45 años, PAS 151 mmHg y PAD 97 mmHg. El 46% de los hipertensos no conocía su condición de tal. De los pacientes con diagnóstico de HTA solo el 2,8% (n=108) presentó cambios en el electrocardiograma (ECG) compatibles con HVI...