Climatic controls on metabolic constraints in the ocean

Observations and models indicate that climate warming is associated with the loss of dissolved oxygen from the ocean. Dissolved oxygen is a fundamental requirement for heterotrophic marine organisms (except marine mammals) and, since the basal metabolism of ectotherms increases with temperature, warming increases organisms' oxygen demands. Therefore, warming and deoxygenation pose a compound threat to marine ecosystems. In this study, we leverage an ecophysiological framework and a compilation of empirical trait data quantifying the temperature sensitivity and oxygen requirements of metabolic rates for a range of marine species (“ecotypes”). Using the Community Earth System Model Large Ensemble, we investigate how natural climate variability and anthropogenic forcing impact the ability of marine environments to support aerobic metabolisms on interannual to multi-decadal timescales. Warming and deoxygenation projected over the next several decades will yield a reduction in the volume of viable ocean habitats. We find that fluctuations in temperature and oxygen associated with natural variability are distinct from those associated with anthropogenic forcing in the upper ocean. Further, the joint temperature–oxygen anthropogenic signal emerges sooner than temperature and oxygen independently from natural variability. Our results demonstrate that anthropogenic perturbations underway in the ocean will strongly exceed those associated with the natural system; in many regions, organisms will be pushed closer to or beyond their physiological limits, leaving the ecosystem more vulnerable to extreme temperature–oxygen events.</p

El cementerio judío medieval de ‘la Encarnación’ en Ávila

The importance of Avila’s medieval community Jews is made evident by the existence of a cemetery. Although burial places of the other two religious communities, Christians and Muslims, have been documented, that of the Jews, while cited in medieval and early modern documents, had not been identified heretofore. Archeological excavations near the Encarnación convent recently brought to light the exact location of one Jewish cemetery, providing evidence of burial pits and their structural typology.La importancia de la aljama de judíos de Ávila durante la Edad Media hacía indudable la existencia, al menos, de un espacio funerario donde enterrar a sus muertos, de acuerdo con su particular ritual funerario. Conocidos, en parte, los lugares de enterramiento de las otras dos comunidades religiosas con las que convivieron, cristianos y musulmanes, tan solo la documentación histórica nos proporcionaba datos sobre su posible emplazamiento. Los trabajos arqueológicos junto al Convento de la Encarnación, han sacado a la luz la situación exacta de un cementerio judío, aportando las fosas de inhumación una característica tipología constructiva

Physical inconsistencies in the representation of the ocean heat-carbon nexus in simple climate models

The Ocean Heat-Carbon Nexus, linking ocean heat and carbon uptake, is crucial for understanding climate responses to cumulative carbon dioxide (CO2) emissions and to net zero CO2 emissions. It results from a suite of processes involving the exchange of heat and carbon across the sea-air interface as well as their storage below the mixed layer and redistribution by the ocean large-scale circulation. The Ocean Heat and Carbon Nexus is assumed to be consistently represented across two modelling platforms used in the latest IPCC assessments: the Earth System Models (ESMs) and the Simple Climate Models (SCMs). However, our research shows significant deficiencies in state-of-the-art SCMs in replicating the ocean heat-carbon nexus of ESMs due to a crude treatment of the ocean thermal and carbon cycle coupling. With one SCM, we show that a more realistic heat-to-carbon uptake ratio exacerbates the projected warming by 0.1 °C in low overshoot scenarios and up to 0.2 °C in high overshoot scenarios. It is therefore critical to explore how SCMs’ physical inconsistencies, such as the representation of the ocean heat-carbon nexus, can affect future warming projections used in climate assessments, not just by SCMs in Working Group 3 but also by ESMs in Working Group 1 via SCM-driven emission-to-concentration translation

Reviews and syntheses: Abrupt ocean biogeochemical change under human-made climatic forcing – warming, acidification, and deoxygenation

Abrupt changes in ocean biogeochemical variables occur as a result of human-induced climate forcing as well as those which are more gradual and occur over longer timescales. These abrupt changes have not yet been identified and quantified to the same extent as the more gradual ones. We review and synthesise abrupt changes in ocean biogeochemistry under human-induced climatic forcing. We specifically address the ocean carbon and oxygen cycles because the related processes of acidification and deoxygenation provide important ecosystem hazards. Since biogeochemical cycles depend also on the physical environment, we also describe the relevant changes in warming, circulation, and sea ice. We include an overview of the reversibility or irreversibility of abrupt marine biogeochemical changes. Important implications of abrupt biogeochemical changes for ecosystems are also discussed. We conclude that there is evidence for increasing occurrence and extent of abrupt changes in ocean biogeochemistry as a consequence of rising greenhouse gas emissions

Dietary α‐Linolenic Acid, Marine ω‐3 Fatty Acids, and Mortality in a Population With High Fish Consumption: Findings From the PREvención con DIeta MEDiterránea (PREDIMED) Study

Background: Epidemiological evidence suggests a cardioprotective role of α‐linolenic acid (ALA), a plant‐derived ω‐3 fatty acid. It is unclear whether ALA is beneficial in a background of high marine ω‐3 fatty acids (long‐chain n‐3 polyunsaturated fatty acids) intake. In persons at high cardiovascular risk from Spain, a country in which fish consumption is customarily high, we investigated whether meeting the International Society for the Study of Fatty Acids and Lipids recommendation for dietary ALA (0.7% of total energy) at baseline was related to all‐cause and cardiovascular disease mortality. We also examined the effect of meeting the society's recommendation for long‐chain n‐3 polyunsaturated fatty acids (≥500 mg/day). Methods and Results: We longitudinally evaluated 7202 participants in the PREvención con DIeta MEDiterránea (PREDIMED) trial. Multivariable‐adjusted Cox regression models were fitted to estimate hazard ratios. ALA intake correlated to walnut consumption (r=0.94). During a 5.9‐y follow‐up, 431 deaths occurred (104 cardiovascular disease, 55 coronary heart disease, 32 sudden cardiac death, 25 stroke). The hazard ratios for meeting ALA recommendation (n=1615, 22.4%) were 0.72 (95% CI 0.56–0.92) for all‐cause mortality and 0.95 (95% CI 0.58–1.57) for fatal cardiovascular disease. The hazard ratios for meeting the recommendation for long‐chain n‐3 polyunsaturated fatty acids (n=5452, 75.7%) were 0.84 (95% CI 0.67–1.05) for all‐cause mortality, 0.61 (95% CI 0.39–0.96) for fatal cardiovascular disease, 0.54 (95% CI 0.29–0.99) for fatal coronary heart disease, and 0.49 (95% CI 0.22–1.01) for sudden cardiac death. The highest reduction in all‐cause mortality occurred in participants meeting both recommendations (hazard ratio 0.63 [95% CI 0.45–0.87]). Conclusions: In participants without prior cardiovascular disease and high fish consumption, dietary ALA, supplied mainly by walnuts and olive oil, relates inversely to all‐cause mortality, whereas protection from cardiac mortality is limited to fish‐derived long‐chain n‐3 polyunsaturated fatty acids. Clinical Trial Registration URL: http://www.Controlled-trials.com/. Unique identifier: ISRCTN35739639

Tracking Improvement in Simulated Marine Biogeochemistry Between CMIP5 and CMIP6

International audiencePurpose of Review The changes or updates in ocean biogeochemistry component have been mapped between CMIP5 and CMIP6 model versions, and an assessment made of how far these have led to improvements in the simulated mean state of marine biogeochemical models within the current generation of Earth system models (ESMs). Recent Findings The representation of marine biogeochemistry has progressed within the current generation of Earth system models. However, it remains difficult to identify which model updates are responsible for a given improvement. In addition, the full potential of marine biogeochemistry in terms of Earth system interactions and climate feedback remains poorly examined in the current generation of Earth system models. This article is part of the Topical Collection on Carbon Cycle and Climate Electronic supplementary material The online version of this article

Dietary α-linolenic acid, marine ω-3 fatty acids, and mortality in a population with high fish consumption: Findings from the PREvención con DIeta MEDiterránea (PREDIMED) Study

12 Páginas.-- 6 Tablas.-- 1 FiguraBackground-Epidemiological evidence suggests a cardioprotective role of α-linolenic acid (ALA), a plant-derived ω-3 fatty acid. It is unclear whether ALA is beneficial in a background of high marine ω-3 fatty acids (long-chain n-3 polyunsaturated fatty acids) intake. In persons at high cardiovascular risk from Spain, a country in which fish consumption is customarily high, we investigated whether meeting the International Society for the Study of Fatty Acids and Lipids recommendation for dietary ALA (0.7% of total energy) at baseline was related to all-cause and cardiovascular disease mortality. We also examined the effect of meeting the society's recommendation for long-chain n-3 polyunsaturated fatty acids (≥500 mg/day). Methods and Results-We longitudinally evaluated 7202 participants in the PREvención con DIeta MEDiterránea (PREDIMED) trial. Multivariable-adjusted Cox regressionmodels were fitted to estimate hazard ratios. ALA intake correlated towalnut consumption (r=0.94). During a 5.9-y follow-up, 431 deaths occurred (104 cardiovascular disease, 55 coronary heart disease, 32 sudden cardiac death, 25 stroke). The hazard ratios formeeting ALArecommendation (n=1615, 22.4%) were 0.72 (95% CI 0.56-0.92) for all-causemortality and 0.95 (95% CI 0.58-1.57) for fatal cardiovascular disease. The hazard ratios formeeting the recommendation for long-chain n-3 polyunsaturated fatty acids (n=5452, 75.7%) were 0.84 (95% CI 0.67-1.05) for all-causemortality, 0.61 (95% CI 0.39-0.96) for fatal cardiovascular disease, 0.54 (95% CI 0.29-0.99) for fatal coronary heart disease, and 0.49 (95% CI 0.22-1.01) for sudden cardiac death. The highest reduction in all-cause mortality occurred in participants meeting both recommendations (hazard ratio 0.63 [95% CI 0.45-0.87]). Conclusions-In participants without prior cardiovascular disease and high fish consumption, dietary ALA, supplied mainly by walnuts and olive oil, relates inversely to all-cause mortality, whereas protection from cardiac mortality is limited to fish-derived long-chain n-3 polyunsaturated fatty acids.This study was funded in part by Instituto de Salud Carlos III (ISCIII) (Spanish Ministry of Economy) through grants RTIC G03/140, RTIC RD 06/0045, Centro Nacional de Investigaciones Cardiovasculares CNIC 06/2007, ISCIII FIS PS09/01292, the Spanish Ministry of Science and Innovation (MICINN) AGL2010‐22319‐C03‐02 and AGL2009‐13906‐C02‐02, and an unrestricted grant from the California Walnut Commission. Sala‐Vila holds a Miguel Servet I fellowship from the Ministry of Economy and Competitiveness through the ISCIII