Search

The physiological tolerances of marine species toward ambient temperature and oxygen can jointly be evaluated in a single metric: the metabolic index. Changes therein characterize a changing aerobic habitat tailored to species‐specific thermal and hypoxia sensitivity traits. If the geographical limits of marine species as indicated by critical thresholds of the metabolic index shift abruptly in response to ocean warming and deoxygenation, aerobic habitat could potentially be lost abruptly. Here, we assess the spatio‐temporal detectability of abrupt shifts in potential habitats for selected marine species within the Shared Socioeconomic Pathway 5–8.5 (SSP5‐8.5) scenario run with the fully coupled Norwegian Earth System Model version 2 (NorESM2‐LM). We use an environmental time series changepoint detection routine and analyze the number and timing of these abrupt changes over the past, present and future. We construct nine ecophysiotypes with low, medium, and high resting vulnerability to hypoxia and sensitivity of hypoxia vulnerability to temperature, respectively, with six different thresholds for minimal oxygen demand. For all ecophysiotypes with positive temperature sensitivity to hypoxia, the volume of non‐viable habitat in the upper ocean expands between 1850 and 2100. Changepoints in the metabolic index are detected in 49.0 ± 9.2% of the volume that eventually becomes non‐viable for all ecophysiotypes over the course of the 21st century. More than 75% of these abrupt shifts occur in response to warming close to the surface, while at depth, the abrupt shifts driven by changes in oxygen partial pressure become more important, with potentially severe consequences for marine species, populations, and ecosystems. Plain Language Summary: Future ocean warming and the accompanying deoxygenation will change the extent of habitats of all marine species. If the rate of future warming and deoxygenation is slow enough, marine species could adapt to the lower oxygen availability or migrate away to places that match their metabolic habitat requirements. However, if these rates are fast, and potentially exacerbated by abrupt shifts, the consequences for the future distribution of marine species will be profound. Here, we analyze abrupt shifts, or changepoints, in the metabolic index as a measure of metabolic habitat requirements for different marine species. Using projections of an Earth system model, we find that approximately half of the eventually lost habitat between 1850 and 2100 experiences abrupt shifts, and most of them occur between 1950 and 2040, mainly driven by the projected warming. Key Points: Marine habitats described by the metabolic index are lost for a range of marine species in a strong emission scenarioAbrupt changes in the metabolic index are detected in all ocean basins over a wide range of depth levelsTemperature changes drive abrupt metabolic index changes close to the surface, while changes in oxygen become important at depth [ABSTRACT FROM AUTHOR]

The microstructural anisotropy caused by the highly oriented solidification of the metal Laser Powder Bed Fusion (PBF-LB/M) process affects mechanical short- and long-term properties. Component build orientation influences grain morphology and orientation, and thus, mechanical properties. While the creep behaviour of samples manufactured parallel and perpendicular to the build direction are studied intensively, the 45° build orientation remains uncharacterised. In this study, IN738LC creep samples are manufactured via PBF-LB/M in three build orientations (0°, 45° and 90°). While the results of 90° and 0° are as expected, where 90° achieves the longest time to rupture and largest rupture strain, the 45° specimen shows the least fracture time. Differences in microstructure and twinning behaviour are identified as one of the root causes for this unexpected behaviour. This study discusses the correlation between microstructure, twinning and build orientation and their effect on creep behaviour, with special focus on the 45° build orientation. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

An integrated magnetic sensor is designed and tested that utilizes the negatively charged nitrogen vacancy centers (NVC) in diamond as a magnetic field‐sensitive quantum material, which is accessed and readout solely optically. The compact sensor device features a side length of 10 mm and includes a small HPHT diamond slab, light‐emitting diode (LED) for excitation, and integrated photodiodes. A microwave‐free approach is used. With the device, DC sensitivity to magnetic fields of 49 nA mT−1 in the range of 5–50 mT is achieved. The sensor device is also capable of detecting very small magnetic fields: Magnetic field dependencies at very low flux densities in the μT range (zero‐magnetic field) show a characteristic fluorescence behavior revealing a sensitivity of 4.8 pA μT−1. Additionally, a ray‐tracing model is applied, to identify loss mechanisms in the setup. Using this device, an ultracompact, reliable, and industry‐ready package is made available for sensor developments in industry and academia. [ABSTRACT FROM AUTHOR]

High blood pressure is the leading risk factor for death worldwide. One of the hallmarks is a rise of peripheral vascular resistance, which largely depends on arteriole tone. [Ca.sup.2+]-activated chloride currents (CaCCs) in vascular smooth muscle cells (VSMCs) are candidates for increasing vascular contractility. We analyzed the vascular tree and identified substantial CaCCs in VSMCs of the aorta and carotid arteries. CaCCs were small or absent in VSMCs of medium-sized vessels such as mesenteric arteries and larger retinal arterioles. In small vessels of the retina, brain, and skeletal muscle, where contractile intermediate cells or pericytes gradually replace VSMCs, CaCCs were particularly large. Targeted disruption of the calcium-activated chloride channel TMEM16A, also known as ANO1, in VSMCs, intermediate cells, and pericytes eliminated CaCCs in all vessels studied. Mice lacking vascular TMEM16A had lower systemic blood pressure and a decreased hypertensive response following vasoconstrictor treatment. There was no difference in contractility of medium-sized mesenteric arteries; however, responsiveness of the aorta and small retinal arterioles to the vasoconstrictioninducing drug U46619 was reduced. TMEM16A also was required for peripheral blood vessel contractility, as the response to U46619 was attenuated in isolated perfused hind limbs from mutant mice. Out data suggest that TMEM16A plays a general role in arteriolar and capillary blood flow and is a promising target for the treatment of hypertension., Introduction With more than 25% of the adult population being affected, hypertension is an important public health challenge worldwide (1). It is a major risk factor for cardiovascular disease, myocardial [...]

A particle field approach to the general circulation model is presented, focusing on particle-reactive species within the ocean water column. Findings include tracking of the nuclide Thorium-230 flux to sediment.

Riverine transport of nutrients and carbon from inland waters to the coastal and finally the open ocean alters marine primary production (PP) and carbon (C) uptake, not only regionally but also globally. So far, this contribution is represented in the state-of-the-art Earth system models with limited effort. Here we assess changes in marine PP and C uptake projected under the Representative Concentration Pathway 4.5 climate scenario using the Norwegian Earth system model, with four riverine configurations: deactivated, fixed at a contemporary level, coupled to simulated freshwater runoff, and following four plausible future scenarios. The inclusion of riverine nutrients and carbon improves the modelled contemporary spatial distribution relative to observations, especially on the continental margins (5.4% reduction in root mean square error [RMSE] for PP) and in the North Atlantic region (7.4% reduction in RMSE for C uptake). Riverine nutrient inputs alleviate nutrient limitation, especially under future warmer conditions as stratification increases, and thus lessen the projected future decline in PP by up to 0.6 PgC yr-1 (27.3%) globally depending on the riverine configuration. The projected C uptake is enhanced along continental margins where increased PP, due to riverine nutrient inputs, dominates over the CO2 outgassing owing to riverine organic matter inputs. Conversely, where the riverine organic matter inputs dominate over the nutrient inputs, the projected C uptake is reduced. The large range of the riverine input across our four riverine configurations does not transfer to a large uncertainty of the projected global PP and ocean C uptake, suggesting that transient riverine inputs are more important for high-resolution regional studies such as in the North Atlantic and along the continental margins. [ABSTRACT FROM AUTHOR]