Multiyear measurements of ebullitive methane flux from three subarctic lakes

Ebullition (bubbling) from small lakes and ponds at high latitudes is an important yet unconstrained source of atmospheric methane (CH4). Small water bodies are most abundant in permanently frozen peatlands, and it is speculated that their emissions will increase as the permafrost thaws. We made 6806 measurements of CH4 ebullition during four consecutive summers using a total of 40 bubble traps that were systematically distributed across the depth zones of three lakes in a sporadic permafrost landscape in northernmost Sweden. We identified significant spatial and temporal variations in ebullition and observed a large spread in the bubbles\u27 CH4 concentration, ranging from 0.04% to 98.6%. Ebullition followed lake temperatures, and releases were significantly larger during periods with decreasing atmospheric pressure. Although shallow zone ebullition dominated the seasonal bubble CH4 flux, we found a shift in the depth dependency towards higher fluxes from intermediate and deep zones in early fall. The average daily flux of 13.4 mg CH4 m−2 was lower than those measured in most other high‐latitude lakes. Locally, however, our study lakes are a substantial CH4 source; we estimate that 350 kg of CH4 is released via ebullition during summer (June–September), which is approximately 40% of total whole year emissions from the nearby peatland. In order to capture the large variability and to accurately scale lake CH4 ebullition temporally and spatially, frequent measurements over long time periods are critical

Energy input is primary controller of methane bubbling in subarctic lakes

Emission of methane (CH4) from surface waters is often dominated by ebullition (bubbling), a transport mode with high‐spatiotemporal variability. Based on new and extensive CH4 ebullition data, we demonstrate striking correlations (r2 between 0.92 and 0.997) when comparing seasonal bubble CH4 flux from three shallow subarctic lakes to four readily measurable proxies of incoming energy flux and daily flux magnitudes to surface sediment temperature (r2 between 0.86 and 0.94). Our results after continuous multiyear sampling suggest that CH4 ebullition is a predictable process, and that heat flux into the lakes is the dominant driver of gas production and release. Future changes in the energy received by lakes and ponds due to shorter ice‐covered seasons will predictably alter the ebullitive CH4 flux from freshwater systems across northern landscapes. This finding is critical for our understanding of the dynamics of radiatively important trace gas sources and associated climate feedback

The Quiescent Intracluster Medium in the Core of the Perseus Cluster

Clusters of galaxies are the most massive gravitationally-bound objects in the Universe and are still forming. They are thus important probes of cosmological parameters and a host of astrophysical processes. Knowledge of the dynamics of the pervasive hot gas, which dominates in mass over stars in a cluster, is a crucial missing ingredient. It can enable new insights into mechanical energy injection by the central supermassive black hole and the use of hydrostatic equilibrium for the determination of cluster masses. X-rays from the core of the Perseus cluster are emitted by the 50 million K diffuse hot plasma filling its gravitational potential well. The Active Galactic Nucleus of the central galaxy NGC1275 is pumping jetted energy into the surrounding intracluster medium, creating buoyant bubbles filled with relativistic plasma. These likely induce motions in the intracluster medium and heat the inner gas preventing runaway radiative cooling; a process known as Active Galactic Nucleus Feedback. Here we report on Hitomi X-ray observations of the Perseus cluster core, which reveal a remarkably quiescent atmosphere where the gas has a line-of-sight velocity dispersion of 164+/-10 km/s in a region 30-60 kpc from the central nucleus. A gradient in the line-of-sight velocity of 150+/-70 km/s is found across the 60 kpc image of the cluster core. Turbulent pressure support in the gas is 4% or less of the thermodynamic pressure, with large scale shear at most doubling that estimate. We infer that total cluster masses determined from hydrostatic equilibrium in the central regions need little correction for turbulent pressure.Comment: 31 pages, 11 Figs, published in Nature July

ENCORT-CDW - Evaluation of the European recovery target for construction and demolition waste

The present EU target for recovery of construction and demolition waste does not promote sustainability. Interpretations of waste and recovery definitions rather than resource efficiency and safe handling affect the monitoring. The general weight-based target has to be altered to favour recycling of resource-rich materials, not only of high weight materials. High grade recycling should be distinguished and prioritized to ensure safe recovery. This requires improved knowledge on waste generation and handling as well as on emissions of dangerous substances. A common Nordic approach is advocated

Exploring the nutrient composition of various shellfish available in Norway and their role in providing key nutrients

Shellfish constitute a diverse group of aquatic animals, encompassing numerous species of molluscs and crustaceans able to supply important nutrients beneficial to human health. However, information regarding their nutritional properties remain scarce. In this paper, we explore the nutrient composition of shellfish, including shrimps, mussels, scallops, crabs, crayfish, and lobsters, collected from supermarkets, local fishermen, and the North Atlantic Ocean. By analysing over 800 samples collected between 2011 and 2021, we show that shellfish are able to provide high quantities of protein (8.1–21 g/100 g), essential amino acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) [sum of 0.061–4.3 g/100 g], vitamin B12 (0.82–65 µg/100 g), vitamin E (0.75–28 mg/100 g), zinc (0.61–7.9 mg/100 g), iodine (3.1–2100 µg/100 g), and selenium (7.2–590 µg/100 g). The hepatopancreas of crustaceans was found to be substantially more nutrient-dense than the white meat. Furthermore, the shellfish included in this study cannot be considered good sources of riboflavin, niacin, folate, and vitamin D3. We conclude that shellfish can substantially contribute to recommended nutrient intakes by providing high quantities of key nutrients. The data presented in this paper are an important contribution to the understanding of shellfish as a source of nutrients and to existing food composition databases.publishedVersio

Ankle, knee and concussion concerns: Unveiling injury patterns in highly trained South African netball players

The original publication is available at: https://www.sciencedirect.com/Objectives To describe the rate and type of netball injuries sustained during women's university-level tournament matches in South Africa. Design Descriptive epidemiological study. Setting Three editions of the women's Varsity Netball tournament (2021–23). Participants Student-athletes representing nine university women's teams. Main outcome measures Medical attention match injuries prospectively recorded by team medical staff. Injuries were classified according to the 2020 consensus statement, with the addition of “concussion” as a separate pathology type. The main outcomes are reported as incidence (injuries per 1000h; 95% confidence intervals - CIs), burden (days lost per 1000h; 95%CIs), and frequency (% of all injuries). Results Sixty-three injuries were recorded from 48 different players (58.8 per 1000h; 45.2–75.3) and the overall injury burden was 401 days per 1000h (364–440). Injury incidence by pathology type was highest for joint sprains (28.9 per 1000h), tendinopathies (7.5 per 1000h), and concussions (4.7 per 1000h). Joint sprains to the ankle accounted for 49% of the overall estimated days lost. Conclusions Ankle joint sprains should be the primary target of injury risk reduction programmes in highly trained netball players. Concussions were reported and efforts should be made to increase awareness among players, coaches and medical staff.https://www.sciencedirect.com/science/article/pii/S1466853X24000804Publisher’s versio

Ankle, knee and concussion concerns : unveiling injury patterns in highly trained South African netball players

OBJECTIVES : To describe the rate and type of netball injuries sustained during women's university-level tournament matches in South Africa. DESIGN : Descriptive epidemiological study. SETTING : Three editions of the women's Varsity Netball tournament (2021–23). PARTICIPANTS : Student-athletes representing nine university women's teams. MAIN OUTCOME MEASURES : Medical attention match injuries prospectively recorded by team medical staff. Injuries were classified according to the 2020 consensus statement, with the addition of “concussion” as a separate pathology type. The main outcomes are reported as incidence (injuries per 1000h; 95% confidence intervals - CIs), burden (days lost per 1000h; 95%CIs), and frequency (% of all injuries). RESULTS : Sixty-three injuries were recorded from 48 different players (58.8 per 1000h; 45.2–75.3) and the overall injury burden was 401 days per 1000h (364–440). Injury incidence by pathology type was highest for joint sprains (28.9 per 1000h), tendinopathies (7.5 per 1000h), and concussions (4.7 per 1000h). Joint sprains to the ankle accounted for 49% of the overall estimated days lost. CONCLUSIONS : Ankle joint sprains should be the primary target of injury risk reduction programmes in highly trained netball players. Concussions were reported and efforts should be made to increase awareness among players, coaches and medical staff.https://www.elsevier.com/ptsphj2024Sports MedicineSDG-03:Good heatlh and well-bein