Methane plume detection after the 2022 Nord Stream pipeline explosion in the Baltic Sea.

On September 26th, 2022, the detonations at the gas pipelines Nord Stream 1 and 2 resulted in some of the largest non-natural releases of methane known. The distribution of methane in the surrounding seawater and the possible effects were not apparent. To trace the pathways of methane we recorded CH4 concentrations and the isotopic signal (δ13C-CH4) in seawater, and air. A week post-explosion, we detected methane concentrations up to 4 orders of magnitude above the natural Baltic Sea background. The released fossil methane created a distinct plume with δ13C-CH4 ratios differing from natural background values. The strong water stratification preserved the distribution pattern initiated by the explosion, shown by the laterally strong concentration gradient within the plume. Our analysis encompasses three stages of the explosion's impact; the initial sea-air methane release, measurements taken during our research expedition one week later, and a third stage triggered by the shift from summer to winter conditions as an outlook on how winter mixing and microbial activity will influence the plume.

Unlocking the secret life of blue mussels: Exploring connectivity in the Skagerrak through biophysical modeling and population genomics.

Knowledge of functional dispersal barriers in the marine environment can be used to inform a wide variety of management actions, such as marine spatial planning, restoration efforts, fisheries regulations, and invasive species management. Locations and causes of dispersal barriers can be studied through various methods, including movement tracking, biophysical modeling, demographic models, and genetics. Combining methods illustrating potential dispersal, such as biophysical modeling, with realized dispersal through, e.g., genetic connectivity estimates, provides particularly useful information for teasing apart potential causes of observed barriers. In this study, we focus on blue mussels (Mytilus edulis) in the Skagerrak-a marginal sea connected to the North Sea in Northern Europe-and combine biophysical models of larval dispersal with genomic data to infer locations and causes of dispersal barriers in the area. Results from both methods agree; patterns of ocean currents are a major structuring factor in the area. We find a complex pattern of source-sink dynamics with several dispersal barriers and show that some areas can be isolated despite an overall high dispersal capability. Finally, we translate our finding into management advice that can be used to sustainably manage this ecologically and economically important species in the future.

The unaccountability case of plastic pellet pollution.

Plastic preproduction pellets are found in environmental samples all over the world and their presence is often linked to spills during production and transportation. To better understand how these pellets end up in the environment we assessed the release of plastic pellets from a polyethylene production site in a case study area on the Swedish west coast. The case study encompasses; field measurements to evaluate the level of pollution and pathways, models and drifters to investigate the potential spread and a revision of the legal framework and the company permits. This case study show that millions of pellets are released from the production site annually but also that there are national and international legal frameworks that if implemented could help prevent these spills. Bearing in mind the negative effects observed by plastic pollution there is an urgent need to increase the responsibility and accountability of these spills.

Use of moist smokeless tobacco (snus) and the risk of development of alcohol dependence: a cohort study in a middle-aged population in Sweden.

BACKGROUND: Convincing evidence shows that smoking is associated with alcohol dependence (AD) and a positive correlation between snus and alcohol consumption was previously shown in cross-sectional studies. We performed a longitudinal evaluation of the risk of snus users to develop AD. METHODS: A cohort study in Västerbotten County, Sweden, linked individual data on socioeconomic situation and health survey data from 21,037 men and women (46.5% men). AD was defined by the CAGE questionnaire and evaluated at baseline 1991-1997 and again after 10 years. The risk of developing AD was assessed using logistic regression analysis and propensity score matching. RESULTS: 2370 men and 430 women used snus and were without AD at baseline. Over the 10-year period, 499 men and 257 women developed AD, among whom 191 and 26, respectively, were baseline snus users. The crude relative risks of AD for male and female snus users compared to non-users were 1.8 with 95% CI (1.5, 2.2) and 2.9 (2.0, 4.3), respectively. Adjusted logistic regression showed a positive dose-response relationship between snus use and risk of AD. Analyses involving propensity score matching revealed 33 and 17 new cases of AD in men and women, respectively, after 10 years given 1000 men and 1000 women without AD had been baseline snus users rather than non-users. Results for current, previous and never smokers were similar. CONCLUSIONS: The use of snus is prospectively associated with an increased risk of AD with a dose-response relationship that is independent of smoking status.

On statistical methods for clustering: a case study on infant mortality, Northern Sweden, 1831-1890.

This article considers the interfamily clustering of infant mortality (defined as mortality during the first year of life). We developed and evaluated statistical tools to detect clustering and a measure to quantify excess clustering for nineteenth-century data from Skellefteå, Sweden. The detection was performed using the standard methods of generalized linear models and logistic regression. The index of clustering was constructed by comparing the observed numbers of families with specific numbers of deaths to the corresponding observed numbers, after correcting for explanatory variables. To the best of our knowledge, no clustering index of this kind has ever been created.

Who is using snus? - Time trends, socioeconomic and geographic characteristics of snus users in the ageing Swedish population.

BACKGROUND: The prevalence of smoking in Sweden has decreased in recent decades, and is now among the lowest in the world. During the same period, the use of Swedish moist oral snuff, a smokeless tobacco called snus, has increased. Few studies have evaluated time trends of the socioeconomic and geographic characteristics of snus users in Sweden. This paper contributes to filling that gap. METHODS: This study utilized the Linnaeus Database, which links national registers with comprehensive individual data on socioeconomic status (SES) to health data from a large ongoing health survey, the Västerbotten Intervention Programme (VIP). The VIP targets the entire middle-aged population of Västerbotten county at ages 40, 50 and 60 years with yearly cross-sectional surveys including self-reported data on tobacco habits. Time trends of snus use among 92,563 VIP-participants across different areas of residence and smoking groups were investigated graphically. Logistic regression was performed to estimate the associations between SES and geographical variables and current use versus non-use of snus. RESULTS: Overall, in parallel to decreasing smoking, the increasing trend of snus use in this middle-aged population continues, particularly in 40-year-olds. In both genders, the highest prevalence of snus use was observed among previous smokers. The prevalence of snus use also increased over time among smokers, and was consistently higher compared to those who had never smoked. Among males - both those who had never smoked and previous smokers - low education (OR 1.21, 95%CI 1.06-1.40 and OR 1.28, 95%CI 1.14-1.43), living alone (OR 1.16, 95%CI 1.07-1.27 and OR 1.13, 95%ci 1.04-1.23), low income and living in rural areas was associated with using snus, while this was not seen among male current smokers. Among women, living alone was associated with using snus irrespective of smoking habits. Among female smokers, the OR for snus use increased with higher education. CONCLUSIONS: A disadvantaged social profile and also higher prevalence in rural areas is observed among male snus users who had never smoked or were previous smokers. Among male smokers there was no association between SES and use of snus. The prevalence of snus use among women is increasing, but is still considerably lower than that of men. The association between snus and SES characteristics is less pronounced among women, although snus is clearly linked to living alone. These patterns should be taken into consideration in tobacco control policies.

Do conditions in early life affect old-age mortality directly and indirectly? Evidence from 19th-century rural Sweden.

Previous research has shown that the disease load experienced during the birth year, measured as the infant mortality rate, had a significant influence on old-age mortality in nineteenth-century rural Sweden. We know that children born in years with very high rates of infant mortality, due to outbreaks of smallpox or whooping cough, and who still survived to adulthood and married, faced a life length several years shorter than others. We do not know, however, whether this is a direct effect, caused by permanent physical damage leading to fatal outcomes later in life, or an indirect effect, via its influence on accumulation of wealth and obtained socio-economic status. The Scanian Demographic Database, with information on five rural parishes in southern Sweden between 1813 and 1894, contains the data needed to distinguish between the two mechanisms. First, the effects of conditions in childhood on obtained socio-economic status as an adult are analyzed, then the effects of both early-life conditions and socio-economic status at various stages of life on old-age mortality. By including random effects, we take into account possible dependencies in the data due to kinship and marriage. We find that a high disease load during the first year of life had a strong negative impact on a person's ability to acquire wealth, never before shown for a historical setting. This means that it is indeed possible that the effects of disease load in the first year of life indirectly affect mortality in old age through obtained socio-economic status. We find, however, no effects of obtained socio-economic status on old-age mortality. While the result is interesting per se, constituting a debatable issue, it means that the argument that early-life conditions indirectly affect old-age mortality is not supported. Instead, we find support for the conclusion that the effect of the disease load in early-life is direct or, in other words, that physiological damage from severe infections at the start of life leads to higher mortality at older ages. Taking random effects at family level into account did not alter this conclusion.

High-risk families: the unequal distribution of infant mortality in nineteenth-century Sweden.

An analysis of infant mortality (based on 133,448 births) in two regions, Sundsvall and Skellefteå, in north-eastern Sweden during the nineteenth century shows that infant mortality was highly clustered with a relatively small number of families accounting for a large proportion of all infant deaths. Using logistic regression, two important factors were found to be associated with high-risk families: (i) a biological component evidenced by an over-representation of women who had experienced stillbirths, and (ii) a social component indicated by an increased risk among women who had remarried. The results strengthen the argument for using the family rather than the single child as the unit of analysis. The clustering of infant deaths points to the need to re-evaluate our interpretations of the causes of infant mortality in the past.

Change in food availability during pregnancy: Is it related to adult sudden death from cerebro- and cardiovascular disease in offspring?

Maternal access to food during pregnancy affects birth weight and other characteristics of offspring. It has been suggested that fluctuations in food availability during infancy, ranging from plentiful to starvation, may influence cerebro-cardiovascular risk factors for the offspring during adult life. This study was designed to test the correlation between food availability changes during life before birth and adult sudden death from disease. This was a follow-up study of ancient cohorts in the parish of Skellefteå, Sweden, comprising 7,572 individuals born between 1805 and 1849 and still alive at age 40. Food availability variations in the parish during their prenatal life were ascertained from historical sources, the main outcome measures being overall mortality and mortality from sudden death in the age range 40-70 years. The risk of sudden death was almost doubled for those whose mothers were struck by a poor harvest during the early stages of pregnancy, but who experienced a good harvest toward the end. Yet almost the same over-risk was evident for the converse case: plentiful food supply in early pregnancy followed by a poor harvest toward the end. A stable maternal access to food during pregnancy is important for the offspring's risk of sudden death from cerebro- and cardiovascular disease as an adult. Am. J. Hum. Biol. 12:447-453, 2000. Copyright 2000 Wiley-Liss, Inc.