Species richness and functional attributes of fish assemblages across a large-scale salinity gradient in shallow coastal areas

Coastal ecosystems are biologically productive, and their diversity underlies various ecosystem services to humans. However, large-scale species richness (SR) and its regulating factors remain uncertain for many organism groups, owing not least to the fact that observed SR (SRobs) depends on sample size and inventory completeness (IC). We estimated changes in SR across a natural geographical gradient using statistical rarefaction and extrapolation methods, based on a large fish species incidence dataset compiled for shallow coastal areas (<30 m depth) from Swedish fish survey databases. The data covered a ca. 1300 km north-south distance and a 12-fold salinity gradient along sub-basins of the Baltic Sea plus the Skagerrak and, depending on the sub-basin, 4 to 47 years of samplings during 1975-2021. Total fish SRobs was 144, and the observed fish species were of 74 % marine and 26 % freshwater origin. In the 10 sub-basins with sufficient data for further analysis, IC ranged from 77 % to 98 %, implying that ca. 2 %-23 % of likely existing fish species had remained undetected. Sample coverage exceeded 98.5 %, suggesting that undetected species represented <1.5 % of incidences across the sub-basins, i.e. highly rare species. To compare sub-basins, we calculated standardized SR (SRstd) and estimated SR (SRest). Sub-basin-specific SRest varied between 35 +/- 7 (SE) and 109 +/- 6 fish species, being ca. 3 times higher in the most saline (salinity 29-32) compared to the least saline sub-basins (salinity < 3). Analysis of functional attributes showed that differences with decreasing salinity particularly reflected a decreasing SR of benthic and demersal fish, of piscivores and invertivores, and of marine migratory species. We conclude that, if climate change continues causing an upper-layer freshening of the Baltic Sea, this may influence the SR, community composition and functional characteristics of fish, which in turn may affect ecosystem processes such as benthic-pelagic coupling and connectivity between coastal and open-sea areas

Securing sustainable access to aquatic foods

Global nutrition needs are increasing and aquatic foods have recently been identified as crucial in addressing many of the world’s urgent challenges, including hunger and malnutrition. This synthesis highlights the importance of aquatic foods as a source of protein, micronutrients and income, its potential to meet increasing food demands, as well as the challenges in aquatic food production and harvesting.Most importantly, it provides an overview of management initiatives and innovative solutions for secured sustainable access to aquatic foods in the future. Aquatic foods provide micronutrient-rich foods for 3.3 billion people and support the livelihoods of more than 800 million people. Small-scale fisheries, in particular, play a key role in supporting the diversity and nutritional benefits of aquatic foods. However, the capture and production of aquatic foods is not always sustainable, and access to these foods may be unequal. At the water-land nexus, new ways of producing aquatic foods hold the potential to reduce the climate footprint in the food system.The governance of, and investment in, aquatic food systems needs to aim to preserve, support and improve aquatic species diversity and to improve access to this highly nutritious food. These efforts need to include multiple stakeholders, such as fishers, community agencies, policy makers and researchers, and be firmly established in both the latest research and in a local/regional context - ecologically and socially. By incorporating different aspects of aquatic foods, this synthesis aims to inspire and inform the reader about the importance of these systems, and means for a sustainable way forward

Less loop diuretic use in patients on sacubitril/valsartan undergoing remote pulmonary artery pressure monitoring

Aims Control of pulmonary pressures monitored remotely reduced heart failure hospitalizations mainly by lowering filling pressures through the use of loop diuretics. Sacubitril/valsartan improves heart failure outcomes and increases the kidney sensitivity for diuretics. We explored whether sacubitril/valsartan is associated with less utilization of loop diuretics in patients guided with haemodynamic monitoring in the CardioMEMS European Monitoring Study for Heart Failure (MEMS-HF). Methods and results The MEMS-HF population (n = 239) was separated by the use of sacubitril/valsartan (n = 68) or no use of it (n = 164). Utilization of diuretics and their doses was prespecified in the protocol and was monitored in both groups. Multivariable regression, ANCOVA, and a generalized linear model were used to fit baseline covariates with furosemide equivalents and changes for 12 months. MEMS-HF participants (n = 239) were grouped in sacubitril/valsartan users [n = 68, 64 ± 11 years, left ventricular ejection fraction (LVEF) 25 ± 9%, cardiac index (CI) 1.89 ± 0.4 L/min/m2] vs. non-users (n = 164, 70 ± 10 years, LVEF 36 ± 16%, CI 2.11 ± 0.58 L/min/m2, P = 0.0002, P < 0.0001, and P = 0.0015, respectively). In contrast, mean pulmonary artery pressure (PAP) values were comparable between groups (29 ± 11 vs. 31 ± 11 mmHg, P = 0.127). Utilization of loop diuretics was lower in patients taking sacubitril/valsartan compared with those without (P = 0.01). Significant predictor of loop diuretic use was a history of renal failure (P = 0.005) but not age (P = 0.091). After subjects were stratified by sacubitril/valsartan or other diuretic use, PAP was nominally, but not significantly lower in sacubitril/valsartan-treated patients (baseline: P = 0.52; 6 months: P = 0.07; 12 months: P = 0.53), while there was no difference in outcome or PAP changes. This difference was observed despite lower CI (P = 0.0015). Comparable changes were not observed for other non-loop diuretics (P = 0.21). Conclusions In patients whose treatment was guided by remote PAP monitoring, concomitant use of sacubitril/valsartan was associated with reduced utilization of loop diuretics, which could potentially be relevant for outcomes

A Timescale for Evolution, Population Expansion, and Spatial Spread of an Emerging Clone of Methicillin-Resistant Staphylococcus aureus

Due to the lack of fossil evidence, the timescales of bacterial evolution are largely unknown. The speed with which genetic change accumulates in populations of pathogenic bacteria, however, is a key parameter that is crucial for understanding the emergence of traits such as increased virulence or antibiotic resistance, together with the forces driving pathogen spread. Methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of hospital-acquired infections. We have investigated an MRSA strain (ST225) that is highly prevalent in hospitals in Central Europe. By using mutation discovery at 269 genetic loci (118,804 basepairs) within an international isolate collection, we ascertained extremely low diversity among European ST225 isolates, indicating that a recent population bottleneck had preceded the expansion of this clone. In contrast, US isolates were more divergent, suggesting they represent the ancestral population. While diversity was low, however, our results demonstrate that the short-term evolutionary rate in this natural population of MRSA resulted in the accumulation of measurable DNA sequence variation within two decades, which we could exploit to reconstruct its recent demographic history and the spatiotemporal dynamics of spread. By applying Bayesian coalescent methods on DNA sequences serially sampled through time, we estimated that ST225 had diverged since approximately 1990 (1987 to 1994), and that expansion of the European clade began in 1995 (1991 to 1999), several years before the new clone was recognized. Demographic analysis based on DNA sequence variation indicated a sharp increase of bacterial population size from 2001 to 2004, which is concordant with the reported prevalence of this strain in several European countries. A detailed ancestry-based reconstruction of the spatiotemporal dispersal dynamics suggested a pattern of frequent transmission of the ST225 clone among hospitals within Central Europe. In addition, comparative genomics indicated complex bacteriophage dynamics

Indications of nitrogen-limited methane uptake in tropical forest soils

Abstract: It is estimated that tropical forest soils contribute 6.2 Tg yr(-1) (28 %) to global methane (CH4) uptake, which is large enough to alter CH4 accumulation in the atmosphere if significant changes would occur to this sink. Elevated deposition of inorganic nitrogen (N) to temperate forest ecosystems has been shown to reduce CH4 uptake in forest soils, but almost no information exists from tropical forest soils even though projections show that N deposition will increase substantially in tropical regions. Here we report the results from two long-term, ecosystem-scale experiments in which we assessed the impact of chronic N addition on soil CH4 fluxes from two old-growth forests in Panama: (1) a lowland, moist (2.7 m yr(-1) rainfall) forest on clayey Cambisol and Nitisol soils with controls and N-addition plots for 9-12yr, and (2) a montane, wet (5.5 m yr(-1) rainfall) forest on a sandy loam Andosol soil with controls and N-addition plots for 1-4 yr. We measured soil CH4 fluxes for 4 yr (2006-2009) in four replicate plots (40 m x 40 m each) per treatment using vented static chambers (four chambers per plot). CH4 fluxes from the lowland control plots and the montane control plots did not differ from their respective N-addition plots. In the lowland forest, chronic N addition did not lead to inhibition of CH4 uptake; instead, a negative correlation of CH4 fluxes with nitrate (NO3-) concentrations in the mineral soil suggests that increased NO3- levels in N-addition plots had stimulated CH4 consumption and/or reduced CH4 production. In the montane forest, chronic N addition also showed negative correlation of CH4 fluxes with ammonium concentrations in the organic layer, which suggests that CH4 consumption was N limited. We propose the following reasons why such N-stimulated CH4 consumption did not lead to statistically significant CH4 uptake: (1) for the lowland forest, this was caused by limitation of CH4 diffusion from the atmosphere into the clayey soils, particularly during the wet season, as indicated by the strong positive correlations between CH4 fluxes and water-filled pore space (WFPS); (2) for the montane forest, this was caused by the high WFPS in the mineral soil throughout the year, which may not only limit CH4 diffusion from the atmosphere into the soil but also favour CH4 production; and (3) both forest soils showed large spatial and temporal variations of CH4 fluxes. We conclude that in these extremely different tropical forest ecosystems there were indications of N limitation on CH4 uptake. Based on these findings, it is unlikely that elevated N deposition on tropical forest soils will lead to a rapid reduction of CH4 uptake