Environmental filtering governs consistent vertical zonation in sedimentary microbial communities across disconnected mountain lakes

Subsurface microorganisms make up the majority of Earth's microbial biomass, but ecological processes governing surface communities may not explain community patterns at depth because of burial. Depth constrains dispersal and energy availability, and when combined with geographic isolation across landscapes, may influence community assembly. We sequenced the 16S rRNA gene of bacteria and archaea from 48 sediment cores across 36 lakes in four disconnected mountain ranges in Wyoming, USA and used null models to infer assembly processes across depth, spatial isolation, and varying environments. Although we expected strong dispersal limitations across these isolated settings, community composition was primarily shaped by environmental selection. Communities consistently shifted from domination by organisms that degrade organic matter at the surface to methanogenic, low-energy adapted taxa in deeper zones. Stochastic processes—like dispersal limitation—contributed to differences among lakes, but because these effects weakened with depth, selection processes ultimately governed subsurface microbial biogeography.     

La calidad de vida en ancianos polimedicados con multimorbilidad

Objectives

To estimate the values of the quality of life dimensions using the SF-12 questionnaire in the elderly on polymedication and with multiple morbidities, and identify the variables associated with it.

Material and methods

A cross-sectional study on a sample of 393 patients selected from the elderly population over 67 years and who took more than 5 drugs. The SF-12 was complemented by a personal interview in the clinic or in the home of the patient. Central tendency, dispersion, and the percentiles of the 8 dimensions were calculated, as well as the SF-36 physical and mental component summary measures (PCS and MCS). All patients below the 25th percentile of the PCS and MCS were classified as patients with a deterioration. Logistic regression was used to determine the variables that were associated with the deterioration in the quality of life.

Results

It is a population with high morbidity. The subjects showed very low scores on the general health scales −mean (SD): 25.7 (17.4)−; physical function −32.6 (32.1)−; and PCS: [(37.8 (25.1)]. Women had a worse quality of life than men in all the scales. Female sex, being over 80 years, frequent falls, chronic pain, cancerous disease, and depression, are variables that determine the health-related quality of life (HR-QoL).

Conclusion

This population has a poor HR-QoL, particularly in the physical dimensions. Chronic pain and depression, together with age and being female are variables that determine the deterioration in the HR-QoL.