Sediment archives reveal irreversible shifts in plankton communities after World War II and agricultural pollution.

To evaluate the stability and resilience1 of coastal ecosystem communities to perturbations that occurred during the Anthropocene,2 pre-industrial biodiversity baselines inferred from paleoarchives are needed.3,4 The study of ancient DNA (aDNA) from sediments (sedaDNA)5 has provided valuable information about past dynamics of microbial species6-8 and communities9-18 in relation to ecosystem variations. Shifts in planktonic protist communities might significantly affect marine ecosystems through cascading effects,19-21 and therefore the analysis of this compartment is essential for the assessment of ecosystem variations. Here, sediment cores collected from different sites of the Bay of Brest (northeast Atlantic, France) allowed ca. 1,400 years of retrospective analyses of the effects of human pollution on marine protists. Comparison of sedaDNA extractions and metabarcoding analyses with different barcode regions (V4 and V7 18S rDNA) revealed that protist assemblages in ancient sediments are mainly composed of species known to produce resting stages. Heavy-metal pollution traces in sediments were ascribed to the World War II period and coincided with community shifts within dinoflagellates and stramenopiles. After the war and especially from the 1980s to 1990s, protist genera shifts followed chronic contaminations of agricultural origin. Community composition reconstruction over time showed that there was no recovery to a Middle Ages baseline composition. This demonstrates the irreversibility of the observed shifts after the cumulative effect of war and agricultural pollutions. Developing a paleoecological approach, this study highlights how human contaminations irreversibly affect marine microbial compartments, which contributes to the debate on coastal ecosystem preservation and restoration.

Perspectives From COPD Subjects on Portable Long-Term Oxygen Therapy Devices.

BACKGROUND: Oxygen therapy for patients with COPD and severe hypoxemia requires the use of oxygen delivery devices that allow mobility as needed. However, the characteristics of some devices may limit the freedom of individuals to be as physically active as they desire. Limited mobility may negatively affect the perceived quality of life of individuals with COPD. The aim of this study was to understand perceived limitations that patients with COPD experience in using long-term oxygen therapy (LTOT) devices. METHODS: We performed a qualitative analysis of 311 responses to an open-ended question from a previously deployed electronic survey designed to investigate how LTOT devices affect oxygen-dependent patients with COPD. Our thematic analysis was facilitated by NVivo, a qualitative data analysis software package. This involved identifying patterns and themes within the robust, text-rich data from the open-ended survey question regarding the survey subjects' experiences with their LTOT devices. Cluster analysis was also performed to highlight relationships between various concepts. RESULTS: Themes generated revealed that subjects experienced decreased mobility, which resulted in feelings of decreased autonomy and isolation. We also found that subjects perceived a decrease in quality of life due to their described experience of portable oxygen cylinders being heavy and cumbersome. Subjects described feelings of fear and anxiety due to insufficient support for breathing provided by pulse-dose portable oxygen concentrators, as well as portable oxygen cylinders that run out before they are able to complete errands and other activities of daily living. Some subjects also reported that they willingly pay for liquid oxygen systems out-of-pocket because of the mobility it affords, which in their perception improves their quality of life. CONCULSIONS: Oxygen-dependent individuals with COPD may be at risk of adverse outcomes associated with decreased mobility encouraged by unsatisfactory physical and technical characteristics of portable oxygen cylinders and concentrators.