Based on the measurement of carbon flux by the methods of eddy covariance and static chamber/gas chromatogram, a comparison was made between the two methods in evaluating ecosystem respiration over winter wheat (Triticum aestivum)--summer maize (Zea mays) double cropland and Kobresia humilis alpine meadow. The results showed that under the conditions of obtained data having good quality, nighttime ecosystem respiration from eddy covariance measurement was significantly agreed with that from static chamber/gas chromatogram measurement, with the correlation coefficients ranging from 0.95 to 0.98, and the daytime ecosystem respiration from these two measurements also had a good consistency though the static chamber/gas chromatogram measurement often produced higher values. The daily mean value of ecosystem respiration was significantly different between these two measurements, but the seasonal pattern was similar. For winter wheat-summer maize double cropland, the difference of mean air temperature inside and outside the chamber was 1.8 degrees C, and the daily mean value of ecosystem respiration across the whole study period was 30.3% lower in eddy covariance measurement than in static chamber/gas chromatogram measurement; while for alpine meadow, the difference of the mean air temperature was 1.9 degrees C, and the daily mean value of ecosystem respiration was 31.4% lower in eddy covariance measurement than in static chamber/gas chromatogram measurement. The variance between the daily mean values of ecosystem respiration obtained from the two measurements was higher in growing season than in dormant season.
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Sci Rep
January 2025
Department of Biological Sciences, Faculty of Science, King AbdulAziz University, Jeddah, Saudi Arabia.
In this study, we present for the first time the landscape of the lung microbiota in patients with ventilator-associated pneumonia in Intensive Care Units in Saudi Arabia. DNA from 83 deep endotracheal aspirate lung samples was subjected to PacBio sequencing to identify pathogens in comparison with conventional diagnostic techniques. Patients on ventilation with pneumonia presented with similar lung flora to those of patients on ventilation without pneumonia.
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January 2025
CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China.
Many alpine ecosystems are undergoing vegetation degradation because of global changes, which are affecting ecosystem functioning and biodiversity. The ecological consequences of alpine pioneer community degradation have been less studied than glacial retreat or meadow degradation in alpine ecosystems. We document the comprehensive responses of microbial community characteristics to degradation processes using field-based sampling, conduct soil microcosm experiments to simulate the effects of global change on microorganisms, and explore their relationships to ecosystem functioning across stages of alpine pioneer community degradation.
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Experimental Physics V, Department of Physics, University of Bayreuth, D-95447 Bayreuth, Germany.
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January 2025
Department of Microbiology, Oregon State University, 220 Nash Hall, Corvallis, OR, USA.
Global oxygen minimum zones (OMZs) often reach hypoxia but seldom reach anoxia. Recently it was reported that Michaelis Menten constants (K) of oxidative enzymes are orders of magnitude higher than respiratory K values, and in the Hypoxic Barrier Hypothesis it was proposed that, in ecosystems experiencing falling oxygen, oxygenase enzyme activities become oxygen-limited long before respiration. We conducted a mesocosm experiment with a phytoplankton bloom as an organic carbon source and controlled dissolved oxygen (DO) concentrations in the dark to determine whether hypoxia slows carbon oxidation and oxygen decline.
View Article and Find Full Text PDFSci Total Environ
January 2025
Department of Forest Sciences, Faculty of Agricultural and Environmental Sciences, Universidad de La Frontera, Temuco, Chile.
Peatlands are key ecosystems for global climate regulation because they provide the most efficient carbon sink on the planet. Despite this, they have been widely degraded by various anthropogenic disturbances, causing imbalances in their ecological functioning. A more recent type of disturbance corresponds to the commercial extraction of Sphagnum mosses, which has been carried out in temperate peatlands distributed in Australasia and Patagonia.
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