Manganese availability is negatively associated with carbon storage in northern coniferous forest humus layers

Carbon sequestration below ground depends on organic matter input and decomposition, but regulatory bottlenecks remain unclear. The relative importance of plant production, climate and edaphic factors has to be elucidated to better predict carbon storage in forests. In Swedish forest soil inventory data from across the entire boreal latitudinal range (n = 2378), the concentration of exchangeable manganese was singled out as the strongest predictor (R-2 = 0.26) of carbon storage in the extensive organic horizon (mor layer), which accounts for one third of the total below ground carbon. In comparison, established ecosystem models applied on the same data have failed to predict carbon stocks (R-2 <0.05), and in our study manganese availability overshadowed both litter production and climatic factors. We also identified exchangeable potassium as an additional strong predictor, however strongly correlated with manganese. The negative correlation between manganese and carbon highlights the importance of Mn-peroxidases in oxidative decomposition of recalcitrant organic matter. The results support the idea that the fungus-driven decomposition could be a critical factor regulating humus carbon accumulation in boreal forests, as Mn-peroxidases are specifically produced by basidiomycetes.Peer reviewe

Evaluating load balancing policies for performance and energy-efficiency

Nowadays, more and more increasingly hard computations are performed in challenging fields like weather forecasting, oil and gas exploration, and cryptanalysis. Many of such computations can be implemented using a computer cluster with a large number of servers. Incoming computation requests are then, via a so-called load balancing policy, distributed over the servers to ensure optimal performance. Additionally, being able to switch-off some servers during low period of workload, gives potential to reduced energy consumption. Therefore, load balancing forms, albeit indirectly, a trade-off between performance and energy consumption. In this paper, we introduce a syntax for load-balancing policies to dynamically select a server for each request based on relevant criteria, including the number of jobs queued in servers, power states of servers, and transition delays between power states of servers. To evaluate many policies, we implement two load balancers in: (i) iDSL, a language and tool-chain for evaluating service-oriented systems, and (ii) a simulation framework in AnyLogic. Both implementations are successfully validated by comparison of the results.Comment: In Proceedings QAPL'16, arXiv:1610.0769

Long-Term Effects of Climate and Litter Chemistry on Rates and Stable Fractions of Decomposing Scots Pine and Norway Spruce Needle Litter—A Synthesis

We have reviewed information on early-, late- and limit-value decomposition stages for litter of Norway spruce (Picea abies) and Scots pine (Pinus silvestris). This synthesis covers c 16 studies/papers made along a climatic gradient; range in mean annual temperature (MAT) from −1 to +7 °C and mean annual precipitation (MAP) from 425 to 1070 mm. Scots pine has an early stage dominated by carbohydrate decomposition and a late stage dominated by decomposition of lignin; Norway spruce has just one stage dominated by lignin decomposition. We used data for annual mass loss to identify rate-regulating factors in both stages; climate data, namely, MAT and MAP, as well as substrate properties, namely, nitrogen (N), acid unhydrolyzable residue (AUR), manganese (Mn). Early-stage decomposition for Scots pine litter was dominated positively by MAT; the late stage was dominated negatively by MAT, N, and AUR, changing with decomposition stage; there was no effect of Mn. Norway spruce litter had no early stage; decomposition in the lignin-dominated stage was mainly negative to MAP, a negative relationship to AUR and non-significant relationships to N and MAT. Mn had a positive relationship. Limit values for decomposition, namely, the accumulated mass loss at which decomposition is calculated to be zero, were related positively to Mn and AUR for Scots pine litter and negatively to AUR for Norway spruce litter. With different sets of rate-regulating factors as well as different compounds/elements related to the limit values, the decomposition patterns or pathways are different

Long-Term Effects of Climate and Litter Chemistry on Rates and Stable Fractions of Decomposing Scots Pine and Norway Spruce Needle Litter—A Synthesis

We have reviewed information on early-, late- and limit-value decomposition stages for litter of Norway spruce (Picea abies) and Scots pine (Pinus silvestris). This synthesis covers c 16 studies/papers made along a climatic gradient; range in mean annual temperature (MAT) from −1 to +7 °C and mean annual precipitation (MAP) from 425 to 1070 mm. Scots pine has an early stage dominated by carbohydrate decomposition and a late stage dominated by decomposition of lignin; Norway spruce has just one stage dominated by lignin decomposition. We used data for annual mass loss to identify rate-regulating factors in both stages; climate data, namely, MAT and MAP, as well as substrate properties, namely, nitrogen (N), acid unhydrolyzable residue (AUR), manganese (Mn). Early-stage decomposition for Scots pine litter was dominated positively by MAT; the late stage was dominated negatively by MAT, N, and AUR, changing with decomposition stage; there was no effect of Mn. Norway spruce litter had no early stage; decomposition in the lignin-dominated stage was mainly negative to MAP, a negative relationship to AUR and non-significant relationships to N and MAT. Mn had a positive relationship. Limit values for decomposition, namely, the accumulated mass loss at which decomposition is calculated to be zero, were related positively to Mn and AUR for Scots pine litter and negatively to AUR for Norway spruce litter. With different sets of rate-regulating factors as well as different compounds/elements related to the limit values, the decomposition patterns or pathways are different

Selective low concentration ammonia sensing in a microfluidic lab-on-a-chip

In the medical community, there is a considerable interest in a diagnostic breath analyzer for ammonia that is selectively enough to measure in exhaled air and small enough for the small volumes available in such an application. An indirect measurement system for low gaseous ammonia concentrations has been miniaturized and integrated on a chip in order to reach this goal. The detection limit of the system was calculated to be 1.1 parts per billion (ppb). The response time was determined to be 1.6 min with a gas How of 50 ml/min. The required gas volume for one measurement is therefore sufficiently small, although sampling assistance is required for breath analysis. The selectivity of the system is sufficient to measure ammonia concentrations in the low-ppb range. The system is even sufficiently selective to be used in environments that contain elevated carbon dioxide levels, like exhaled air. The lower ammonia concentration expected in diagnostic breath analysis applications, 50 ppb, was demonstrated to be detectable

Humusica 1, article 2 : Essential bases-Functional considerations

Humusica 1 and 2 Applied Soil Ecology Special issues are field guides for humipedon classification. Contrary to other similar manuals dedicated to soil, the objects that one can describe with these guides are living, dynamic, functional, and relatively independent soil units. This is the reason to why the authors dedicated the whole article number 2 to functional considerations even before readers could go in the field and face the matter to be classified. Experienced lectors can overstep many of the sections reported in this article. If the titles of sections "1 A functional classification", "2 What is a humus system?" and "3 Energetic considerations in terrestrial systems" stimulate the reader's curiosity, then we suggest to pass through them. Otherwise, only section "4 Climatic, plant litter, or nutritional constraints?" is crucial. Readers will understand how the soil works in terms of litter and Carbon accumulation, which one(s) among climatic, vegetational, or geological factors that intervene and strongly affect the formation processes of terrestrial (oxygenated) soils. The article concludes with a debate about a tergiversated question: can temperature influence humus decomposition? Preceding statements were used for explaining how the biological soil net can store in the soil a maximum of energy in the form of SOM, by raising a plateau partially independent of climatic conditions.Peer reviewe

Effects of different forms of nitrogen addition on microbial extracellular enzyme activity in temperate grassland soil

Funding Information: We want to thank the reviewers for their insightful comments towards improving the manuscript. We acknowledge the valuable help from all the staff of the Erguna Forest-Steppe Ecotone Ecosystem Research Station of IAE, CAS. Funding Information: The funding for this research was supported by the National Natural Science Foundation of China (32022054 and 31901137), and China Postdoctoral Science Foundation (2018M640263), Instrument Developing Project of CAS (YJKYYQ20190079), Strategic Priority Research Program of CAS (Grant No. XDA28120100) and Youth Innovation Promotion Association of CAS (2019198). Publisher Copyright: © 2022, The Author(s).Background: Nitrogen (N) deposition alters litter decomposition and soil carbon (C) sequestration by influencing the microbial community and its enzyme activity. Natural atmospheric N deposition comprises of inorganic N (IN) and organic N (ON) compounds. However, most studies have focused on IN and its effect on soil C cycling, whereas the effect of ON on microbial enzyme activity is poorly understood. Here we studied the effects of different forms of externally supplied N on soil enzyme activities related to decomposition in a temperate steppe. Ammonium nitrate was chosen as IN source, whereas urea and glycine were chosen as ON sources. Different ratios of IN to ON (Control, 10:0, 7:3, 5:5, 3:7, and 0:10) were mixed with equal total amounts of N and then used to fertilize the grassland soils for 6 years. Results: Our results show that IN deposition inhibited lignin-degrading enzyme activity, such as phenol oxidase (POX) and peroxidase (PER), which may restrain decomposition and thus induce accumulation of recalcitrant organic C in grassland soils. By contrast, deposition of ON and mixed ON and IN enhanced most of the C-degrading enzyme activities, which may promote the organic matter decomposition in grassland soils. In addition, the β-N-acetyl-glucosaminidase (NAG) activity was remarkably stimulated by fertilization with both IN and ON, maybe because of the elevated N availability and the lack of N limitation after long-term N fertilization at the grassland site. Meanwhile, differences in soil pH, soil dissolved organic carbon (DOC), and microbial biomass partially explained the differential effects on soil enzyme activity under different forms of N treatments. Conclusions: Our results emphasize the importance of organic N deposition in controlling soil processes, which are regulated by microbial enzyme activities, and may consequently change the ecological effect of N deposition. Thus, more ON deposition may promote the decomposition of soil organic matter thus converting C sequestration in grassland soils into a C source.Peer reviewe

Nasale High – Flow - Sauerstofftherapie bei Patienten mit hypoxischem Lungenversagen : Einfluss auf funktionelle und subjektive Atmungsparameter im Vergleich zur konventionellen O2-Therapie und zur nicht-invasiven Beatmung

Background: Aim of the study was to compare the short-term effects of oxygen therapy via a high-flow nasal cannula (HFNC) on functional and subjective respiratory parameters in patients with acute hypoxic respiratory failure in comparison to non-invasive ventilation (NIV) and standard treatment via a Venturi mask. Methods: Fourteen patients with acute hypoxic respiratory failure were treated with HFNC (FiO2 0.6, gas flow 55 l/min), NIV (FiO2 0.6, PEEP 5 cm H2O Hg, tidal volume 6–8 ml/kg ideal body weight,) and Venturi mask (FiO2 0.6, oxygen flow 15 l/min,) in a randomized order for 30 min each. Data collection included objective respiratory and circulatory parameters as well as a subjective rating of dyspnea and discomfort by the patients on a 10-point scale. In a final interview, all three methods were comparatively evaluated by each patient using a scale from 1 (=very good) to 6 (=failed) and the patients were asked to choose one method for further treatment. Results: PaO2 was highest under NIV (129 ± 38 mmHg) compared to HFNC (101 ± 34 mmHg, p <0.01 vs. NIV) and VM (85 ± 21 mmHg, p <0.001 vs. NIV, p <0.01 vs. HFNC, ANOVA). All other functional parameters showed no relevant differences. In contrast, dyspnea was significantly better using a HFNC (2.9 ± 2.1, 10-point Borg scale) compared to NIV (5.0 ± 3.3, p <0.05), whereas dyspnea rating under HFNC and VM (3.3 ± 2.3) was not significantly different. A similar pattern was found when patients rated their overall discomfort on the 10 point scale: HFNC 2.7 ± 1.8, VM 3.1 ± 2.8 (ns vs. HFNC), NIV 5.4 ± 3.1 (p <0.05 vs. HFNC). In the final evaluation patients gave the best ratings to HFNC 2.3 ± 1.4, followed by VM 3.2 ± 1.7 (ns vs. HFNC) and NIV 4.5 ± 1.7 (p <0.01 vs. HFNC and p <0.05 vs. VM). For further treatment 10 patients chose HFNC, three VM and one NIV. Conclusions: In hypoxic respiratory failure HFNC offers a good balance between oxygenation and comfort compared to NIV and Venturi mask and seems to be well tolerated by patients

Comparison of the nutrient resorption stoichiometry of Quercus variabilis Blume growing in two sites contrasting in soil phosphorus content

Key message Foliar phosphorus (P) resorption in Quercus variabilis Blume was significantly lower at a P-rich than at a P-deficient site. Moreover, P resorption strongly decreased, and nitrogen: phosphorus and carbon: phosphorus resorption ratios increased with soil P content. This demonstrates a strong link between foliar P resorption and P content in soils, and emphasizes the importance of P resorption in leaves of trees growing in soils with contrasted P content. Context Subtropical ecosystems are generally characterized by P-deficient soils. However, P-rich soils develop in phosphate rock areas. Aims We compared the patterns of nutrient resorption, in terms of ecological stoichiometry, for two sites naturally varying in soil P content. Methods The resorption efficiency (percentage of a nutrient recovered from senescing leaves) and proficiency (level to which nutrient concentration is reduced in senesced leaves) of 12 elements were determined in two oak (Q. variabilis) populations growing at a P-rich or a P-deficient site in subtropical China. Results P resorption efficiency dominated the intraspecific variation in nutrient resorption between the two sites. Q. variabilis exhibited a low P resorption at the P-rich site and a high P resorption at the P-deficient site. Both P resorption efficiency and proficiency strongly decreased with soil P content only and were positively related to the N:P and C:P ratios in green and senesced leaves. Moreover, resorption efficiency ratios of both N:P and C:P were positively associated with soil P. Conclusion These results revealed a strong link between P resorption and P stoichiometry in response to a P deficiency in the soil, and a single- and limiting-element control pattern of P resorption. Hence, these results provide new insights into the role of P resorption in plant adaptations to geologic variations of P in the subtropics.Peer reviewe