Phylogenetic Signal, Root Morphology, Mycorrhizal Type, and Macroinvertebrate Exclusion: Exploring Wood Decomposition in Soils Conditioned by 13 Temperate Tree Species

Woodlands are pivotal to carbon stocks, but the process of cycling C is slow and may be most effective in the biodiverse root zone. How the root zone impacts plants has been widely examined over the past few decades, but the role of the root zone in decomposition is understudied. Here, we examined how mycorrhizal association and macroinvertebrate activity influences wood decomposition across diverse tree species. Within the root zone of six predominantly arbuscular mycorrhizal (AM) (Acer negundo, Acer saccharum, Prunus serotina, Juglans nigra, Sassafras albidum, and Liriodendron tulipfera) and seven predominantly ectomycorrhizal (EM) tree species (Carya glabra, Quercus alba, Quercus rubra, Betula alleghaniensis, Picea rubens, Pinus virginiana, and Pinus strobus), woody litter was buried for 13 months. Macroinvertebrate access to woody substrate was either prevented or not using 0.22 mm mesh in a common garden site in central Pennsylvania. Decomposition was assessed as proportionate mass loss, as explained by root diameter, phylogenetic signal, mycorrhizal type, canopy tree trait, or macroinvertebrate exclusion. Macroinvertebrate exclusion significantly increased wood decomposition by 5.9%, while mycorrhizal type did not affect wood decomposition, nor did canopy traits (i.e., broad leaves versus pine needles). Interestingly, there was a phylogenetic signal for wood decomposition. Local indicators for phylogenetic associations (LIPA) determined high values of sensitivity value in Pinus and Picea genera, while Carya, Juglans, Betula, and Prunus yielded low values of sensitivity. Phylogenetic signals went undetected for tree root morphology. Despite this, roots greater than 0.35 mm significantly increased woody litter decomposition by 8%. In conclusion, the findings of this study suggest trees with larger root diameters can accelerate C cycling, as can trees associated with certain phylogenetic clades. In addition, root zone macroinvertebrates can potentially limit woody C cycling, while mycorrhizal type does not play a significant role

Metatranscriptomic Sequencing of a Cyanobacterial Soil-Surface Consortium with and without a Diverse Underlying Soil Microbiome.

Soil surface consortia are easily observed and sampled, allowing examination of their interactions with soil microbiomes. Here, we present metatranscriptomic sequences from Dark Green 1 (DG1), a cyanobacterium-based soil surface consortium, in the presence and absence of an underlying soil microbiome and/or urea

Manure amendments for mitigation of dairy ammonia and greenhouse gas emissions: preliminary screening

 Amendments can be practical and cost-effective for reducing ammonia [NH3] and greenhouse gas [GHG] emissions from dairy manure.  In this study, the effect of 22 amendments on NH3 and GHG carbon dioxide [CO2], methane [CH4] and nitrous oxide [N2O] emissions from dairy manure were simultaneous investigated at room temperature (20℃).  Dairy manure slurry (2 kg; 1:1.7 urine: feces; 12% total solids) was treated with various amendments, representing different classes of product, following the suppliers’ recommended rates.  In this screening of products, one sample of each amendment was evaluated along with untreated manure slurry with repeated measurements over 24 h.  Gas emissions were measured after short (3 d) and medium (30 d) storage duration using a photoacoustic multi-gas analyzer.  Six amendment products that acted as microbial digest, oxidizing agent, masking agent or adsorbent significantly reduced NH3 by >10% (P = 0.04 to <0.001) after both 3 and 30 d.  Microbial digest/enzymes with nitrogen substrate appeared effective in reducing CH4 fluxes for both storage times.  Most of the masking agents and disinfectants significantly increased CH4 in both storage periods (P = 0.04 to <0.001).  For both CH4 and CO2 fluxes, aging the manure slurry for 30 d significantly reduced gas production by 11 to 100% (P<0.001).  While some products reduced emissions at one or both storage times, results showed that the ability of amendments to mitigate emissions from dairy manure is finite and re-application may be required even for a static amount of manure.  Simultaneous measurement of gases identified glycerol as a successful NH3 reduction agent while increasing CH4 in contrast to a digestive-microbial product that significantly reduced CH4 while enhancing NH3 release.Keywords: methane, greenhouse gas, emission, amendment, additive, dairy manure, ammonia, mitigatio

Evaluation of odor emissions from amended dairy manure: preliminary screening

Manure amendments have shown variable effectiveness in reducing odor.  Twenty-two amendments were applied to dairy manure then evaluated for odor reduction efficacy after storage at 20℃ for 3 d and 30 d.  Amendments represented differing primary modes of action including: microbial digestive, oxidizing, disinfecting, masking, and adsorbent.  Each amendment was added to 2 kg dairy manure (1:1.7 urine:feces; 12% total solids) following recommended rates.  In this preliminary screening, one sample (n=1) of each amendment was evaluated along with untreated manure (Control).  Odor emission from each treated manure and Control was estimated twice by five or six qualified odor assessors (n=10 or 12) after each storage duration, using an international standard for triangular forced-choice olfactometry.  Odor quality was defined using hedonic tone, Labeled Magnitude Scale and ASTM methods for supra-threshold odor intensity, and an odor character wheel for descriptors.  For selected treatments, odor emissions were significantly reduced relative to Control at 30 d versus 3 d incubation (P<0.0001).  However, no amendment was significantly effective for both incubation times.  Likewise, for all amendments tested, aging the manure slurry for 30 d significantly reduced odor emission and odor intensity (P<0.0001).  A proprietary microbial amendment (Alken Enz-Odor + Clear Flo: aerobic/ facultative microbes with growth factors), disinfectant (hydrogen peroxide), and masking agent (Hyssopus officinalis essential oil) provided significant short-term control of odor (P <0.06).  However, after 30 d seven amendments significantly increased odor emission (P<0.02) while only two amendments offered a significant efficacy (P<0.0001): a proprietary microbial aerobic/facultative product (Bio-Regen) and a proprietary mix of chemicals (Greaseater), both with weekly re-application.  Hedonic tone observations suggested an improvement to “slightly to moderately unpleasant” smell versus untreated manure for all amendments except clinoptilolite zeolite adsorbent.  Hedonic tone improvement was correlated with reduced manure odor supra-threshold intensity.Keywords: odor, hedonic tone, odor strength, amendments, additives, dairy manure, United States of Americ

Phylogenetic Signal, Root Morphology, Mycorrhizal Type, and Macroinvertebrate Exclusion: Exploring Wood Decomposition in Soils Conditioned by 13 Temperate Tree Species

Woodlands are pivotal to carbon stocks, but the process of cycling C is slow and may be most effective in the biodiverse root zone. How the root zone impacts plants has been widely examined over the past few decades, but the role of the root zone in decomposition is understudied. Here, we examined how mycorrhizal association and macroinvertebrate activity influences wood decomposition across diverse tree species. Within the root zone of six predominantly arbuscular mycorrhizal (AM) (Acer negundo, Acer saccharum, Prunus serotina, Juglans nigra, Sassafras albidum, and Liriodendron tulipfera) and seven predominantly ectomycorrhizal (EM) tree species (Carya glabra, Quercus alba, Quercus rubra, Betula alleghaniensis, Picea rubens, Pinus virginiana, and Pinus strobus), woody litter was buried for 13 months. Macroinvertebrate access to woody substrate was either prevented or not using 0.22 mm mesh in a common garden site in central Pennsylvania. Decomposition was assessed as proportionate mass loss, as explained by root diameter, phylogenetic signal, mycorrhizal type, canopy tree trait, or macroinvertebrate exclusion. Macroinvertebrate exclusion significantly increased wood decomposition by 5.9%, while mycorrhizal type did not affect wood decomposition, nor did canopy traits (i.e., broad leaves versus pine needles). Interestingly, there was a phylogenetic signal for wood decomposition. Local indicators for phylogenetic associations (LIPA) determined high values of sensitivity value in Pinus and Picea genera, while Carya, Juglans, Betula, and Prunus yielded low values of sensitivity. Phylogenetic signals went undetected for tree root morphology. Despite this, roots greater than 0.35 mm significantly increased woody litter decomposition by 8%. In conclusion, the findings of this study suggest trees with larger root diameters can accelerate C cycling, as can trees associated with certain phylogenetic clades. In addition, root zone macroinvertebrates can potentially limit woody C cycling, while mycorrhizal type does not play a significant role

Geoeconomic variations in epidemiology, ventilation management, and outcomes in invasively ventilated intensive care unit patients without acute respiratory distress syndrome: a pooled analysis of four observational studies

Background: Geoeconomic variations in epidemiology, the practice of ventilation, and outcome in invasively ventilated intensive care unit (ICU) patients without acute respiratory distress syndrome (ARDS) remain unexplored. In this analysis we aim to address these gaps using individual patient data of four large observational studies. Methods: In this pooled analysis we harmonised individual patient data from the ERICC, LUNG SAFE, PRoVENT, and PRoVENT-iMiC prospective observational studies, which were conducted from June, 2011, to December, 2018, in 534 ICUs in 54 countries. We used the 2016 World Bank classification to define two geoeconomic regions: middle-income countries (MICs) and high-income countries (HICs). ARDS was defined according to the Berlin criteria. Descriptive statistics were used to compare patients in MICs versus HICs. The primary outcome was the use of low tidal volume ventilation (LTVV) for the first 3 days of mechanical ventilation. Secondary outcomes were key ventilation parameters (tidal volume size, positive end-expiratory pressure, fraction of inspired oxygen, peak pressure, plateau pressure, driving pressure, and respiratory rate), patient characteristics, the risk for and actual development of acute respiratory distress syndrome after the first day of ventilation, duration of ventilation, ICU length of stay, and ICU mortality. Findings: Of the 7608 patients included in the original studies, this analysis included 3852 patients without ARDS, of whom 2345 were from MICs and 1507 were from HICs. Patients in MICs were younger, shorter and with a slightly lower body-mass index, more often had diabetes and active cancer, but less often chronic obstructive pulmonary disease and heart failure than patients from HICs. Sequential organ failure assessment scores were similar in MICs and HICs. Use of LTVV in MICs and HICs was comparable (42·4% vs 44·2%; absolute difference -1·69 [-9·58 to 6·11] p=0·67; data available in 3174 [82%] of 3852 patients). The median applied positive end expiratory pressure was lower in MICs than in HICs (5 [IQR 5-8] vs 6 [5-8] cm H2O; p=0·0011). ICU mortality was higher in MICs than in HICs (30·5% vs 19·9%; p=0·0004; adjusted effect 16·41% [95% CI 9·52-23·52]; p<0·0001) and was inversely associated with gross domestic product (adjusted odds ratio for a US$10 000 increase per capita 0·80 [95% CI 0·75-0·86]; p<0·0001). Interpretation: Despite similar disease severity and ventilation management, ICU mortality in patients without ARDS is higher in MICs than in HICs, with a strong association with country-level economic status