Biochar effects on methane emissions from soils: a meta-analysis

Methane (CH4) emissions have increased by more than 150% since 1750, with agriculture being the major source. Further increases are predicted as permafrost regions start thawing, and rice and ruminant animal production expand. Biochar is posited to increase crop productivity while mitigating climate change by sequestering carbon in soils and by influencing greenhouse gas fluxes. There is a growing understanding of biochar effects on carbon dioxide and nitrous oxide fluxes from soil. However, little is known regarding the effects on net methane exchange, with single studies often reporting contradictory results. Here we aim to reconcile the disparate effects of biochar application to soil in agricultural systems on CH4 fluxes into a single interpretive framework by quantitative meta-analysis. This study shows that biochar has the potential to mitigate CH4 emissions from soils, particularly from flooded (i.e. paddy) fields (Hedge's d = −0.87) and/or acidic soils (Hedge's d = −1.56) where periods of flooding are part of the management regime. Conversely, addition of biochar to soils that do not have periods of flooding (Hedge's d = 0.65), in particular when neutral or alkaline (Hedge's d = 1.17 and 0.44, respectively), may have the potential to decrease the CH4 sink strength of those soils. Global methane fluxes are net positive as rice cultivation is a much larger source of CH4 than the sink contribution of upland soils. Therefore, this meta-study reveals that biochar use may have the potential to reduce atmospheric CH4 emissions from agricultural flooded soils on a global scale

Plant functional types and elevated CO2: A method of scanning for causes of community alteration

In this paper, a general method for an a posteriori plant functional type (PFT) analysis of global change effects on community composition is developed. We apply the method to a case study, specifically the Giessen-FACE experiment. This experiment involves a Central European meadow that has been exposed to moderate CO2-enrichment since May 1998.The method for an a posteriori PFT-analysis: The method consists of four working steps and uses a combination of standard gradient analysis and Random Forests (RF). (1) The trait composition of the species is studied using Principal Components Analysis. Species trait information is gathered from databases. Natural PFT, i.e. groups of species with similar trait-sets, are identified specifically for the community under study. (2) A ranking of the species according to standardized/absolute CO2 abundance response is obtained from Redundancy Analysis. Initially, species with a response above or below the median are grouped into three response groups (RG) each having similar behaviour, i.e. positive/negative or no-response. (3) The outlyingness measure of RF is used to shift RG boundaries until satisfactory RG homogeneity is achieved. RF is utilized to find the best traits for the RG classification. The behaviour of species representative of the RG is derived from RF class centers. (4) From knowledge gained in steps 1-3, hypotheses about the causes underlying the community alteration are built. Strengths/weaknesses of the method are discussed.Application of the method to the case study: The community consists of three natural PFT. Five species are summer-green forbs of varying competitiveness. Four species are evergreen ruderal forbs characterized as (semi-) basal rosette plants. The third natural PFT contains evergreen, more or less competitive species, mostly grasses, but also a few forbs.Negative standardized CO2-response was practically restricted to two natural PFT, i.e. the summer-greens, irrespective of their competitiveness, and the evergreen ruderals. Standard positive response covered part of the evergreen competitive natural PFT. Among them was Glechoma hederacea, one of the forbs with the greatest similarity to grasses. Two hypotheses were formulated to explain the response pattern: (1) Summer-greens lost in competition with evergreens, because the annual time-integral they can use for enhanced growth was more limited with year-round CO2-enrichment. (2) As rosette plants, ruderal evergreens lagged behind evergreen competitors because periods with full sunlight, which enabled them to gain additional carbon, were shorter for them.Absolute responses were additionally dependent on dominance patterns. The most striking difference to standard responses was the restriction of positive response to (sub-)dominant grasses

Possible Signatures of a Cold-Flow Disk from MUSE using a z=1 galaxy--quasar pair towards SDSSJ1422-0001

We use a background quasar to detect the presence of circum-galactic gas around a $z=0.91$ low-mass star forming galaxy. Data from the new Multi Unit Spectroscopic Explorer (MUSE) on the VLT show that the host galaxy has a dust-corrected star-formation rate (SFR) of 4.7$\pm$0.2 Msun/yr, with no companion down to 0.22 Msun/yr (5 $\sigma$) within 240 kpc (30"). Using a high-resolution spectrum (UVES) of the background quasar, which is fortuitously aligned with the galaxy major axis (with an azimuth angle $\alpha$ of only $15^\circ$), we find, in the gas kinematics traced by low-ionization lines, distinct signatures consistent with those expected for a "cold flow disk" extending at least 12 kpc ($3\times R_{1/2}$). We estimate the mass accretion rate $\dot M_{\rm in}$ to be at least two to three times larger than the SFR, using the geometric constraints from the IFU data and the HI column density of $\log N_{\rm HI} \simeq 20.4$ obtained from a {\it HST}/COS NUV spectrum. From a detailed analysis of the low-ionization lines (e.g. ZnII, CrII, TiII, MnII, SiII), the accreting material appears to be enriched to about 0.4 $Z_\odot$ (albeit with large uncertainties: $\log Z/Z_\odot=-0.4~\pm~0.4$), which is comparable to the galaxy metallicity ($12+\log \rm O/H=8.7\pm0.2$), implying a large recycling fraction from past outflows. Blue-shifted MgII and FeII absorptions in the galaxy spectrum from the MUSE data reveal the presence of an outflow. The MgII and FeII doublet ratios indicate emission infilling due to scattering processes, but the MUSE data do not show any signs of fluorescent FeII* emission.Comment: 17 pages, 11 figures, in press (ApJ), minor edits after the proofs. Data available at http://muse-vlt.eu/science/j1422

The Non-linear Optical Spin Hall Effect and Long-Range Spin Transport in Polariton Lasers

We report on the experimental observation of the non-linear analogue of the optical spin Hall effect under highly non-resonant circularly polarized excitation of an exciton polariton condensate in a GaAs/AlGaAs microcavity. Initially circularly polarized polariton condensates propagate over macroscopic distances while the collective condensate spins coherently precess around an effective magnetic field in the sample plane performing up to four complete revolutions

Intracellularly Released Cholesterol from Polymer-Based Delivery Systems Alters Cellular Responses to Pneumolysin and Promotes Cell Survival

Cholesterol is highly abundant within all human body cells and modulates critical cellular functions related to cellular plasticity, metabolism, and survival. The cholesterol-binding toxin pneumolysin represents an essential virulence factor of Streptococcus pneumoniae in establishing pneumonia and other pneumococcal infections. Thus, cholesterol scavenging of pneumolysin is a promising strategy to reduce S. pneumoniae induced lung damage. There may also be a second cholesterol-dependent mechanism whereby pneumococcal infection and the presence of pneumolysin increase hepatic sterol biosynthesis. Here we investigated a library of polymer particles varying in size and composition that allow for the cellular delivery of cholesterol and their effects on cell survival mechanisms following pneumolysin exposure. Intracellular delivery of cholesterol by nanocarriers composed of Eudragit E100-PLGA rescued pneumolysin-induced alterations of lipid homeostasis and enhanced cell survival irrespective of neutralization of pneumolysin

Spatial analysis of bladder, kidney, and pancreatic cancer on upper Cape Cod: an application of generalized additive models to case-control data

<p>Abstract</p> <p>Background</p> <p>In 1988, elevated cancer incidence in upper Cape Cod, Massachusetts prompted a large epidemiological study of nine cancers to investigate possible environmental risk factors. Positive associations were observed, but explained only a portion of the excess cancer incidence. This case-control study provided detailed information on individual-level covariates and residential history that can be spatially analyzed using generalized additive models (GAMs) and geographical information systems (GIS).</p> <p>Methods</p> <p>We investigated the association between residence and bladder, kidney, and pancreatic cancer on upper Cape Cod. We estimated adjusted odds ratios using GAMs, smoothing on location. A 40-year residential history allowed for latency restrictions. We mapped spatially continuous odds ratios using GIS and identified statistically significant clusters using permutation tests.</p> <p>Results</p> <p>Maps of bladder cancer are essentially flat ignoring latency, but show a statistically significant hot spot near known Massachusetts Military Reservation (MMR) groundwater plumes when 15 years latency is assumed. The kidney cancer map shows significantly increased ORs in the south of the study area and decreased ORs in the north.</p> <p>Conclusion</p> <p>Spatial epidemiology using individual level data from population-based studies addresses many methodological criticisms of cluster studies and generates new exposure hypotheses. Our results provide evidence for spatial clustering of bladder cancer near MMR plumes that suggest further investigation using detailed exposure modeling.</p

Biochar as a tool to reduce the agricultural greenhouse-gas burden – knowns, unknowns and future research needs

Agriculture and land use change has significantly increased atmospheric emissions of the non-CO2 green-house gases (GHG) nitrous oxide (N2O) and methane (CH4). Since human nutritional and bioenergy needs continue to increase, at a shrinking global land area for production, novel land management strategies are required that reduce the GHG footprint per unit of yield. Here we review the potential of biochar to reduce N2O and CH4 emissions from agricultural practices including potential mechanisms behind observed effects. Furthermore, we investigate alternative uses of biochar in agricultural land management that may significantly reduce the GHG-emissions-per-unit-of-product footprint, such as (i) pyrolysis of manures as hygienic alternative to direct soil application, (ii) using biochar as fertilizer carrier matrix for underfoot fertilization, biochar use (iii) as composting additive or (iv) as feed additive in animal husbandry or for manure treatment. We conclude that the largest future research needs lay in conducting life-cycle GHG assessments when using biochar as an on-farm management tool for nutrient-rich biomass waste streams

Biochars in soils : towards the required level of scientific understanding

Key priorities in biochar research for future guidance of sustainable policy development have been identified by expert assessment within the COST Action TD1107. The current level of scientific understanding (LOSU) regarding the consequences of biochar application to soil were explored. Five broad thematic areas of biochar research were addressed: soil biodiversity and ecotoxicology, soil organic matter and greenhouse gas (GHG) emissions, soil physical properties, nutrient cycles and crop production, and soil remediation. The highest future research priorities regarding biochar's effects in soils were: functional redundancy within soil microbial communities, bioavailability of biochar's contaminants to soil biota, soil organic matter stability, GHG emissions, soil formation, soil hydrology, nutrient cycling due to microbial priming as well as altered rhizosphere ecology, and soil pH buffering capacity. Methodological and other constraints to achieve the required LOSU are discussed and options for efficient progress of biochar research and sustainable application to soil are presented.Peer reviewe

Developmental toxicity and brain aromatase induction by high genistein concentrations in zebrafish embryos

Genistein is a phytoestrogen found at a high level in soybeans. In vitro and in vivo studies showed that high concentrations of genistein caused toxic effects. This study was designed to test the feasibility of zebrafish embryos for evaluating developmental toxicity and estrogenic potential of high genistein concentrations. The zebrafish embryos at 24 h post-fertilization were exposed to genistein (1 × 10−4 M, 0.5 × 10−4 M, 0.25 × 10−4 M) or vehicle (ethanol, 0.1%) for 60 h. Genistein-treated embryos showed decreased heart rates, retarded hatching times, decreased body length, and increased mortality in a dose-dependent manner. After 0.25 × 10−4 M genistein treatment, malformations of survived embryos such as pericardial edema, yolk sac edema, and spinal kyphosis were also observed. TUNEL assay results showed apoptotic DNA fragments in brain. This study also confirmed the estrogenic potential of genistein by EGFP expression in the brain of the mosaic reporter zebrafish embryos. This study first demonstrated that high concentrations of genistein caused a teratogenic effect on zebrafish embryos and confirmed the estrogenic potential of genistein in mosaic reporter zebrafish embryos