13 research outputs found

    Diversity and taxonomic revision of methanogens and other archaea in the intestinal tract of terrestrial arthropods

    No full text
    International audienceMethane emission by terrestrial invertebrates is restricted to millipedes, termites, cockroaches, and scarab beetles. The arthropod-associated archaea known to date belong to the orders Methanobacteriales, Methanomassiliicoccales, Methanomicrobiales, and Methanosarcinales, and in a few cases also to non-methanogenic Nitrososphaerales and Bathyarchaeales. However, all major host groups are severely undersampled, and the taxonomy of existing lineages is not well developed. Full-length 16S rRNA gene sequences and genomes of arthropod-associated archaea are scarce, reference databases lack resolution, and the names of many taxa are either not validly published or under-classified and require revision. Here, we investigated the diversity of archaea in a wide range of methane-emitting arthropods, combining phylogenomic analysis of isolates and metagenome-assembled genomes (MAGs) with amplicon sequencing of full-length 16S rRNA genes. Our results allowed us to describe numerous new species in hitherto undescribed taxa among the orders Methanobacteriales (Methanacia, Methanarmilla, Methanobaculum, Methanobinarius, Methanocatella, Methanoflexus, Methanorudis, and Methanovirga, all gen. nova), Methanomicrobiales (Methanofilum and Methanorbis, both gen. nova), Methanosarcinales (Methanofrustulum and Methanolapillus, both gen. nova), Methanomassiliicoccales (Methanomethylophilaceae fam. nov., Methanarcanum, Methanogranum, Methanomethylophilus, Methanomicula, Methanoplasma, Methanoprimaticola, all gen. nova), and the new family Bathycorpusculaceae (Bathycorpusculum gen. nov.). Reclassification of amplicon libraries from this and previous studies using this new taxonomic framework revealed that arthropods harbor only CO2 and methyl-reducing hydrogenotrophic methanogens. Numerous genus-level lineages appear to be present exclusively in arthropods, suggesting long evolutionary trajectories with their termite, cockroach, and millipede hosts, and a radiation into various microhabitats and ecological niches provided by their digestive tracts (e.g., hindgut compartments, gut wall, or anaerobic protists). The distribution patterns among the different host groups are often complex, indicating a mixed mode of transmission and a parallel evolution of invertebrate and vertebrate-associated lineages

    Is a scaling factor required to obtain closure between measured and modelled atmospheric O-4 absorptions? An assessment of uncertainties of measurements and radiative transfer simulations for 2 selected days during the MAD-CAT campaign

    No full text
    © 2019 Author(s). In this study the consistency between MAX-DOAS measurements and radiative transfer simulations of the atmospheric O 4 absorption is investigated on 2 mainly cloud-free days during the MAD-CAT campaign in Mainz, Germany, in summer 2013. In recent years several studies indicated that measurements and radiative transfer simulations of the atmospheric O 4 absorption can only be brought into agreement if a so-called scaling factor (<1) is applied to the measured O 4 absorption. However, many studies, including those based on direct sunlight measurements, came to the opposite conclusion, that there is no need for a scaling factor. Up to now, there is no broad consensus for an explanation of the observed discrepancies between measurements and simulations. Previous studies inferred the need for a scaling factor from the comparison of the aerosol optical depths derived from MAX-DOAS O 4 measurements with that derived from coincident sun photometer measurements. In this study a different approach is chosen: the measured O 4 absorption at 360nm is directly compared to the O 4 absorption obtained from radiative transfer simulations. The atmospheric conditions used as input for the radiative transfer simulations were taken from independent data sets, in particular from sun photometer and ceilometer measurements at the measurement site. This study has three main goals: first all relevant error sources of the spectral analysis, the radiative transfer simulations and the extraction of the input parameters used for the radiative transfer simulations are quantified. One important result obtained from the analysis of synthetic spectra is that the O 4 absorptions derived from the spectral analysis agree within 1% with the corresponding radiative transfer simulations at 360nm. Based on the results from sensitivity studies, recommendations for optimised settings for the spectral analysis and radiative transfer simulations are given. Second, the measured and simulated results are compared for 2 selected cloud-free days with similar aerosol optical depths but very different aerosol properties. On 18 June, measurements and simulations agree within their (rather large) uncertainties (the ratio of simulated and measured O 4 absorptions is found to be 1.01±0.16). In contrast, on 8 July measurements and simulations significantly disagree: for the middle period of that day the ratio of simulated and measured O 4 absorptions is found to be 0.82±0.10, which differs significantly from unity. Thus, for that day a scaling factor is needed to bring measurements and simulations into agreement. Third, recommendations for further intercomparison exercises are derived. One important recommendation for future studies is that aerosol profile data should be measured at the same wavelengths as the MAX-DOAS measurements. Also, the altitude range without profile information close to the ground should be minimised and detailed information on the aerosol optical and/or microphysical properties should be collected and used. The results for both days are inconsistent, and no explanation for a O 4 scaling factor could be derived in this study. Thus, similar but more extended future studies should be performed, including more measurement days and more instruments. Also, additional wavelengths should be included.status: publishe

    Rising atmospheric CO<sub>2</sub> explains 26–52% of the recent delay in autumnal senescence in important forest and crop species

    No full text
    There is strong evidence to suggest that global warming is leading to an extended growing season by altering the timing of autumnal events such as bud set and leaf abscission 1,2,3, with important impacts on ecosystem productivity and global carbon cycling. However, while temperature is an important driver of spring phenological events, the relationship between temperature and autumn phenology is weak4. Here, we present results from three open-air field experiments in which elevated atmospheric CO2 concentration [CO2] at the concentration likely to exist in 2050, extended the growing season of: (1) three abundant North American forest trees; (2) the world’s most extensively grown broad-leaved crop (soybean); and (3) two European poplars. Across experiments and over multiple years, elevated [CO2] delayed autumnal declines in leaf area, chlorophyll concentration, photosynthesis and normalized vegetation difference index (NVDI) by 2-7 days for soybean and 5-15 days for trees. These findings indicate that [CO2] alters growing season length and the rise in atmospheric [CO2] over the past 30 years could explain 26-52% of the extended growing season now ascribed to warming3

    Is a scaling factor required to obtain closure between measured and modelled atmospheric O₄ absorptions? An assessment of uncertainties of measurements and radiative transfer simulations for 2 selected days during the MAD-CAT campaign

    Get PDF
    In this study the consistency between MAX-DOAS measurements and radiative transfer simulations of the atmospheric O4 absorption is investigated on 2 mainly cloud-free days during the MAD-CAT campaign in Mainz, Germany, in summer 2013. In recent years several studies indicated that measurements and radiative transfer simulations of the atmospheric O4 absorption can only be brought into agreement if a so-called scaling factor (<1) is applied to the measured O4 absorption. However, many studies, including those based on direct sunlight measurements, came to the opposite conclusion, that there is no need for a scaling factor. Up to now, there is no broad consensus for an explanation of the observed discrepancies between measurements and simulations. Previous studies inferred the need for a scaling factor from the comparison of the aerosol optical depths derived from MAX-DOAS O4 measurements with that derived from coincident sun photometer measurements. In this study a different approach is chosen: the measured O4 absorption at 360 nm is directly compared to the O4 absorption obtained from radiative transfer simulations. The atmospheric conditions used as input for the radiative transfer simulations were taken from independent data sets, in particular from sun photometer and ceilometer measurements at the measurement site. This study has three main goals: first all relevant error sources of the spectral analysis, the radiative transfer simulations and the extraction of the input parameters used for the radiative transfer simulations are quantified. One important result obtained from the analysis of synthetic spectra is that the O4 absorptions derived from the spectral analysis agree within 1 % with the corresponding radiative transfer simulations at 360 nm. Based on the results from sensitivity studies, recommendations for optimised settings for the spectral analysis and radiative transfer simulations are given. Second, the measured and simulated results are compared for 2 selected cloud-free days with similar aerosol optical depths but very different aerosol properties. On 18 June, measurements and simulations agree within their (rather large) uncertainties (the ratio of simulated and measured O4 absorptions is found to be 1.01±0.16). In contrast, on 8 July measurements and simulations significantly disagree: for the middle period of that day the ratio of simulated and measured O4 absorptions is found to be 0.82±0.10, which differs significantly from unity. Thus, for that day a scaling factor is needed to bring measurements and simulations into agreement. Third, recommendations for further intercomparison exercises are derived. One important recommendation for future studies is that aerosol profile data should be measured at the same wavelengths as the MAX-DOAS measurements. Also, the altitude range without profile information close to the ground should be minimised and detailed information on the aerosol optical and/or microphysical properties should be collected and used. The results for both days are inconsistent, and no explanation for a O4 scaling factor could be derived in this study. Thus, similar but more extended future studies should be performed, including more measurement days and more instruments. Also, additional wavelengths should be included

    Feminist Ecological Economics and Sustainability

    No full text
    feminist economics, ecological economics, sustainable development, unpaid work, economic valuation, caring labor, material throughput, economic growth, gender, equity, social reproduction, local economies, social change, sustaining services, social sustainability, feminism, provisioning, sustainable livelihoods, service sector, quality of life, work time, multi-tasking, discourse-based valuation, community economies, social resilience, B54, D10, D13, D19, D46, D62, D63, D64, E26, F01, J16, Q56, Q57,
    corecore