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Curtis A. Suttle - One of the best experts on this subject based on the ideXlab platform.
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Marine viruses — major players in the Global Ecosystem
Nature Reviews Microbiology, 2007Co-Authors: Curtis A. SuttleAbstract:Viruses can be found in every environment on the Earth, but their importance is perhaps most evident in the oceans, where they are known to be the reservoir of most of the genetic diversity. Viruses kill approximately 20% of the oceanic microbial biomass daily, which has a significant impact on nutrient and energy cycles. This Review highlights areas in which marine virology is advancing quickly or seems to be poised for paradigm-shifting discoveries. Developing the necessary techniques to obtain accurate and reproducible estimates of the distribution and abundance of marine viruses has been a challenge for researchers. Sub-populations of both viruses and host cells can now be discriminated using flow cytometry. Viral abundance generally co-varies with prokaryotic abundance and productivity, but marked differences in this relationship have been reported in different marine environments. Quantifying the effects of viruses on marine prokaryotic and eukaryotic heterotrophic and autotrophic communities is also a challenging area, and remains one of the biggest obstacles to incorporating viral-mediated processes into Global models of nutrient and energy cycling. Our knowledge of the diversity of viruses in marine environments has increased greatly with the development of metagenomic approaches. The interactions between viruses and the organisms they infect ultimately control the genetic diversity of viruses and potentially influence the composition of microbial communities. However, the experimental evidence that supports the hypothesis that viruses regulate microbial diversity in nature is ambiguous. This is perhaps not surprising as the effects of viruses on their host cells depend on transient associations, which might lead us to expect that the influences of viruses on host populations will also be spatially and temporally variable. If stretched end to end, the estimated 10^30viruses in the oceans would span farther than the nearest 60 galaxies. This reservoir of genetic and biological diversity continues to yield exciting discoveries and, in this Review, Curtis A. Suttle highlights the areas that are likely to be of greatest interest in the next few years. Viruses are by far the most abundant 'lifeforms' in the oceans and are the reservoir of most of the genetic diversity in the sea. The estimated 10^30 viruses in the ocean, if stretched end to end, would span farther than the nearest 60 galaxies. Every second, approximately 10^23 viral infections occur in the ocean. These infections are a major source of mortality, and cause disease in a range of organisms, from shrimp to whales. As a result, viruses influence the composition of marine communities and are a major force behind biogeochemical cycles. Each infection has the potential to introduce new genetic information into an organism or progeny virus, thereby driving the evolution of both host and viral assemblages. Probing this vast reservoir of genetic and biological diversity continues to yield exciting discoveries.
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marine viruses major players in the Global Ecosystem
Nature Reviews Microbiology, 2007Co-Authors: Curtis A. SuttleAbstract:If stretched end to end, the estimated 1030 viruses in the oceans would span farther than the nearest 60 galaxies. This reservoir of genetic and biological diversity continues to yield exciting discoveries and, in this Review, Curtis A. Suttle highlights the areas that are likely to be of greatest interest in the next few years.
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Marine viruses — major players in the Global Ecosystem
Nature Reviews Microbiology, 2007Co-Authors: Curtis A. SuttleAbstract:If stretched end to end, the estimated 1030 viruses in the oceans would span farther than the nearest 60 galaxies. This reservoir of genetic and biological diversity continues to yield exciting discoveries and, in this Review, Curtis A. Suttle highlights the areas that are likely to be of greatest interest in the next few years.
Stephen P Good - One of the best experts on this subject based on the ideXlab platform.
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estimating Global Ecosystem isohydry anisohydry using active and passive microwave satellite data
Journal of Geophysical Research, 2017Co-Authors: Kaiyu Guan, Pierre Gentine, Alexandra G. Konings, Frederick C. Meinzer, John S. Kimball, William R. L. Anderegg, Nate G. Mcdowell, Jordi Martinezvilalta, D G Long, Stephen P GoodAbstract:The concept of iso/anisohydry describes the degree to which plants regulate their water status, operating from isohydric with strict regulation to anisohydric with less regulation. Though some species-level measures of iso/anisohydry exist at a few locations, Ecosystem-scale information is still largely unavailable. In this study, we use diurnal observations from active (Ku-Band backscatter from QuikSCAT) and passive (X-band Vegetation Optical Depth [VOD] from AMSR-E) microwave satellite data to estimate Global Ecosystem iso/anisohydry. Here, diurnal observations from both satellites approximate predawn and midday plant canopy water contents, which are used to estimate iso/anisohydry. The two independent estimates from radar backscatter and VOD show reasonable agreement at low and mid-latitudes but diverge at high latitudes. Grasslands, croplands, wetlands, and open shrublands are more anisohydric, whereas evergreen broadleaf and deciduous broadleaf forests are more isohydric. The direct validation with upscaled in-situ species iso/anisohydry estimates indicates that the VOD-based estimates have much better agreement than the backscatter-based estimates. The indirect validation with prior knowledge suggests that both estimates are generally consistent in that vegetation water status of anisohydric Ecosystems more closely tracks environmental fluctuations of water availability and demand than their isohydric counterparts. However, uncertainties still exist in the iso/anisohydry estimate, primarily arising from the remote sensing data and, to a lesser extent, from the methodology. The comprehensive assessment in this study can help us better understand the robustness, limitation, and uncertainties of the satellite-derived iso/anisohydry estimates. The Ecosystem iso/anisohydry has the potential to reveal new insights into spatio-temporal Ecosystem response to droughts.
Kaiyu Guan - One of the best experts on this subject based on the ideXlab platform.
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Estimating Global Ecosystem Isohydry/Anisohydry Using Active and Passive Microwave Satellite Data
Journal of Geophysical Research: Biogeosciences, 2017Co-Authors: Kaiyu Guan, Pierre Gentine, Alexandra G. Konings, Frederick C. Meinzer, John S. Kimball, William R. L. Anderegg, Nate G. Mcdowell, Jordi Martínez-vilaltaAbstract:The concept of iso/anisohydry describes the degree to which plants regulate their water status, operating from isohydric with strict regulation to anisohydric with less regulation. Though some species-level measures of iso/anisohydry exist at a few locations, Ecosystem-scale information is still largely unavailable. In this study, we use diurnal observations from active (Ku-Band backscatter from QuikSCAT) and passive (X-band Vegetation Optical Depth [VOD] from AMSR-E) microwave satellite data to estimate Global Ecosystem iso/anisohydry. Here, diurnal observations from both satellites approximate predawn and midday plant canopy water contents, which are used to estimate iso/anisohydry. The two independent estimates from radar backscatter and VOD show reasonable agreement at low and mid-latitudes but diverge at high latitudes. Grasslands, croplands, wetlands, and open shrublands are more anisohydric, whereas evergreen broadleaf and deciduous broadleaf forests are more isohydric. The direct validation with upscaled in-situ species iso/anisohydry estimates indicates that the VOD-based estimates have much better agreement than the backscatter-based estimates. The indirect validation with prior knowledge suggests that both estimates are generally consistent in that vegetation water status of anisohydric Ecosystems more closely tracks environmental fluctuations of water availability and demand than their isohydric counterparts. However, uncertainties still exist in the iso/anisohydry estimate, primarily arising from the remote sensing data and, to a lesser extent, from the methodology. The comprehensive assessment in this study can help us better understand the robustness, limitation, and uncertainties of the satellite-derived iso/anisohydry estimates. The Ecosystem iso/anisohydry has the potential to reveal new insights into spatio-temporal Ecosystem response to droughts.
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estimating Global Ecosystem isohydry anisohydry using active and passive microwave satellite data
Journal of Geophysical Research, 2017Co-Authors: Kaiyu Guan, Pierre Gentine, Alexandra G. Konings, Frederick C. Meinzer, John S. Kimball, William R. L. Anderegg, Nate G. Mcdowell, Jordi Martinezvilalta, D G Long, Stephen P GoodAbstract:The concept of iso/anisohydry describes the degree to which plants regulate their water status, operating from isohydric with strict regulation to anisohydric with less regulation. Though some species-level measures of iso/anisohydry exist at a few locations, Ecosystem-scale information is still largely unavailable. In this study, we use diurnal observations from active (Ku-Band backscatter from QuikSCAT) and passive (X-band Vegetation Optical Depth [VOD] from AMSR-E) microwave satellite data to estimate Global Ecosystem iso/anisohydry. Here, diurnal observations from both satellites approximate predawn and midday plant canopy water contents, which are used to estimate iso/anisohydry. The two independent estimates from radar backscatter and VOD show reasonable agreement at low and mid-latitudes but diverge at high latitudes. Grasslands, croplands, wetlands, and open shrublands are more anisohydric, whereas evergreen broadleaf and deciduous broadleaf forests are more isohydric. The direct validation with upscaled in-situ species iso/anisohydry estimates indicates that the VOD-based estimates have much better agreement than the backscatter-based estimates. The indirect validation with prior knowledge suggests that both estimates are generally consistent in that vegetation water status of anisohydric Ecosystems more closely tracks environmental fluctuations of water availability and demand than their isohydric counterparts. However, uncertainties still exist in the iso/anisohydry estimate, primarily arising from the remote sensing data and, to a lesser extent, from the methodology. The comprehensive assessment in this study can help us better understand the robustness, limitation, and uncertainties of the satellite-derived iso/anisohydry estimates. The Ecosystem iso/anisohydry has the potential to reveal new insights into spatio-temporal Ecosystem response to droughts.
Christoph Müller - One of the best experts on this subject based on the ideXlab platform.
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Simulating the effect of tillage practices with the Global Ecosystem model LPJmL (version 5.0-tillage)
Geoscientific Model Development, 2019Co-Authors: Femke Lutz, Susanne Rolinski, Tobias Herzfeld, Sibyll Schaphoff, Werner Von Bloh, Jens Heinke, Jetse J. Stoorvogel, Christoph MüllerAbstract:Abstract. The effects of tillage on soil properties, crop productivity, and Global greenhouse gas emissions have been discussed in the last decades. Global Ecosystem models have limited capacity to simulate the various effects of tillage. With respect to the decomposition of soil organic matter, they either assume a constant increase due to tillage or they ignore the effects of tillage. Hence, they do not allow for analysing the effects of tillage and cannot evaluate, for example, reduced tillage or no tillage (referred to here as “no-till”) practises as mitigation practices for climate change. In this paper, we describe the implementation of tillage-related practices in the Global Ecosystem model LPJmL. The extended model is evaluated against reported differences between tillage and no-till management on several soil properties. To this end, simulation results are compared with published meta-analyses on tillage effects. In general, the model is able to reproduce observed tillage effects on Global, as well as regional, patterns of carbon and water fluxes. However, modelled N fluxes deviate from the literature values and need further study. The addition of the tillage module to LPJmL5 opens up opportunities to assess the impact of agricultural soil management practices under different scenarios with implications for agricultural productivity, carbon sequestration, greenhouse gas emissions, and other environmental indicators.
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Options to model the effects of tillage on N2O emissions at the Global scale
Ecological Modelling, 2019Co-Authors: Femke Lutz, Jetse J. Stoorvogel, Christoph MüllerAbstract:Strategies on agricultural management can help to reduce Global greenhouse gas (GHG) emissions. However, the potential of agricultural management to reduce GHG emissions at the Global scale is unclear. Global Ecosystem models often lack sufficient detail in their representation of management, such as tillage. This paper explores whether and how tillage can be incorporated in Global Ecosystem models for the analysis of nitrous oxide (N2O) emissions. We identify the most important nitrogen processes in soils and their response to tillage. We review how these processes and tillage effects are described in field-scale models and evaluate whether they can be incorporated in the Global-scale models while considering the data requirements for a Global application. The most important processes are described in field-scale models and the basic data requirements can be met at the Global scale. We therefore conclude that there is potential to incorporate tillage in Global Ecosystem models for the analysis of N2O emissions. There are several options for how the relevant processes can be incorporated into Global Ecosystem models, so that generally there is potential to study the effects of tillage on N2O emissions Globally. Given the many interactions with other processes, modelers need to identify the modelling approaches that are consistent with their modelling framework and test these.
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Simulating the effect of tillage practices with the Global Ecosystem model LPJmL (version 5.0-tillage)
2018Co-Authors: Femke Lutz, Susanne Rolinski, Tobias Herzfeld, Sibyll Schaphoff, Werner Von Bloh, Jens Heinke, Jetse J. Stoorvogel, Christoph MüllerAbstract:<p><strong>Abstract.</strong> The effects of tillage on soil properties (e.g. soil carbon and nitrogen), crop productivity, and Global greenhouse gas emissions have been discussed in the last decades. Global Ecosystem models are limited in simulating tillage. Hence, they do not allow for analyzing the effects of tillage and cannot evaluate, for example, reduced-tillage or no-till as mitigation practices for climate change. In this paper, we describe the implementation of tillage related practices in the Global Ecosystem model LPJmL. The model is subsequently evaluated against reported differences between tillage and no-till management on several soil properties. To this end, simulation results are compared with published meta-analysis on tillage effects. In general, the model is able to reproduce observed tillage effects on Global, as well as regional patterns of carbon and water fluxes. However, modeled N-fluxes deviate from the literature and need further study. The addition of the tillage module to LPJmL 5.0 opens opportunities to assess the impact of agricultural soil management practices under different scenarios with implications for agricultural productivity, carbon sequestration, greenhouse gas emissions and other environmental indicators.</p>
Pierre Gentine - One of the best experts on this subject based on the ideXlab platform.
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Estimating Global Ecosystem Isohydry/Anisohydry Using Active and Passive Microwave Satellite Data
Journal of Geophysical Research: Biogeosciences, 2017Co-Authors: Kaiyu Guan, Pierre Gentine, Alexandra G. Konings, Frederick C. Meinzer, John S. Kimball, William R. L. Anderegg, Nate G. Mcdowell, Jordi Martínez-vilaltaAbstract:The concept of iso/anisohydry describes the degree to which plants regulate their water status, operating from isohydric with strict regulation to anisohydric with less regulation. Though some species-level measures of iso/anisohydry exist at a few locations, Ecosystem-scale information is still largely unavailable. In this study, we use diurnal observations from active (Ku-Band backscatter from QuikSCAT) and passive (X-band Vegetation Optical Depth [VOD] from AMSR-E) microwave satellite data to estimate Global Ecosystem iso/anisohydry. Here, diurnal observations from both satellites approximate predawn and midday plant canopy water contents, which are used to estimate iso/anisohydry. The two independent estimates from radar backscatter and VOD show reasonable agreement at low and mid-latitudes but diverge at high latitudes. Grasslands, croplands, wetlands, and open shrublands are more anisohydric, whereas evergreen broadleaf and deciduous broadleaf forests are more isohydric. The direct validation with upscaled in-situ species iso/anisohydry estimates indicates that the VOD-based estimates have much better agreement than the backscatter-based estimates. The indirect validation with prior knowledge suggests that both estimates are generally consistent in that vegetation water status of anisohydric Ecosystems more closely tracks environmental fluctuations of water availability and demand than their isohydric counterparts. However, uncertainties still exist in the iso/anisohydry estimate, primarily arising from the remote sensing data and, to a lesser extent, from the methodology. The comprehensive assessment in this study can help us better understand the robustness, limitation, and uncertainties of the satellite-derived iso/anisohydry estimates. The Ecosystem iso/anisohydry has the potential to reveal new insights into spatio-temporal Ecosystem response to droughts.
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estimating Global Ecosystem isohydry anisohydry using active and passive microwave satellite data
Journal of Geophysical Research, 2017Co-Authors: Kaiyu Guan, Pierre Gentine, Alexandra G. Konings, Frederick C. Meinzer, John S. Kimball, William R. L. Anderegg, Nate G. Mcdowell, Jordi Martinezvilalta, D G Long, Stephen P GoodAbstract:The concept of iso/anisohydry describes the degree to which plants regulate their water status, operating from isohydric with strict regulation to anisohydric with less regulation. Though some species-level measures of iso/anisohydry exist at a few locations, Ecosystem-scale information is still largely unavailable. In this study, we use diurnal observations from active (Ku-Band backscatter from QuikSCAT) and passive (X-band Vegetation Optical Depth [VOD] from AMSR-E) microwave satellite data to estimate Global Ecosystem iso/anisohydry. Here, diurnal observations from both satellites approximate predawn and midday plant canopy water contents, which are used to estimate iso/anisohydry. The two independent estimates from radar backscatter and VOD show reasonable agreement at low and mid-latitudes but diverge at high latitudes. Grasslands, croplands, wetlands, and open shrublands are more anisohydric, whereas evergreen broadleaf and deciduous broadleaf forests are more isohydric. The direct validation with upscaled in-situ species iso/anisohydry estimates indicates that the VOD-based estimates have much better agreement than the backscatter-based estimates. The indirect validation with prior knowledge suggests that both estimates are generally consistent in that vegetation water status of anisohydric Ecosystems more closely tracks environmental fluctuations of water availability and demand than their isohydric counterparts. However, uncertainties still exist in the iso/anisohydry estimate, primarily arising from the remote sensing data and, to a lesser extent, from the methodology. The comprehensive assessment in this study can help us better understand the robustness, limitation, and uncertainties of the satellite-derived iso/anisohydry estimates. The Ecosystem iso/anisohydry has the potential to reveal new insights into spatio-temporal Ecosystem response to droughts.