scholarly journals An approach to the investigation of CO<sub>2</sub> uptake by soil microorganisms

2011 ◽  
Vol 8 (5) ◽  
pp. 9235-9281 ◽  
Author(s):  
K. M. Hart ◽  
B. W. Moran ◽  
C. C. R. Allen ◽  
V. Kouloumbos ◽  
S. F. Oppenheimer ◽  
...  
Keyword(s):  
Soil Microorganisms ◽  
Atmospheric Co2 ◽  
Co2 Uptake ◽  
Soil Algae ◽  
Soil Slurry ◽  
Soil Microbial ◽  
Atmospheric Co2 Concentrations ◽  
Short Incubation Time

Abstract. Sequestration of CO2 via biological sinks is a matter of great scientific importance due to their potential to lower atmospheric CO2 levels. In this study a custom built incubation chamber was used to cultivate a soil microbial community, under ideal conditions, to investigate soil chemoautotrophy. The internal atmospheric CO2 concentrations were monitored and used to estimate the mass of CO2 uptake. It was found after careful background corrections that 256.4 μg CO2 kg−1 dry soil was removed from the chamber atmosphere over 16 h. Comparisons were made to photosynthetic controls (i.e. grass and soil algae) whereupon it was observed that the chemoautotrophic fraction sequestered 2.6 and 5.4 % of that taken up by grass and soil algae respectively. Using isotopically labelled 13CO2 and GCMS-IRMS it was also possible to extract and identify labelled fatty acids after a short incubation time, hence confirming the CO2 uptake potential of the soil slurry. Provided with favourable conditions, chemoautotrophic soil bacteria have the potential to make a significant impact on inorganic carbon sequestration within the environment. The results of this in vivo study have provided ground work for future studies intending to mimic the in situ environment by providing a reliable method for investigating CO2 uptake by soil microorganisms.

scholarly journals Can seasonal and interannual variation in landscape CO<sub>2</sub> fluxes be detected by atmospheric observations of CO<sub>2</sub> concentrations made at a tall tower?

2014 ◽  
Vol 11 (3) ◽  
pp. 735-747 ◽  
Author(s):  
T. L. Smallman ◽  
M. Williams ◽  
J. B. Moncrieff
Keyword(s):  
Interannual Variation ◽  
Atmospheric Transport ◽  
Co2 Exchange ◽  
Atmospheric Co2 ◽  
Co2 Uptake ◽  
Post Harvest ◽  
Co2 Concentrations ◽  
Prevailing Wind Direction ◽  
Atmospheric Co2 Concentrations ◽  
Tall Tower

Abstract. The coupled numerical weather model WRF-SPA (Weather Research and Forecasting model and Soil-Plant-Atmosphere model) has been used to investigate a 3 yr time series of observed atmospheric CO2 concentrations from a tall tower in Scotland, UK. Ecosystem-specific tracers of net CO2 uptake and net CO2 release were used to investigate the contributions to the tower signal of key land covers within its footprint, and how contributions varied at seasonal and interannual timescales. In addition, WRF-SPA simulated atmospheric CO2 concentrations were compared with two coarse global inversion models, CarbonTrackerEurope and the National Oceanic and Atmospheric Administration's CarbonTracker (CTE-CT). WRF-SPA realistically modelled both seasonal (except post harvest) and daily cycles seen in observed atmospheric CO2 at the tall tower (R2 = 0.67, rmse = 3.5 ppm, bias = 0.58 ppm). Atmospheric CO2 concentrations from the tall tower were well simulated by CTE-CT, but the inverse model showed a poorer representation of diurnal variation and simulated a larger bias from observations (up to 1.9 ppm) at seasonal timescales, compared to the forward modelling of WRF-SPA. However, we have highlighted a consistent post-harvest increase in the seasonal bias between WRF-SPA and observations. Ecosystem-specific tracers of CO2 exchange indicate that the increased bias is potentially due to the representation of agricultural processes within SPA and/or biases in land cover maps. The ecosystem-specific tracers also indicate that the majority of seasonal variation in CO2 uptake for Scotland's dominant ecosystems (forests, cropland and managed grassland) is detectable in observations within the footprint of the tall tower; however, the amount of variation explained varies between years. The between years variation in detectability of Scotland's ecosystems is potentially due to seasonal and interannual variation in the simulated prevailing wind direction. This result highlights the importance of accurately representing atmospheric transport used within atmospheric inversion models used to estimate terrestrial source/sink distribution and magnitude.

Sources and Sinks of Atmospheric CO2

1992 ◽  
Vol 40 (5) ◽  
pp. 407 ◽  
Author(s):  
JA Taylor ◽  
J Lloyd
Keyword(s):  
Climate Change ◽  
Biomass Burning ◽  
Transport Model ◽  
Atmospheric Co2 ◽  
Tropical Rainforests ◽  
Co2 Uptake ◽  
Tracer Transport ◽  
Intergovernmental Panel ◽  
Co2 Concentrations ◽  
Atmospheric Co2 Concentrations

The biosphere plays an important role in determining the sources, sinks, levels and rates of change of atmospheric CO2 concentrations. Significant uncertainties remain in estimates of the fluxes of CO2 from biomass burning and deforestation, and uptake and storage of CO2 by the biosphere arising from increased atmospheric CO2 concentrations. Calculation of probable rates of carbon sequestration for the major ecosystem complexes and global 3-D tracer transport model runs indicate the possibility that a significant net CO2 uptake (> 1 Pg C yr-1), a CO2 'fertilisation effect', may be occurring in tropical rainforests, effectively accounting for much of the 'missing sink'. This sink may currently balance much of the CO2 added to the atmosphere from deforestation and biomass burning. Interestingly, CO2 released from biomass burning may itself be playing an important role in enhanced carbon storage by tropical rainforests. This has important implications for predicting future CO2 concentrations. If tropical rainforest destruction continues then much of the CO2 stored as a result of the CO2 'fertilisation effect' will be rereleased to the atmosphere and much of the 'missing sink' will disappear. These effects have not been considered in the IPCC (Intergovernmental Panel on Climate Change) projections of future atmospheric CO2 concentrations. Predictions which take account of the combined effects of deforestation, the return of carbon previously stored through the CO2 'fertilisation effect' and the loss of a large proportion of the 'missing sink' as a result of deforestation, would result in much higher predicted concentrations and rates of increase of atmospheric CO2 and, as a consequence, accelerated rates of climate change.

scholarly journals Regional Impacts of Climate Change and Atmospheric CO2 on Future Ocean Carbon Uptake: A Multimodel Linear Feedback Analysis

2011 ◽  
Vol 24 (9) ◽  
pp. 2300-2318 ◽  
Author(s):  
Tilla Roy ◽  
Laurent Bopp ◽  
Marion Gehlen ◽  
Birgit Schneider ◽  
Patricia Cadule ◽  
...  
Keyword(s):  
Climate Change ◽  
North Atlantic Ocean ◽  
Climate Change Impacts ◽  
Atmospheric Co2 ◽  
Linear Feedback ◽  
Co2 Uptake ◽  
Co2 Solubility ◽  
Feedback Analysis ◽  
Anthropogenic Co2 ◽  
Atmospheric Co2 Concentrations

Abstract The increase in atmospheric CO2 over this century depends on the evolution of the oceanic air–sea CO2 uptake, which will be driven by the combined response to rising atmospheric CO2 itself and climate change. Here, the future oceanic CO2 uptake is simulated using an ensemble of coupled climate–carbon cycle models. The models are driven by CO2 emissions from historical data and the Special Report on Emissions Scenarios (SRES) A2 high-emission scenario. A linear feedback analysis successfully separates the regional future (2010–2100) oceanic CO2 uptake into a CO2-induced component, due to rising atmospheric CO2 concentrations, and a climate-induced component, due to global warming. The models capture the observation-based magnitude and distribution of anthropogenic CO2 uptake. The distributions of the climate-induced component are broadly consistent between the models, with reduced CO2 uptake in the subpolar Southern Ocean and the equatorial regions, owing to decreased CO2 solubility; and reduced CO2 uptake in the midlatitudes, owing to decreased CO2 solubility and increased vertical stratification. The magnitude of the climate-induced component is sensitive to local warming in the southern extratropics, to large freshwater fluxes in the extratropical North Atlantic Ocean, and to small changes in the CO2 solubility in the equatorial regions. In key anthropogenic CO2 uptake regions, the climate-induced component offsets the CO2-induced component at a constant proportion up until the end of this century. This amounts to approximately 50% in the northern extratropics and 25% in the southern extratropics and equatorial regions. Consequently, the detection of climate change impacts on anthropogenic CO2 uptake may be difficult without monitoring additional tracers, such as oxygen.

scholarly journals The ocean carbon sink – impacts, vulnerabilities, and challenges

2014 ◽  
Vol 5 (2) ◽  
pp. 1607-1672
Author(s):  
C. Heinze ◽  
S. Meyer ◽  
N. Goris ◽  
L. Anderson ◽  
R. Steinfeldt ◽  
...  
Keyword(s):  
Carbon Sink ◽  
Mitigation Strategies ◽  
Atmospheric Co2 ◽  
Co2 Uptake ◽  
Spatial And Temporal Scales ◽  
The Past ◽  
Research Fields ◽  
Co2 Concentrations ◽  
Ocean Carbon ◽  
Atmospheric Co2 Concentrations

Abstract. Carbon dioxide (CO2) is, next to water vapour, considered to be the most important natural greenhouse gas on Earth. Rapidly rising atmospheric CO2 concentrations caused by human actions such as fossil-fuel burning, land-use change or cement production over the past 250 years have given cause for concern that changes in Earth's climate system may progress at a much faster pace and larger extent than during the past 20 000 years. Investigating global carbon cycle pathways and finding suitable mitigation strategies has, therefore, become of major concern in many research fields. The oceans have a key role in regulating atmospheric CO2 concentrations and currently take up about 25% of annual anthropogenic carbon emissions to the atmosphere. Questions that yet need to be answered are what the carbon uptake kinetics of the oceans will be in the future and how the increase in oceanic carbon load will affect its ecosystems and their services. This requires comprehensive investigations, including high-quality ocean carbon measurements on different spatial and temporal scales, the management of data in sophisticated data bases, the application of state-of-the-art Earth system models to provide future projections for given emission scenarios as well as a global synthesis and outreach to policy makers. In this paper, the current understanding of the ocean as an important carbon sink is reviewed with respect to these topics. Emphasis is placed on the complex interplay of different physical, chemical, and biological processes that yield both positive and negative air–sea flux values for natural and anthropogenic CO2 as well as on increased CO2 (uptake) as the regulating force of the radiative warming of the atmosphere and the gradual acidification of the oceans. Major future ocean carbon challenges in the fields of ocean observations, modelling, and process research as well as the relevance of other biogeochemical cycles and greenhouse gases are discussed.

scholarly journals Evaluation of atmosphere-biosphere exchange estimations with TCCON measurements

2012 ◽  
Vol 12 (5) ◽  
pp. 12759-12800 ◽  
Author(s):  
J. Messerschmidt ◽  
N. Parazoo ◽  
N. M. Deutscher ◽  
C. Roehl ◽  
T. Warneke ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Large Scale ◽  
Growing Season ◽  
Atmospheric Co2 ◽  
Total Carbon ◽  
Co2 Uptake ◽  
Co2 Concentrations ◽  
Time Period ◽  
Atmospheric Co2 Concentrations ◽  
Biosphere Model

Abstract. Three estimates of the atmosphere-biosphere exchange are evaluated using Total Carbon Column Observing Network (TCCON) measurements. We investigate the Carnegie-Ames-Stanford Approach (CASA), the Simple Biosphere (SiB) and the GBiome-BGC models transported by the GEOS-Chem model to simulate atmospheric CO2 concentrations for the time period between 2006 and 2010. The CO2 simulations are highly dependent on the choice of the atmosphere-biosphere model and large-scale errors in the estimates are identified through a comparison with TCCON data. Enhancing the CO2 uptake in the boreal forest by 40% and shifting the onset of the growing season significantly improve the simulated seasonal CO2 cycle using CASA estimates. The SiB model gives the best estimate for the atmosphere-biosphere exchange in the comparison with TCCON measurements.

scholarly journals The mechanisms of North Atlantic CO<sub>2</sub> uptake in a large Earth System Model ensemble

2014 ◽  
Vol 11 (10) ◽  
pp. 14551-14585 ◽  
Author(s):  
P. R. Halloran ◽  
B. B. B. Booth ◽  
C. D. Jones ◽  
F. H. Lambert ◽  
D. J. McNeall ◽  
...  
Keyword(s):  
North Atlantic ◽  
Earth System Model ◽  
Atmospheric Co2 ◽  
System Model ◽  
Sink Strength ◽  
Co2 Uptake ◽  
Earth System ◽  
Co2 Sink ◽  
Atmospheric Co2 Concentrations

Abstract. The oceans currently take up around a quarter of the carbon dioxide (CO2) emitted by human activity. While stored in the ocean, this CO2 is not influencing Earth's radiation budget; the ocean CO2 sink therefore plays an important role in mitigating global warming. CO2 uptake by the oceans is heterogeneous, with the subpolar North Atlantic being the strongest CO2 sink region. Observations over the last two decades have indicated that CO2 uptake by the subpolar North Atlantic sink can vary rapidly. Given the importance of this sink and its apparent variability, it is critical that we understand the mechanisms behind its operation. Here we explore subpolar North Atlantic CO2 uptake across a large ensemble of Earth System Model simulations, and find that models show a peak in sink strength around the middle of the century after which CO2 uptake begins to decline. We identify different drivers of change on interannual and multidecadal timescales. Short-term variability appears to be driven by fluctuations in regional seawater temperature and alkalinity, whereas the longer-term evolution throughout the coming century is largely occurring through a counterintuitive response to rising atmospheric CO2 concentrations. At high atmospheric CO2 concentrations the contrasting Ravelle factors between the subtropical and subpolar gyres, combined with the transport of surface waters from the subtropical to subpolar gyre, means that the subpolar CO2 uptake capacity is largely satisfied from its southern boundary rather than through air–sea CO2 flux. Our findings indicate that: (i) we can explain the mechanisms of subpolar North Atlantic CO2 uptake variability across a broad range of Earth System Models, (ii) a focus on understanding the mechanisms behind contemporary variability may not directly tell us about how the sink will change in the future, (iii) to identify long-term change in the North Atlantic CO2 sink we should focus observational resources on monitoring subtropical as well as the subpolar seawater CO2, (iv) recent observations of a weakening subpolar North Atlantic CO2 sink suggests that the sink strength is already in long-term decline.

scholarly journals Can seasonal and interannual variation in landscape CO<sub>2</sub> fluxes be detected by atmospheric observations of CO<sub>2</sub> concentrations made at a tall tower?

2013 ◽  
Vol 10 (8) ◽  
pp. 14301-14331
Author(s):  
T. L. Smallman ◽  
M. Williams ◽  
J. B. Moncrieff
Keyword(s):  
Interannual Variation ◽  
Co2 Exchange ◽  
Atmospheric Co2 ◽  
Co2 Uptake ◽  
Post Harvest ◽  
Terrestrial Ecosystem Model ◽  
Co2 Concentrations ◽  
Atmospheric Co2 Concentrations ◽  
Source Sink ◽  
Tall Tower

Abstract. The Weather Research and Forecasting (WRF) meteorological model has been coupled to the Soil Plant Atmosphere (SPA) terrestrial ecosystem model, hereafter known as WRF-SPA. SPA generates realistic land-atmosphere exchanges through fully coupled hydrological, carbon and energy cycles. Here we have used WRF-SPA to investigate regional scale observations of atmospheric CO2 concentrations made over a multi-annual period from a tall tower in Scotland. WRF-SPA realistically models both seasonal and daily cycles, predicting CO2 at the tall tower (R2 = 0.67, RMSE = 3.5 ppm, bias = 0.58 ppm), indicating realistic transport, and appropriate source sink distribution and magnitude of CO2 exchange. We have highlighted a consistent post harvest increase in model-observation residuals in atmospheric CO2 concentrations. This increase in model-observation residuals post harvest is likely related to a lack of an appropriate representation of uncultivated components (~ 36% of agricultural holding in Scotland) of agricultural land (e.g., hedgerows and forest patches) which continue to photosynthesise after the crop has been harvested. Through the use of ecosystem specific CO2 tracers we have shown that tall tower observations here do not detect a representative fraction of Scotland's ecosystem CO2 uptake. Cropland CO2 uptake is the dominant ecosystem signal detected at the tall tower, consistent with the dominance of cropland in the area surrounding the tower. However cropland is over-represented in the atmospheric CO2 concentrations simulated to be at the tall tower, relative to the simulated surface cropland CO2 uptake. Observations made at the tall tower were able to detect seasonal variation in ecosystem CO2 uptake, however a majority of variation was only detected for croplands. We have found evidence that interannual variation in weather has a greater impact than interannual variation of the simulated land surface CO2 exchange on tall tower observations for the simulated years. This highlights the importance of accurately representing atmospheric transport used within atmospheric inversion models used to estimate terrestrial source/sink distribution and magnitude.

scholarly journals The ocean carbon sink – impacts, vulnerabilities and challenges

2015 ◽  
Vol 6 (1) ◽  
pp. 327-358 ◽  
Author(s):  
C. Heinze ◽  
S. Meyer ◽  
N. Goris ◽  
L. Anderson ◽  
R. Steinfeldt ◽  
...  
Keyword(s):  
Carbon Sink ◽  
Mitigation Strategies ◽  
Atmospheric Co2 ◽  
Co2 Uptake ◽  
Spatial And Temporal Scales ◽  
The Past ◽  
Research Fields ◽  
Co2 Concentrations ◽  
Ocean Carbon ◽  
Atmospheric Co2 Concentrations

Abstract. Carbon dioxide (CO2) is, next to water vapour, considered to be the most important natural greenhouse gas on Earth. Rapidly rising atmospheric CO2 concentrations caused by human actions such as fossil fuel burning, land-use change or cement production over the past 250 years have given cause for concern that changes in Earth's climate system may progress at a much faster pace and larger extent than during the past 20 000 years. Investigating global carbon cycle pathways and finding suitable adaptation and mitigation strategies has, therefore, become of major concern in many research fields. The oceans have a key role in regulating atmospheric CO2 concentrations and currently take up about 25% of annual anthropogenic carbon emissions to the atmosphere. Questions that yet need to be answered are what the carbon uptake kinetics of the oceans will be in the future and how the increase in oceanic carbon inventory will affect its ecosystems and their services. This requires comprehensive investigations, including high-quality ocean carbon measurements on different spatial and temporal scales, the management of data in sophisticated databases, the application of Earth system models to provide future projections for given emission scenarios as well as a global synthesis and outreach to policy makers. In this paper, the current understanding of the ocean as an important carbon sink is reviewed with respect to these topics. Emphasis is placed on the complex interplay of different physical, chemical and biological processes that yield both positive and negative air–sea flux values for natural and anthropogenic CO2 as well as on increased CO2 (uptake) as the regulating force of the radiative warming of the atmosphere and the gradual acidification of the oceans. Major future ocean carbon challenges in the fields of ocean observations, modelling and process research as well as the relevance of other biogeochemical cycles and greenhouse gases are discussed.

Suivi atmosphérique des émissions de CO2 de la région parisienne

2021 ◽  
pp. 030
Author(s):  
Philippe Ciais ◽  
Michel Ramonet ◽  
Thomas Lauvaux ◽  
François-Marie Bréon ◽  
Jinghui Lian ◽  
...  
Keyword(s):  
Atmospheric Co2 ◽  
Atmospheric Measurements ◽  
Strong Reduction ◽  
Research Directions ◽  
Reduction Of Emissions ◽  
Atmospheric Co2 Concentrations ◽  
The City ◽  
Meteorological Models ◽  
Atmospheric Inversion

Les avancées scientifiques permettent un suivi des émissions des villes à partir de mesures des concentrations atmosphériques de CO2 sur un réseau de stations et de méthodes d'inversion fondées sur des modèles de météorologie et de transport atmosphérique à méso-échelle. Nous prenons pour exemple l'agglomération de Paris. Les mesures atmosphériques collectées par un réseau de stations urbaines et périurbaines sont présentées, ainsi que les résultats d'une inversion des émissions et les directions de recherche pour affiner ces estimations. Enfin, la signature du premier confinement lié à la Covid-19 pendant le printemps 2020 sur les mesures atmosphériques de CO2 est présentée et suggère une forte réduction des émissions. Scientific advances enable the monitoring of urban CO2 emissions from in situ measurements of atmospheric CO2 concentrations and atmospheric inversion methods based on mesoscale meteorological models. We use the Paris urban area as an example. Atmospheric measurements collected at a network of urban and suburban stations are presented, as well as the results of an atmospheric inversion of the city emissions, and research directions to refine these estimates. The signature of the Covid-19 lockdown measures in the spring 2020 on the urban atmospheric CO2 signals is presented, indicative of a strong reduction of emissions.

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

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