scholarly journals The Choiyoi magmatism in south western Gondwana: implications for the end-permian mass extinction - a review

2017 ◽  
Vol 44 (3) ◽  
pp. 328 ◽  
Author(s):  
Luis A. Spalletti ◽  
Carlos O. Limarino
Keyword(s):  
Carbon Dioxide ◽  
Mass Extinction ◽  
Atmospheric Carbon Dioxide ◽  
Sedimentary Basins ◽  
Fire Frequency ◽  
Large Igneous Province ◽  
Volcanic Emissions ◽  
Gas Generation ◽  
Study Region ◽  
Carbon Dioxide Co2

The end of the Permian period is marked by global warming and the biggest known mass extinction on Earth. The crisis is commonly attributed to the formation of large igneous provinces because continental volcanic emissions have the potential to control atmospheric carbon dioxide (CO2) levels and climate change. We propose that in southwestern Gondwana the long-term hothouse Permian environmental conditions were associated with the development of the Choiyoi magmatism. This large igneous province was developed between the Cisuralian and the early Triassic. It covers an area estimated at 1,680,000 km2 with an average thickness of 700 m, so that the volume of effusive and consanguineous rocks is estimated at 1,260,000 km3. Towards the western sector of the study region, a major overlap exists between the regional development of the Choiyoi magmatism and the Carboniferous sedimentary basins, which include paralic and continental deposits with intercalations of peat and coal beds. Commonly, these upper Palaeozoic deposits accumulated on a thick substrate composed of Cambro-Ordovician carbonates and Ordovician to Devonian terrigenous sedimentary rocks characterised by a large proportion of dark organic-rich shales and turbidite successions. While extensive volcanism released large masses of carbon dioxide into the Permian atmosphere, the heating of Palaeozoic organic-rich shales, peat and carbonates by ascending magma led to CO2 and CH4 gas generation in sufficient volumes to amplify the major climatic change. The analysis of the almost continuous record of Permian redbeds in the Paganzo basin, where the Choiyoi magmatism is not recorded, allowed us to recognize two main pulses of strong environmental desiccation, one at the Cisuralian and the second around the end-Permian. These two drastic climatic crisis are attributed to peaks of CO2 and CH4 outbursts to the atmosphere and related collateral effects, such as acid rain, impoverishment of soils and increase in forest-fire frequency. We propose that the combination of these multiple mechanisms triggered the decline of biodiversity in southwestern Gondwana and caused the end-Permian extinction of most of the Glossopteridales.

scholarly journals Using airborne HIAPER Pole-to-Pole Observations (HIPPO) to evaluate model and remote sensing estimates of atmospheric carbon dioxide

2016 ◽  
Author(s):  
C. Frankenberg ◽  
S. S. Kulawik ◽  
S. Wofsy ◽  
F. Chevallier ◽  
B. Daube ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Atmospheric Carbon Dioxide ◽  
Correlation Coefficients ◽  
Added Value ◽  
Total Carbon ◽  
Accuracy And Precision ◽  
Atmospheric Carbon ◽  
Carbon Dioxide Co2 ◽  
Global Carbon ◽  
Comparable Quality

Abstract. In recent years, space-borne observations of atmospheric carbon-dioxide (CO2) have become increasingly used in global carbon-cycle studies. In order to obtain added value from space-borne measurements, they have to suffice stringent accuracy and precision requirements, with the latter being less crucial as it can be reduced by just enhanced sample size. Validation of CO2 column averaged dry air mole fractions (XCO2) heavily relies on measurements of the Total Carbon Column Observing Network TCCON. Owing to the sparseness of the network and the requirements imposed on space-based measurements, independent additional validation is highly valuable. Here, we use observations from the HIAPER Pole-to-Pole Observations (HIPPO) flights from January 2009 through September 2011 to validate CO2 measurements from satellites (GOSAT, TES, AIRS) and atmospheric inversion models (CarbonTracker CT2013B, MACC v13r1). We find that the atmospheric models capture the XCO2 variability observed in HIPPO flights very well, with correlation coefficients (r2) of 0.93 and 0.95 for CT2013B and MACC, respectively. Some larger discrepancies can be observed in profile comparisons at higher latitudes, esp. at 300 hPa during the peaks of either carbon uptake or release. These deviations can be up to 4 ppm and hint at misrepresentation of vertical transport. Comparisons with the GOSAT satellite are of comparable quality, with an r2 of 0.85, a mean bias μ of −0.06 ppm and a standard deviation σ of 0.45 ppm. TES exhibits an r2 of 0.75, μ of 0.34 ppm and σ of 1.13 ppm. For AIRS, we find an r2 of 0.37, μ of 1.11 ppm and σ of 1.46 ppm, with latitude-dependent biases. For these comparisons at least 6, 20 and 50 atmospheric soundings have been averaged for GOSAT, TES and AIRS, respectively. Overall, we find that GOSAT soundings over the remote pacific ocean mostly meet the stringent accuracy requirements of about 0.5 ppm for space-based CO2 observations.

scholarly journals Reduction of Plant Suitability for Corn Leaf Aphid (Hemiptera: Aphididae) Under Elevated Carbon Dioxide Condition

2019 ◽  
Vol 48 (4) ◽  
pp. 935-944 ◽  
Author(s):  
Yu Chen ◽  
Laurent Serteyn ◽  
Zhenying Wang ◽  
KangLai He ◽  
Frederic Francis
Keyword(s):  
Carbon Dioxide ◽  
Feeding Behavior ◽  
Atmospheric Carbon Dioxide ◽  
Global Climate ◽  
Nutrient Content ◽  
Electrical Penetration Graph ◽  
Hordeum Vulgare L ◽  
Feeding Site ◽  
Corn Leaf Aphid ◽  
Carbon Dioxide Co2

Abstract In the current context of global climate change, atmospheric carbon dioxide (CO2) concentrations are continuously rising with potential influence on plant–herbivore interactions. The effect of elevated CO2 (eCO2) on feeding behavior of corn leaf aphid, Rhopalosiphum maidis (Fitch) on barley seedlings Hordeum vulgare L. was tracked using electrical penetration graph (EPG). The nutrient content of host plant and the developmental indexes of aphids under eCO2 and ambient CO2 (aCO2) conditions were also investigated. Barley seedlings under eCO2 concentration had lower contents of crude protein and amino acids. EPG analysis showed the plants cultivated under eCO2 influenced the aphid feeding behavior, by prolonging the total pre-probation time of the aphids (wandering and locating the feeding site) and the ingestion of passive phloem sap. Moreover, fresh body weight, fecundity and intrinsic population growth rate of R. maidis was significantly decreased in eCO2 in contrast to aCO2 condition. Our findings suggested that changes in plant nutrition caused by eCO2, mediated via the herbivore host could affect insect feeding behavior and population dynamics.

scholarly journals Development and field testing of a rapid and ultra-stable atmospheric carbon dioxide spectrometer

2014 ◽  
Vol 7 (8) ◽  
pp. 8101-8123
Author(s):  
B. Xiang ◽  
D. D. Nelson ◽  
J. B. McManus ◽  
M. S. Zahniser ◽  
R. Wehr ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Field Test ◽  
Atmospheric Carbon Dioxide ◽  
Field Measurements ◽  
Field Testing ◽  
Thermal Control ◽  
Long Term Ecological Research ◽  
Calibration Protocol ◽  
Atmospheric Carbon ◽  
Carbon Dioxide Co2

Abstract. We present field test results for a new spectroscopic instrument to measure atmospheric carbon dioxide (CO2) with high precision (0.02 ppm at 1 Hz) and demonstrate high stability (within 0.1 ppm over more than 8 months), without the need for hourly, daily, or even monthly calibration against high-pressure gas cylinders. The technical novelty of this instrument (ABsolute Carbon dioxide, ABC) is the spectral null method using an internal quartz reference cell with known CO2 column density. Compared to a previously described prototype, the field instrument has better stability and benefits from more precise thermal control of the optics and more accurate pressure measurements in the sample cell (at the mTorr level). The instrument has been deployed at a long-term ecological research site (the Harvard Forest, USA), where it has measured for eight months without on-site calibration and with minimal maintenance, showing drift bounds of less than 0.1 ppm. Field measurements agree well with those of another commercially available cavity ring-down CO2 instrument (Picarro G2301) run with a standard calibration protocol. This field test demonstrates that ABC is capable of performing high-accuracy, unattended, continuous field measurements with minimal use of calibration cylinders.

Australian grains free-air carbon dioxide enrichment (AGFACE) facility: design and performance

2009 ◽  
Vol 60 (8) ◽  
pp. 697 ◽  
Author(s):  
Mahabubur Mollah ◽  
Rob Norton ◽  
Jeff Huzzey
Keyword(s):  
Carbon Dioxide ◽  
Atmospheric Carbon Dioxide ◽  
Operating Time ◽  
Carbon Dioxide Concentration ◽  
Growth Yield ◽  
Triticum Aestivum L ◽  
Interactive Effects ◽  
Temporal And Spatial Distribution ◽  
And Performance ◽  
Carbon Dioxide Co2

The AGFACE project commenced in June 2007 at Horsham (36°45′07″S, 142°06′52″E; 127 m elevation), Victoria, Australia. Its aim is to quantify the interactive effects of elevated atmospheric carbon dioxide concentration (e[CO2]), nitrogen, temperature (accomplished by early and late sowing times), and soil moisture on the growth, yield, and water use of wheat (Triticum aestivum L.) under Australian conditions. The main engineering goal of the project was to maintain an even temporal and spatial distribution of carbon dioxide (CO2) at 550 μmol/mol within AGFACE rings containing the experimental treatments. Monitoring showed that e[CO2] at the ring-centres was maintained at or above 90% of the target (495 μmol/mol) between 93 and 98% of the operating time across the 8 rings and within ±10% of the target (495–605 μmol/mol) between 86 and 94% of the time. The carbon dioxide concentration ([CO2]) measured inside the rings declined non-linearly with increasing distance downwind of the CO2 source and differed by 3–13% in concentration between the two canopy heights in each ring, but was not affected by wind speed or small variations in [CO2] at the ring-centres. The median values for model-predicted concentrations within the inner 11-m-diameter portion of the rings (>80% of the ring area) varied between 524 and 871 μmol/mol but remained close to target near the centres. The design criteria adopted from existing pure CO2 fumigating FACE systems and new ideas incorporated in the AGFACE system provided a performance similar to its equivalent systems. This provides confidence in the results that will be generated from experiments using the AGFACE system.

scholarly journals Assessment of recent advances in measurement techniques for atmospheric carbon dioxide and methane observations

2016 ◽  
Vol 9 (9) ◽  
pp. 4737-4757 ◽  
Author(s):  
Christoph Zellweger ◽  
Lukas Emmenegger ◽  
Mohd Firdaus ◽  
Juha Hatakka ◽  
Martin Heimann ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Atmospheric Carbon Dioxide ◽  
Measurement Techniques ◽  
Spectroscopic Techniques ◽  
Cavity Output ◽  
The World ◽  
Atmospheric Carbon ◽  
Carbon Dioxide Co2 ◽  
Improved Accuracy ◽  
Flame Ionisation

Abstract. Until recently, atmospheric carbon dioxide (CO2) and methane (CH4) measurements were made almost exclusively using nondispersive infrared (NDIR) absorption and gas chromatography with flame ionisation detection (GC/FID) techniques, respectively. Recently, commercially available instruments based on spectroscopic techniques such as cavity ring-down spectroscopy (CRDS), off-axis integrated cavity output spectroscopy (OA-ICOS) and Fourier transform infrared (FTIR) spectroscopy have become more widely available and affordable. This resulted in a widespread use of these techniques at many measurement stations. This paper is focused on the comparison between a CRDS "travelling instrument" that has been used during performance audits within the Global Atmosphere Watch (GAW) programme of the World Meteorological Organization (WMO) with instruments incorporating other, more traditional techniques for measuring CO2 and CH4 (NDIR and GC/FID). We demonstrate that CRDS instruments and likely other spectroscopic techniques are suitable for WMO/GAW stations and allow a smooth continuation of historic CO2 and CH4 time series. Moreover, the analysis of the audit results indicates that the spectroscopic techniques have a number of advantages over the traditional methods which will lead to the improved accuracy of atmospheric CO2 and CH4 measurements.

scholarly journals The importance of freshwater systems to the net exchange of atmospheric carbon dioxide and methane with rapidly changing high Arctic landscapes

2016 ◽  
Author(s):  
Craig A. Emmerton ◽  
Vincent L. St. Louis ◽  
Igor Lehnherr ◽  
Jennifer A. Graydon ◽  
Jane L. Kirk ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Atmospheric Carbon Dioxide ◽  
High Arctic ◽  
Atmospheric Co2 ◽  
Arctic Ecosystems ◽  
Freshwater Systems ◽  
Atmospheric Exchange ◽  
Net Uptake ◽  
Carbon Dioxide Co2 ◽  
Few Data

Abstract. A warming climate is rapidly changing the distribution and exchanges of carbon within high Arctic ecosystems. Few data exist, however, which quantify exchange of both carbon dioxide (CO2) and methane (CH4) between the atmosphere and freshwater systems, or estimate freshwater contributions to total catchment exchange of these gases, in the high Arctic. During the summers of 2005 and 2007–2012, we quantified CO2 and CH4 concentrations in, and atmospheric exchange with, common freshwater systems in the high Arctic watershed of Lake Hazen, Nunavut, Canada. We identified four types of biogeochemically-distinct freshwater systems in the watershed, however mean CO2 concentrations (21–28 μmol L−1) and atmospheric exchange (−0.013–0.046 g C-CO2 m−2 d−1) were similar between these systems. Seasonal flooding of ponds bordering Lake Hazen generated considerable CH4 emissions to the atmosphere (0.008 g C-CH4 m−2 d−1), while all other freshwater systems were minimal emitters of this gas (< 0.001 g C-CH4 m−2 d−1). Measurements made on terrestrial landscapes in the same watershed between 2008–2012 determined that the near-barren polar semidesert was a very weak consumer of atmospheric CO2 (−0.004 g C-CO2 m−2 d−1), but an important consumer of atmospheric CH4 (−0.001 g C-CH4 m−2 d−1). Alternatively, meadow wetlands were very productive consumers of atmospheric CO2 (−0.96 g C-CO2 m−2 d−1) but relatively weak emitters of CH4 to the atmosphere (0.001 g C-CH4m−2 d−1). When using ecosystem-cover classification mapping, we found that freshwaters were unimportant contributors to total watershed carbon exchange, in part because they covered less than 10 % of total cover in the watershed. High Arctic watersheds are experiencing warmer and wetter climates than in the past, which may have implications for the net uptake of carbon greenhouse gases by currently underproductive polar semidesert and freshwater systems.

scholarly journals IRIS analyser assessment reveals sub-hourly variability of isotope ratios in carbon dioxide at Baring Head, New Zealand's atmospheric observatory in the Southern Ocean

2021 ◽  
Author(s):  
Peter Sperlich ◽  
Gordon W. Brailsford ◽  
Rowena C. Moss ◽  
John McGregor ◽  
Ross J. Martin ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Southern Ocean ◽  
Atmospheric Carbon Dioxide ◽  
Isotope Ratios ◽  
Limiting Factor ◽  
Analytical Technique ◽  
Plot Analysis ◽  
Keeling Plot ◽  
Carbon Dioxide Co2 ◽  
End Members

Abstract. We assess the performance of an Isotope Ratio Infrared Spectrometer (IRIS) to measure carbon (δ13C) and oxygen (δ18O) isotope ratios in atmospheric carbon dioxide (CO2) and report observations from a 26 day field deployment trial at Baring Head, New Zealand, NIWA's atmospheric observatory for Southern Ocean baseline air. Our study describes an operational method to improve the performance in comparison to previous publications on this analytical technique. By using a calibration technique that reflected the principle of identical treatment of sample and reference gases, we achieved a reproducibility of 0.07 ‰ for δ13C-CO2 and 0.06 ‰ for δ18O-CO2 over multiple days. This performance is within the "extended compatibility goal" of 0.1 ‰ for both δ13C-CO2 and δ18O-CO2, which was recommended by the World Meteorological Organisation (WMO) for studies of regional or urban CO2 fluxes. One goal of this study was to assess the capabilities and limitations of the IRIS analyser to resolve δ13C-CO2 and δ18O-CO2 variations under field conditions. Therefore, we selected multiple events within the 26 day record for Keeling Plot Analysis. This resolved the isotopic composition of end members with an uncertainty of ≤ 1 ‰ when the magnitude of CO2 signals is larger than 10 ppm. The uncertainty of the Keeling Plot Analysis strongly increased for smaller CO2 events (2–7 ppm), where the instrument performance is the limiting factor and may only allow for the distinction between very different end members, such as the role of terrestrial versus oceanic carbon cycle processes. Further improvement in measurement performance is desirable to meet the WMO "network compatibility goal" of 0.01 ‰ for δ13C-CO2 and 0.05 ‰ for δ18O-CO2, which is needed to resolve the small variability that is typical for background air observatories such as Baring Head.

scholarly journals Preservation of terrestrial organic carbon in marine sediments off shore Taiwan: mountain building and atmospheric carbon dioxide sequestration

2013 ◽  
Vol 1 (1) ◽  
pp. 177-206
Author(s):  
S.-J. Kao ◽  
R. G. Hilton ◽  
K. Selvaraj ◽  
M. Dai ◽  
F. Zehetner ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Organic Carbon ◽  
Marine Sediments ◽  
Atmospheric Carbon Dioxide ◽  
Climatic Variability ◽  
Deep Ocean ◽  
Sediment Traps ◽  
Terrestrial Biosphere ◽  
Atmospheric Carbon ◽  
Carbon Dioxide Co2

Abstract. Geological sequestration of atmospheric carbon dioxide (CO2) can be achieved by the erosion of organic carbon (OC) from the terrestrial biosphere and its burial in long-lived marine sediments. Rivers on mountain islands of Oceania in the western Pacific have very high rates of OC export to the ocean, yet its preservation offshore remains poorly constrained. Here we use the OC content (Corg, %), radiocarbon (Δ14Corg) and stable isotope (δ13Corg) composition of sediments offshore Taiwan to assess the fate of terrestrial OC. We account for rock-derived fossil OC to assess the preservation of OC eroded from the terrestrial biosphere (non-fossil OC) during flood discharges (hyperpycnal river plumes) and when river inputs are dispersed more widely (hypopycnal). The Corg, Δ14Corg and δ13Corg of marine sediment traps and cores indicate that during flood discharges, terrestrial OC is transferred efficiently to the deep ocean and accumulates offshore with little evidence for terrestrial OC loss. In marine sediments fed by dispersive river inputs, the Corg, Δ14Corg and δ13Corg are consistent with mixing of marine OC and terrestrial OC and suggest that efficient preservation of terrestrial OC (> 70%) is also associated with hypopycnal delivery. Re-burial of fossil OC is pervasive. Our findings from Taiwan suggest that erosion and marine burial of terrestrial non-fossil OC may sequester > 8 TgC yr−1 across Oceania, a significant geological CO2 sink which requires better constraint. We postulate that mountain islands of Oceania provide strong link between tectonic uplift and the carbon cycle, one moderated by the climatic variability that controls terrestrial OC delivery to the ocean.

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