Use of shallow samples to estimate the total carbon storage in pastoral soils

Using data from pastoral soils sampled by horizon at 56 locations across New Zealand, we conducted a meta-analysis. On average, the total depth sampled was 0.93 ± 0.026 m (± SEM), and on a volumetric basis, the total C storage averaged 26.9 ± 1.8, 13.9 ± 0.6 and 9.2 ± 1.4 kg C m⁻² for allophanic (n=12), non-allophanic (n=40) and pumice soils (n=4), respectively. We estimated the total C storage, and quantified the uncertainty, using the data for samples taken from the uppermost A-horizon whose depth averaged 0.1 ± 0.003 m. For A-horizon samples of the allophanic soils, the mean C content was 108 ± 6 g C kg⁻¹ and the bulk density was 772 ± 29 kg m⁻³, for non-allophanic soils they were 51 ± 4 g C kg⁻¹ and 1055 ± 29 kg m⁻³, and for pumice soils they were 68 ± 9 g C kg⁻¹ and 715 ± 45 kg m⁻³. The C density —a product of the C content and bulk density —of the A-horizon samples was proportional to their air-dried water content, a proxy measure for the mineral surface area. By linear regression with C density of the A-horizon, the total C storage could be estimated with a standard error of 3.1 kg C m⁻², 19% of the overall mean

Combustion Analysis of a Meteorite Debris

In this research paper, nature and origins of a meteorite debris identified near village Lehri in district Jhelum, Pakistan have been determined. Total carbon content of a specimen of the meteorite debris is determined using combustion analysis and this abundance has been compared with values reported in literature to establish likely origins of the debris

Comparison of Algorithms for Baseline Correction of LIBS Spectra for Quantifying Total Carbon in Brazilian Soils

LIBS is a promising and versatile technique for multi-element analysis that usually takes less than a minute and requires minimal sample preparation and no reagents. Despite the recent advances in elemental quantification, the LIBS still faces issues regarding the baseline produced by background radiation, which adds non-linear interference to the emission lines. In order to create a calibration model to quantify elements using LIBS spectra, the baseline has to be properly corrected. In this paper, we compared the performance of three filters to remove random noise and five methods to correct the baseline of LIBS spectra for the quantification of total carbon in soil samples. All combinations of filters and methods were tested, and their parameters were optimized to result in the best correlation between the corrected spectra and the carbon content in a training sample set. Then all combinations with the optimized parameters were compared with a separate test sample set. A combination of Savitzky-Golay filter and 4S Peak Filling method resulted in the best correction: Pearson's correlation coefficient of 0.93 with root mean square error of 0.21. The result was better than using a linear regression model with the carbon emission line 193.04 nm (correlation of 0.91 with error of 0.26). The procedure proposed here opens a new possibility to correct the baseline of LIBS spectra and to create multivariate methods based on the a given spectral range.Comment: 13 pages, 5 figure

THE IMPACTS OF REMOVING FOSSIL FUEL SUBSIDIES AND INCREASING CARBON TAX IN IRELAND. RESEARCH SERIES NUMBER 98 December 2019

A subsidy is classified as potentially environmentally damaging if it is likely to incentivise behaviour that could be damaging to the environment irrespective of its importance for other policy purposes. Examples of such subsidies include providing fossil fuels (including diesel, kerosene, fuel oil, and peat) at lower prices to certain industries and providing fuel allowances to households to alleviate fuel poverty. While some publicly-funded supports can have important social and economic purposes, they can have a negative impact on the environment. While the main approach in Ireland to address this has been to use different excise duties, Ireland also introduced a carbon tax in 2010. The carbon tax is one of the primary fiscal policy tools used in several countries to reduce human-induced greenhouse gas (GHG) emissions. For the first time after the equalisation of its level on all fossil fuels in 2014, the Irish government increased the carbon tax from C20 per tonne of CO2 to C26 in 2020. It is expected that the total carbon tax revenues will increase by C100 million in 2020, compared to 2019. Notwithstanding this, the total budgetary cost of these fossil fuel subsidies, excluding the agriculturerelated ones, was around C2.44 billion in 2014, whereas the government’s total carbon tax collection was C390.9 million. In other words, the monetary value of environmentally damaging subsidies was over six times higher than carbon tax revenues. In 2017, the same ratio was slightly higher, since the total value of subsidies increased by 11.85%, whereas the growth rate of total carbon tax revenues was only 7.7%. This report analyses the economic and environmental impacts of the removal of eight different fossil fuel subsidies in Ireland by using the Ireland Economy-Energy-Environment (I3E) model. In addition, a separate set of scenarios in which the removal of each subsidy is accompanied by a gradual increase in the level of the carbon tax are run to quantify the combined effects of these policy instruments

Equilibrium responses of global net primary production and carbon storage to doubled atmospheric carbon dioxide: sensitivity to changes in vegetation nitrogen concentration

We ran the terrestrial ecosystem model (TEM) for the globe at 0.5° resolution for atmospheric CO2 concentrations of 340 and 680 parts per million by volume (ppmv) to evaluate global and regional responses of net primary production (NPP) and carbon storage to elevated CO2 for their sensitivity to changes in vegetation nitrogen concentration. At 340 ppmv, TEM estimated global NPP of 49.0 1015 g (Pg) C yr−1 and global total carbon storage of 1701.8 Pg C; the estimate of total carbon storage does not include the carbon content of inert soil organic matter. For the reference simulation in which doubled atmospheric CO2 was accompanied with no change in vegetation nitrogen concentration, global NPP increased 4.1 Pg C yr−1 (8.3%), and global total carbon storage increased 114.2 Pg C. To examine sensitivity in the global responses of NPP and carbon storage to decreases in the nitrogen concentration of vegetation, we compared doubled CO2 responses of the reference TEM to simulations in which the vegetation nitrogen concentration was reduced without influencing decomposition dynamics (“lower N” simulations) and to simulations in which reductions in vegetation nitrogen concentration influence decomposition dynamics (“lower N+D” simulations). We conducted three lower N simulations and three lower N+D simulations in which we reduced the nitrogen concentration of vegetation by 7.5, 15.0, and 22.5%. In the lower N simulations, the response of global NPP to doubled atmospheric CO2 increased approximately 2 Pg C yr−1 for each incremental 7.5% reduction in vegetation nitrogen concentration, and vegetation carbon increased approximately an additional 40 Pg C, and soil carbon increased an additional 30 Pg C, for a total carbon storage increase of approximately 70 Pg C. In the lower N+D simulations, the responses of NPP and vegetation carbon storage were relatively insensitive to differences in the reduction of nitrogen concentration, but soil carbon storage showed a large change. The insensitivity of NPP in the N+D simulations occurred because potential enhancements in NPP associated with reduced vegetation nitrogen concentration were approximately offset by lower nitrogen availability associated with the decomposition dynamics of reduced litter nitrogen concentration. For each 7.5% reduction in vegetation nitrogen concentration, soil carbon increased approximately an additional 60 Pg C, while vegetation carbon storage increased by only approximately 5 Pg C. As the reduction in vegetation nitrogen concentration gets greater in the lower N+D simulations, more of the additional carbon storage tends to become concentrated in the north temperate-boreal region in comparison to the tropics. Other studies with TEM show that elevated CO2 more than offsets the effects of climate change to cause increased carbon storage. The results of this study indicate that carbon storage would be enhanced by the influence of changes in plant nitrogen concentration on carbon assimilation and decomposition rates. Thus changes in vegetation nitrogen concentration may have important implications for the ability of the terrestrial biosphere to mitigate increases in the atmospheric concentration of CO2 and climate changes associated with the increases

Determinants of soil organic matter chemistry in maritime temperate forest ecosystems

While the influence of climate, vegetation, management and abiotic site factors on total carbon budgets and turn-over is intensively assessed, the influences of these ecosystem properties on the chemical complexity of soil organic matter (SOM) remains poorly understood. This study addresses the chemical composition of NaOH-extracted SOM from maritime temperate forest sites in Flanders (Belgium) by pyrolysis-GC/MS. The studied forests were chosen based on dominant tree species (Pinus sylvestris, Fagus sylvatica, Quercus robur and Populus spp.), soil texture and soil-moisture conditions. Differences in extractable-SOM pyrolysis products were correlated to site variables including dominant tree species, management of the woody biomass, site history, soil properties, total carbon stocks and indicators for microbial activity. Despite of a typical high intercorrelation between these site variables, the influence of the dominant tree species is prominent. The extractable-SOM composition is strongly correlated to litter quality and available nutrients. In nutrient-poor forests with low litter quality, the decomposition of relatively recalcitrant compounds (i.e. short and mid-chain alkanes/alkenes and aromatic compounds) appears hampered, causing a relative accumulation of these compounds in the soil. However, if substrate quality is favorable, no accumulations of recalcitrant compounds were observed, not even under high soil-moisture conditions. Former heathland vegetation still had a profound influence on extractable-SOM chemistry of young pine forests after a minimum of 60 year

Photochemical degradation of organic pollutants in wastewaters

In the present work, the photochemical treatment of a synthetic wastewater in a batch recycle photochemical reactor using ultraviolet irradiation (254 nm, 6 W), hydrogen peroxide and ferric ions was studied. The wastewater was composed of peptone, lab lemco, glucose, ammonia hydrogen carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate and had initial total carbon 1080 mg L-1. Its volume was 250 mL, and the active (irradiated) volume in the annular photoreactor was 55.8 mL. The effect of initial total carbon, initial hydrogen peroxide amount, and Fe(III) added, on total carbon removal was studied aiming at optimizing operating parameters. Each experiment lasted 120 min, and the process was attended via pH, total carbon and HPLC analysis (for determination of phenolic compounds conversion). The results obtained showed that the addition of Fe(III) markedly increased the mineralization of the wastewater, especially during the first 60 min. Specifically, for initial carbon concentration 528 mg L-1, hydrogen peroxide 2664 mg L-1, without any Fe(III) added, the total carbon removal achieved after two hours was 50%, whereas after adding 240 mg L-1 Fe(III) the total carbon removal observed was 87%. The difference was even more pronounced during the first 60 min since the total carbon removal was increased from 19% in the absence of Fe(III) to 79% in the presence of 240 mg L-1 Fe(III). The effect of phenol presence (0-100 mg L-1) on total carbon removal was also examined. In all experiments, complete removal of phenol was observed, whereas TC removal was around 75%. The results obtained were applied for the treatment of real wastewater (landfill leachate) with initial carbon concentration 2650 mg L-1, and pH 8.3. It was observed that pH adjustment markedly increased the percentage of carbon removal. With pH adjustment from 8 to 5 the results for total carbon removal improved from 3% (using only 13320 mg L-1 H2O2) to 75% after pH adjustment with HCl (using 13320 mg L-1 H2O2, 400 mg L-1 Fe(III))

Molecules, grains, and shocks: A comparison of CO, H I, and IRAS data

The IR and H I properties, and CO content were compared for a set of 26 isolated, degree-sized interstellar clouds. The comparisons offer some conclusions concerning the effects of kinematics on molecular content and grain size distribution. It was also found that some clouds must have very large fractions of their total Carbon in the form of polycyclic aromatic hydrocarbons

Comparison of Diatom, Total Carbon, and Grain Size Proxies for Sea-Level Reconstruction

Sediment lithology and biological assemblages from low energy intertidal environments (tidal flat to salt-marsh then upland communities) are valuable archives of relative sea level (RSL) information. Sediment organic matter and grain size are often recorded in addition to microfossil data to aid environmental interpretation. This study aims to assess use of sediment organic matter and grain size as indicators of former tidal level to aid diatom based RSL reconstructions. This study firstly investigates modern (top 1cm) sediments from Loch Laxford in northwest Scotland. Grain size analysis in these sediments shows local processes are overprinting the general expected pattern of decreasing grain size away from the sea. Analysis of the modern total carbon distribution shows there a linear increase in percentage total carbon with elevation (r=0.92) between the low marsh and high marsh. Comparison of the modern total carbon distribution at a contrasting site, Beluga Slough in Alaska, shows the linear relationship still exists, but with lower total carbon values for equivalent elevations. This shows the importance of location, and climate, for total carbon distribution. Secondly, this study applies the modern Loch Laxford total carbon – elevation distribution to reconstruct paleo marsh surface elevation (PMSE) and RSL at Loch Laxford, and in an older sediment sequence from Mointeach Mhor in western Scotland. These are compared with diatom based reconstructions from the same sites. Decomposition complicates the use of organic carbon as a sea-level proxy but does appear to stabilise. At Loch Laxford, this occurs after approximately 100 years. Sediment grain size appears to influence the total carbon value and should also be investigated. Total carbon has most potential as a sea-level proxy in sediments from the last millennium, where a local modern distribution is available and it is unlikely that large changes in grain size or volume, or organic matter accumulation have occurred