Carbon pools in China’s terrestrial ecosystems Tang, Xuli; Zhao, Xia; Bai, Yongfei ...
Proceedings of the National Academy of Sciences - PNAS,
04/2018, Letnik:
115, Številka:
16
Journal Article
Recenzirano
Odprti dostop
China’s terrestrial ecosystems have functioned as important carbon sinks. However, previous estimates of carbon budgets have included large uncertainties owing to the limitations of sample size, ...multiple data sources, and inconsistent methodologies. In this study, we conducted an intensive field campaign involving 14,371 field plots to investigate all sectors of carbon stocks in China’s forests, shrublands, grasslands, and croplands to better estimate the regional and national carbon pools and to explore the biogeographical patterns and potential drivers of these pools. The total carbon pool in these four ecosystems was 79.24 ± 2.42 Pg C, of which 82.9% was stored in soil (to a depth of 1 m), 16.5% in biomass, and 0.60% in litter. Forests, shrublands, grasslands, and croplands contained 30.83 ± 1.57 Pg C, 6.69 ± 0.32 Pg C, 25.40 ± 1.49 Pg C, and 16.32 ± 0.41 Pg C, respectively. When all terrestrial ecosystems are taken into account, the country’s total carbon pool is 89.27 ± 1.05 Pg C. The carbon density of the forests, shrublands, and grasslands exhibited a strong correlation with climate: it decreased with increasing temperature but increased with increasing precipitation. Our analysis also suggests a significant sequestration potential of 1.9–3.4 Pg C in forest biomass in the next 10–20 years assuming no removals, mainly because of forest growth. Our results update the estimates of carbon pools in China’s terrestrial ecosystems based on direct field measurements, and these estimates are essential to the validation and parameterization of carbon models in China and globally.
This research quantified the available residual biomass obtained from pruning olive trees. The additional biomass quantified could be used as a source of energy or as raw material for the wood ...industry and would provide additional income for fruit producers and also a more sustainable system. Several factors were analyzed: Variety, aim of the pruning, age of the plants, size of the plantation, crop yield and irrigation. Regression models were also calculated to predict the weight of dry biomass obtained per tree and tonnes of dry biomass obtained per hectare according to the significant factors. These equations could implement logistic planning as the Borvemar model, which defines a logistics network for supplying bio-energy systems. Olive tree varieties were classified into two groups for annual pruning: high residual biomass productivity (average yield 10.5 kg dry biomass tree
−1) and low productivity (average yield 3.5 kg dry biomass tree
−1). Some varieties are in transition between the two groups. There are no differences in biennial pruning, reaching an average residual biomass of 33 kg tree
−1. This means that in Mediterranean areas the residual biomass from olive pruning reaches an average 1.31 t ha
−1 in annual pruning and 3.02 t ha
−1 in biennial pruning.
► In this work the residual biomass obtained from different varieties of olive trees was quantified and the influence of the different factors involved was analyzed. ► The regression equations for the prediction of the biomass produced, based on the influence of these factors, were also obtained. ► These estimations will permit surveys to be carried out of the available biomass in a given zone from the cadastral register divided into plots and the agronomic characteristic of the different olive groves.
Propyl-sulfonic acid-functionalized nanoparticles were synthesized, characterized and evaluated as catalysts for pretreatment of corn stover. Silica coated nanoparticles were functionalized with 0.5% ...mercaptopropyltrimethoxysilane at neutral pH in a mixture of water and ethanol. Sulfur contents of the acid functionalized nanoparticles, measured in a CHNS analyzer, varied from 6%-10%, and the acid load ranged from 0.040 to 0.066 mmol H+/g. A Box-Behnken design was employed to calculate the minimum number experiments required to obtain an estimate of the surface response for temperature, catalyst load, and %S content of the catalyst. Complete hydrolysis of glucose was reached at 200 degree C but the average xylose yield was 4.6%, and about 20.2% of the combined glucose and xylose were lost as hydroxymethylfurfural and furfural. Results showed that acid-functionalized nanoparticles can be potential catalysts for the pretreatment of biomass for its later conversion to ethanol.
Plants adapt phenotypically to different conditions of light and nutrient supply, supposedly in order to achieve colimitation of these resources. Their key variable of adjustment is the ratio of leaf ...area to root length, which relies on plant biomass allocation and organ morphology. We recorded phenotypic differences in leaf and root mass fractions (LMF, RMF), specific leaf area (SLA) and specific root length (SRL) of 12 herbaceous species grown in factorial combinations of high/low irradiance and fertilization treatments. Leaf area and root length ratios, and their components, were influenced by nonadditive effects between light and nutrient supply, and differences in the strength of plant responses were partly explained by Ellenberg's species values representing ecological optima. Changes in allocation were critical in plant responses to nutrient availability, as the RMF contribution to changes in root length was 2.5× that of the SRL. Contrastingly, morphological adjustments (SLA rather than LMF) made up the bulk of plant response to light availability. Our results suggest largely predictable differences in responses of species and groups of species to environmental change. Nevertheless, they stress the critical need to account for adjustments in below‐ground mass allocation to understand the assembly and responses of communities in changing environments.
Marine stratocumulus clouds cover nearly one-quarter of the ocean surface and thus play an extremely important role in determining the global radiative balance. The semipermanent marine stratocumulus ...deck over the southeastern Atlantic Ocean is of particular interest, because of its interactions with seasonal biomass burning aerosols that are emitted in southern Africa. Understanding the impacts of biomass burning aerosols on stratocumulus clouds and the implications for regional and global radiative balance is still very limited. Previous studies have focused on assessing the magnitude of the warming caused by solar scattering and absorption by biomass burning aerosols over stratocumulus (the direct radiative effect) or cloud adjustments to the direct radiative effect (the semidirect effect). Here, using a nested modeling approach in conjunction with observations from multiple satellites, we demonstrate that cloud condensation nuclei activated from biomass burning aerosols entrained into the stratocumulus (the microphysical effect) can play a dominant role in determining the total radiative forcing at the top of the atmosphere, compared with their direct and semidirect radiative effects. Biomass burning aerosols over the region and period with heavy loadings can cause a substantial cooling (daily mean −8.05 W m−2), primarily as a result of clouds brightening by reducing the cloud droplet size (the Twomey effect) and secondarily through modulating the diurnal cycle of cloud liquid water path and coverage (the cloud lifetime effect). Our results highlight the importance of realistically representing the interactions of stratocumulus with biomass burning aerosols in global climate models in this region.
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•Biomass gasification coupled with PEM electrolysis doubles overall efficiency.•The produced methanol can be carbon-negative along its entire lifecycle.•Renewable methanol is ...competitive with fossil fuels at high carbon credits.•Biofuels represent key opportunities for lower carbon intensity of shipping.•Forest residue quantities in California can meet high shipping fuel demand.
At scale, biomass-based fuels are seen as long-term alternatives to conventional shipping fuels to reduce greenhouse gas emissions in the maritime sector. While the operational benefits of renewable methanol as a marine fuel are well-known, its cost and environmental performance depend largely on production method and geographic context. In this study, a techno-economic and environmental assessment of renewable methanol produced by gasification of forestry residues is performed. Two biorefinery systems are modeled thermodynamically for the first time, integrating several design changes to extend past work: (1) methanol synthesized by gasification of torrefied biomass while removing and storing underground a fraction of the carbon initially contained in it, and (2) integration of a polymer electrolyte membrane (PEM) electrolyzer for increased carbon efficiency via hydrogen injection into the methanol synthesis process. The chosen use case is set in California, with forest residue biomass as the feedstock and the ports of Los Angeles and Long Beach as the shipping fuel demand point. Methanol produced by both systems achieves substantial lifecycle greenhouse gas emissions savings compared to traditional shipping fuels, ranging from 38 to 165%, from biomass roadside to methanol combustion. Renewable methanol can be carbon-negative if the CO2 captured during the biomass conversion process is sequestered underground with net greenhouse gas emissions along the lifecycle amounting to −57 gCO2eq/MJ. While the produced methanol in both pathways is still more expensive than conventional fossil fuels, the introduction of CO2eq abatement incentives available in the U.S. and California could bring down minimum fuel selling prices substantially. The produced methanol can be competitive with fossil shipping fuels at credit amounts ranging from $150 to $300/tCO2eq, depending on the eligible credits.
The comprehensive utilization of biomass to obtain energy‐storage carbonaceous materials with special microstructures is of great significance. Herein, a universal method is proposed to fabricate ...oriented carbon microspheres (OCMSs) and 3D porous carbon (3DPC) block at the same time via high‐temperature hydrothermal “disproportionation” of biomass including but not limited to basswood, pinus sylvestris, red walnut, beech, bamboo, and sorghum straw. Through nuclear magnetic resonance, gas chromatography mass spectrometry, as well as various morphologic and structural characterizations, it is demonstrated that OCMS with (002) orientation originates from the carbonization of organic matters produced by the successive decomposition of hemicellulose, cellulose, and lignin during the high‐temperature hydrothermal process, while the 3DPC blocks exhibit abundant sp3 defects and micropores with a surface area of 855.12 m2 g−1 due to the constant loss of organic components from basswood blocks. As a result, the OCMS anode exhibits a high capacity of 201.1 mA h g−1 at 2000 mA g−1 after 2000 cycles, 3DPC cathode delivers a capacity of 95.7 mA h g−1 at 1.0 A g−1 after 5000 cycles. Remarkably, the as‐assembled OCMS//3DPC potassium ion hybrid capacitor exhibits an energy of 140.7 Wh kg−1 at 643.8 W kg−1, with a long cycle life over 8500 cycles.
A high‐temperature hydrothermal induced disproportionation‐like process is developed for converting biomass (including but not limited to basswood, pinus sylvestris, red walnut, beech, bamboo, and sorghum straw) into two types of carbon: oriented carbon microspheres anode and a 3D porous carbon cathode with abundant sp3 defects and large surface area (855.12 m2 g−1) for a high‐performance potassium ion hybrid capacitor.
The rapid depletion of conventional fossil fuels and day-by-day growth of environmental pollution due to extensive use of fossil fuels have raised concerns over the use of the fossil fuels; and thus ...search for alternate renewable and sustainable sources for fuels has started in the last few decades. In this context biomass derived fuels seems to be the promising path; and various routes are available for the biomass processing such as pyrolysis, transesterification, hydrothermal liquefaction, steam reforming, etc.; and the hydrothermal liquefaction (HTL) of wet biomass seems to be the promising route. Therefore, this article briefly enlightened a few concepts of HTL such as the elemental composition of bio-crude obtained by HTL, different types of feedstock adopted for HTL, mechanism of HTL processes, possible process flow diagrams for HTL of both wet and dry biomass and energy efficiency of the process. In addition, this article also enlisted possible future research scope for concerned researchers and a few of them are setting up HTL plant suitable for both wet and dry biomass feedstock; analyzing influence of parameters such as temperature, pressure, residence time, catalytic effects, etc.; deriving optimized pathways for better conversion; and development of theoretical models representing the process to the best possible accuracy depending on nature of feedstock.
Aims
Nitrogen is correlated with plant biomass and Cd concentration, collectively influencing phytoextraction of Cd-polluted soil. The Cd phytoextraction by hyperaccumulating plants and high biomass ...plants as affected by nitrogen remains elusive.
Methods
Sweet sorghum (
Sorghum bicolor
(L.) Moench), a high biomass energy plant, and
Solanum nigrum
L., a Cd hyperaccumulator were investigated. Plant growth, Cd accumulation and soil properties as affected by different forms and dosages of nitrogen supply in Cd-polluted soil were studied. Additionally, rhizosphere soil bacterial and fungal community changes of the two species and their relationships with plant Cd accumulation were determined.
Results
A high level of nitrate resulted in the highest and equal Cd accumulation in shoots of the two plants. Sweet sorghum exhibited high photosynthesis rates with capacity for bioethanol production, enabling the re-utilization of post-harvested Cd materials. Consequently, sweet sorghum demonstrated a greater potential for Cd phytoextraction than
S. nigrum
. Regarding microbial community, clay was the driving factor influencing rhizosphere soil bacterial community in sweet sorghum as affected by nitrogen under Cd stress, while soil available Cd played a vital role in
S. nigrum
. Moreover,
Pseudomonas
and AKYG1722 bacteria showed a positive correlation with shoot Cd accumulation in sweet sorghum. AKYG1722,
Sphingobium herbicidovorans
,
Sphingobium chlorophenolicum
,
Streptomyces scabiei
,
Devosia
sp. I507,
Bacillus simplex
and
Ensifer meliloti
were positively correlated with shoot Cd accumulation in
S. nigrum
.
Conclusions
Nitrate performs better than ammonium and urea for improving phytoremediation of Cd-polluted soil using sweet sorghum and
S. nigrum
, but their rhizosphere soil microbial communities were species-dependent.
Graphical abstract
The purpose of this study was to evaluate the effect of ash from combustion of plant biomass of energy willow and Pennsylvania fanpetals on yields of willow grown as an energy crop and on soil ...properties. A three-year pot experiment was carried out on substrates with a loamy sand texture. Ash application rates were based on the potassium fertilisation demand. An incubation experiment was carried out to determine the effect of biomass-based ash on soil properties. Three soils with textural categories were incubated for 3 months with the ashes, the doses of which were determined on the basis of the hydrolytic acidity of soils (¼; ½ and 1.0 Hh). It was found that ashes generated from burning willow or Pennsylvania fanpetals can be applied instead of phosphorus, potassium and magnesium fertilisers in the cultivation of energy willow. The plant uptake of P, K and Mg from the ashes did not diverge from their absorption by plants when supplied with mineral salts. The application of these alkaline ashes will increase the soil content of phytoavailable forms of phosphorus, potassium and magnesium. The examined ashes enriched the soil with micronutrients.
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