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1.
Environ Monit Assess ; 192(11): 674, 2020 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-33011837

RESUMO

Prediction of dissolved organic carbon (DOC) based on catchment characteristics is a useful tool for efficient and effective water management, but in the case of arid and semi-arid regions, such predictive capacity is scarce. Accordingly, the main objective of this study was to evaluate the significance of principal components for predicting DOC concentrations and fluxes in nine headwater catchments of the Hiv catchment located in the Southern Alborz Mountains in the west of Tehran, Iran. To achieve this aim, data were assembled on 24 headwater catchment characteristics comprising soil properties, physiography, seasonal rainfall, and flow attributes, as well as estimates of DOC concentrations and fluxes across four seasons. The results revealed a major positive correlation between DOC and soil organic matter parameters related to soil biological processes. Using general linear modelling, an organic matter component related to soil biology, a seasonal component related to the dummy effect of sampling seasons, and a soil physical component related to soil texture were found to be the best predictors for DOC responses in the study area.


Assuntos
Ciclo do Carbono , Monitoramento Ambiental , Carbono/análise , Irã (Geográfico) , Solo
2.
J Environ Qual ; 49(1): 74-84, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33016354

RESUMO

Plants release carbon-based exudates from their roots into the rhizosphere to increase phosphorus (P) supply to the soil solution. However, if more P than required is brought into solution, additional P could be available for leaching from riparian soils. To investigate this further, soil columns containing a riparian arable and buffer strip soil, which differed in organic matter contents, were sown with three common agricultural and riparian grass species. The P loads in leachate were measured and compared with those from unplanted columns, which were 0.17 ± 0.01 and 0.89 ± 0.04 mg kg-1 for the arable and buffer strip soil, respectively. A mixture of ryegrass and red fescue significantly (p ≤ .05) increased dissolved inorganic P loads in leachate from the arable (0.23 ± 0.01 mg kg-1 ) and buffer strip soil (1.06 ± 0.05 mg kg-1 ), whereas barley significantly reduced P leaching from the buffer strip soil (0.53 ± 0.08 mg kg-1 ). This was dependent on the dissolved organic C released under different plant species and on interactions with soil management history and biogeochemical conditions, rather than on plant uptake of P and accumulation into biomass. This suggested that the amount and forms of P present in the soil and the ability of the plants to mobilize them could be key factors in determining how plants affect leaching of soil P. Selecting grass species for different stages of buffer strip development, basing species selection on root physiological traits, and correcting soil nutrient stoichiometry in riparian soils through vegetative mining could help to lower this contribution.


Assuntos
Fósforo , Poaceae , Carbono , Rizosfera , Solo
3.
J Environ Qual ; 49(3): 688-699, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-33016403

RESUMO

Ecosystem reconstruction after mining disturbance is a challenge considering the multitude of factors that affect soil formation and revegetation. In the boreal forest of western Canada, peat material is often used as the organic amendment for land reclamation to upland forest. Carbon and water dynamics of peat-dominated ecosystems differ from natural upland forest soils. The objective of this work was to evaluate the evolution of soils reconstructed after mining disturbance using 13 C and 2 H analyses of n-alkane tracers. Ten soils from natural ecosystems were sampled (0-10 cm) and compared with 11 soils from novel ecosystems ranging in age from 0 to 30 yr, as well as a fresh peat sample. Soils supported different vegetation, including pine (Pinus spp.), aspen (Populus spp.), and white spruce [Picea glauca (Moench) Voss]. Despite overlaps for some individual n-alkanes, we found a dominance of n-C25 in reconstructed soils, also dominant in the peat material, and a dominance of n-C27 in natural soils, one of the dominant n-alkanes in natural forest vegetation. In addition, there was a significant difference in odd n-alkane δ2 H and δ13 C values between natural and reconstructed soils (p < .05). Differences in δ2 H values, more negative for reconstructed soils than for natural soils, were attributed to changes in soil moisture, from wetter peat-dominated soils to drier upland forests; among forest types, δ2 H values were most negative under pine vegetation. The δ13 C composition of odd n-alkanes, in particular n-C27 , was significantly related to tree age (p < .05). Overall, both 2 H and 13 C isotopic signatures of odd n-alkanes exhibited differences between natural and reconstructed soils. However, within the reconstructed soils, neither isotopic signature showed a clear evolution with age since reclamation.


Assuntos
Carbono , Solo , Alcanos , Canadá , Ecossistema , Hidrogênio , Isótopos
4.
J Environ Qual ; 49(2): 460-471, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33016418

RESUMO

The agricultural reuse of urban sewage sludge (USS) modifies soil properties depending on sludge quality, management, and pedo-environmental conditions. The aim of this microcosm study was to assess C mineralization and subsequent changes in soil properties after USS addition to two typical Mediterranean soils: sandy (Soil S) and sandy loam (Soil A) at equivalent field rates of 40 t ha-1 (USS-40) and 120 t ha-1 (USS-120). Outcomes proved the biodegradability of USS through immediate CO2 release inside incubation bottles in a dose-dependent manner. Accordingly, the highest rates of daily C emission were recorded with USS-120 (3.7 and 3.9 mg kg-1 d-1 for Soils S and A, respectively) after 84 d of incubation at 25 °C. The addition of USS also improved soil fertility by enhancing soil macronutrients, microbial proliferation, and protease activity. Protease showed significant correlation with N, total organic C, and heterotrophic bacteria, reflecting the biostimulation and bioaugmentation effects of sludge. Soil indices like C/N/P stoichiometry and metabolic quotient (qCO2 ) varied mostly with mineralization rates of C and P in both soils. Despite a significant increase of soil salinity and total heavy metal content (lead, nickel, zinc, and copper) with USS dose, wheat germination was not affected by these changes. Both experimental soils showed intrinsic (Soil A) and incubation-induced (Soil S) phytotoxicities that were alleviated by USS addition. This was likely due to the enhancement of biodegradation and/or retention of phytotoxicants originating from previous land uses. Urban sewage sludge amendments could have applications in soil remediation by reducing the negative effects of allelopathic and/or anthropogenic phytoinhibitors.


Assuntos
Poluentes do Solo/análise , Poluentes do Solo/toxicidade , Solo , Carbono/análise , Biomarcadores Ambientais , Esgotos
5.
J Environ Qual ; 49(5): 1251-1263, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33016452

RESUMO

Restoring soil carbon (C) lost due to intensive farming is a long-term endeavor under current conservation management practices. Application of coal combustion residue (293 g C kg-1 ) from a sugar beet (Beta vulgaris L.) processing factory, hereafter referred to as char, could rapidly restore soil C and productivity in degraded croplands, but data on this potential strategy are unavailable. We assessed the impacts of char application to two relatively low-C soils (10.1 and 12.2 g C kg-1 ) and one relatively high-C soil (17.3 g C kg-1 ) on soil C, soil physical and fertility properties, and crop yields in no-till systems in the Great Plains after 2 yr. Char was disked to 15 cm soil depth at char-C application rates ranging from 0 to 19.7 Mg C ha-1 , corresponding to char application rates ranging from 0 to 67.3 Mg ha-1 . The highest char rate increased C concentration in all soils but increased C stock only in low-C soils. Char did not affect soil penetration resistance, available water, aggregate stability, most nutrients, and crop yields. Char application at high rates increased sulfate, Ca, Mg, and Na concentrations but did not influence other properties. Carbon recovery of the char applied at the highest rate varied among soils from 50 to 85%, but the mechanisms for such differences need further investigation. Short-term duration, low char C concentration, and low application rates may explain the limited char effects. Overall, char application at 19.7 Mg char-C ha-1 (i.e., 67.3 Mg char ha-1 ) increased soil C concentration but had negligible effects on other soil properties and crop yields after 2 yr.


Assuntos
Poluentes do Solo , Solo , Agricultura , Carbono , Dióxido de Carbono
6.
J Environ Qual ; 49(4): 1011-1019, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33016487

RESUMO

The pharmaceutical compound carbamazepine (CBZ) is a contaminant of emerging concern. Wastewater irrigation can be a long-term, frequent source of CBZ; therefore, understanding the fate and transport of CBZ as a result of wastewater reuse practices has important environmental implications. The objective of this study was to estimate long-term soil transport of CBZ originating from treated wastewater irrigation on plots under different land uses. Field data from a previous study comparing CBZ concentrations in soil under different land uses were used in numerical modeling with HYDRUS-2D for the estimation of CBZ soil transport during 20 yr of irrigation with treated wastewater. This study showed high CBZ retention in soil under all investigated land uses. Adequate modeling results were obtained by using soil organic carbon-water partitioning coefficient (Koc ) for the CBZ linear sorption coefficient (Kd ) estimation, yet an underestimation of CBZ concentration in soil was still noted. Thus, results suggest that, although highly important, organic carbon content is probably not the only soil property governing CBZ sorption at this site, indicating the potential research perspective. Modeling results showed wastewater irrigation containing CBZ for 20 yr increased the CBZ concentration in the soil profile and its vertical movement, with the slowest vertical transport rate occurring on the forested plots. Overall results suggest that a beneficial management practice could be to increase soil organic carbon (e.g., compost addition) when using treated wastewater for irrigation in order to retain CBZ in the surface soil and thus limit its leaching through the soil profile.


Assuntos
Poluentes do Solo/análise , Águas Residuárias , Carbamazepina/análise , Carbono , Solo , Eliminação de Resíduos Líquidos
7.
8.
BMJ ; 371: m3884, 2020 10 08.
Artigo em Inglês | MEDLINE | ID: mdl-33032985
9.
Medicine (Baltimore) ; 99(41): e22548, 2020 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-33031299

RESUMO

OBJECTIVE: To investigate the efficacy and complications that might be associated with pyrocarbon compared with silicone in patients undergoing joint replacement surgery. METHODS: The full-text papers about the clinical efficacy of pyrocarbon and silicone were retrieved from multiple databases. Review Manager version 5.0 was adopted for meta-analysis and analyses of sensitivity and bias. RESULTS: Ultimately, we studied 232 patients across eight studies that met the eligibility criteria. The meta-analysis suggested a significant difference between the pyrocarbon and silicone groups in terms of the Disabilities of the Arm, Shoulder, and Hand (DASH) score (standard mean difference (SMD) = 1.48; 95% CI [0.97, 1.99]; P = .009; P for Heterogeneity <0.00001; I = 63%); Visual Analogue Score (VAS) (SMD = 1.68; 95% CI [1.36, 1.99]; P < .00001; P for heterogeneity = 0.01; I = 61%), and the abnormal radiolucent line (RR = 6.66; 95% CI [3.19, 13.89]; P < .00001; P for heterogeneity = 0.87, I = 0%); and ossification development (RR = 0.90; 95% CI [0.56, 1.44], P = .66; P for heterogeneity = 0.94, I = 0%). CONCLUSION: This study showed that pyrocarbon might be an efficient material compared with silicone for joint replacement surgery, but resulted in poorer functional and pain outcomes compared with silicone.


Assuntos
Artroplastia de Substituição , Carbono , Prótese Articular , Silicones , Materiais Biocompatíveis , Avaliação da Deficiência , Humanos , Medição da Dor , Desenho de Prótese
10.
Water Sci Technol ; 82(6): 1120-1130, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33055402

RESUMO

As a byproduct of agriculture, rice bran can be a good alternative carbon source to mass-produce microalgae and increase lipid content. The purpose of this study was to investigate the effects of rice bran extract (RBE) on the mass culture and oil content of microalgae. Various parameters were applied to the growth rate model to explain the dynamics of substrate inhibition and growth of microalgae. The rice bran contains 46.1% of carbohydrates, in which is 38.3% glucose, and is very suitable as a carbon source for microalgae growth. The culture with RBE had a four times higher biomass production than microalgae cultured on Jaworski's medium (JM) with a small amount of 1 g/L. In addition, for RBE, the lipid content was three times higher and saturated fatty acid was 3% lower than were those of JM. According to the above results, when Chlorella vulgaris is cultured using RBE, a high amount of biomass and high lipid content can be obtained with a small amount of RBE. RBE is a discarded waste and has a high content of glucose, so it can be replaced by an organic carbon source to increase microbial biomass growth and lipid content at low cost.


Assuntos
Chlorella vulgaris , Oryza , Agricultura , Biomassa , Carbono , Lipídeos
11.
Yakugaku Zasshi ; 140(9): 1101-1106, 2020.
Artigo em Japonês | MEDLINE | ID: mdl-32879242

RESUMO

Organoselenium compounds have attracted significant interest because of their use as important reagents in organic syntheses and potential biological activities, necessitating the development of simple and general synthetic methods. This article reviews our studies to develop of copper-catalyzed C-Se bond formation reactions via cross coupling and C-H activation. A number of unsymmetrical and symmetrical diaryl selenides were synthesized via Se-arylation of diaryl diselenides or selenium powder with triarylbismuthanes under aerobic conditions, achieving moderate to excellent yields. When the reaction of triphenylbismuthane with elemental Se was monitored with gas chromatography, diphenyl diselenide and diphenyl selenide formation was confirmed. Subsequently, 1-pot 2-step reactions were performed under mild conditions to obtain 3-selanyl imidazo[1,2-a]pyridines from triarylbismuthanes and diimidazopyridyl diselenides, which were generated from imidazo[1,2-a]pyridines and Se powder, in good to excellent yields. It should be noted that all three aryl groups in the bismuth and both selanyl groups in the diaryl diselenide generated from the selenium source were transferred to the coupling products. Cu-catalyzed tandem cyclization of 2-(2-iodophenyl)imidazo[1,2-a]pyridines with selenium for the synthesis of benzo[b]selenophene-fused imidazo[1,2-a]pyridines is also described herein. The molecular structure of the tetracyclic compound features nearly coplanar rings, and the maximum absorption is red-shifted compared to those of imidazo[1,2-a]pyridine and benzoselenophene.


Assuntos
Carbono/química , Cobre/química , Hidrogênio/química , Compostos Organosselênicos/síntese química , Catálise , Ciclização , Ligação de Hidrogênio , Fenômenos de Química Orgânica
12.
Nat Commun ; 11(1): 4241, 2020 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-32901006

RESUMO

Land vegetation is currently taking up large amounts of atmospheric CO2, possibly due to tree growth stimulation. Extant models predict that this growth stimulation will continue to cause a net carbon uptake this century. However, there are indications that increased growth rates may shorten trees' lifespan and thus recent increases in forest carbon stocks may be transient due to lagged increases in mortality. Here we show that growth-lifespan trade-offs are indeed near universal, occurring across almost all species and climates. This trade-off is directly linked to faster growth reducing tree lifespan, and not due to covariance with climate or environment. Thus, current tree growth stimulation will, inevitably, result in a lagged increase in canopy tree mortality, as is indeed widely observed, and eventually neutralise carbon gains due to growth stimulation. Results from a strongly data-based forest simulator confirm these expectations. Extant Earth system model projections of global forest carbon sink persistence are likely too optimistic, increasing the need to curb greenhouse gas emissions.


Assuntos
Sequestro de Carbono , Carbono/metabolismo , Árvores/crescimento & desenvolvimento , Mudança Climática , Simulação por Computador , Longevidade , Mortalidade , Árvores/metabolismo
13.
Chemosphere ; 254: 126881, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32957288

RESUMO

Application of biochar (BC) derived from rice straw has generated increasing interest in long-term storage of soil organic carbon (SOC), however its carbon (C) sequestration potential vary widely among agricultural soils despite the same BC dose used. These discrepancies in the ability of soils to sequester C after BC application are poorly understood. Metabolic quotient (qCO2) is a reflection of "microbial efficiency" and linked to SOC turnover across ecosystems. Therefore, we investigated the SOC sequestration and qCO2 in a Yellow River alluvium paddy soil (YP) and a quaternary red clay paddy soil (QP) under rice-wheat annual rotation following 4-year of BC application rate of 11.3 Mg ha-1 per cropping season. BC application consistently brought 65.3 Mg C ha-1 into the soils over 4-year experimental period but increased SOC by 57.6 Mg C ha-1 in YP and 64.5 Mg C ha-1 in QP. Calculating SOC mass balance showed 11.7% of BC-C losses from YP and only 1.16% from QP. BC application stimulated the G+ bacterial, fungi, and actinomycetes by increasing O-alkyl C content in YP, while decreased the same microorganisms by decreasing anomeric C-H content in QP. Importantly, higher clay and amorphous Fe (Feo) contents in QP after BC application protected SOC from further decomposition, which in turn decreased microorganisms and resulted in higher SOC sequestration than YP. Our results indicated that soil properties controlled the extent of SOC sequestration after BC application and site-specific soil properties must be carefully considered to maximize long-term SOC sequestration after BC application.


Assuntos
Agricultura/métodos , Sequestro de Carbono , Carvão Vegetal/química , Carbono/metabolismo , Argila , Ecossistema , Oryza/metabolismo , Solo/química
14.
Sci Total Environ ; 740: 140057, 2020 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-32927541

RESUMO

Existing related researches have focused on the linear relationship between population aging and carbon emissions, which easily lead to partial understanding of the effect of population aging on carbon emissions. In order to more comprehension of the effect of population aging on carbon emissions, this study explores the nonlinear relationship between population aging and carbon emission through empirical analysis of ten selected provinces in China from 2000 to 2016 using the panel threshold model. In the proposed panel threshold model, carbon emission is set as the explained variable, population aging is set as the core explanatory variable, the levels of population aging and trade openness are set as threshold variables, the levels of economic development, energy consumption structure, industrial structure, and technological innovation are set as the controlling variables, respectively. The results show that population aging has a threshold effect on curbing carbon emission. The levels of population aging and trade openness are two key factors that affect the relationship between population aging and carbon emission. Whether the level of popultion aging is lower or higher than the threshold value of 0.12937, the population aging has a negative coefficient on carbon emissions. Moreover, the higher the level of population aging, the greater the offsetting effect of population aging on carbon emission. When the level of trade openness is below the threshold value of 0.30990, the effect of population aging on carbon emission is negligible. When the level of trade openness is higher than the threshold value of 0.30990, the offesetting effect of population aging on carbon emission begins to appear. In other words, population aging has an offsetting effect on carbon emission when trade openness is in relatively high level, whereas the offsetting effect disappears when trade openness is lower than threshold value.


Assuntos
Dióxido de Carbono/análise , Carbono , China , Desenvolvimento Econômico
15.
J Environ Sci (China) ; 97: 149-161, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32933730

RESUMO

Transboundary and domestic aerosol transport during 2018-2019 affecting Bangkok air quality has been investigated. Physicochemical characteristics of size-segregated ambient particles down to nano-particles collected during 2017 non-haze and 2018-2019 haze periods were analyzed. The average PM2.5 concentrations at KU and KMUTNB sites in Bangkok, Thailand during the haze periods were about 4 times higher than in non-haze periods. The highest average organic carbon and elemental carbon concentrations were 4.6 ± 2.1 µg/m3 and 1.0 ± 0.4 µg/m3, respectively, in PM0.5-1.0 range at KU site. The values of OC/EC and char-EC/soot-EC ratios in accumulation mode particles suggested the significant influence of biomass burning, while the nuclei and coarse mode particles were from mixed sources. PAH concentrations during 2018-2019 haze period at KU and KMUTNB were 3.4 ± 0.9 ng/m3 and 1.8 ± 0.2 ng/m3, respectively. The PAH diagnostic ratio of PM2.5 also suggested the main contributions were from biomass combustion. This is supported by the 48-hrs backward trajectory simulation. The higher PM2.5 concentrations during 2018-2019 haze period are also associated with the meteorological conditions that induce thermal inversions and weak winds in the morning and evening. Average values of benzo(a)pyrene toxic equivalency quotient during haze period were about 3-6 times higher than during non-haze period. This should raise a concern of potential human health risk in Bangkok and vicinity exposing to fine and ultrafine particulate matters in addition to regular exposure to traffic emission.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar , Aerossóis/análise , Biomassa , Carbono/análise , Monitoramento Ambiental , Humanos , Tamanho da Partícula , Material Particulado/análise , Estações do Ano , Tailândia
16.
Anticancer Res ; 40(10): 5497-5502, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32988872

RESUMO

BACKGROUND/AIM: The cell-killing and radiosensitizing effects of carbon-ion (C-ion) beams with low linear energy transfer (LET) are underexplored. We aimed to demonstrate the cell-killing effects of 60Co gamma rays and C-ion beams at various LET values and the radiosensitizing effect of C-ion beams at various LET and cisplatin levels. MATERIALS AND METHODS: Human uterine cervical cancer cells were irradiated with 60Co gamma rays and C-ion beams at different levels of LET, with and without cisplatin treatment. RESULTS: Low-LET C-ion beams had a superior cell-killing effect compared to 60Co gamma rays. Survival curves under low-LET C-ion beams were more similar to that of 60Co gamma rays than that of high-LET C-ion beams. Cisplatin significantly reduced cell survival after 1, 2, and 3 Gy C-ion beam irradiations at LET values of 13/30/70 keV/µm, 13/30 keV/µm, and 13 keV/µm, respectively. CONCLUSION: Low-LET C-ion beams combined with cisplatin have higher radiosensitizing effects than high-LET C-ion beams.


Assuntos
Carbono/uso terapêutico , Radioisótopos de Cobalto/uso terapêutico , Radiossensibilizantes/uso terapêutico , Neoplasias do Colo do Útero/radioterapia , Apoptose/efeitos dos fármacos , Apoptose/efeitos da radiação , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Cisplatino/farmacologia , Relação Dose-Resposta à Radiação , Feminino , Raios gama , Humanos , Transferência Linear de Energia/efeitos da radiação , Neoplasias do Colo do Útero/tratamento farmacológico , Neoplasias do Colo do Útero/patologia
17.
Water Sci Technol ; 82(1): 107-119, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32910796

RESUMO

Dissolved organic matter (DOM) has an important impact on the water treatment and reuse of petroleum refinery wastewater. In order to improve the treatment efficiency, it is necessary to understand the chemical composition of the DOM in the treatment processes. In this paper, the molecular composition of DOM in wastewater samples from a representative refinery were characterized. The transformation of various compounds along the wastewater treatment processes was investigated. A total of 61 heteroatomic class species were detected from the DOM extracts, in which CHO (molecules composed of carbon, hydrogen, and oxygen atoms) and CHOS (CHO molecules that also contained sulfur) class species were the most abundant and account for 78.43% in relative mass peak abundance. The solid phase extraction DOM from the dichloromethane unextractable fraction exhibited a more complex molecular composition and contained more oxygen atoms than in the dichloromethane extract. During wastewater treatment processes, the chemical oxygen demand (COD) and ammonia-nitrogen were reduced by more than 90%. Volatile organic compounds (VOCs) accounted for about 30% of the total COD, in which benzene and toluene were dominant. After biochemical treatment, the VOCs were effectively removed but the molecular diversity of the DOM was increased and new compounds were generated. Sulfur-containing class species were more recalcitrant to biodegradation, so the origin and transformation of these compounds should be the subject of further research.


Assuntos
Águas Residuárias , Purificação da Água , Biodegradação Ambiental , Carbono , Nitrogênio
18.
J Environ Manage ; 273: 110979, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32889312

RESUMO

Reducing inequality, eradicating poverty and achieving a carbon-neutral society are recognized as important components of the United Nations' Sustainable Development Goals. In this study, we focus on carbon and energy inequality between and within ten Latin American and Caribbean (LAC) countries. Detailed carbon and energy footprint were estimated by combining the consumption profiles (2014) in ten LAC countries with environmental extended multi-regional input-output (MRIO) analysis. Our results show significant inequality of regional total and per capita carbon and energy footprint across the studied LAC countries in 2014. The top 10% income category was responsible for 29.1% and 26.3% of the regional total carbon and energy footprint, and their per capita carbon and energy footprint were 12.2 and 7.5 times of the bottom 10% earners in that region. The average carbon footprint of studied LAC countries varied between 0.53 and 2.21 t CO2e/cap (ton of CO2 equivalent, per capita), and the energy footprint ranged from 0.38 to 1.76 t SOE/cap (ton of Standard Oil Equivalent, per capita). The huge difference in total and per capita carbon emissions and energy consumption of different income groups suggests notable differences in climate change responsibility, and supports policies for achieving sustainable consumption in terms of carbon tax, renewable energy subsidy, and decarbonizing the consumption structure in different LAC countries.


Assuntos
Pegada de Carbono , Carbono , Dióxido de Carbono/análise , Região do Caribe , América Latina , Fatores Socioeconômicos
19.
Mar Environ Res ; 160: 104990, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32907728

RESUMO

The study of a Posidonia sinuosa sedimentary archive has delivered a millenary record of environmental change in Cockburn Sound (Western Australia). Ecosystem change is a major environmental problem challenging sustainable coastal development worldwide, and this study shows baseline trends and shifts in ecological processes in coastal ecosystems under environmental stress. The concentrations and fluxes of biogeochemical elements over the last 3,500 years indicate that important changes in ecosystem dynamics occurred over the last 1,000 years, in particular after ~1900's, probably related to establishment of seagrass meadows in the area and to local and regional human activities (industry and coastal development), respectively. The establishment of seagrasses ~1,000 years ago in the area of study is supported by the appearance of Posidonia fibres from ~40 cm soil depth until the core top, higher δ13C values indicating a larger contribution of seagrass-matter to the soil organic carbon pool, and increased concentration of fine sediments driven by the effect of seagrass canopy in enhancing sedimentation. The comparison of organic carbon, nutrients and metal concentrations and fluxes between pre- and post-establishment of seagrasses shows that seagrass establishment resulted in up to 9-fold increase in the soil biogeochemical sink. In ~1900's, shifts in the concentrations of metals, carbonates, organic carbon, sediment grain size, and δ13C and δ15N values of the organic matter were detected, demonstrating an alteration in seagrass ecosystem functioning following the onset of European settlement. Anthropogenic activities, and in particular the construction of a causeway in 1970's, enhanced seagrass soil organic carbon and metal accumulation rates by 36- and 39-fold, respectively, showing that human-made structures can enhance the biogeochemical sink capacity of seagrasses. Here we reconstruct the impact of human activities on seagrass ecosystem dynamics and blue carbon, which can inform local management of Cockburn Sound and seagrass conservation for climate change mitigation and adaptation.


Assuntos
Ecossistema , Sedimentos Geológicos , Desenvolvimento Industrial , Carbono , Solo
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