Carbon Conversion Factors Research Articles

SHORT INTRODUCTION ON PRESENT DESIGN AND TRENDS REGARDING

This paper covers some aspects regarding present technology used in large crude oil carriers design and operation, as well as requirements regarding energy management on board. Obviously, due to complexity of such subject, there cannot be an exhaustive presentation. It is intended as a mere starting point for further discussion and research regarding possibilities to improve vessel’s general energy efficiency, including ways of using non-conventional and renewable energy, with due regard to specific trading routes involving large oil tankers. Some practical figures achieved typically on a Very Large Crude Oil Carriers engaged in international voyages are presented. A brief explanation on Energy Efficiency Index (EEI) and Carbon Conversion Factors (CF), as accepted by IMO, is also included. Work may be continued with further theoretical research in energy efficiency improvement on board such vessels. The article is structured in five parts: Introduction, Main Particulars of Large Tankers, Oil Tankers Outfitting, Energy Management Plan and Conclusion.

Drivers of microbial carbon biomass variability in two oceanic regions of the Gulf of Mexico

The microbial plankton community is an integral part of the pelagic ecosystem. It hosts essential functional groups that play a vital role in organic carbon production, release, uptake, and degradation within open-ocean ecosystems. Given its significance, carbon biomass estimates are urgently needed, especially in oligotrophic regions, to provide and enhance our knowledge of biogenic carbon pools. They also aid in validating biogeochemical models that characterize the functioning of these extensive marine ecosystems within the global carbon cycle. This study addresses the temporal variability of microbial community biomass in two oceanic zones: the west-central (Perdido) and southern (Coatzacoalcos) areas of the Gulf of Mexico. During three seasonally contrasting periods (nortes, rainy, and dry seasons), seawater samples were collected from the euphotic zone in both regions to estimate the carbon biomass of different pico- (<2–3 µm), nano-, and microplankton groups (>3–200 µm). Carbon biomass assessments for the microbial groups were based on their abundance and carbon conversion factors. Overall, we found a significant contribution of pico-prokaryotic components (heterotrophic bacteria, Prochloroccocus, and Synechoccocus) to the total microbial carbon stock of the euphotic zone (84–89 % global estimates). The finding suggests these microorganisms are key functional groups that drive carbon production and fate in the Gulf of Mexico ecosystem. Pico-cyanobacteria, especially Prochloroccocus, were the dominant primary producers (68–82 % total autotrophic carbon), mainly in the upper layer of the oligotrophic euphotic zone. This vertical pattern implies that the deep chlorophyll-a maximum (DCM) depth level was unrelated to a net increase in phytoplankton biomass in the three study periods. The distribution of microbial carbon biomass exhibited striking differences associated with winter mixing (the nortes season), high river discharge accompanied by cross-shelf transport (the rainy season), and the dynamics of mesoscale structures. Ecological aspects, such as the habitat preference of the organisms and the seasonal complementary development of mixotrophic and heterotrophic grazers and their prey, were also essential drivers in regulating the microbial carbon pool of both oceanic regions. The microbial carbon assessments conducted in this study contribute to identifying and quantifying key planktonic functional groups involved in the biogeochemical carbon cycle in the Gulf of Mexico open-ocean ecosystem.

Estimation of carbon emissions associated with tibial plateau levelling osteotomies in 10 dogs

ObjectiveTo describe a method of estimating the carbon emissions resulting from 10 clinical canine surgical procedures. Study designProspective observational cohort study. AnimalsA total of 10 adult client-owned dogs presenting to two private referral centres in the UK for tibial plateau levelling osteotomy (TPLO) using either isoflurane or sevoflurane for maintenance of anaesthesia. MethodsSingle-use consumables, pharmaceuticals and waste streams were recorded. Volatile anaesthetic use was calculated based on fresh gas flow (FGF) and vaporizer setting. Travel of owners and staff involved in the procedure was recorded (the latter adjusted by procedure length relative to working day). Energy use was calculated based on the clinic’s monthly usage adjusted for floor area of rooms used. Overnight hospitalisation, kennelling consumables and a revisit for postoperative radiography were excluded. Carbon accounting was performed using published carbon conversion factors (‘bottom-up analysis’) if available, or conversion factors based on cost (‘top-down’). Data are presented as median (range) and totals per emission category. ResultsCarbon emissions from all cases amounted to 667.2 kgCO2e. In these two clinics, median carbon emissions from a canine TPLO were 63.5 (47.6–93) kgCO2e, which is equivalent to driving 372 km (231 miles) in an average UK passenger car. Travel accounted for 30.1% of carbon emissions. Volatile anaesthetics accounted for 21.4% of carbon emissions, with other pharmaceuticals accounting for 24.0%. Consumables, building energy and waste disposal accounted for 19.7%, 3.9% and 0.9% of carbon emissions, respectively. Conclusionsand clinical relevanceand clinical relevance Likely carbon hotspots for canine orthopaedic procedures include travel and pharmaceuticals, particularly volatile anaesthetic agents. Carbon reductions should focus on reducing travel emissions, streamlining pharmaceutical use and lower-carbon anaesthetic techniques. Future research should focus on improving carbon accounting methodology and widening the range of cases assessed.

Above-ground carbon stocks and its functional relationship with tree species diversity: the case of Kakamega and North Nandi Forests, Kenya

Estimating aboveground carbon (AGC) dynamics and tree diversity functionality relationships is critical in understanding the role of vegetation in implementing climate change mitigation strategies and promoting sustainable forest management. This study aimed to evaluate AGC stocks and their functional relationship with tree species diversity in Kakamega and North Nandi Forests, Kenya. A nested approach was adopted in sampling aboveground vegetation for biomass estimation in least disturbed, transformed, and disturbed sites. Tree biomass was estimated using an allometric equation based on tree diameter, tree height, and wood density. The biomass was then converted to carbon stocks using the carbon conversion factor. One-way ANOVA was used to determine the variation in carbon and tree diversity between forests and forest types. The correlation between tree diversity and AGC was evaluated. It was established that Kakamega Forest had the highest AGC (157.93 ± 26.91tha−1). The least disturbed areas had the highest AGC (65.96 ± 8.56tha−1). Additionally, Shannon diversity revealed a higher tree species diversity in Kakamega Forest (H′ = 1.82 ± 0.95). There was a significant positive correlation between AGC and tree species diversity (r = 0.62, p < 0.05). Kakamega and North Nandi forests vary in their AGC, and that tree species diversity positively influences the AGC of the two forests.

Blue carbon storage in a tropical coastal estuary: Insights for conservation priorities

Seagrass ecosystems have been determined as necessary sinks in the global carbon cycle and contribute towards climate change mitigations. In the recent past, there has been an increase of studies focused on blue carbon opportunities provided by seagrasses but large knowledge gaps and uncertainties remain, particularly in tropical seagrass meadows in the South Asian regions. Therefore, the current study aims to quantify the organic carbon stocks in the seagrass meadows on the tropical estuary in southern coast of Sri Lanka and highlights the need of conserving seagrasses specially in the context of effective management of lagoons to achieve Sustainable Development Goals. Landsat 9 (OLI/TIRS) images were used to develop seagrass distribution maps for 2022 and the data were verified with ground truthing. Vegetation and soil samples were taken from eight sampling locations representing the Rekawa Lagoon. Aboveground biomass (AGB) and belowground biomass (BGB) were determined by multiplying the biomass with the carbon conversion factor whereas the loss-on-ignition (LOI) technique was applied to calculate the soil organic carbon. Results revealed that the soil core carbon content of the study site were ranged between 2.56 ± 0.29 to 3.04 ± 0.44 Mg C/ha. The calculated total carbon content of the 0.0324 km2 study area in Rekawa Lagoon was 10.21 Mg C, giving 87.06 % contribution from sediment organic carbon pool. This study provides insights for the conservation of these critical ecosystems and highlights the need of policy and action agendas for better management.

Net zero roadmap modelling for sustainable dairy manufacturing and distribution

Energy-derived carbon emissions from dairy manufacturing and distribution are significant. Meeting a net zero carbon target is a global priority, and to that end the dairy industry is engaging an emission-reduction strategy. Modelling tools that can predict energy consumption and related carbon-emissions can aid decision-making towards energy transitioning. This study presents an energy consumption model for dairy skimmed milk and cream manufacturing and distribution, which has been developed following a mechanistic modelling approach. This approach integrates chemical engineering process design, heat exchange principles, and empirical modelling to simulate energy consumption for each individual supply chain component, sequence-by-sequence. The model offers simulation flexibility, allowing the projection of the product’s embodied energy and carbon-emissions under diverse manufacturing and distribution scenarios. To investigate the model capabilities, scenario analysis was performed for 12 different scenarios. These scenarios resulted by testing the use of three fuel types for the heating requirements in manufacturing (oil, natural gas and hydrogen), two categories of refrigerated vehicles (diesel and electric), and two different distribution infrastructures (centralised and decentralised). The evaluated skimmed milk product-embodied energy ranged between 309 and 869 kJ/L. The scenarios were also simulated towards 2050 using the UK projections for electricity’s carbon conversion factor to predict the anticipated carbon-emission reductions. These 2050 projections allowed for roadmap planning towards decarbonising energy for skimmed milk and cream manufacturing and distribution, with outcomes demonstrating up to 90.2% carbon-emission reductions by 2050. The developed model can support safe decision-making and assist the dairy industry in meeting the net zero carbon target.

Above- and Belowground Biomass Carbon Stock and Net Primary Productivity Maps for Tidal Herbaceous Marshes of the United States

Accurate assessments of greenhouse gas emissions and carbon sequestration in natural ecosystems are necessary to develop climate mitigation strategies. Regional and national-level assessments of carbon sequestration require high-resolution data to be available for large areas, increasing the need for remote sensing products that quantify carbon stocks and fluxes. The Intergovernmental Panel on Climate Change (IPCC) provides guidelines on how to quantify carbon flux using land cover land change and biomass carbon stock information. Net primary productivity (NPP), carbon uptake, and storage in vegetation, can also be used to model net carbon sequestration and net carbon export from an ecosystem (net ecosystem carbon balance). While biomass and NPP map products for terrestrial ecosystems are available, there are currently no conterminous United States (CONUS) biomass carbon stock or NPP maps for tidal herbaceous marshes. In this study, we used peak soil adjusted vegetation index (SAVI) values, derived from Landsat 8 composites, and five other vegetation indices, plus a categorical variable for the CONUS region (Pacific Northwest, California, Northeast, Mid-Atlantic, South Atlantic-Gulf, or Everglades), to model spatially explicit aboveground peak biomass stocks in tidal marshes (i.e., tidal palustrine and estuarine herbaceous marshes) for the first time. Tidal marsh carbon conversion factors, root-to-shoot ratios, and vegetation turnover rates, were compiled from the literature and used to convert peak aboveground biomass to peak total (above- and belowground) biomass and NPP. An extensive literature search for aboveground turnover rates produced sparse and variable values; therefore, we used an informed assumption of a turnover rate of one crop per year for all CONUS tidal marshes. Due to the lack of turnover rate data, the NPP map is identical to the peak biomass carbon stock map. In reality, it is probable that turnover rate varies by region, given seasonal length differences; however, the NPP map provides the best available information on spatially explicit CONUS tidal marsh NPP. This study identifies gaps in the scientific knowledge, to support future studies in addressing this lack of turnover data. Across CONUS, average total peak biomass carbon stock in tidal marshes was 848 g C m−2 (871 g C m−2 in palustrine and 838 g C m−2 in estuarine marshes), and based on a median biomass turnover rate of 1, it is expected that the mean NPP annual flux for tidal marshes is similar (e.g., 848 g C m−2 y−1). Peak biomass carbon stocks in tidal marshes were lowest in the Florida Everglades region and highest in the California regions. These are the first fine-scale national maps of biomass carbon and NPP for tidal wetlands, spanning all of CONUS. These estimates of CONUS total peak biomass carbon stocks and NPP rates for tidal marshes can support regional- and national-scale assessments of greenhouse gas emissions, as well as natural resource management of coastal wetlands, as part of nature-based climate solution efforts.

Evaluation of the chemical effect of carbon dioxide dilution to fuel on soot formation in co-flow laminar ethylene and propane diffusion flames

In this study, the effects of carbon dioxide (CO2) addition on soot evolution were isolated systematically by adding 50% N2, 31% Ar+19% CO2, and 50% CO2 to the fuel side, respectively. Two series of diffusion flames, ethylene and propane, were experimentally investigated. Optical diagnostics, including laser-induced fluorescence (LIF), ratio pyrometry, and laser-induced incandescence (LII), were utilized to measure the spatial distributions of polycyclic aromatic hydrocarbons (PAHs), flame temperature, soot volume fraction fv, primary particle size dp, and number density of soot np. It was found that the flame height decreased gradually for the ethylene flame with adding N2/Ar + CO2/CO2. In contrast, the flame height remained essentially unchanged for propane-based flames. The results showed that adding N2/Ar + CO2/CO2 increased the temperature in the upper part of the ethylene flame, while the temperature change in the upper part of the propane flame was subtle and almost negligible. The total PAHs-LIF loading and the spatial distributions of fv/dp/np indicated that the chemical effect of CO2 added to ethylene flames in inhibiting the formation of large-size PAHs and retarding the soot inception stage was insignificant. However, it was not negligible for propane flames. The quantitative results revealed that the inhibition of total soot loading ST in propane flames was dominated by the chemical effect of CO2, while in ethylene flames, it was dominated by the thermal and dilution effect of CO2. The same conclusion was also found in the results of the maximum carbon conversion factor ηmax and the average particle size of soot. The specific growth rate of soot mass was almost unchanged regardless of the mixture on the fuel side. Adding CO2 had a more substantial chemical effect in inhibiting soot formation in propane flames than that in ethylene flames, which could mainly be attributed to a more effective reduction in the time for the increase of soot mass τg during soot evolution.

CARBON STORAGE IN SEAGRASS BEDS IN THE LITORAL ZONE OF SANCANG BEACH, GARUT

The vast expanse of seagrass beds in coastal areas can provide many ecosystem services, one of which is the ability of seagrass beds to absorb and store carbon dioxide (CO2). Carbon dioxide gas (CO2) is one of the components of greenhouse gases that contribute to global warming. So the role of seagrass is very important in the ecosystem. This study aims to determine carbon storage in seagrass in the littoral zone of Sancang Beach, Garut Regency, which was carried out in April-June 2022. Determination of potential carbon storage was carried out by taking seagrass samples with a size of 20 cm x 20 cm, then drying to a constant weight. and calculated using a carbon conversion factor for seagrass biomass of 0.34. The results showed that the carbon content at Station 1 Cibako (145.9331 g C/m2) was higher than Station 2 Cikujangjambe (110.026 g C/m2) and Station 3 Ciporeang (117.771 g C/m2). The average carbon content at Sancang beach is 124,577 g C/m2. The conclusion is that in general the carbon storage below the substrate (below ground) in seagrass in the Litoral Zone of Sancang Beach has a greater value than the value of carbon storage above the substrate (above ground).

Study on Predicting the Gasification Process of Acacia Wood on a Downdraft Gasifier: Using the Non-stoichiometric Equilibrium Model

This study presents a prediction of acacia wood of Vietnam gasification in a downdraft gasifier based on the thermodynamic equilibrium model. Analytical solution for the mathematical model obtained by using an EES (Engineering Equation Solver) program. In the survey, moisture content per mole of biomass MC= 10 ¸ 30%, The ratio of the actual amount of oxygen used for gasification with the amount of oxygen for complete combustion of the biomass ER= 0.21 ¸ 0.4. Results indicated that the lower heating value of syngas decreases with increasing MC or ER. Thermal efficiency tends to increase with rising ER from 0.21 to 0.374, and it will decrease if ER continues to increase. The lower heating value of dry products from 4.51 to 6.51 MJ/nm3, the heat efficiency from 49.62 to 75.53%. The carbon conversion factor tends to increase with an increase as MC or ER. The influence of MC on the carbon conversion factor is insignificant. The content of CO2 and CH4 increased, the content of CO decreased with increased MC or ER. The composition of H2 increases as MC increases while the H2 component increases slightly and then decreases with increasing ER.

Can corn stove bioethanol production substantially contribute to China's carbon neutrality ambition?

China has posed a great ambition for carbon neutrality by 2060. Bioethanol production is expected to contribute to this target. Corn stover (CS), which is highly productive but underutilized, is an attractive feedstock for bioethanol. We collected provincial data of corn production and CS utilization over 2010–2019 to predict the bioethanol potential and carbon conversion factor. In an ideal situation, bioethanol can amount to 40.3 Mt, which displaces 4.4% of the total national petroleum use in 2019. However, in energy sector, the CO2 reduction of bioethanol substitution was almost offset by the CO2 emission from energy consumption for bioethanol conversion. The application of by-product can provide a GHG emission abatement of 77.6 Mt CO2 eq and input savings of 23.9 billion RMB nationally. Overall, GHG emission can be reduced by over 170 Mt CO2 eq annually. These findings will help policy-makers reconsider the utilization of CS to achieve carbon neutrality.

Quantification of blue carbon in tropical salt marshes and their role in climate change mitigation

Vegetated coastal ecosystems (VCE) display a promising potential to act as natural carbon sinks in climate change mitigation. Although growing interest in wetland carbon has intensified the global level carbon stock estimation studies, large knowledge gaps and uncertainties remain, particularly in tropical salt marshes in the South and Southeast Asian regions. Therefore, the current study aims to quantify the organic carbon stocks in the salt marsh habitats on the Northwest coast of Sri Lanka and to showcase the relevance of salt marsh carbon in local and regional contexts. Vegetation and soil up to a depth of 50 cm were sampled from four sites representing the Wedithalathive Nature Reserve (WNR). Species-specific allometric relationships developed for the major succulent halophytic species indicated a significant positive correlation between dry biomass and plant height. The loss-on-ignition (LOI) technique was applied in combination with a carbon conversion factor to calculate the soil organic carbon (SOC) content across 4 depth intervals. The study provided an average total organic carbon (TOC) storage of 73 ± 14.47 Mg C ha−1 up to a depth of 50 cm, in which the aboveground vegetation accounted for ~2% share. Sri Lankan salt marshes hold 2.01 Tg of organic carbon and directly reflect their potential for inclusion in Nationally Determined Contributions (NDCs) under the Paris Agreement. This has been the first comprehensive study on salt marsh blue carbon stocks in Sri Lanka and the findings of this study will strengthen the knowledge base on regional and global saltmarsh carbon stocks and their potential role in climate change mitigation.

Evaluating the environmental impact of the Welsh national childhood oral health improvement programme, Designed to Smile.

Designed to Smile (D2S) is a national oral health improvement programme, aimed to reduce the prevalence of dental caries in young children in Wales. D2S has a responsibility to consider the environmental impact of the service it provides and demonstrate adherence to the sustainable development principle legislated within the Wellbeing of Future Generations (Wales) Act. To review the environmental impact of D2S by estimating the carbon footprint of the programme and identify carbon hotspots for future targeted action. Process mapping identified the steps to deliver the supervised toothbrushing and fluoride varnish elements of D2S. Annual estimates of business travel mileage, financial spend on procurement, total number of plastic consumables and waste disposal were made. An online survey enabled calculation of staff commuting behaviour. These contributors were converted to carbon emissions using established carbon conversion factors. The annual carbon footprint of D2S was estimated at 388 tonnes of CO²e (tCO²e) with 31% attributed to staff travel, 23% to business travel and 46% to procurement. An estimated 1 million plastic items were distributed. By promoting good oral care and preventing the need for future carbon intensive restorative dental treatments, D2S exemplifies a sustainable model of healthcare. Adopting reduce, reuse, recycle principles for plastic consumables and introducing sustainable procurement procedures could lead to further decarbonisation and reduction in plastic waste.

Effects of afforestation with different species on carbon pools and soil and forest floor properties

Land use and land use change are factors that affect carbon and nutrient stocks in ecosystems. The aim of this research was to determine the effects of forest land use types on carbon pools and soil and forest floor features. This study was conducted in areas afforested with black pine (Pinus nigra Arn. subsp. pallasiana Lamb. Holmboe) and Scots pine (Pinus sylvestris L.) and on adjacent bare land within the Akdağ Nature Park, which is located in the West-Central Anatolia Region of Turkey. Three 20 × 20 m sample plots were selected within each forest land use, and the diameters at breast height and heights of all trees were measured. Tree biomass and carbon stocks in the unit areas were calculated using tree biomass equations, and carbon conversion factors were developed for two tree species. Within each sample plot, disturbed and core soil samples and forest floor samples were taken at three points at depths of 0–10, 10–20 and 20–30 cm. The physical and chemical properties of the soil and forest floor samples were determined in the laboratory and measurements were converted to a unit area using volume values. The data were evaluated using independent sample t-tests and analysis of variance. The results showed that the ecosystem carbon (C) stocks differed significantly with forest land use type; black pine plantations, Scots pine plantations and bare land accumulated 235.2 t C ha−1, 206.1 t C ha−1 and 37.4 t C ha−1, respectively. We found that in addition to the positive effect of afforestation on soil, black pine had a greater impact on some forest floor and soil characteristics in the region than Scots pine. Thus, we suggest that priority should be given to black pine in afforestation of the region and in other ecosystems with similar climates. Additionally, our results reveal the importance of afforestation on bare lands for reducing the impact of global climate change.

Physiological limits to life in anoxic subseafloor sediment.

ABSTRACTIn subseafloor sediment, microbial cell densities exponentially decrease with depth into the fermentation zone. Here, we address the classical question of 'why are cells dying faster than they are growing?’ from the standpoint of physiology. The stoichiometries of fermentative ATP production and consumption in the fermentation zone place bounds on the conversion of old cell biomass into new. Most fermentable organic matter in deep subseafloor sediment is amino acids from dead cells because cells are mostly protein by weight. Conversion of carbon from fermented dead cell protein into methanogen protein via hydrogenotrophic and acetoclastic methanogenesis occurs at ratios of ∼200:1 and 100:1, respectively, while fermenters can reach conversion ratios approaching 6:1. Amino acid fermentations become thermodynamically more efficient at lower substrate and product concentrations, but the conversion of carbon from dead cell protein into fermenter protein is low because of the high energetic cost of translation. Low carbon conversion factors within subseafloor anaerobic feeding chains account for exponential declines in cellular biomass in the fermentation zone of anoxic sediments. Our analysis points to the existence of a life–death transition zone in which the last biologically catalyzed life processes are replaced with purely chemical reactions no longer coupled to life.

Estructura del manglar y su influencia en el almacén de carbono en la Reserva La Encrucijada, Chiapas, México

Se ha destacado la importancia de los manglares en el almacén de carbono, el cual se estima que supera significativamente al contenido de los bosques terrestres. Aunque la cuantificación del carbono en el componente arbóreo de los manglares se ha realizado en varias regiones de México, la costa del Pacífico sur ha sido escasamente analizada. El objetivo de este estudio fue evaluar la estructura de los manglares ribereños en 32 unidades de muestreo circulares (400 m2) en la Reserva La Encrucijada, Chiapas, caracterizando su altura, cobertura, diámetro a la altura del pecho y la estimación de los índices de complejidad y valor de importancia; así como su relación con el almacén de carbono. El carbono se cuantificó con ecuaciones alométricas para especies de mangles neotropicales con alto desarrollo estructural y el factor de conversión de biomasa a carbono de 0.48. La influencia de las variables estructurales e intersticiales (pH, salinidad, temperatura) en el carbono almacenado se determinó con análisis de varianza y covarianza. El manglar presentó una densidad de 2103 individuos por hectárea (ind ha-1) y valores promedio de altura de 12 m; de área basal, 18.7 m2 ha-1; cobertura, 9.9 m2 y diámetro a la altura del pecho, 8.4 cm. Se registró un índice de complejidad de 40.1; el orden de importancia de las especies fue Rhizophora mangle/Avicennia germinans/Laguncularia racemosa. El almacén de carbono arbóreo fue 87.0 Mg ha-1. Los parámetros estructurales presentaron alta correlación (R = 1.0, 0.94 y 0.85) con la biomasa del manglar. Según su estructura, este ecosistema se clasificó en la etapa sucesional de comunidad intermedia y con alta complejidad estructural.

Allometric models to estimate above-ground biomass and carbon stocks in Rhizophora apiculata tropical managed mangrove forests (Southern Viet Nam)

Mangrove forests can fix and store high quantities of carbon both in their soil and in their biomass, the latter peaking in the equatorial regions and decreasing with latitude. In Vietnam, more than 80% of the mangroves develop either in the Mekong Delta or in the Can Gio Estuary, which are characterized by tropical monsoon climates. Most of these mangroves were planted and are dominated by Rhizophora apiculata Blume. The main objectives of this study were to determine forest structure, above-ground biomass and carbon conversion factors for each tree component in order to obtain allometric equations and to derive carbon stocks for managed Rhizophora stands of different ages developing within this context. Thirty-six trees, having a diameter at breast height (DBH) ranging from 7.0 to 36.2 cm, from a planted mangrove forest were harvested in Ca Mau (Mekong Delta) to determine allometric equations. In addition, thirteen plots were established in both Ca Mau and Can Gio mangrove forests, to determine above-ground carbon densities. We proposed the following specific allometric equation to estimate total above-ground biomass (kg) for managed R. apiculata mangrove stands in Southern Vietnam: WTotal = 0.38363 * DBH2.2348 (R2 = 0.976, SE = 1.17, F = 1401, P < 0.001). The total above-ground biomass ranged from 135.4 to 523.6 Mg ha−1 depending on forest age and tree density. Consequently, and taking into account a carbon conversion factor of 44.09%, carbon stocks in the above-ground biomass of R. apiculata mangrove forests in Southern Vietnam ranged from 59.7 to 230.9 Mg C ha−1. The mean carbon partitioning in the tree biomass was: 77.11% for trunks, 11.87% for branches, 8.66% for prop roots, and 2.36% for leaves. However, this distribution, as well as annual height increments and biomass increase rates, also varied with forest age and tree densities. We suggested that tree density reduction through thinning activities allowed easier tree development, resulting in an increased biomass with enhanced allocation to branches and above-ground prop roots for the stability of the trees. Using the specific allometric equation and specific carbon conversion factor reduced the uncertainty in the estimation of above-ground biomass and carbon stocks.

Supplying hydrogen vehicles and ferries in Western Norway with locally produced hydrogen from municipal solid waste

Gibbs free energy minimization has been used to estimate the hydrogen production potential of air gasification of the wet organic fractions of municipal solid waste available in the Bergen region in Western Norway. The aim of this work was to obtain an upper limit of the amount of hydrogen that could be produced and to estimate of the number of vehicles: passenger ferries and cars that could be supplied with an alternative fuel. The hydrogen production potential was investigated as function of waste composition, moisture content, heat loss, and carbon conversion factor. The amount of hydrogen annually available for both gasification and gasification combined with water-gas-shift-reaction was calculated for different scenarios. Up to 2700 tonne H2 per year could be produced in the best case scenario; which would, if only utilised for maritime operations, be enough to supply nine ferries and ten fast passenger boat connections in the Hordaland region in Western Norway with hydrogen.

수확된 목제품의 탄소격리 성능 평가기준 변화 동향

'Climate change' means a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods. ‘Greenhouse Gas’ is main anthropogenic cause of Global Warming and Climate Change of the Ecosystem, 'The Earth'. International society and UN have focused on the Greenhouse Gases ― CO2, CH4, N2O, HFCs, PFCs, SF6 ―, and made many efforts to mitigate the Climate Change by lowering the greenhouse gas inventory with international cooperation. They started to organize UNEP, WCED to arouse the issue of the development and environment problem, and finally IPCC (Inter-governmental Panel on Climate Change) to support UNFCCC with information and knowledge by expert working group and research activities. IPCC developed and improved some guidelines to evaluate national greenhouse gas inventory since 1995 to get more complete, consistent, comparable, tranparent and accurate greenhouse gas emission and removal calculation results of each country. It paid attention to the effect of 'Harvested Wood Products(HWP)' as the sink of Carbon Dioxide sequestration and developed the approaches and calculation formula for the HWP with carbon conversion factor and half life. Consequently, 2006 IPCC guidelines and 2013 KP supplementary and Good Practice Guidance are the officially accepted two evaluation tools with different HWP sorting accompanied with different conversion factor, half life and tier classification. Comparison of the greenhouse gas inventory data from these evaluating tool would be meaningful to supply measurable, reportable and verifiable greenhouse gas inventory including the effect of HWP for each country during Paris Climate Agreement era.

Estimating Primary Production of Picophytoplankton Using the Carbon-Based Ocean Productivity Model: A Preliminary Study

Picophytoplankton are acknowledged to contribute significantly to primary production (PP) in the ocean while now the method to measure PP of picophytoplankton (PPPico) at large scales is not yet well established. Although the traditional 14C method and new technologies based on the use of stable isotopes (e.g., 13C) can be employed to accurately measure in situ PPPico, the time-consuming and labor-intensive shortage of these methods constrain their application in a survey on large spatiotemporal scales. To overcome this shortage, a modified carbon-based ocean productivity model (CbPM) is proposed for estimating the PPPico whose principle is based on the group-specific abundance, cellular carbon conversion factor (CCF), and temperature-derived growth rate of picophytoplankton. Comparative analysis showed that the estimated PPPico using CbPM method is significantly and positively related (r2 = 0.53, P < 0.001, n = 171) to the measured 14C uptake. This significant relationship suggests that CbPM has the potential to estimate the PPPico over large spatial and temporal scales. Currently this model application may be limited by the use of invariant cellular CCF and the relatively small data sets to validate the model which may introduce some uncertainties and biases. Model performance will be improved by the use of variable conversion factors and the larger data sets representing diverse growth conditions. Finally, we apply the CbPM-based model on the collected data during four cruises in the Bohai Sea in 2005. Model-estimated PPPico ranged from 0.1 to 11.9, 29.9 to 432.8, 5.5 to 214.9, and 2.4 to 65.8 mg C m-2 d-1 during March, June, September, and December, respectively. This study shed light on the estimation of global PPPico using carbon-based production model.