ESTIMASI KANDUNGAN KARBON ATAS PERMUKAAN TANAH PADA HUTAN ALAM DAN HUTAN REHABILITASI MANGROVE TAMAN HUTAN RAYA NGURAH RAI BALI

Mangroves are ecosystems that play an important role in absorbing and storing carbon from the air, one of which is in the form of mangrove vegetation biomass. As the largest mangrove area in Bali which consists of natural and rehabilitation vegetation, Taman Hutan Raya Ngurah Rai has a large potential for high carbon content. To determine the carbon potential of mangroves in natural and rehabilitation forests, a research was conducted using the purposive sampling method based on the canopy density level which was divided into 5 categories, namely very rare, rare, moderate, dense, very dense. Based on the results of measurements and calculations, the total carbon content of Ngurah Rai Grand Forest Park is 86.521,74 tons C, consisting of natural forest content 66.857,53 tons C and rehabilitation forest 19.664,21 tons C. Above ground carbon per hectare in natural forest was not significantly different from the above ground carbon per hectare in rehabilitation forest, these results indicate that the carbon content per hectare of rehabilitation forest over 20 years old is almost close to the carbon content per hectare in natural forest. The diameter of trees and vegetation types did not significantly affect the carbon content of mangroves, these results indicate that the increase in carbon stocks in each type of vegetation in natural and rehabilitation forests is in line with diameter growth. Keywords: Biomass; Density; Diameter; Canopy.

A Circular Approach for Making Fischer–Tropsch E-fuels and E-chemicals From Biogas Plants in Europe

In a mature circular economy model of carbon material, no fossil compound is extracted from the underground. Hence, the C1 molecule from non-fossil sources such as biogas, biomass, or carbon dioxide captured from the air represents the raw material to produce various value-added products through carbon capture and utilization routes. Accordingly, the present work investigates the utilization of the full potential of biogas and digestate waste streams derived from anaerobic digestion processes available at the European level to generate synthetic Fischer–Tropsch products focusing on the wax fraction. This study estimates a total amount of available carbon dioxide of 33.9 MtCO2/y from the two above-mentioned sources. Of this potential, 10.95 MtCO2/y is ready-to-use as separated CO2 from operating biogas-upgrading plants. Similarly, the total amount of ready-to-use wet digestate corresponds to 29.1 Mtdig/y. Moreover, the potential out-take of Fischer–Tropsch feedstock was evaluated based on process model results. Utilizing the full biogas plants’ carbon potential available in Europe, a total of 10.1 Mt/h of Fischer–Tropsch fuels and 3.86 Mt/h of Fischer–Tropsch waxes can be produced, covering up to 79% of the global wax demand. Utilizing only the streams derived from biomethane plants (installed in Europe), 136 ton/h of FT liquids and 48 ton/h of FT wax can be generated, corresponding to about 8% of the global wax demand. Finally, optimal locations for cost-effective Fischer–Tropsch wax production were also identified.

Future low-carbon electricity in Africa: how much material is needed?

African countries are expected to experience some of the worst climate effects, while trying to provide higher electricity access and increase wellbeing.Concrete, steel, and aluminium pre­sent the largest opportunities for action, given their high mass or embodied emissions projections.Embodied emissions related to material use for electricity plants are evaluated in three scenarios: a refer­ence scenario, and two scenarios related to the Paris Agreement (where renewable energy increases), resulting in higher embodied emissions as renewables are integrated.Pursuing strategies to increase the use of renewables should be done along material efficiency strategies to reach the total low-carbon potential.

Carbon stock and vegetation estimation the abandoned pond, Pulau Sembilan, North Sumatra, Indonesia

The purpose of the study was to determine the species vegetation and carbon stock assessment derived from abandoned aquaculture ponds. Analysis of plant (tree, sapling, and seedling) was performed at Pulau Sembilan, Langkat, North Sumatra, Indonesia. The stage of the seedlings, saplings, and trees was analyzed from four transects. Each transect contained 100 m in length. Each estimated plot of a total of four transects comprised of 30 plots. The abandoned pond was dominated by Rhizophora apiculata and Bruguiera parviflora, the lowest on the species of Morinda citrifolia and Rhizophora mucronata. The diversity index of Shannon-Weiner was 1.44-1.72. The total biomass in the pond was 4,557.43 k/ha with a carbon potential of 2.10 tons/ha.

Analisis Perubahan Penutupan Lahan dan Potensi Karbon di Taman Hutan Raya Pocut Meurah Intan, Aceh Indonesia

Perubahan penutupan lahan merupakan sektor penyumbang emisi gas rumah kaca terbesar, termasuk di dalamnya adalah pemanfaatan lahan. Analisis tutupan lahan menjadi bagian penting dalam menentukan jumlah potensi karbon yang tersedia. Penelitian bertujuan untuk menganalisis perubahan tutupan lahan dari tahun 2003 hingga 2018 dan menghitung potensi karbon di Taman Hutan Raya Pocut Meurah Intan dengan luas objek penelitian 6.215 ha. Penelitian dilaksanakan selama 5 (lima) bulan. Penelitian ini menggunakan metode stock difference, yaitu metode perhitungan luas tutupan lahan dan stok karbon pada dua titik waktu. Hasil penelitian menunjukkan bahwa perubahan luas tertinggi tahun 2018 seluas 263 ha dan terendah tahun 2009 seluas 108 ha. Lahan terbuka meningkat seluas 100 ha, pemukiman 81 ha, semak belukar 65 ha, pertanian lahan kering campur semak 32 ha. Sementara hutan lahan kering sekunder menurun 79 ha, hutan tanaman 76 ha, savanna 21 ha dan pertanian lahan kering 103 ha. Selama kurun waktu 15 tahun berdasarkan kelas penutupan lahan, cadangan karbon tertinggi pada tahun 2003 sebesar 656.053 ton, terendah tahun 2012 sebesar 620.992 ton. Laju serapan karbon tertinggi pada periode tahun 2015-2018 sebesar 94.615 ton CO2 dan terendah pada periode tahun 2009-2012 sebesar 1.981 ton CO2. Laju emisi tertinggi pada periode tahun 2003-2006 sebesar 79.559 ton CO2 dan terendah periode tahun 2006-2009 sebesar 9.069 ton CO2. Peningkatan serapan karbon diakibatkan oleh meningkatnya luas tutupan lahan pada hutan lahan kering sekunder dan adanya pemanfaatan lahan untuk pertanian lahan kering campur semak.ABSTRACTChanges in land cover are the largest contributor to greenhouse gas emissions, including land use. Land cover analysis is an important part in determining the potential amount of carbon available. The study aims to analyze changes in land cover from 2003 to 2018 and calculating the carbon potential in the Pocut Meurah Intan Forest Park with a research object area of 6,215 ha. The research was conducted for 5 (five) months. This research uses the stock difference method, namely the method of calculating land cover area dan stok karbon pada dua titik waktu. The results showed that the highest area change in 2018 was 263 ha and the lowest was in 2009 at 108 ha. Open land increased by 100 ha, settlement 81 ha, scrub 65 ha, dry land agriculture mixed with shrubs 32 ha. Meanwhile, secondary dry land forest decreased by 79 ha, plantation forest 76 ha, savanna 21 ha and dry land agriculture 103 ha. Over a 15 year period based on land cover class, the highest carbon stock in 2003 was 656,053 tons, the lowest was in 2012 at 620,992 tons. The highest carbon absorption rate in the 2015-2018 period was 94,615 tons of CO2 and the lowest was in the 2009-2012 period of 1,981 tons of CO2. The highest emission rate in the 2003-2006 period was 79,559 tonnes of CO2 and the lowest for the 2006-2009 period was 9,069 tonnes of CO2. The increase in carbon sequestration is caused by the increase in land cover in secondary dryland forest and the use of land for mixed dry land agriculture.

Factors Affecting the Hardness Characteristics of Microstructures in Gas Carburized Chromium Alloy Steels

We analyzed the factors affecting the gas carburizing microstructure of parts for constant velocity joints. Gas carburizing 0.15-0.20C1.13-1.14Cr chromium alloy steel used in automobile drive units is characterized by changing the properties of the carburizing layer in the depth direction. The experimental conditions were set to enable field application. The components of the specimen to be used for gas carburization were analyzed by X-ray fluorescence. Changes in the mechanical properties of the carburized layer were analyzed by micro-hardness, microstructure, and carburizing content. The gas carburization cycle was selected based on the simulation results. The characteristics change before and after carburization of two samples with different carbon and chromium content were analyzed. The carburization temperature that can be used for manufacturing automobile parts was 930°C, the carbon potential required for carburization was 0.90wt%, and the carbon potential required for diffusion was 0.75wt%. The inner and outer hardness values of the carburized layer satisfying the effective hardening depth of 550Hv were 400Hv-740Hv. In the case of 0.20C alloy steel, the effective hardening depth with a carburizing amount of 0.36wt% and a hardness of 550Hv was 1.467 mm. also in the case of 0.15C steel, its effective hardening depth was 0.746 mm. The simulation results for selecting the carburizing heat treatment conditions and the carbon change in the carburizing layer showed a similar trend. The carburizing structure related to hardness change was martensite. As a result of EPMA, SEM, and XRD analysis, the amount of carburized and the amount of martensite structure correlated, and the martensite increased as the amount of carburized increasing. As a result of EPMA analysis, the smaller the carburizing content the greater the depth of carburization. We intend to proceed with optimization conditions for mass production in connection with wear resistance and fatigue. It is expected that these results will contribute to the improvement of durability of automobile driving parts.

Remediation of antibiotic and heavy metal pollution in marine environment

<p>Pollution of marine environment by antibiotics and/or heavy metals is a serious global issue. Remediation of polluted marine environments is urgently needed for achieving the United Nations Sustainable Development Goals (SDGs) to end poverty and protect the planet from degradation. Biochar, as an environmentally friendly material, has been widely used as adsorbents to remediate contaminated soil or fresh water. However, application of biochar in remediation of marine environment is poorly understood. Therefore, a batch of biochars produced from pyrolysis of two marine algae residues, Enteromorpha (Enteromorpha prolifera) and blended seaweed wastes, at 300–700 °C was used to investigate their performance in sulfamethoxazole (SMX) sorption in seawater. Additionally, a modified biochar (MBC) was prepared by pyrolyzing AlCl<sub>3</sub> pretreated sawdust to improve their performance in remediating a marine sediment contaminated with heavy metals and antibiotics using two mesocosmic experiments. The results showed the algae-derived biochars had relatively low C content, but high contents of O- and S-containing functional groups and crystalline minerals associated with S, Ca, K, and Mg. The maximum adsorption capacity of these algae-derived biochars to SMX was 4880 mg kg<sup>-1</sup>, equivalent to a commercial coconut shell derived activated carbon. Potential mechanisms responsible for the SMX sorption mainly included pore-filling, cation bridging, negative charge-assisted H-bond [(–)CAHB], and π-π EDA interaction. The surface of MBC was rough with layered homogeneous sheets, and the nano-scale Al minerals formed on the C matrix. Moreover, its settling properties and adsorption capacities to Cu, Cd, SMX, and tetracycline (TC) were highly improved relative to the unmodified sawdust derived biochar (SBC). As a result, addition of MBC at 4% (w/w) performed  better in improving the survival rate and condition index of the clams in the contaminated sediments than SBC. Furthermore, MBC application decreased bioaccumulation of Cu and Cd in the clams. Both SBC and MBC increased the microbial abundance and diversity in the contaminated sediments, and MBC decreased the abundance of Cu resistant bacteria (e.g., Firmicute and Gemmatimonadetes). For the sediment contaminated by antibiotics, lower content of SMX and TC in the overlying water and pore water was observed in the sediment amended with MBC than SBC, leading to the reduction of total antibiotic resistance genes. Therefore, these findings show the potential of functional/modified biochar to remediate marine sediments contaminated with heavy metals and antibiotics.</p>

Applying Molecular Phenotyping Tools to Explore Sugarcane Carbon Potential

Sugarcane (Saccharum spp.), a C4 grass, has a peculiar feature: it accumulates, gradient-wise, large amounts of carbon (C) as sucrose in its culms through a complex pathway. Apart from being a sustainable crop concerning C efficiency and bioenergetic yield per hectare, sugarcane is used as feedstock for producing ethanol, sugar, high-value compounds, and products (e.g., polymers and succinate), and bioelectricity, earning the title of the world’s leading biomass crop. Commercial cultivars, hybrids bearing high levels of polyploidy, and aneuploidy, are selected from a large number of crosses among suitable parental genotypes followed by the cloning of superior individuals among the progeny. Traditionally, these classical breeding strategies have been favoring the selection of cultivars with high sucrose content and resistance to environmental stresses. A current paradigm change in sugarcane breeding programs aims to alter the balance of C partitioning as a means to provide more plasticity in the sustainable use of this biomass for metabolic engineering and green chemistry. The recently available sugarcane genetic assemblies powered by data science provide exciting perspectives to increase biomass, as the current sugarcane yield is roughly 20% of its predicted potential. Nowadays, several molecular phenotyping tools can be applied to meet the predicted sugarcane C potential, mainly targeting two competing pathways: sucrose production/storage and biomass accumulation. Here we discuss how molecular phenotyping can be a powerful tool to assist breeding programs and which strategies could be adopted depending on the desired final products. We also tackle the advances in genetic markers and mapping as well as how functional genomics and genetic transformation might be able to improve yield and saccharification rates. Finally, we review how “omics” advances are promising to speed up plant breeding and reach the unexplored potential of sugarcane in terms of sucrose and biomass production.