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.

Fluidized Bed Combustion and Gasification of Fossil and Renewable Slurry Fuels

This article provides a comprehensive review of the state of the art and more recent developments of the thermochemical treatments of slurry fuels in fluidized beds (FB). The review focuses on FB combustion and gasification of slurry fuels based on coal, biomass, sludge, and wastes from industry, agriculture, and the civil sector. The investigations at research and industrial levels over the last decades are presented and discussed, highlighting the adopted technological solutions, the results in terms of feasibility and efficiency, and the perspectives of future development. The different behavior between bubbling and circulating beds was addressed, in particular the optimal choice depending on the process (combustion/gasification/pyrolysis) and fuel properties (e.g., water content). Fundamental studies on interactions between the slurry fuels and the hot bed materials are also reviewed. The cumulative trend of reviewed investigations over the last decades depicts the abandonment of coal-based mixtures used in large plants, and the growing interest in the use of biomass-based slurries for small size application. In this respect, the shift from coal to biomass opens new challenges because of the different properties of biomass (density, fibrous structure, spontaneous degradation, hydrophilic behavior, etc.). Biomass-based slurries circumvent problems posed by using solid dry biomass, particularly in handling, storing, and feeding. Although slurry fuels represent a narrow sector, the results of the research investigations and the experience gained with coal can be exploited to contribute to the achievement of a circular approach based on renewable resources in the near future.

Quantifying status and trends from monitoring surveys: application to Pygmy Whitefish (Prosopium coulterii) in Lake Superior

Population assessments of fish species often rely on data from surveys with different objectives such as measuring biodiversity or community dynamics. These surveys often contain spatial-temporal dependencies that can greatly influence conclusions drawn from analyses. Pygmy whitefish (PWF, Prosopium coulterii) populations in Lake Superior were recently assessed as Threatened by the Committee on the Status of Endangered Species in Canada which motivated a thorough analysis of available data to improve our understanding of its population status. The U.S. Geological Survey conducts annual bottom trawl surveys in Lake Superior that commonly captures PWF. We used these data (1989-2018) to model temporal trends in PWF biomass-density and make lake-wide population projections. We used a Bayesian approach, Integrated Nested Laplace Approximation (INLA), and compared the impact of including different random structures on model fit. Inclusion of spatial structure improved model fit and conclusions differed from models omitting random effects. PWF populations have experienced periodic fluctuations in biomass-density since 1989, though 2018 may represent the lowest density in the 30-year time series. Lake-wide biomass was estimated to be 71.5t.

A global map of root biomass across the world's forests

As a key component of the Earth system, roots play a key role in linking Earth's lithosphere, hydrosphere, biosphere and atmosphere. Here we combine 10 307 field measurements of forest root biomass worldwide with global observations of forest structure, climatic conditions, topography, land management and soil characteristics to derive a spatially explicit global high-resolution (∼ 1 km) root biomass dataset, including fine and coarse roots. In total, 142 ± 25 (95 % CI) Pg of live dry-matter biomass is stored belowground, representing a global average root : shoot biomass ratio of 0.25 ± 0.10. Earlier studies (Jackson et al., 1997; Robinson, 2007; Saugier et al., 2001) are 44 %–226 % larger than our estimations of the total root biomass in tropical, temperate and boreal forests. The total global forest root biomass from a recent estimate (Spawn et al., 2020) is 24 % larger than this study. The smaller estimation from this study is attributable to the updated forest area, spatially explicit aboveground biomass density used to predict the patterns of root biomass, new root measurements and the upscaling methodology. We show specifically that the root shoot allometry is one underlying driver that has led to methodological overestimation of root biomass in previous estimations. Raw datasets and global maps generated in this study are deposited at the open-access repository Figshare (https://doi.org/10.6084/m9.figshare.12199637.v1; Huang et al., 2020).

Real-Time Monitoring of Microalgal Biomass in Pilot-Scale Photobioreactors Using Nephelometry

The increasing cultivation of microalgae in photobioreactors warrants efficient and non-invasive methods to quantify biomass density in real time. Nephelometric turbidity assessment, a method that measures light scatter by particles in suspension, was introduced already several decades ago but was only recently validated as a high-throughput tool to monitor microalgae biomass. The light scatter depends on the density of the suspended particles as well as on their physical properties, but so far there are hardly any accounts on how nephelometric assessment relates to classic methods such as dry weight and spectrophotometric measurement across a broad biomass density range for different microalgae species. Here, we monitored biomass density online and in real time during the semi-continuous cultivation of three commercial microalgae species Chloromonas typhlos, Microchloropsis gaditana and Porphyridium purpureum in pilot-scale photobioreactors, and relate nephelometric turbidity to dry weight and optical density. The results confirm a relatively strong (R2 = 0.87–0.93) and nonlinear relationship between turbidity and biomass density that differs among the three species. Overall, we demonstrate how nephelometry can be used to monitor microalgal biomass in photobioreactors, and provide the necessary means to estimate the biomass density of the studied species from turbidity data to facilitate automated biomass monitoring.

Transcriptomics and Metabolomics Analyses Provide Novel Insights into Glucose-Induced Trophic Transition of the Marine Diatom Nitzschia laevis

Diatoms have important ecological roles and are natural sources of bioactive compounds. Nitzschia laevis is a member of marine diatoms that accumulates high-value products including fucoxanthin and eicosapentaenoic acid (EPA). In this study, physiological data showed that comparing to autotrophic growth, mixotrophic cultivation with glucose supplementation led to a decrease of chlorophyll and fucoxanthin content in N. laevis, and an increase of biomass density and EPA yield. To further examine the metabolic barriers for fucoxanthin and EPA biosynthesis, comparative transcriptomic and metabolome analyses were conducted, with a focus on the genes related to carotenoids biosynthesis and fatty acid metabolism. The results indicated that phytoene desaturase (PDS) and zeta-carotene isomerase (ZISO) could be the rate-limiting enzymes in carotenoid biosynthesis. The transcription regulation of 3-ketoacyl-CoA synthase (KCS) and elongation of very long chain fatty acids protein (EVOVL) are important contributors associated with polyunsaturated fatty acids (PUFAs) accumulation. Furthermore, we also investigated the glucose-associated regulatory genes using weighted gene co-expression network analysis, and identified potential hub genes linked with cell cycle, carbohydrate metabolism, purine biosynthesis, and lipid metabolism. This study offers a high-quality transcriptome resource for N. laevis and provides a molecular framework for further metabolic engineering studies on fucoxanthin and EPA production.

Utilização da técnica de liquefação visando o adensamento de biomassas / Use of the liquefaction process to higher biomass density

O uso da biomassa para a produção de produtos químicos denominados “bioprodutos” tem sido investigado para a produção de biomateriais e biocombustíveis, a fim de substituir a matéria-prima sintética oriunda dos compostos do petróleo. Nesse contexto, a liquefação surge como um processo promissor para transformar matéria orgânica em poliol e aumentar a densidade da biomassa. O presente trabalho investigou o processo de liquefação de três resíduos lignocelulósicos (casca de mandioca, bagaço de limão e casca de arroz), em temperaturas moderadas (100, 150 e 200 ºC) e em três tempos (30, 60 e 90 minutos). Os polióis foram sintetizados a partir da liquefação da biomassa nas condições: razão 2: 1 entre solvente (glicerol) e biomassa e 7 % em massa de ácido sulfúrico concentrado (catalisador). A partir deste trabalho observou-se que as condições de processo e a composição da biomassa influenciaram no rendimento da liquefação. Em condições de temperatura moderada, os valores de rendimento de liquefação do bagaço de limão foram acima de 80 % em massa. Para a casca da mandioca, os rendimentos alcançaram valores acima de 77 % em massa, nas corridas experimentais a 100 ºC e em todos os intervalos de tempo. A liquefação da casca de arroz obteve valores de rendimento abaixo de 54 % em massa para todas as condições de processo. Esses resultados podem ser devidos ao maior teor de cinzas e lignina na casca de arroz. De acordo com os resultados, as biomassas em estudo apresentam potencial para a produção de poliol, por meio do processo de liquefação.