Tropical forest CH4: from termite mounds to tower  measurements

2021 ◽  
Author(s):  
Hella van Asperen ◽  
Thorsten Warneke ◽  
Alessandro C De Araújo ◽  
Bruce Forsberg ◽  
Leonardo Ramos de Oliveira ◽  
...  
Keyword(s):  
Tropical Forest ◽  
Flux Chamber ◽  
Termite Mounds ◽  
Forest Region ◽  
Different Types ◽  
Emission Estimate ◽  
Flux Measurements ◽  
Set Up ◽  
Chamber Measurements

<div> <div> <div> <p>Methane (CH<sub>4</sub>) is one of the most important anthropogenic greenhouse gases.  Despite its importance, natural sources of methane, such as tropical wetlands and termites, are still not well understood and a large source of uncertainty in the tropical CH<sub>4</sub> budget. The Amazon rainforest is a key region for the (global) CH<sub>4</sub> budget but, due to its remote location, continous CH<sub>4</sub> concentration and flux measurements are still rare.</p> <p>The 50 m high K34 tower (field site ZF2) is located in a pristine ‘Terra Firme’ tropical forest region 60 km northwest of Manaus (Brazil), and is located next to a waterlogged valley, a possible location for anaerobic CH<sub>4</sub> production. In October 2018, in addition to the existing EC CO<sub>2</sub> system, an in-situ FTIR-analyzer (measuring CO<sub>2</sub>, CO, CH<sub>4</sub>, N<sub>2</sub>O and δ<sup>13</sup>CO<sub>2</sub>) was set up to measure tower profile concentrations, above and below the canopy, continuously. By analyses of vertical and temporal nighttime concentrations patterns, an emission estimate for all gases could be made, and an ecosystem emission of ~1 nmol CH<sub>4</sub> m<sup>-2</sup> s<sup>-1</sup>  was estimated. In addition, by use of different types of flux chambers, possible  CH<sub>4</sub> sinks and sources such as soils, trees, water and termite mounds were measured.</p> <p>By combining tower and flux chamber measurements, the role and magnitude of different ecosystem sources could be assessed. In this presentation, an overview of the measured CH<sub>4</sub> forest concentrations and fluxes will be given.</p> </div> </div> </div>

Tropical forest CH4: from flux chambers to micrometeorological tower measurements

2020 ◽  
Author(s):  
Hella van Asperen ◽  
Thorsten Warneke ◽  
Alessandro Carioca de Araújo ◽  
Bruce Rider Forsberg ◽  
Leonardo Ramos de Oliveira ◽  
...  
Keyword(s):  
Tropical Forest ◽  
Amazon Basin ◽  
Flux Chamber ◽  
System A ◽  
Forest Region ◽  
Amazonian Rain Forest ◽  
Annual Total ◽  
High Precipitation ◽  
Set Up

<p>Methane (CH<sub>4</sub>) is the second most important long-lived anthropogenic atmospheric greenhouse gas. Despite its importance, natural sources of methane, such as tropical wetlands, are still not well understood and a large source of uncertainty to the global CH<sub>4</sub> budget. The Amazonian rain forest is estimated to hold 90-120 Pg of carbon, which is approximately 14-27% of the carbon stored in vegetation worldwide. The region is characterized by high precipitation rates and large wetlands, and it has been estimated that the Amazon basin emits 7% of the annual total CH<sub>4</sub> emissions. Due to its remote location, micro-meteorological measurements are rare and absent for other gases than CO<sub>2</sub>.</p><p>The 50 m high K34 tower (field site ZF2) is located in a pristine tropical forest region 60 km northwest of Manaus (Brazil), and is located next to a waterlogged valley, a possible location for anaerobic CH<sub>4</sub> production. In October 2018, in addition to the existing EC CO<sub>2</sub> system, a Relaxed Eddy Accumulation (REA) system was set up at this tower, connected to an in-situ FTIR-analyzer. This set up continually measures fluxes and concentration profiles of CO<sub>2</sub>, CO, CH<sub>4</sub>, N<sub>2</sub>O and δ<sup>13</sup>CO<sub>2</sub>. In addition, CH<sub>4</sub>, CO<sub>2</sub>, and N<sub>2</sub>O uptake and emission processes were studied by flux chamber measurements in the footprint of the REA tower, focusing on different possible sources (soil, stream, trees and termites). In this presentation, an overview of the measured CH<sub>4</sub> and N<sub>2</sub>O forest concentrations and fluxes will be shown.</p>

Biases in methane chamber measurements in peatlands

2013 ◽  
Vol 27 (2) ◽  
pp. 159-168 ◽  
Author(s):  
R. Juszczak
Keyword(s):  
Methane Flux ◽  
Dynamic Chamber ◽  
Methane Fluxes ◽  
Flux Measurements ◽  
Underestimation Rate ◽  
Methane Measurement ◽  
Linear Technique ◽  
Chamber Measurements ◽  
Calculated Flux

Abstract The paper presents results of CH4 emission measurements at peatland with the application of the dynamic chamber technique. The measurements were conducted in two types of chambers differing in shape, height, volume and technology used to assure their tightness. The study tested how the following factors: 1) forced chamber headspace mixing or its absence, 2) mistakes of the person conducting measurements, 3) improper application of linear technique for calculating CH4 fluxes, and 4) simulated air sampling typical for static chambers, influence the significance of errors and the underestimation rate of CH4 fluxes measured in situ. It was indicated that chamber headspace mixing allows estimating methane fluxes with a smaller error than in the case of measurements conducted without mixing, and CH4 fluxes in such conditions can be 47 to 58% higher (depending on the chamber type) than in a chamber without fans. Using dynamic chambers and a fast analyzer to measure methane fluxes allows shortening the methane measurement process to a few minutes. On the other hand, using static chambers for methane flux measurements may lead to 70% underestimation of the calculated flux.

scholarly journals COMPARISON OF SEDIMENT TRANSPORT MODELS WITH IN-SITU SAND FLUX MEASUREMENTS AND BEACH MORPHODYNAMIC EVOLUTION

2012 ◽  
Vol 1 (33) ◽  
pp. 19
Author(s):  
Adrien Cartier ◽  
Philippe Larroudé ◽  
Arnaud Héquette
Keyword(s):  
Sediment Transport ◽  
Mediterranean Coast ◽  
Sand Transport ◽  
Transport Models ◽  
In Situ Data ◽  
Flux Measurements ◽  
Coastal Sediment Transport ◽  
Set Up ◽  
Sand Flux

The aim of this study is to set up a procedure of linking of three codes to be able to simulate realistic coastal sediment transport and associated morphological change. In order to calibrate sediment transport formulae, comparisons of our simulations were carried out with in-situ data of sand transport measured on macrotidal beaches of northern France on the shore of the English Channel and Dover Strait. This technique of simulation was then used to compare and investigate the efficiency of several sediment transport models on the site of Sète (microtidal beach on the Mediterranean coast) during two storms events.

Pb Electrodeposition in the Presence of Chlorine Ions on Cu(100): An in Situ Optical Reflectivity Difference Study

2003 ◽  
Vol 781 ◽  
Author(s):  
J. Gray ◽  
W. Schwarzacher ◽  
X.D. Zhu
Keyword(s):  
Oblique Incidence ◽  
Opposite Sign ◽  
Bulk Phase ◽  
Phase Layer ◽  
Optical Reflectivity ◽  
Scan Rate ◽  
Different Types ◽  
Chlorine Ions ◽  
High Overpotentials

AbstractWe studied the initial stages of the electrodeposition of Pb in the presence of chlorine ions on Cu(100), using an oblique-incidence optical reflectivity difference (OIRD) technique. The OI-RD results reveal that immediately following the underpotential deposition (UPD) of the first Pb monolayer, two different types of bulk-phase films grow depending upon the magnitude of overpotential and cyclic voltammetry (CV) scan rate. At low overpotentials and/or slow scan rates, we propose that a bulk-phase Pb film grows on top of the UPD monolayer. At high overpotentials and/or fast scan rates, either a PbO, PbCl2, or a rough Pb bulk-phase layer grows on top of the UPD layer such that the reflectivity difference signal from such a film has an opposite sign.

scholarly journals Comparison of Hydrocarbon-Degrading Consortia from Surface and Deep Waters of the Eastern Mediterranean Sea: Characterization and Degradation Potential

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2246
Author(s):  
Georgia Charalampous ◽  
Efsevia Fragkou ◽  
Konstantinos A. Kormas ◽  
Alexandre B. De Menezes ◽  
Paraskevi N. Polymenakou ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Oil Spills ◽  
Eastern Mediterranean ◽  
Sole Source ◽  
Eastern Mediterranean Sea ◽  
Deep Waters ◽  
Degradation Rates ◽  
Polycyclic Aromatic ◽  
Set Up

The diversity and degradation capacity of hydrocarbon-degrading consortia from surface and deep waters of the Eastern Mediterranean Sea were studied in time-series experiments. Microcosms were set up in ONR7a medium at in situ temperatures of 25 °C and 14 °C for the Surface and Deep consortia, respectively, and crude oil as the sole source of carbon. The Deep consortium was additionally investigated at 25 °C to allow the direct comparison of the degradation rates to the Surface consortium. In total, ~50% of the alkanes and ~15% of the polycyclic aromatic hydrocarbons were degraded in all treatments by Day 24. Approximately ~95% of the total biodegradation by the Deep consortium took place within 6 days regardless of temperature, whereas comparable levels of degradation were reached on Day 12 by the Surface consortium. Both consortia were dominated by well-known hydrocarbon-degrading taxa. Temperature played a significant role in shaping the Deep consortia communities with Pseudomonas and Pseudoalteromonas dominating at 25 °C and Alcanivorax at 14 °C. Overall, the Deep consortium showed a higher efficiency for hydrocarbon degradation within the first week following contamination, which is critical in the case of oil spills, and thus merits further investigation for its exploitation in bioremediation technologies tailored to the Eastern Mediterranean Sea.

scholarly journals Selected In Situ Hybridization Methods: Principles and Application

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3874
Author(s):  
Dominika Veselinyová ◽  
Jana Mašlanková ◽  
Katarina Kalinová ◽  
Helena Mičková ◽  
Mária Mareková ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Imaging Techniques ◽  
Cell Communication ◽  
Probe Design ◽  
Rapid Progress ◽  
In Situ Techniques ◽  
Different Types ◽  
Laboratory Procedures ◽  
The Individual

We are experiencing rapid progress in all types of imaging techniques used in the detection of various numbers and types of mutation. In situ hybridization (ISH) is the primary technique for the discovery of mutation agents, which are presented in a variety of cells. The ability of DNA to complementary bind is one of the main principles in every method used in ISH. From the first use of in situ techniques, scientists paid attention to the improvement of the probe design and detection, to enhance the fluorescent signal intensity and inhibition of cross-hybrid presence. This article discusses the individual types and modifications, and is focused on explaining the principles and limitations of ISH division on different types of probes. The article describes a design of probes for individual types of in situ hybridization (ISH), as well as the gradual combination of several laboratory procedures to achieve the highest possible sensitivity and to prevent undesirable events accompanying hybridization. The article also informs about applications of the methodology, in practice and in research, to detect cell to cell communication and principles of gene silencing, process of oncogenesis, and many other unknown processes taking place in organisms at the DNA/RNA level.

Use of a crystallization robot to set up sitting-drop vapor-diffusion crystallization andin situcrystallization screens

2000 ◽  
Vol 33 (2) ◽  
pp. 344-349 ◽  
Author(s):  
Christopher F. Snook ◽  
Michael D. Purdy ◽  
Michael C. Wiener
Keyword(s):  
Membrane Proteins ◽  
Protein Crystallization ◽  
Integral Membrane Proteins ◽  
Vapor Diffusion ◽  
Liquid Handling ◽  
General Utility ◽  
Crystallization Experiments ◽  
Automated Screening ◽  
Set Up

A commercial crystallization robot has been modified for use in setting up sitting-drop vapor-diffusion crystallization experiments, and for setting up protein crystallization screensin situ. The primary aim of this effort is the automated screening of crystallization of integral membrane proteins in detergent-containing solutions. However, the results of this work are of general utility to robotic liquid-handling systems. Sources of error that can prevent the accurate dispensing and mixing of solutions have been identified, and include local environmental, machine-specific and solution conditions. Solutions to each of these problems have been developed and implemented.

Mixing and Comparative Properties of NR Compounds Filled with Different Types of Reinforcing Fillers

2017 ◽  
Vol 266 ◽  
pp. 172-176
Author(s):  
Pattarawadee Maijan ◽  
Nitinart Saetung ◽  
Wisut Kaewsakul
Keyword(s):  
Carbon Black ◽  
Silica Surface ◽  
High Viscosity ◽  
Cure Rate ◽  
Modified Silica ◽  
Reinforcing Fillers ◽  
Silane Coupling ◽  
Different Types ◽  
Cure Time

Mixing behaviors of the compounds filled with different reinforcing fillers were studied in correlation with compound and vulcanizate properties. Four filler systems were used including: 1) silica plus small amount of silane coupling agent; 2) carbon black; 3) pre-modified silica; and 4) silica+silane-carbon black mixed one. The results have shown that silica provides longer optimum cure time and shorter cure rate than carbon black due to accelerator adsorption on silica surface. In addition, owing to highly polar nature on silica surface the silica-based compounds show rather high viscosity, attributed to stronger filler-filler interaction as can be confirmed by Payne effect and reinforcement index. However, the commercial surface treatment or pre-modified form of silica shows superior properties than in-situ modification of silica by silane during mixing, while it gives comparable properties to carbon black-based compound. Tensile properties of vulcanizates show a good correlation with the basic properties of their compounds.

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