scholarly journals Estimating the interconversion between CO2 and organic matter in the environment using mathematical models and some considerations

2020 ◽  
Vol 17 (1) ◽  
pp. 56-67
Author(s):  
Tomás Aquino Portes
Keyword(s):  
Organic Chemistry ◽  
Organic Matter ◽  
Mathematical Models ◽  
Chemical Reactions ◽  
Co2 Concentration ◽  
Compensation Point ◽  
Photosynthetic Organisms ◽  
Co2 Compensation Point ◽  
The Earth ◽  
Organic Products

The aims was to use mathematical models to analyze the interconversion between the amount of organic matter produced and the consequent variation in the concentration of CO2 in the atmosphere and to discuss, supported by the data presented and the literature, possible changes in the Earth's environment. Scientific findings and evidence indicate that the concentrations of CO2 and O2 varied throughout the existence of the Earth. These variations were a consequence of the existing environment in different Eras, resulting in changes in all other processes that depended on these gases. Chemical reactions occurred and organic products such as petroleum arose abiotically. These products gave origin to organic chemistry and drastically reduced the concentration of CO2 and elevated O2 in the atmosphere. In the current plants, for each O2 produced in the photochemical step of photosynthesis, one CO2 is assimilated in the biochemical step. Supported by this relationship and by the results presented in this work, it can be inferred that the first photosynthetic organisms originated on Earth when the concentration of CO2 was possibly at a concentration below 1000 ppm. Biochemistry started with these organisms. The results suggest that the reduction in CO2 concentration was linear in relation to the age of the Earth, before the origin of photosynthetic organisms. This relationship changed with origin of these organisms, due to the major changes that occurred in the environment. There is evidence that in certain periods, CO2 concentrations have been reduced below the CO2 compensation point for certain plants resulting in the extinction of these plants and the organisms that depended on them.

High-throughput chlorophyll fluorescence screening of Setaria viridis for mutants with altered CO2 compensation points

2018 ◽  
Vol 45 (10) ◽  
pp. 1017 ◽  
Author(s):  
Robert A. Coe ◽  
Jolly Chatterjee ◽  
Kelvin Acebron ◽  
Jacqueline Dionora ◽  
Reychelle Mogul ◽  
...  
Keyword(s):  
High Throughput ◽  
Photosynthetic Efficiency ◽  
Co2 Concentration ◽  
Compensation Point ◽  
Wild Type Plant ◽  
Setaria Viridis ◽  
Photosynthetic Pathway ◽  
Ambient Conditions ◽  
Co2 Compensation Point ◽  
A Value

To assist with efforts to engineer a C4 photosynthetic pathway into rice, forward-genetic approaches are being used to identify the genes modulating key C4 traits. Currently, a major challenge is how to screen for a variety of different traits in a high-throughput manner. Here we describe a method for identifying C4 mutant plants with increased CO2 compensation points. This is used as a signature for decreased photosynthetic efficiency associated with a loss of C4 function. By exposing plants to a CO2 concentration close to the CO2 compensation point of a wild-type plant, individuals can be identified from measurements of chlorophyll a fluorescence. We use this method to screen a mutant population of the C4 monocot Setaria viridis (L.)P.Beauv. generated using N-nitroso-N-methylurea (NMU). Mutants were identified at a frequency of 1 per 157 lines screened. Forty-six candidate lines were identified and one line with a heritable homozygous phenotype selected for further characterisation. The CO2 compensation point of this mutant was increased to a value similar to that of C3 rice. Photosynthesis and growth was significantly reduced under ambient conditions. These data indicate that the screen was capable of identifying mutants with decreased photosynthetic efficiency. Characterisation and next-generation sequencing of all the mutants identified in this screen may lead to the discovery of novel genes underpinning C4 photosynthesis. These can be used to engineer a C4 photosynthetic pathway into rice.

scholarly journals Earth CO2 dynamics: from CO2 to organic matter and organic matter back to CO2 – an estimate of fluxes

2020 ◽  
Vol 17 (1) ◽  
pp. 47-55
Author(s):  
Tomás Aquino Portes
Keyword(s):  
Organic Matter ◽  
Carbon Sources ◽  
Value Added ◽  
Co2 Concentration ◽  
The Other ◽  
Biochemical Processes ◽  
Average Value ◽  
The Earth ◽  
Other Hand ◽  
Life On Earth

The Earth CO2 is constantly changing. During photosynthesis CO2 is assimilated and immobilized in the form of organic matter. In the other way around, under the action of chemical and biochemical processes, the CO2 of the organic matter is released again into the atmosphere. The current concentration of CO2 in the atmosphere is about 390 ppm. Based on information from the literature, it is possible to estimate the amount of organic matter produced from the CO2 available in the atmosphere. On the other hand, by incinerating all the plant and animal organic matter on the Earth, it is possible to estimate the amount of CO2 produced and released to the atmosphere. In order to test these hypotheses, mathematical models were developed. By the models it is possible to estimate that if all CO2 in the atmosphere is assimilated via photosynthesis, it would produce 296 Mg.ha-1 of organic matter. On the other hand, by incinerating all vegetable and animal organic matter from the Earth, excluding petroleum, coal and other carbon sources, and considering an average value of 100 Mg.ha-1 the CO2 concentration in the atmosphere would increase by 131.8 ppm. This value added to the existing 390 ppm would raise CO2 concentration to 521.8 ppm. According to the models and results presented, forests may not be as important as carbon accumulators, making the environment conducive to life on Earth, but according to literature they are essential in the formation of rainfalls and maintenance of humidity, especially in areas far from the oceans and seas.

scholarly journals Extraction of organic chemistry grammar from unsupervised learning of chemical reactions

2021 ◽  
Vol 7 (15) ◽  
pp. eabe4166
Author(s):  
Philippe Schwaller ◽  
Benjamin Hoover ◽  
Jean-Louis Reymond ◽  
Hendrik Strobelt ◽  
Teodoro Laino
Keyword(s):  
Organic Chemistry ◽  
Neural Networks ◽  
Chemical Synthesis ◽  
Unsupervised Learning ◽  
Chemical Reactions ◽  
Data Driven ◽  
Experimental Task ◽  
Rule Based ◽  
Atom Mapping ◽  
Mapping Information

Humans use different domain languages to represent, explore, and communicate scientific concepts. During the last few hundred years, chemists compiled the language of chemical synthesis inferring a series of “reaction rules” from knowing how atoms rearrange during a chemical transformation, a process called atom-mapping. Atom-mapping is a laborious experimental task and, when tackled with computational methods, requires continuous annotation of chemical reactions and the extension of logically consistent directives. Here, we demonstrate that Transformer Neural Networks learn atom-mapping information between products and reactants without supervision or human labeling. Using the Transformer attention weights, we build a chemically agnostic, attention-guided reaction mapper and extract coherent chemical grammar from unannotated sets of reactions. Our method shows remarkable performance in terms of accuracy and speed, even for strongly imbalanced and chemically complex reactions with nontrivial atom-mapping. It provides the missing link between data-driven and rule-based approaches for numerous chemical reaction tasks.

Data augmentation and transfer learning strategies for reaction prediction in low chemical data regimes

2021 ◽  
Author(s):  
Yun Zhang ◽  
Ling Wang ◽  
Xinqiao Wang ◽  
Chengyun Zhang ◽  
Jiamin Ge ◽  
...  
Keyword(s):  
Organic Chemistry ◽  
Deep Learning ◽  
Drug Discovery ◽  
Research And Development ◽  
Learning Strategies ◽  
Transfer Learning ◽  
Chemical Reactions ◽  
Data Augmentation ◽  
Learning Method ◽  
Reaction Prediction

An effective and rapid deep learning method to predict chemical reactions contributes to the research and development of organic chemistry and drug discovery.

The influence of red and blue light on the rate of photosynthesis and the CO2 compensation point at various oxygen concentrations

1970 ◽  
Vol 48 (6) ◽  
pp. 1251-1257 ◽  
Author(s):  
N. P. Voskresenskaya ◽  
G. S. Grishina ◽  
S. N. Chmora ◽  
N. M. Poyarkova
Keyword(s):  
Nicotiana Tabacum ◽  
Blue Light ◽  
Photosynthetic Rate ◽  
Prolonged Exposure ◽  
Red Light ◽  
Compensation Point ◽  
Gas Analyzer ◽  
Co2 Compensation Point ◽  
Rate Of Photosynthesis ◽  
Light Inhibition

Apparent photosynthesis of attached leaves of Phaseolus vulgaris, Vicia faba, Pisum sativum, and Nicotiana tabacum at various intensities of blue and red light was measured by infrared CO2 gas analyzer in a closed system. Simultaneously the CO2 compensation point was measured.It was found that light-limited photosynthetic rate in blue light was equal to or more than that in red light. Inhibition of photosynthesis, which sometimes occurred at light-saturated intensities of blue light, could be avoided by addition of red light, prolonged exposure of the plants to blue light, or by lowering the O2 concentration. Accordingly, the increase of photosynthetic rate due to change of O2 concentration from 21 to 3% O2 is higher in blue light only when photosynthesis is inhibited by blue light at 21% O2. The data on the action of blue and red light on the CO2 compensation point seems to exclude the activation of photorespiration by blue light.The possible effects of blue light on apparent photosynthesis are discussed on the basis of the results presented.

scholarly journals Adsorption of tetracyclines on marine sediment during organic matter diagenesis

2013 ◽  
Vol 67 (11) ◽  
pp. 2616-2621 ◽  
Author(s):  
Ying-Heng Fei ◽  
Xiao-Yan Li
Keyword(s):  
Experimental Study ◽  
Organic Matter ◽  
Marine Sediment ◽  
Dynamic Process ◽  
Emerging Pollutants ◽  
Experimental Results ◽  
Sediment Organic Matter ◽  
Artificial Sediment ◽  
Adsorption Sites ◽  
Organic Products

The effect of decomposition and diagenesis of sediment organic matter (SOM) on the adsorption of emerging pollutants by the sediment has been seldom addressed. In the present experimental study, artificial sediment was incubated to simulate the natural organic diagenesis process and hence investigate the influence of organic diagenesis on the adsorption of tetracyclines (TCs) by marine sediment. During a period of 4 months of incubation, SOM initially added into the sediment underwent biodegradation and diagenesis. The results showed an early decrease in TC adsorption by the sediment, which was likely caused by the competition between the microbial organic products and TC molecules for the adsorption sites. Afterward, TC adsorption by the sediment increased significantly, which was mainly due to the accumulation of condensed SOM. The experimental results indicate the interactions between TCs and the sediment during the dynamic process of SOM diagenesis. Moreover, the remaining SOM is shown to have an increasing affinity with the antibiotics.

scholarly journals Liquid-phase exfoliated graphene: functionalization, characterization, and applications

2014 ◽  
Vol 5 ◽  
pp. 2328-2338 ◽  
Author(s):  
Mildred Quintana ◽  
Jesús Iván Tapia ◽  
Maurizio Prato
Keyword(s):  
Organic Chemistry ◽  
Liquid Phase ◽  
Chemical Reactions ◽  
Functional Materials ◽  
Atomic Plane ◽  
Graphene Sheets ◽  
Exfoliated Graphene ◽  
Graphene Functionalization ◽  
Chemical Strategies ◽  
Insight Into

The development of chemical strategies to render graphene viable for incorporation into devices is a great challenge. A promising approach is the production of stable graphene dispersions from the exfoliation of graphite in water and organic solvents. The challenges involve the production of a large quantity of graphene sheets with tailored distribution in thickness, size, and shape. In this review, we present some of the recent efforts towards the controlled production of graphene in dispersions. We also describe some of the chemical protocols that have provided insight into the vast organic chemistry of the single atomic plane of graphite. Controlled chemical reactions applied to graphene are expected to significantly improve the design of hierarchical, functional platforms, driving the inclusion of graphene into advanced functional materials forward.

scholarly journals Oxygen uptake during mineralization of photosynthesized carbon from phytoplankton of the Barra Bonita Reservoir: a mesocosm study

2008 ◽  
Vol 68 (1) ◽  
pp. 115-122 ◽  
Author(s):  
MB. Cunha-Santino ◽  
SP. Gouvêa ◽  
I. Bianchini Jr ◽  
AAH. Vieira
Keyword(s):  
Electrical Conductivity ◽  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Dissolved Oxygen ◽  
Water Samples ◽  
Microbial Respiration ◽  
Co2 Concentration ◽  
Ph Values ◽  
Organic Products ◽  
Aulacoseira Granulata

This study aimed to discuss and describe the oxygen consumption during aerobic mineralization of organic products (cells and excretion products) from five unialgal cultures: Cryptomonas sp., Microcystis aeruginosa, Anabaena spiroides, Thalassiosira sp. and Aulacoseira granulata. These species were isolated from Barra Bonita reservoir (22º 29’ S and 48º 34’ W) and cultivated in the laboratory. From each culture, two decomposition chambers were prepared; each chamber contained about 130 mg.L-1 of carbon from water samples of the reservoir. The chambers were aerated and incubated in the dark at 20.0 ºC. The concentration of dissolved oxygen, pH values and electrical conductivity of the solutions were determined during a period of 10 days. The results indicated increases in oxygen consumption for all the solutions studied and also for electrical conductivity. The pH values presented a decreasing tendency throughout the experiment. Oxygen consumption varied from 43 (Aulacoseira granulata chamber) to 345 mg O2 g-1 C (Anabaena spiroides chamber). Decrease in pH values was probably due to increase in CO2 concentration from microbial respiration. Increase in electrical conductivity might be due to the liberation of ions during decomposition. The results demonstrate the potentiality of the studied genera in influencing oxygen availability followed by a die-off event. It also indicates the possibility of changing of the electrical conductivity and pH values in the water column due the aerobic algae mineralization.

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