scholarly journals Modeling banded vegetation patterns in semiarid regions: Interdependence between biomass growth rate and relevant hydrological processes

2007 ◽  
Vol 43 (4) ◽  
Author(s):  
N. Ursino
Keyword(s):  
Growth Rate ◽  
Hydrological Processes ◽  
Vegetation Patterns ◽  
Biomass Growth ◽  
Semiarid Regions ◽  
Banded Vegetation

Irregular Striped Vegetation Patterns in Arid and Semiarid Regions Resulted from Oscillatory Instability

2014 ◽  
Vol 707 ◽  
pp. 263-266
Author(s):  
Tou Sheng Huang ◽  
Hua Yong Zhang ◽  
Fei Fan Zhang
Keyword(s):  
Pattern Formation ◽  
Vegetation Pattern ◽  
Theoretical Explanation ◽  
Ecological Systems ◽  
Oscillatory Instability ◽  
Vegetation Patterns ◽  
Modified Model ◽  
Semiarid Regions ◽  
Nonlinear Mechanism ◽  
Arid And Semiarid

Striped vegetation pattern formation in arid and semiarid regions has attracted many researchers in ecological field. In this research, we modify the classical Klausmeier model and study nonlinear mechanism of oscillatory instability which can also possibly lead to pattern formation in ecological systems. Via simulation, irregular striped vegetation patterns are numerically obtained for the modified model. From the mechanism of oscillatory instability, this research provides a theoretical explanation for the formation of irregular striped vegetation patterns in nature.

scholarly journals Investigation of a new effective bacterium for cellulosic degradation

2021 ◽  
Author(s):  
Weining Lin
Keyword(s):  
Growth Rate ◽  
Mathematical Models ◽  
Incubation Temperature ◽  
Biogas Production ◽  
Substrate Utilization ◽  
Gas Production ◽  
Biomass Growth ◽  
Growth Substrate ◽  
Wide Range ◽  
Modelling Approach

Clostridium phytofermentans, a newly isolated mesophilic anaerobic bacterium from forest soil, has received considerable attention for its potential application in producing ethanol directly from cellulose. This microorganism produces ethanol, acetate, CO₂ and H₂ as major metabolites from cellulose. Potential applications of this research include the transformation of waste materials into valuable products, such as fuels and organic acids. As an initial part of a multi-staged project, this study is to focus on the characerization of this microorganism growth and to verify the bacterium kinetics, including biomass growth, substrate utilization, and gas production. A series of batch fermentation experiments using cellulose substrate (GS-2C) was performed under the incubation temperature of 37°C. To investigate the effects of pH and substrate concentration (S₀) on growth, 12 trial experiments were conducted with various controlled pH values (7.0 to 8.5) and with various initial cellulose concentration settings (0.1 to 6.0 g/L). Our experimental results showed that the optimal growth condition for C. phytofermentans in batch culture was at pH = 8.4 amd S₀ = 6.0 g/L. Under such condition, the maximum growth rate of 0.37h⁻¹ was observed. Comparing results with other celluloytic clostridium studies, relatively high biomass growth rate using C. phytofermentans is confirmed by our experiments. Mathematical models, using a combination modelling approach with the logistic equation. Monod model, and Luedeking-Piret model, were developed for biomass growth, substrate degradation, and biogas production, respectively, base on our experiment results. This study demonstrated the determination of the four parameters (µmax, Ks, Y, and Smin), which can describe satisfactorily growth or degradation phenomena, using the proposed integration modelling approach. The experiments conducted under wide range conditions, such as changing pH and S₀, not only provide insight into growth kinetics but also provide an opportunity to evaluate the performance of the mathematical models and understand their limitations. This leads to look for improvement or modification to the models. It is foreseen that the findings in this study will enhance the overall understanding of the kinetics of growth and substrate utilization and product formation of this bacterium, and provide important information on the design of the bench-scale anaerobic bioreactor for future studies.

scholarly journals Influence of Engineered Microorganisms on Vermicomposting of Pre-processed Vegetable Waste

2018 ◽  
Vol 7 (3.12) ◽  
pp. 784
Author(s):  
Senthilkumar Palaniappan ◽  
Murugappan Alagappan
Keyword(s):  
Growth Rate ◽  
High Volume ◽  
Volume Reduction ◽  
Optimum Level ◽  
Biomass Growth ◽  
Vegetable Waste ◽  
High Biomass ◽  
Land Area ◽  
Set Up ◽  
Substrate Depth

The low optimum level of vermi pile depth (10 cm-15 cm) warrants encroachment of large land area and consume more time in the vermicomposting process.  In engineered vermicomposting, the acceleration of digestion of high volume of waste was done by eliminating the pre-composting and introducing pre-processing the waste.  This process involves chopping, pulverizing, stocking, and drying the waste followed by injecting the engineered microorganisms (EM) at various depths in vermi bin during the vermicomposting process. Pre-processing and injection of EM enabled to increase the substrate depth by two-to-three-fold (30 cm).  Experimentation was conducted in five vermi bins with same quantity of worms (100 gms of E. fetida in each bin), with different stock loads of EM  (0.3ml, 0.4ml, 0.5ml, 0.6ml and 0.7ml) named as Bin 1, Bin 2, Bin 3, Bin 4 and Bin 5 respectively.  In parallel, a control (Bin C1) and conventional (Bin C2) vermi bin were also set up to compare the differences observed.  The outcome of the study clearly showed that the bin loaded with 0.7ml EM (Bin 5) stock achieved high volume reduction (70%). Moreover, the trail unit loaded with 0.5ml of EM stock (Bin 3) exhibited high biomass growth rate than its counter trail units.   

scholarly journals Regular and Irregular Vegetation Pattern Formation in Semiarid Regions: A Study on Discrete Klausmeier Model

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Huayong Zhang ◽  
Tousheng Huang ◽  
Liming Dai ◽  
Ge Pan ◽  
Zhao Liu ◽  
...  
Keyword(s):  
Pattern Formation ◽  
Discrete Model ◽  
Theoretical Models ◽  
Vegetation Pattern ◽  
Vegetation Patterns ◽  
Vegetation Types ◽  
Semiarid Regions ◽  
Parametric Data ◽  
Nonlinear Mechanism ◽  
Important Field

The research on regular and irregular vegetation pattern formation in semiarid regions is an important field in ecology. Applying the framework of coupled map lattice, a novel nonlinear space- and time-discrete model is developed based on discretizing the classical Klausmeier model and the vegetation pattern formation in semiarid regions is restudied in this research. Through analysis of Turing-type instability for the discrete model, the conditions for vegetation pattern formation are determined. The discrete model is verified by Klausmeier’s results with the same parametric data, and shows advantages in quantitatively describing diverse vegetation patterns in semiarid regions, such as the patterns of regular mosaicirregular patches, stripes, fractured stripesspots, and stripes-spots, in comparing with former theoretical models. Moreover, the discrete model predicts variations of rainfall and vegetation types can cause transitions of vegetation patterns. This research demonstrates that the nonlinear mechanism of the discrete model better captures the diversity and complexity of vegetation pattern formation in semiarid regions.

scholarly journals OPTIMALIZATION OF PHOTOREACTOR GEOMETRY FOR THE CULTIVATION OF CHLAMYDOMONAS REINHARDTII

2018 ◽  
Vol 58 (2) ◽  
pp. 92
Author(s):  
Roman Fekete ◽  
Terézia Žáková ◽  
Ľudmila Gabrišová ◽  
Peter Kotora ◽  
Peter Peciar ◽  
...  
Keyword(s):  
Growth Rate ◽  
Chlamydomonas Reinhardtii ◽  
Biomass Yield ◽  
Scale Up ◽  
Model Organism ◽  
Biomass Growth ◽  
Hydrodynamic Conditions ◽  
Optimal Conditions ◽  
Optimal Ratio ◽  
Kinetics Of

At the present time, a great attention is being paid to the use of algae. Algae can adapt to different conditions and can produce substances corresponding to responsible environments. The main problem in their cultivation is the design of a suitable photoreactor. It should create the optimal conditions for their growth, which is mainly dependent on the contact of the algae with the light. The intensity of the light depends on the hydrodynamic conditions in the photoreactor and on its geometry. This paper deals with the study of kinetics of growth and gross biomass yield of biomass in laboratory photobioreactors, respecting their geometrical similarity as a basis for a possible scale-up. An optimal ratio between biomass growth rate and its gross biomass yield as a function of the photoreactor geometry is searched. <em>Chlamydomonas reinhardtii</em> were used as the model organism.

scholarly journals Increasing Phosphorus Uptake Efficiency by Phosphorus-Starved Microalgae for Municipal Wastewater Post-Treatment

2021 ◽  
Vol 9 (8) ◽  
pp. 1598
Author(s):  
Aigars Lavrinovičs ◽  
Fredrika Murby ◽  
Elīna Zīverte ◽  
Linda Mežule ◽  
Tālis Juhna
Keyword(s):  
Growth Rate ◽  
Municipal Wastewater ◽  
Removal Rate ◽  
Reference Conditions ◽  
Phosphorus Uptake ◽  
Molar Ratio ◽  
Biomass Growth ◽  
Activity Increase ◽  
Phosphorus Starvation ◽  
P Content

Four microalgal species, Chlorella vulgaris, Botryococcus braunii, Ankistrodesmus falcatus, and Tetradesmus obliquus were studied for enhanced phosphorus removal from municipal wastewater after their exposure to phosphorus starvation. Microalgae were exposed to phosphorus starvation conditions for three and five days and then used in a batch experiment to purify an effluent from a small WWTP. After 3-day P-starvation, C. vulgaris biomass growth rate increased by 50% and its PO4 removal rate reached >99% within 7 days. B. braunii maintained good biomass growth rate and nutrient removal regardless of the P-starvation. All species showed 2–5 times higher alkaline phosphatase activity increase for P-starved biomass than at the reference conditions, responding to the decline of PO4 concentration in wastewater and biomass poly-P content. The overall efficiency of biomass P-starvation on enhanced phosphorus uptake was found to be dependent on the species, N/P molar ratio in the wastewater, as well as the biomass P content.

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