scholarly journals Thermal plasticity of growth and chain formation of the dinoflagellates Alexandrium affine and Alexandrium pacificum with respect to ocean acidification

ALGAE ◽  
2021 ◽  
Vol 36 (4) ◽  
pp. 285-298
Author(s):  
Chung Hyeon Lee ◽  
Juhee Min ◽  
Hyun-Gwan Lee ◽  
Kwang Young Kim
Keyword(s):  
Growth Rate ◽  
Chain Length ◽  
Functional Traits ◽  
Elevated Pco2 ◽  
Marine Phytoplankton ◽  
Chain Formation ◽  
Thermal Plasticity ◽  
Partial Pressures ◽  
Pco2 Condition ◽  
Cardinal Temperatures

The amount of CO2 absorbed by the oceans continues to rise, resulting in further acidification, altering some functional traits of phytoplankton. To understand the effect of elevated partial pressures of CO2 (pCO2) on functional traits of dinoflagellates Alexandrium affine and A. pacificum, the cardinal temperatures and chain formation extent were examined under two pCO2 (400 and 1,000 μatm) over the range of temperature expected to be associated with growth. The growth rate and chain formation extent of A. affine increased with higher pCO2, showing significant changes in cardinal temperatures and a substantial increase in middle chain-length (4‒8 cells) fractionation under elevated pCO2 condition. By contrast, there were no significant differences in specific growth rate and any chain-length fractionation of A. pacificum between ambient and elevated pCO2 conditions. The observed interspecies variation in the functional traits may reflect differences in ability of species to respond to environmental change with plasticity. Moreover, it allows us to understand the shifting biogeography of marine phytoplankton and predict their phenology in the Korea Strait.

A polycentric growth model of gallium arsenide epitaxial layers from the gas phase with simultaneous diffusion, adsorption and chemical reaction

1988 ◽  
Vol 53 (12) ◽  
pp. 2995-3013
Author(s):  
Emerich Erdös ◽  
Jindřich Leitner ◽  
Petr Voňka ◽  
Josef Stejskal ◽  
Přemysl Klíma
Keyword(s):  
Growth Rate ◽  
Gallium Arsenide ◽  
Epitaxial Growth ◽  
Gas Phase ◽  
Surface Reaction ◽  
Quantitative Description ◽  
The Other ◽  
Rate Equations ◽  
Impact Interaction ◽  
Partial Pressures

For a quantitative description of the epitaxial growth rate of gallium arsenide, two models are proposed including two rate controlling steps, namely the diffusion of components in the gas phase and the surface reaction. In the models considered, the surface reaction involves a reaction triple - or quadruple centre. In both models three mechanisms are considered which differ one from the other by different adsorption - and impact interaction of reacting particles. In every of the six cases, the pertinent rate equations were derived, and the models have been confronted with the experimentally found dependences of the growth rate on partial pressures of components in the feed. The results are discussed with regard to the plausibility of individual mechanisms and of both models, and also with respect to their applicability and the direction of further investigations.

Exploring SiC Growth Limitation of Vapor-Liquid-Solid Mechanism when Using Two Different Carbon Precursors

2013 ◽  
Vol 740-742 ◽  
pp. 323-326
Author(s):  
Kassem Alassaad ◽  
François Cauwet ◽  
Davy Carole ◽  
Véronique Soulière ◽  
Gabriel Ferro
Keyword(s):  
Growth Rate ◽  
High Growth ◽  
High Growth Rate ◽  
Carbon Precursor ◽  
Growth Limitation ◽  
Vapor Liquid Solid ◽  
Partial Pressures ◽  
Vapor Liquid Solid Mechanism ◽  
Vls Growth ◽  
Vapor Liquid

Abstract. In this paper, conditions for obtaining high growth rate during epitaxial growth of SiC by vapor-liquid-solid mechanism are investigated. The alloys studied were Ge-Si, Al-Si and Al-Ge-Si with various compositions. Temperature was varied between 1100 and 1300°C and the carbon precursor was either propane or methane. The variation of layers thickness was studied at low and high precursor partial pressure. It was found that growth rates obtained with both methane and propane are rather similar at low precursor partial pressures. However, when using Ge based melts, the use of high propane flux leads to the formation of a SiC crust on top of the liquid, which limits the growth by VLS. But when methane is used, even at extremely high flux (up to 100 sccm), no crust could be detected on top of the liquid while the deposit thickness was still rather small (between 1.12 μm and 1.30 μm). When using Al-Si alloys, no crust was also observed under 100 sccm methane but the thickness was as high as 11.5 µm after 30 min growth. It is proposed that the upper limitation of VLS growth rate depends mainly on C solubility of the liquid phase.

Disentangling the role of competition, light interception, and functional traits in tree growth rate variation in South Asian tropical moist forests

2021 ◽  
Vol 483 ◽  
pp. 118908
Author(s):  
Mizanur Rahman ◽  
Masum Billah ◽  
Md Obydur Rahman ◽  
Debit Datta ◽  
Muhammad Ahsanuzzaman ◽  
...  
Keyword(s):  
Growth Rate ◽  
Functional Traits ◽  
South Asian ◽  
Tree Growth ◽  
Light Interception ◽  
Rate Variation ◽  
Tree Growth Rate

Evaluation of temperature effect on growth rate of Lactobacillus rhamnosus GG in milk using secondary models

2013 ◽  
Vol 67 (7) ◽  
Author(s):  
Ľubomír Valík ◽  
Alžbeta Medveďová ◽  
Michal Čižniar ◽  
Denisa Liptáková
Keyword(s):  
Growth Rate ◽  
Growth Parameters ◽  
Lactobacillus Rhamnosus ◽  
Probiotic Bacterium ◽  
Extended Model ◽  
Temperature Model ◽  
Lactobacillus Rhamnosus Gg ◽  
Model Application ◽  
Cardinal Temperature ◽  
Cardinal Temperatures

AbstractThe application of secondary temperature models on growth rates of Lactobacillus rhamnosus GG, the much studied probiotic bacterium, is investigated. Growth parameters resulting from a primary fitting were modelled against temperature using the following models: Hinshelwood model (H), Ratkowsky extended model (RTK2), Zwietering model (ZWT), and cardinal temperature model with inflection (CTMI). As experienced by other authors, the RTK2, ZWT, and CTMI models provided the best statistical indices related to fitting the experimental data. Moreover, with the biological background, the following cardinal temperatures of L. rhamnosus GG resulted from the study by the model application: t min = 2.7°C, t opt = 44.4°C, t max = 52.0°C. The growth rate of the strain under study at optimal temperature was 0.88 log10(CFU mL−1 h−1).

Temperature-Growth Relations and Genetic Diversity of A2 Mating-Type Isolates of Phytophthora cinnamomi in Australia

1974 ◽  
Vol 22 (2) ◽  
pp. 231 ◽  
Author(s):  
CJ Shepherd ◽  
BH Pratt
Keyword(s):  
Growth Rate ◽  
First Generation ◽  
Phytophthora Cinnamomi ◽  
Phytophthora Species ◽  
Temperature Growth ◽  
Field Isolates ◽  
Place Of Origin ◽  
Successive Generations ◽  
Cardinal Temperatures ◽  
Range Of Values

Determinations of cardinal temperatures for growth on various media of 50 Australian isolates of Phytophthova cinnamomi showed that growth did not occur outside the range 5-35°C. The range of temperatures at which growth optima occurred varied according to the isolate and medium used and encompassed the whole range of values reported by overseas authors. Growth rates of 361 isolates on corn meal agar at 25°C varied within the range 4.7-10.5 mm/day. There was no correlation between optimum temperature and whether isolates were slow- or fastgrowing or their place of origin. Fast-growing isolates (6-11 mm/day) were obtained from all States, but slower-growing isolates (<6 mm/day) were obtained only from southern and western regions of Australia. Populations from different regions of Australia exhibited different growth rate parameters. The variability of mycelial isolates in culture was studied by examining differences in growth rate among replicated parent, single-zoospore, single-zoosporangium and single terminal-hyphal isolates. Extensive variation was found among first generation single-zoospore progenies of field isolates, with lesser variation among progeny of single zoosporangia, terminal hyphal cultures and second and third generation zoospore derivatives. The origin of this variation is discussed and it is suggested that field isolates are heterokaryotic, since zoospores proved to be predominantly uninucleate. When various Phytophthora species were incubated at temperatures above those at which growth was possible and then returned to 25°C, their subsequent ability to resume growth depended on the particular time-temperature combination used. Considerable variation of response was found among a number of isolates of P. cinnamomi and, following the establishment of single zoospore isolates, the potential variability of field isolates was shown to persist through successive generations of zoospore propagation. It is suggested that a cytoplasmic mechanism of inheritance may be responsible for this variation.

Effect of chain segment length on crystallization behaviors of poly(l-lactide-b-ethylene glycol-b-l-lactide) triblock copolymer

2019 ◽  
Vol 28 (2) ◽  
pp. 77-88
Author(s):  
Yongji Gong ◽  
Weihua Song ◽  
Yifan Wu ◽  
Daohai Zhang ◽  
Yufei Liu ◽  
...  
Keyword(s):  
Growth Rate ◽  
Ethylene Glycol ◽  
Chain Length ◽  
Triblock Copolymer ◽  
Triblock Copolymers ◽  
Segment Length ◽  
Resonance Spectroscopy ◽  
Chain Segment ◽  
Scanning Calorimetry ◽  
Crystallization Behaviors

The poly(l-lactide-b-ethylene glycol-b-l-lactide) (PLLA-PEG-PLLA) triblock copolymers with different chain segment length are fabricated by ring-opening polymerization. The structure, molecular weight, and crystallization behaviors of the triblock copolymers are characterized by Fourier transform infrared, nuclear magnetic resonance spectroscopy, gel permeation in chromatography, X-ray diffraction, differential scanning calorimetry, and polarizing optical microscopy (POM). The results show that the increase of block length is beneficial to improve its crystallization. In addition, the triblock copolymer exhibits a double crystallization phenomenon. The POM results indicate that PEG and PLLA chains of the copolymer crystallize in their respective crystallization temperature regions. The growth rate of the PLLA spherocrystal decreases and the dendritic spherocrystals appear with increasing the PEG chain length when the PLLA chain of the copolymer is isothermal crystallized at 80°C and PLLA chain length is constant. The growth rate of the PEG spherocrystal decreases and the spherocrystal morphology changes little with increasing PLLA chain length when the PEG chain is isothermal crystallized at 25°C and the length of PEG chain remained unchanged.

scholarly journals Combined effects of elevated pCO2, temperature, and starvation stress on larvae of a large tropical marine fish

2016 ◽  
Vol 74 (4) ◽  
pp. 1220-1229 ◽  
Author(s):  
Sean Bignami ◽  
Su Sponaugle ◽  
Martha Hauff ◽  
Robert K. Cowen
Keyword(s):  
Growth Rate ◽  
Environmental Changes ◽  
Synergistic Effects ◽  
Development Rate ◽  
Elevated Pco2 ◽  
Starvation Resistance ◽  
Starvation Stress ◽  
Larval Fishes ◽  
Negative Effect ◽  
Larval Condition

Ocean acidification and other environmental changes pose an ecological challenge to marine organisms globally. Although the youngest life stages of these organism are likely to be most affected, a limited number of studies of larval fishes have investigated the effects of combined stressors. We conducted two experiments on larval cobia (Rachycentron canadum) raised under combinations of elevated pCO2 and increased temperature or starvation stress. Larvae responded to individual CO2, temperature, and rationing treatments, and there was a negative effect of elevated pCO2 on starvation resistance, but few synergistic effects of combined stressors. Elevated pCO2 (1700–2100 μatm pCO2) caused a transient but significant reduction in larval standard length (SL), growth rate, and development rate, while warmer temperature (32 vs. 27 °C) caused a consistent increase in SL, development rate, and swimming ability. Larval condition (RNA:DNA ratio) was unaffected by elevated pCO2 although larvae fed a 25% ration had significantly reduced SL, growth rate, and development rate. Under complete feeding cessation, larvae in elevated-pCO2 seawater demonstrated lower starvation resistance, indicating that acidification may increase starvation risk in a patchy marine environment. Overall, our results indicate that larval cobia are resistant to any major direct impact of combined elevated pCO2 and temperature or rationing stress.

Response of plant functional traits at species and community levels to grazing exclusion on Inner Mongolian steppe, China

2018 ◽  
Vol 40 (2) ◽  
pp. 179 ◽  
Author(s):  
Jinghui Zhang ◽  
Yongmei Huang ◽  
Huiying Chen ◽  
Jirui Gong ◽  
Yu Qi ◽  
...  
Keyword(s):  
Growth Rate ◽  
Functional Traits ◽  
Ecosystem Function ◽  
High Capacity ◽  
Plant Functional Traits ◽  
Grazing Management ◽  
Short Term ◽  
Grazing Exclusion ◽  
Typical Steppe

Variations in ecosystem function in response to land-use changes may be expected to reflect differences in the functional traits of plants. In this study, we sought to reveal the relationship between trait variability and grazing management on typical steppe in Inner Mongolia, and explore the implications of this relationship for ecosystem functioning. We measured aboveground biomass and 18 functional traits of the most abundant plant species in a grassland subject to three grazing-management regimes: long-term grazing, short-term grazing exclusion (since 2008) and long-term grazing exclusion (since 1956). Principal component analysis of the variation in species-level traits revealed trade-offs between the traits that enabled rapid acquisition of resources by fast-growing annual species and those that promoted conservation of resources by perennial grasses, especially Stipa grandis. However, there was no systematic pattern of intra-specific variation in trait values recorded among sites. Aggregation of plant functional traits to the community level revealed a gradient of responses of typical steppe to grazing exclusion. Long-term grazing favoured species whose traits indicate low forage quality and relatively low growth rate. Exclusion of grazing for several years favoured species whose traits indicate relatively high growth rate and high capacity to acquire resources. Exclusion of grazing for several decades favoured species whose morphological and physiological traits indicated low growth rates and high capacity for resource conservation. These community-level traits imply that ecosystem carbon and nutrient stores will change in response to the grazing regime. Long-term grazing will result in decreased plant carbon and nitrogen content, and will lead to carbon and nutrient loss, whereas short-term and long-term grazing exclusion are beneficial to the recovery of carbon and nutrient storage. The findings support the value of community aggregated traits as indicators of environmental or management change and for explaining changes in ecosystem function.

The influence of low partial pressures of oxygen on the rhythm in the growth rate of theAvena coleoptile

Planta ◽  
1963 ◽  
Vol 60 (3) ◽  
pp. 261-273 ◽  
Author(s):  
Malcolm B. Wilkins ◽  
Diana M. Warren
Keyword(s):  
Growth Rate ◽  
Partial Pressures
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