scholarly journals Effect of CO2 concentration of growth and carbon fixation rate of pleurochrysis carterae.

1995 ◽  
Vol 28 (4) ◽  
pp. 474-476 ◽  
Author(s):  
Minoru Seki ◽  
Takahiko Hirokawa ◽  
Hajime Hasegawa ◽  
Shintaro Furusaki
Keyword(s):  
Carbon Fixation ◽  
Co2 Concentration ◽  
Fixation Rate ◽  
Pleurochrysis Carterae

scholarly journals Carbon fixation prediction during a bloom of <i>Emiliania huxleyi</i> is highly sensitive to the assumed regulation mechanism

2009 ◽  
Vol 6 (3) ◽  
pp. 5339-5372 ◽  
Author(s):  
O. Bernard ◽  
A. Sciandra ◽  
S. Rabouille
Keyword(s):  
Large Scale ◽  
Carbon Fixation ◽  
Co2 Concentration ◽  
Carbon Fluxes ◽  
Emiliania Huxleyi ◽  
Regulation Mechanism ◽  
Fixation Rate ◽  
Saturation State ◽  
Calcite Saturation ◽  
Order Of Magnitude

Abstract. Large scale precipitation of calcium carbonate in the oceans by coccolithophorids plays an important role in carbon sequestration. However, there is a controversy on the effect of an increase in atmospheric CO2 concentration on both calcification and photosynthesis of coccolithophorids. Indeed recent experiments, performed under nitrogen limitation, revealed that the associated fluxes may be slowed down, while other authors claim the reverse. We designed models to account for various scenarii of calcification and photosynthesis regulation in chemostat cultures of Emiliania huxleyi, based on different hypotheses on the regulation mechanism. These models consider that either carbon dioxide, bicarbonate, carbonate or calcite saturation state (Ω) is the regulating factor. All were calibrated to predict the same carbon fixation rate in nowadays pCO2, but they turn out to respond differently to an increase in CO2 concentration. Thus, using the four possible models, we simulated a large bloom of Emiliania huxleyi. It results that models assuming a regulation by CO32− or Ω predicted much higher carbon fluxes. The response when considering a doubled pCO2 was different and models controlled by CO2 or HCO3 − led to increased carbon fluxes. In addition, the variability between the various scenarii proved to be in the same order of magnitude than the response to pCO2 increase. These sharp discrepancies reveal the consequences of model assumptions on the simulation outcome.

scholarly journals Ocean acidification mediates photosynthetic response to UV radiation and temperature increase in the diatom <i>Phaeodactylum tricornutum</i>

2012 ◽  
Vol 9 (10) ◽  
pp. 3931-3942 ◽  
Author(s):  
Y. Li ◽  
K. Gao ◽  
V. E. Villafañe ◽  
E. W. Helbling
Keyword(s):  
Ocean Acidification ◽  
Elevated Co2 ◽  
Uv Radiation ◽  
Phaeodactylum Tricornutum ◽  
Carbon Fixation ◽  
Co2 Concentration ◽  
Photochemical Quenching ◽  
Fixation Rate ◽  
Ps Ii ◽  
Temperature Levels

Abstract. Increasing atmospheric CO2 concentration is responsible for progressive ocean acidification, ocean warming as well as decreased thickness of upper mixing layer (UML), thus exposing phytoplankton cells not only to lower pH and higher temperatures but also to higher levels of solar UV radiation. In order to evaluate the combined effects of ocean acidification, UV radiation and temperature, we used the diatom Phaeodactylum tricornutum as a model organism and examined its physiological performance after grown under two CO2 concentrations (390 and 1000 μatm) for more than 20 generations. Compared to the ambient CO2 level (390 μatm), growth at the elevated CO2 concentration increased non-photochemical quenching (NPQ) of cells and partially counteracted the harm to PS II (photosystem II) caused by UV-A and UV-B. Such an effect was less pronounced under increased temperature levels. The ratio of repair to UV-B induced damage decreased with increased NPQ, reflecting induction of NPQ when repair dropped behind the damage, and it was higher under the ocean acidification condition, showing that the increased pCO2 and lowered pH counteracted UV-B induced harm. As for photosynthetic carbon fixation rate which increased with increasing temperature from 15 to 25 °C, the elevated CO2 and temperature levels synergistically interacted to reduce the inhibition caused by UV-B and thus increase the carbon fixation.

scholarly journals Design and in vitro realization of carbon-conserving photorespiration

2018 ◽  
Vol 115 (49) ◽  
pp. E11455-E11464 ◽  
Author(s):  
Devin L. Trudeau ◽  
Christian Edlich-Muth ◽  
Jan Zarzycki ◽  
Marieke Scheffen ◽  
Moshe Goldsmith ◽  
...  
Keyword(s):  
Carbon Fixation ◽  
Calvin Cycle ◽  
Computational Design ◽  
Carbon Loss ◽  
Fixation Rate ◽  
Bisphosphate Carboxylase ◽  
Stoichiometric Model ◽  
Synthetic Routes ◽  
Coa Reductase

Photorespiration recycles ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) oxygenation product, 2-phosphoglycolate, back into the Calvin Cycle. Natural photorespiration, however, limits agricultural productivity by dissipating energy and releasing CO2. Several photorespiration bypasses have been previously suggested but were limited to existing enzymes and pathways that release CO2. Here, we harness the power of enzyme and metabolic engineering to establish synthetic routes that bypass photorespiration without CO2 release. By defining specific reaction rules, we systematically identified promising routes that assimilate 2-phosphoglycolate into the Calvin Cycle without carbon loss. We further developed a kinetic–stoichiometric model that indicates that the identified synthetic shunts could potentially enhance carbon fixation rate across the physiological range of irradiation and CO2, even if most of their enzymes operate at a tenth of Rubisco’s maximal carboxylation activity. Glycolate reduction to glycolaldehyde is essential for several of the synthetic shunts but is not known to occur naturally. We, therefore, used computational design and directed evolution to establish this activity in two sequential reactions. An acetyl-CoA synthetase was engineered for higher stability and glycolyl-CoA synthesis. A propionyl-CoA reductase was engineered for higher selectivity for glycolyl-CoA and for use of NADPH over NAD+, thereby favoring reduction over oxidation. The engineered glycolate reduction module was then combined with downstream condensation and assimilation of glycolaldehyde to ribulose 1,5-bisphosphate, thus providing proof of principle for a carbon-conserving photorespiration pathway.

scholarly journals Comparing chemical composition and lignin structure of Miscanthus x giganteus and Miscanthus nagara harvested in autumn and spring and separated into stems and leaves

RSC Advances ◽  
2020 ◽  
Vol 10 (18) ◽  
pp. 10740-10751 ◽  
Author(s):  
Michel Bergs ◽  
Xuan Tung Do ◽  
Jessica Rumpf ◽  
Peter Kusch ◽  
Yulia Monakhova ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Carbon Fixation ◽  
Frost Tolerance ◽  
Miscanthus X Giganteus ◽  
Fixation Rate ◽  
Stems And Leaves ◽  
Lignin Structure

Miscanthus crops possess attractive properties such as high photosynthesis yield and carbon fixation rate. Moreover, M. nagara, shows good frost tolerance. Monolignol ratio and most abundant linkages of the isolated lignins have been identified.

Quantum Efficiency and Photosynthetic Production of a Temperate Turf Algal Community

1997 ◽  
Vol 45 (2) ◽  
pp. 343 ◽  
Author(s):  
Grant Westphalen ◽  
Anthony C. Cheshire
Keyword(s):  
Quantum Efficiency ◽  
Photosynthetic Efficiency ◽  
Carbon Fixation ◽  
Preliminary Investigation ◽  
Algal Community ◽  
Specific Productivity ◽  
Fixation Rate ◽  
Photosynthetic Production ◽  
Photosynthesis And Respiration

A preliminary investigation of the production and photosynthetic efficiency of a temperate, sub-tidal, turf algal community using in situ measurements of photosynthesis and respiration is reported. Results indicated that temperate turfs have high biomass specific productivity, but are less productive on an areal basis than either the surrounding macro-algal community or their tropical counterparts. Net 24 h production ranges between 12 and 78 mmol O2 m-2 d-1 (corresponding to a carbon fixation rate of 0.1–0.9 g C m-2 d-1). Inefficient use of the available substrata, due to the early successional nature of these communities, is considered to be the cause of this low productivity. A quantum efficiency of 0.034 µmol O2 µmol photons-1 and a sub-saturating light itensity of 134–210 µmol photons m-2 s-1 indicate that photosynthetic saturation was easily achieved and suggests that self-shading in the turf community was not significant.

Regulation of assimilate partitioning in leaves

2000 ◽  
Vol 27 (6) ◽  
pp. 507 ◽  
Author(s):  
Charlotte E. Lewis ◽  
Graham Noctor ◽  
David Causton ◽  
Christine H. Foyer
Keyword(s):  
Carbon Fixation ◽  
Starch Synthesis ◽  
Co2 Concentration ◽  
Building Blocks ◽  
Energy Budgets ◽  
Assimilate Partitioning ◽  
Fixed Carbon ◽  
Carbon And Nitrogen ◽  
Cellular Energy ◽  
Photosynthetic Carbon

Concepts of the regulation of assimilate partitioning in leaves frequently consider only the allocation of carbon between sucrose and starch synthesis, storage and export. While carbohydrate metabolism accounts for a large proportion of assimilated carbon, such analyses provide only a restricted view of carbon metabolism and partitioning in leaf cells since photosynthetic carbon fixation provides precursors for all other biosynthetic pathways in the plant. Most of these precursors are required for biosynthesis of amino acids that form the building blocks for many compounds in plants. We have used leaf carbon : nitrogen ratios to calculate the allocation of photosynthetic electrons to the assimilation of nitrogen necessary for amino acid formation, and conclude that this allocation is variable but may be higher than values often quoted in the literature. Respiration is a significant fate of fixed carbon. In addition to supplying biosynthetic precursors, respiration is required for energy production and may also act, in both light and dark, to balance cellular energy budgets. We have used growth CO2 concentration and irradiance to modify source activity in Lolium temulentum in order to explore the interactions between photosynthetic carbon and nitrogen assimilation, assimilate production, respiration and export. It is demonstrated that there is a robust correlation between source activity and foliar respiration rates. Under some conditions concomitant increases in source activity and respiration may be necessary to support faster growth. In other conditions, increases in respiration appear to result from internal homeostatic mechanisms that may be candidate targets for increasing yield.

SECULAR VARIATIONS IN THE 14C CONCENTRATION OF DOUGLAS FIR TREE RINGS

1966 ◽  
Vol 3 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Willy Dyck
Keyword(s):  
Large Scale ◽  
Carbon Fixation ◽  
Douglas Fir ◽  
Sunspot Activity ◽  
Short Term ◽  
Fixation Rate ◽  
Pumping Rate ◽  
Counting Error ◽  
Annual Growth Rings

Measurements of the 14C concentration in a Douglas fir from Vancouver Island indicate a maximum variation of 44‰, during the past 1 100 years. The magnitude and trend of these variations are similar to those observed by de Vries (1958) in oak from Germany and by Willis et al. (1960) in sequoias from California, confirming earlier observations that atmospheric mixing of CO2 takes place rapidly on a large scale.14C measurements of successive annual growth rings from the piths of two firs (346 years and 1 142 years old) show no variations beyond those attributable to the statistical counting error of ± 6‰. Thus, cyclic variations in sunspot activity and (or) climate, if present during these intervals, did not affect the 14C concentration in the biosphere appreciably.A mechanism, based on a climate-sensitive carbon pumping rate of the biosphere coupled with the temperature-dependent oceanic CO2 content is postulated to explain, qualitatively, the observed short-term (150 years or less) and long-term (1 000 years or more) 14C variations in the land biosphere. Short-term fluctuations are directly proportional to temperature because variations in the carbon fixation rate lead to a pulsating CO2 content of the atmosphere. Long-term changes are inversely proportional to temperature because large quantities of carbon, normally stored in deeper regions of the ocean, are exchanged between biosphere and hydrosphere.

scholarly journals Development of photosynthetic carbon fixation model using multi-excitation wavelength fast repetition rate fluorometry in Lake Biwa

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0238013
Author(s):  
Takehiro Kazama ◽  
Kazuhide Hayakawa ◽  
Victor S. Kuwahara ◽  
Koichi Shimotori ◽  
Akio Imai ◽  
...  
Keyword(s):  
Repetition Rate ◽  
Carbon Fixation ◽  
Lake Biwa ◽  
Freshwater Ecosystems ◽  
Cyanobacterial Blooms ◽  
Excitation Wavelength ◽  
Freshwater Ecosystem ◽  
Fixation Rate ◽  
Excitation Light ◽  
Fast Repetition Rate Fluorometry

Direct measurements of gross primary productivity (GPP) in the water column are essential, but can be spatially and temporally restrictive. Fast repetition rate fluorometry (FRRf) is a bio-optical technique based on chlorophyll a (Chl-a) fluorescence that can estimate the electron transport rate (ETRPSII) at photosystem II (PSII) of phytoplankton in real time. However, the derivation of phytoplankton GPP in carbon units from ETRPSII remains challenging because the electron requirement for carbon fixation (Фe,C), which is mechanistically 4 mol e− mol C−1 or above, can vary depending on multiple factors. In addition, FRRf studies are limited in freshwater lakes where phosphorus limitation and cyanobacterial blooms are common. The goal of the present study is to construct a robust Фe,C model for freshwater ecosystems using simultaneous measurements of ETRPSII by FRRf with multi-excitation wavelengths coupled with a traditional carbon fixation rate by the 13C method. The study was conducted in oligotrophic and mesotrophic parts of Lake Biwa from July 2018 to May 2019. The combination of excitation light at 444, 512 and 633 nm correctly estimated ETRPSII of cyanobacteria. The apparent range of Фe,C in the phytoplankton community was 1.1–31.0 mol e− mol C−1 during the study period. A generalised linear model showed that the best fit including 12 physicochemical and biological factors explained 67% of the variance in Фe,C. Among all factors, water temperature was the most significant, while photosynthetically active radiation intensity was not. This study quantifies the in situ FRRf method in a freshwater ecosystem, discusses core issues in the methodology to calculate Фe,C, and assesses the applicability of the method for lake GPP prediction.

Sign in / Sign up

Export Citation Format

Share Document