Controlled degassing of lakes with high CO2 content in Cameroon: an opportunity for ecosystem CO2-enrichment experiments

1997 ◽  
pp. 45-55 ◽  
Author(s):  
M. Mousseau ◽  
Z.H. Enoch ◽  
J.C. Sabroux
Keyword(s):  
Co2 Enrichment ◽  
High Co2 ◽  
Enrichment Experiments

scholarly journals Photosynthesis, carboxylation and leaf nitrogen responses of 16 species to elevated pCO2 across four free-air CO2 enrichment experiments in forest, grassland and desert

2004 ◽  
Vol 10 (12) ◽  
pp. 2121-2138 ◽  
Author(s):  
David S. Ellsworth ◽  
Peter B. Reich ◽  
Elke S. Naumburg ◽  
George W. Koch ◽  
Mark E. Kubiske ◽  
...  
Keyword(s):  
Co2 Enrichment ◽  
Leaf Nitrogen ◽  
Elevated Pco2 ◽  
Free Air Co2 Enrichment ◽  
Free Air ◽  
Enrichment Experiments

Detecting changes in soil carbon in CO2 enrichment experiments

1995 ◽  
Vol 187 (2) ◽  
pp. 135-145 ◽  
Author(s):  
Bruce A. Hungate ◽  
Robert B. Jackson ◽  
Christopher B. Field ◽  
F. Stuart Chapin
Keyword(s):  
Soil Carbon ◽  
Co2 Enrichment ◽  
Enrichment Experiments

scholarly journals CO<sub>2</sub> increases <sup>14</sup>C primary production in an Arctic plankton community

2013 ◽  
Vol 10 (3) ◽  
pp. 1291-1308 ◽  
Author(s):  
A. Engel ◽  
C. Borchard ◽  
J. Piontek ◽  
K. G. Schulz ◽  
U. Riebesell ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Primary Production ◽  
Bacterial Biomass ◽  
Co2 Enrichment ◽  
Nutrient Addition ◽  
The Arctic ◽  
Net Community Production ◽  
High Co2 ◽  
Chl A ◽  
Doc Production

Abstract. Responses to ocean acidification in plankton communities were studied during a CO2-enrichment experiment in the Arctic Ocean, accomplished from June to July 2010 in Kongsfjorden, Svalbard (78°56′ 2′′ N, 11°53′ 6′′ E). Enclosed in 9 mesocosms (volume: 43.9–47.6 m3), plankton was exposed to CO2 concentrations, ranging from glacial to projected mid-next-century levels. Fertilization with inorganic nutrients at day 13 of the experiment supported the accumulation of phytoplankton biomass, as indicated by two periods of high chl a concentration. This study tested for CO2 sensitivities in primary production (PP) of particulate organic carbon (PPPOC) and of dissolved organic carbon (PPDOC). Therefore, 14C-bottle incubations (24 h) of mesocosm samples were performed at 1 m depth receiving about 60% of incoming radiation. PP for all mesocosms averaged 8.06 ± 3.64 μmol C L−1 d−1 and was slightly higher than in the outside fjord system. Comparison between mesocosms revealed significantly higher PPPOC at elevated compared to low pCO2 after nutrient addition. PPDOC was significantly higher in CO2-enriched mesocosms before as well as after nutrient addition, suggesting that CO2 had a direct influence on DOC production. DOC concentrations inside the mesocosms increased before nutrient addition and more in high CO2 mesocosms. After addition of nutrients, however, further DOC accumulation was negligible and not significantly different between treatments, indicating rapid utilization of freshly produced DOC. Bacterial biomass production (BP) was coupled to PP in all treatments, indicating that 3.5 ± 1.9% of PP or 21.6 ± 12.5% of PPDOC provided on average sufficient carbon for synthesis of bacterial biomass. During the later course of the bloom, the response of 14C-based PP rates to CO2 enrichment differed from net community production (NCP) rates that were also determined during this mesocosm campaign. We conclude that the enhanced release of labile DOC during autotrophic production at high CO2 exceedingly stimulated activities of heterotrophic microorganisms. As a consequence, increased PP induced less NCP, as suggested earlier for carbon-limited microbial systems in the Arctic.

Submergence of Rice. I. Growth and Photosynthetic Response to CO2 Enrichment of Floodwater

1989 ◽  
Vol 16 (3) ◽  
pp. 251 ◽  
Author(s):  
TL Setter ◽  
I Waters ◽  
I Wallace ◽  
P Bhekasut ◽  
H Greenway
Keyword(s):  
Co2 Enrichment ◽  
Co2 Concentration ◽  
O2 Evolution ◽  
Photosynthetic Response ◽  
Submerged Plants ◽  
High Co2 ◽  
Low Co2 ◽  
O2 Concentration ◽  
Photosynthetic O2 Evolution ◽  
Rice Leaves

Growth and photosynthetic response of lowland rice following complete submergence is related to the concentration of CO2 dissolved in floodwater. Submergence of plants in stagnant solution at low CO2 concentration or solution gassed with air at 0.03 kPa CO2 (equilibrium of 0.01 mol m-3 dissolved CO2) decreased carbohydrates, and little or no growth occurred. Plants submerged in solutions gassed with 3-20 kPa CO2 in air (equilibrium of 0.9-6 mol m-3 CO2) showed at most small decreases in carbohydrates, and growth was up to 100% of the non-submerged plants. At pH 7.5, there was little net photosynthetic O2 evolution by detached submerged leaves even at high HCO3- concentrations, which suggests that these rice leaves could utilise only CO2 and not HCO3-. At pH 6.5, O2 evolution in solutions in equilibrium with 7.4 kPa CO2 was 3-4 fold higher than in solutions in equilibrium with 0.6 kPa CO2. Photorespiration was indicated by a decrease in the rate of net O2 evolution with increasing external O2. In stagnant solutions this reduction of O2 evolution was pronounced; at a CO2 concentration of 0.25 mol m-3 net O2 evolution ceased when the O2 concentration in the water had reached only 0.125 mol m-3. The requirement of photosynthesis for a combination of high CO2 concentrations and low external O2 was presumably due to slow diffusion of these gases in the unstirred layer of solution around the leaves.

Ocean Acidification: Knowns, Unknowns, and Perspectives

2011 ◽  
Author(s):  
Jean-Pierre Gattuso ◽  
Jelle Bijma
Keyword(s):  
Ocean Acidification ◽  
Elevated Co2 ◽  
Acoustic Noise ◽  
Current Knowledge ◽  
Co2 Enrichment ◽  
Marine Organisms ◽  
Societal Implications ◽  
Future Research ◽  
First Results ◽  
Enrichment Experiments

Although the changes in the chemistry of seawater driven by the uptake of CO2 by the oceans have been known for decades, research addressing the effects of elevated CO2 on marine organisms and ecosystems has only started recently (see Chapter 1). The first results of deliberate experiments on organisms were published in the mid 1980s (Agegian 1985) and those on communities in 2000 (Langdon et al. 2000; Leclercq et al. 2000 ). In contrast, studies focusing on the response of terrestrial plant communities began much earlier, with the first results of free-air CO2 enrichment experiments (FACE) being published in the late 1960s (see Allen 1992 ). Not surprisingly, knowledge about the effects of elevated CO2 on the marine realm lags behind that concerning the terrestrial realm. Yet ocean acidification might have significant biological, ecological, biogeochemical, and societal implications and decision-makers need to know the extent and severity of these implications in order to decide whether they should be considered, or not, when designing future policies. The goals of this chapter are to summarize key information provided in the preceding chapters by highlighting what is known and what is unknown, identify and discuss the ecosystems that are most at risk, as well as discuss prospects and recommendation for future research. The chemical, biological, ecological, biogeochemical, and societal implications of ocean acidification have been comprehensively reviewed in the previous chapters with one minor exception. Early work has shown that ocean acidification significantly affects the propagation of sound in seawater and suggested possible consequences for marine organisms sensitive to sound (Hester et al . 2008). However, sub sequent studies have shown that the changes in the upper-ocean sound absorption coefficient at future pH levels will have no or a small impact on ocean acoustic noise (Joseph and Chiu 2010; Udovydchenkov et al . 2010). The goal of this section is to condense the current knowledge about the consequences of ocean acidification in 15 key statements. Each statement is given levels of evidence and, when possible, a level of confidence as recommended by the Intergovernmental Panel on Climate Change (IPCC) for use in its 5th Assessment Report (Mastrandrea et al. 2010).

scholarly journals Cotyledon Cells and Seed Growth Relationships in CO2-enriched Peanut1

1990 ◽  
Vol 17 (1) ◽  
pp. 4-6 ◽  
Author(s):  
F. J. M. Sung ◽  
J. J. Chen
Keyword(s):  
Cell Size ◽  
Seed Size ◽  
Co2 Enrichment ◽  
Dynamic Component ◽  
Factors Affecting ◽  
High Co2 ◽  
Arachis Hypogaea L ◽  
Seed Growth ◽  
Cotyledon Cell ◽  
Cotyledon Cells

Abstract Seed size is a dynamic component of seed yield. Factors affecting seed size in peanut (Arachis hypogaea L.) are not well defined. The objectives of this study were to investigate the effects of CO2 enrichment and timing of pod formation on cotyledon cell and seed growth in virginia-type peanut. The results indicated that the number of cotyledon cells was relatively constant across all the treatments. However, size of cotyledon cells and seed growth rate (SGR) increased in the pods developed in high CO2 conditions. Striking differences in both cell size and SGR also existed between early and late formed pods. Our data indicate that assimilate supplies strongly limit cotyledon cell size, and accordingly affect SGR and final seed size

scholarly journals Elevated CO2 has concurrent effects on leaf and grain metabolism but minimal effects on yield in wheat

2020 ◽  
Vol 71 (19) ◽  
pp. 5990-6003 ◽  
Author(s):  
Guillaume Tcherkez ◽  
Sinda Ben Mariem ◽  
Luis Larraya ◽  
Jose M García-Mina ◽  
Angel M Zamarreño ◽  
...  
Keyword(s):  
Elevated Co2 ◽  
Geographical Location ◽  
Co2 Enrichment ◽  
Interactive Effects ◽  
General Effect ◽  
Free Air ◽  
The Usa ◽  
Amino Acid Methionine ◽  
Multi Level ◽  
Enrichment Experiments

Abstract While the general effect of CO2 enrichment on photosynthesis, stomatal conductance, N content, and yield has been documented, there is still some uncertainty as to whether there are interactive effects between CO2 enrichment and other factors, such as temperature, geographical location, water availability, and cultivar. In addition, the metabolic coordination between leaves and grains, which is crucial for crop responsiveness to elevated CO2, has never been examined closely. Here, we address these two aspects by multi-level analyses of data from several free-air CO2 enrichment experiments conducted in five different countries. There was little effect of elevated CO2 on yield (except in the USA), likely due to photosynthetic capacity acclimation, as reflected by protein profiles. In addition, there was a significant decrease in leaf amino acids (threonine) and macroelements (e.g. K) at elevated CO2, while other elements, such as Mg or S, increased. Despite the non-significant effect of CO2 enrichment on yield, grains appeared to be significantly depleted in N (as expected), but also in threonine, the S-containing amino acid methionine, and Mg. Overall, our results suggest a strong detrimental effect of CO2 enrichment on nutrient availability and remobilization from leaves to grains.

Influence of Elevated CO2 and Phosphorus Nutrition on the Growth and Yield of a Short-Duration Rice (Oryza sativa L. Cv. Jarrah)

1994 ◽  
Vol 21 (3) ◽  
pp. 281 ◽  
Author(s):  
S Seneweera ◽  
P Milham ◽  
J Conroy
Keyword(s):  
Oryza Sativa ◽  
Elevated Co2 ◽  
Short Duration ◽  
Oryza Sativa L ◽  
Co2 Enrichment ◽  
Grain Number ◽  
High Co2 ◽  
Soil P ◽  
High Soil ◽  
Co2 Levels

The growth and development of a short-duration rice cultivar (Oryza sativa L. cv. Jarrah), grown in flooded soil with a range of phosphorus (P) levels and exposed to atmospheric CO2 concentrations of either 350 or 700 μL L-1 was followed for 146 days after planting (DAP). Development (estimated by rate of tiller production and time to flowering) was faster with higher soil P levels and CO2 enrichment, the effect being more pronounced with CO2 enrichment. During the early vegetative phase (up to 35 DAP), when rates of tiller production were low, shoot growth and rates of leaf expansion were faster at elevated CO2 concentrations and high soil P levels. Rates of tiller production were greater with these treatments during the 35-56 DAP period, when tillering was at a maximum. Shoot elongation was reduced at elevated CO2 levels and at high soil P levels during this period. By 146 DAP leaf weight was greater at high P levels, but CO2 enrichment accelerated tiller production to such an extent that final leaf weight was lower at high CO2, probably because there were fewer, and smaller, leaves on each tiller. Despite this, grain yield was increased by up to 58% by CO2 enrichment, with increases occurring even at low soil P levels. This was due mainly to an increase in grain number per panicle, although panicle number also increased. Higher soil P levels also increased grain number and yield. The P concentration in the foliage was unaffected by the CO2 treatments and the concentration required to produce maximum yield was 0.18% (dry wt basis) at both CO2 levels. Greater starch accumulation in the stems of high-CO2-grown plants may have accounted for the higher number of grains in each panicle.

scholarly journals Response of key stress-related genes of the seagrass <i>Posidonia oceanica</i> in the vicinity of submarine volcanic vents

2015 ◽  
Vol 12 (13) ◽  
pp. 4185-4194 ◽  
Author(s):  
C. Lauritano ◽  
M. Ruocco ◽  
E. Dattolo ◽  
M. C. Buia ◽  
J. Silva ◽  
...  
Keyword(s):  
Target Genes ◽  
Quantitative Polymerase Chain Reaction ◽  
Expression Patterns ◽  
Co2 Enrichment ◽  
Posidonia Oceanica ◽  
Careful Consideration ◽  
Environmental Pressures ◽  
High Co2 ◽  
Metal Detoxification ◽  
Stress Related Genes

Abstract. Submarine volcanic vents are being used as natural laboratories to assess the effects of increased ocean acidity and carbon dioxide (CO2) concentration on marine organisms and communities. However, in the vicinity of volcanic vents other factors in addition to CO2, which is the main gaseous component of the emissions, may directly or indirectly confound the biota responses to high CO2. Here we used for the first time the expression of antioxidant and stress-related genes of the seagrass Posidonia oceanica to assess the stress levels of the species. Our hypothesis is that unknown factors are causing metabolic stress that may confound the putative effects attributed to CO2 enrichment only. We analyzed the expression of 35 antioxidant and stress-related genes of P. oceanica in the vicinity of submerged volcanic vents located in the islands of Ischia and Panarea, Italy, and compared them with those from control sites away from the influence of vents. Reverse-transcription quantitative polymerase chain reaction (RT-qPCR) was used to characterize gene expression patterns. Fifty-one percent of genes analyzed showed significant expression changes. Metal detoxification genes were mostly down-regulated in relation to controls at both Ischia and Panarea, indicating that P. oceanica does not increase the synthesis of heavy metal detoxification proteins in response to the environmental conditions present at the two vents. The up-regulation of genes involved in the free radical detoxification response (e.g., CAPX, SODCP and GR) indicates that, in contrast with Ischia, P. oceanica at the Panarea site faces stressors that result in the production of reactive oxygen species, triggering antioxidant responses. In addition, heat shock proteins were also activated at Panarea and not at Ischia. These proteins are activated to adjust stress-accumulated misfolded proteins and prevent their aggregation as a response to some stressors, not necessarily high temperature. This is the first study analyzing the expression of target genes in marine plants living near natural CO2 vents. Our results call for contention to the general claim of seagrasses as "winners" in a high-CO2 world, based on observations near volcanic vents. Careful consideration of factors that are at play in natural vents sites other than CO2 and acidification is required. This study also constitutes a first step for using stress-related genes as indicators of environmental pressures in a changing ocean.

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