Research note: Increasing Amb a 1 content in common ragweed (Ambrosia artemisiifolia) pollen as a function of rising atmospheric CO2 concentration

2005 ◽  
Vol 32 (7) ◽  
pp. 667 ◽  
Author(s):  
Ben D. Singer ◽  
Lewis H. Ziska ◽  
David A. Frenz ◽  
Dennis E. Gebhard ◽  
James G. Straka

Although the impact of increasing atmospheric carbon dioxide concentration ([CO2]) on production of common ragweed (Ambrosia artemisiifolia L.) pollen has been examined in both indoor and outdoor experiments, the relationship between allergen expression and [CO2] is not known. An enzyme-linked immunosorbent assay (ELISA) was used to quantify Amb a 1, ragweed’s major allergen, in protein extracted from pollen of A. artemisiifolia grown at different [CO2] values in a previous experiment. The concentrations used approximated atmospheric pre-industrial conditions (i.e. at the end of the 19th century), current conditions, and the CO2 concentration projected for the middle of the 21st century (280, 370 and 600 μmol mol–1 CO2, respectively). Although total pollen protein remained unchanged, significant increases in Amb a 1 allergen were observed between pre-industrial and projected future [CO2] and between current and projected future [CO2] (1.8 and 1.6 times, respectively). These data suggest that recent and projected increases in [CO2] could directly increase the allergenicity of ragweed pollen and consequently the prevalence and / or severity of seasonal allergic disease. However, genetic and abiotic factors governing allergen expression will need to be better established to fully understand these data and their implications for public health.

2000 ◽  
Vol 27 (10) ◽  
pp. 893 ◽  
Author(s):  
Lewis H. Ziska ◽  
Frances A. Caulfield

Although environmental factors such as precipitation and temperature are recognized as influencing pollen production, the impact of rising atmospheric carbon dioxide concentration ([CO2]) on the potential growth and pollen production of hay-fever-inducing plants is unknown. Here we present measurements of growth and pollen production of common ragweed (Ambrosia artemisiifolia L.) from pre-industrial [CO2] (280 mol mol–1) to current concentrations (370 mol mol–1) to a projected 21st century concentration (600 mol mol–1). We found that exposure to current and elevated [CO2] increased ragweed pollen production by 131 and 320%, respectively, compared to plants grown at pre-industrial [CO2]. The observed stimulations of pollen production from the pre-industrial [CO2] were due to an increase in the number (at 370 mol mol–1) and number and size (at 600 mol mol–1) of floral spikes. Overall, floral weight as a percentage of total plant weight decreased (from 21% to 13%), while investment in pollen increased (from 3.6 to 6%) between 280 and 600 mol mol–1 CO2. Our results suggest that the continuing increase in atmospheric [CO2] could directly influence public health by stimulating the growth and pollen production of allergy-inducing species such as ragweed.


Sci ◽  
2020 ◽  
Vol 2 (4) ◽  
pp. 77
Author(s):  
Demetris Koutsoyiannis ◽  
Zbigniew Kundzewicz

It is common knowledge that increasing CO2 concentration plays a major role in enhancement of the greenhouse effect and contributes to global warming. The purpose of this study is to complement the conventional and established theory that increased CO2 concentration due to human emissions causes an increase of temperature, by considering the reverse causality. Since increased temperature causes an increase in CO2 concentration, the relationship of atmospheric CO2 and temperature may qualify as belonging to the category of “hen-or-egg” problems, where it is not always clear which of two interrelated events is the cause and which the effect. We examine the relationship of global temperature and atmospheric carbon dioxide concentration at the monthly time step, covering the time interval 1980–2019, in which reliable instrumental measurements are available. While both causality directions exist, the results of our study support the hypothesis that the dominant direction is T → CO2. Changes in CO2 follow changes in T by about six months on a monthly scale, or about one year on an annual scale. We attempt to interpret this mechanism by involving biochemical reactions, as at higher temperatures soil respiration, and hence CO2 emission, are increasing.


2021 ◽  
pp. 5-16
Author(s):  
Kneev Sharma ◽  
Dimitre Karamanev

Understanding the fundamental relationship between atmospheric carbon dioxide concentration and temperature rise is essential for tackling the problem of climate change that faces us today. Misconceptions regarding the relationship are widespread due to media and political influences. This investigation aims to address the popular misconception that CO2 concentration directly and naturally leads to global temperature rise. While anthropogenic CO2 emissions seem to affect the rising global atmospheric temperature with a confidence of 95%, it falters when the historical relationship using ice core data is studied. This investigation uses two statistical approaches to determine an accurate range and direction for this important relationship. Through a combined approach, it was found that historically CO2 concentration in the last 650 000 years lags global temperature rise by 1020-1080 years with a maximum correlation coefficient of 0.8371-0.8372. This result is important for the investigation of climate change.


2012 ◽  
Vol 8 (3) ◽  
pp. 907-918 ◽  
Author(s):  
J. Yang ◽  
W. R. Peltier ◽  
Y. Hu

Abstract. Geochemical and geological evidence has suggested that several global-scale glaciation events occurred during the Neoproterozoic Era in the interval from 750–580 million years ago. The initiation of these glaciations is thought to have been a consequence of the combined influence of a low level of atmospheric carbon dioxide concentration and an approximately 6% weakening of solar luminosity. The latest version of the Community Climate System Model (CCSM4) is employed herein to explore the detailed combination of forcings required to trigger such extreme glaciation conditions under present-day circumstances of geography and topography. It is found that runaway glaciation occurs in the model under the following conditions: (1) an 8–9% reduction in solar radiation with 286 ppmv CO2 or (2) a 6% reduction in solar radiation with 70–100 ppmv CO2. These thresholds are moderately different from those found to be characteristic of the previously employd CCSM3 model reported recently in Yang et al. (2012a,b), for which the respective critical points corresponded to a 10–10.5% reduction in solar radiation with 286 ppmv CO2 or a 6% reduction in solar radiation with 17.5–20 ppmv CO2. The most important reason for these differences is that the sea ice/snow albedo parameterization employed in CCSM4 is believed to be more realistic than that in CCSM3. Differences in cloud radiative forcings and ocean and atmosphere heat transports also influence the bifurcation points. These results are potentially very important, as they are to serve as control on further calculations which will be devoted to an investigation of the impact of continental configuration. We demonstrate that there exist ''soft Snowball'' Earth states, in which the fractional sea ice coverage reaches approximately 60–65%, land masses in low latitudes are covered by perennial snow, and runaway glaciation does not develop. This is consistent with our previous results based upon CCSM3. Although our results cannot exclude the possibility of a ''hard Snowball'' solution, it is suggested that a ''soft Snowball'' solution for the Neoproterozoic remains entirely plausible.


2018 ◽  
Vol 8 (2) ◽  
pp. 214-220
Author(s):  
Jaime Luiz Albuquerque Conceição ◽  
FRANCISLENE ANGELOTTI ◽  
Ana Rosa Peixoto ◽  
Raquel Ghini

The experiments were carried out under controlled conditions to evaluate the impact of increased temperature and concentration of carbon dioxide on infection of Xanthomonas campestris pv viticola, the causal agent of bacterial canker in Vine seedlings. It proceeded the evaluation of the following epidemiological components: incubation period (PI), severity (SEV) and using that data were calculated the area under the disease progress curve (AUDPC). It used grape seedlings (Italia, Crimson Seedless, Sugraone and Selection 8) inoculated with bacterial suspension (108 CFU mL-1). The experimental design was completely randomized, factorial arrangement 4x4 (cultivar x temperature) and 4x2 (cultivar x carbon dioxide concentration) which was carried out twice. The data were subjected to variance analysis. Increasing temperature reduced bacterium’s incubation period with significant differences between genotypes. For Selection 8 and Crimson temperature increase caused enhancement on severity and AUDPC. For Seleção 8 the incubation period (PI) was extended from 7.93 to 30.18 days when the concentration changed from 390 to 770 µmol/mol. The increased CO2 concentration reduced AACPSD and SEV for Sugraone and Selection 8. The results show that the temperature and carbon dioxide (CO2) concentration of the air may have different effects on bacterial canker of grapevine.


2021 ◽  
Vol 42 (4) ◽  
pp. 2151-2162
Author(s):  
Jéssica de Oliveira Santos ◽  
◽  
Francislene Angelotti ◽  
Tiago Cardoso da Costa-Lima ◽  
◽  
...  

An increase in the carbon dioxide concentration (CO2) in the atmosphere has occurred in recent years, influencing the different biological aspects of herbivorous insects. The present study aimed to evaluate the effect of CO2 increase on the biological aspects of Liriomyza sativae Blanchard leafminer in melon plants. For this, two experiments were carried out: (i) to evaluate the effect of melon plants grown in CO2-enriched environments on the immature developmental stages of L. sativae and L. sativae adult longevity, and (ii) to verify the impact of increased CO2 concentration on L. sativae adult survival, feeding punctures, and oviposition. The experiments were carried out in growth chambers maintained in the temperature regime of 20-26-33 °C (simulating the minimum, average, and maximum daily temperature) and under two CO2 concentrations (400 ppm and 770 ppm). The immature stages and the egg-adult period of L. sativae were longer when they developed on plants grown in high CO2 levels (770 ppm), but no difference in adult longevity was observed. The viability of the immature phases was not different between the two CO2 concentrations. Furthermore, there was no difference in the number of eggs and feeding punctures between treatments. Thus, the increase in CO2 concentration prolongs the duration of the immature stages of L. sativae; however, it does not affect their viability. Adult survival, fertility, and feeding punctures were also unmodified by the environment enriched with CO2.


Sci ◽  
2020 ◽  
Vol 2 (3) ◽  
pp. 72
Author(s):  
Demetris Koutsoyiannis ◽  
Zbigniew Kundzewicz

It is common knowledge that increasing CO2 concentration plays a major role in enhancement of the greenhouse effect and contributes to global warming. The purpose of this study is to complement the conventional and established theory that increased CO2 concentration due to human emissions causes an increase of temperature, by considering the reverse causality. Since increased temperature causes an increase in CO2 concentration, the relationship of atmospheric CO2 and temperature may qualify as belonging to the category of “hen-or-egg” problems, where it is not always clear which of two interrelated events is the cause and which the effect. We examine the relationship of global temperature and atmospheric carbon dioxide concentration at the monthly time step, covering the time interval 1980–2019, in which reliable instrumental measurements are available. While both causality directions exist, the results of our study support the hypothesis that the dominant direction is T → CO2. Changes in CO2 follow changes in T by about six months on a monthly scale, or about one year on an annual scale. We attempt to interpret this mechanism by involving biochemical reactions, as at higher temperatures soil respiration, and hence CO2 emission, are increasing.


Sci ◽  
2020 ◽  
Vol 2 (3) ◽  
pp. 81
Author(s):  
Demetris Koutsoyiannis ◽  
Zbigniew Kundzewicz

It is common knowledge that increasing CO2 concentration plays a major role in enhancement of the greenhouse effect and contributes to global warming. The purpose of this study is to complement the conventional and established theory that increased CO2 concentration due to human emissions causes an increase of temperature, by considering the reverse causality. Since increased temperature causes an increase in CO2 concentration, the relationship of atmospheric CO2 and temperature may qualify as belonging to the category of “hen-or-egg” problems, where it is not always clear which of two interrelated events is the cause and which the effect. We examine the relationship of global temperature and atmospheric carbon dioxide concentration at the monthly time step, covering the time interval 1980–2019, in which reliable instrumental measurements are available. While both causality directions exist, the results of our study support the hypothesis that the dominant direction is T → CO2. Changes in CO2 follow changes in T by about six months on a monthly scale, or about one year on an annual scale. We attempt to interpret this mechanism by involving biochemical reactions, as at higher temperatures soil respiration, and hence CO2 emission, are increasing.


2019 ◽  
Vol 33 (04) ◽  
pp. 627-632 ◽  
Author(s):  
Shawn C. Beam ◽  
Steven Mirsky ◽  
Charlie Cahoon ◽  
David Haak ◽  
Michael Flessner

AbstractHerbicide resistance is a major problem in United States and global agriculture, driving farmers to consider other methods of weed control. One of these methods is harvest weed seed control (HWSC), which has been demonstrated to be effective in Australia. HWSC studies were conducted across Virginia in 2017 and 2018, targeting Italian ryegrass in continuous winter wheat as well as common ragweed and Palmer amaranth in continuous soybean. These studies assessed the impact of HWSC (via weed seed removal) on weed populations in the next year’s crop compared with conventional harvest (weed seeds returned). HWSC reduced Italian ryegrass tillers compared with the conventional harvest at two locations in April (29% and 69%), but no difference was observed at a third location. At wheat harvest, HWSC at one location reduced Italian ryegrass seed heads (41 seed heads m−2) compared with conventional harvest (125 seed heads m−2). In soybean, before preplant herbicide applications and POST herbicide applications, HWSC reduced common ragweed densities by 22% and 26%, respectively, compared with the conventional harvest plots. By soybean harvest, no differences in common ragweed density, seed retention, or crop yield were observed, because of effectiveness of POST herbicides. No treatment differences were observed at any evaluation timing for Palmer amaranth, which is attributed to farmer weed management (i.e., effective herbicides) and low weed densities making any potential treatment differences difficult to detect. Across wheat and soybean, there were no differences observed in crop yield between treatments. Overall, HWSC was demonstrated to be a viable method to reduce Italian ryegrass and common ragweed populations.


2020 ◽  
Author(s):  
Tiehan Zhou ◽  
Kevin DallaSanta ◽  
Larissa Nazarenko ◽  
Gavin A. Schmidt

Abstract. Stratospheric radiative damping increases as atmospheric carbon dioxide concentration rises. We use the one-dimensional mechanistic models of the QBO to conduct sensitivity experiments and find that when atmospheric carbon dioxide concentration increases, the simulated QBO period shortens due to the enhancing of radiative damping in the stratosphere. This result suggests that increasing stratospheric radiative damping due to rising CO2 may play a role in determining the QBO period in a warming climate along with wave momentum flux entering the stratosphere and tropical vertical residual velocity, both of which also respond to increasing CO2.


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