Ambient Carbon Dioxide Concentration Research Articles

Evaluation of Ambient Air Quality Levels at Various Locations within Lead City University, Ibadan

Universities are big metropolitan institutions with sizable populations of students, employees, and visitors. However, university settings can contribute to air pollution, with diverse activities such as lab work, cooking in dorms, and vehicle traffic, among others, causing interior and ambient air pollution. It is impossible to overestimate how much air pollution affects the health and happiness of students. Based on this, evaluation of ambient air quality (i.e., temperature, relative humidity (RH), CO2, and particulate matter (PM2.5)) at various locations within Lead City University, Ibadan, is essential. Ambient concentrations of carbon monoxide (CO), carbon dioxide (CO2), relative humidity (RH), temperature (TEMP), and particulate matter (PM) were recorded from 15 locations across Lead City University over a two-week period. Morning temperatures in all the locations measured ranged from 23.7°C to 29.2°C, while afternoon temperatures fluctuated more significantly, with the lowest recorded at 27.2°C and the highest at a notably warmer 35.8°C in all the locations measured. The morning RH levels ranged from 63.8% to 74.7%, while afternoon RH values ranged from 58.2% to 63.4%. The findings also show that afternoon CO2 levels range from 468.5 ppm to 971.6 ppm, with Location 13 having an unusually high average. Morning CO levels ranged from 4.1 µg/m³ to 49 µg/m³, with location 13 showing an outlier at 184.2 µg/m³. CO2 and CO levels are mostly within acceptable ranges. Conclusively, variability in these parameters has implications for human health; therefore, adequate ventilation and pollution control measures are thereby recommended for the university management in order to improve indoor air quality.

Ambient carbon dioxide concentration correlates with SARS-CoV-2 aerostability and infection risk

An improved understanding of the underlying physicochemical properties of respiratory aerosol that influence viral infectivity may open new avenues to mitigate the transmission of respiratory diseases such as COVID-19. Previous studies have shown that an increase in the pH of respiratory aerosols following generation due to changes in the gas-particle partitioning of pH buffering bicarbonate ions and carbon dioxide is a significant factor in reducing SARS-CoV-2 infectivity. We show here that a significant increase in SARS-CoV-2 aerostability results from a moderate increase in the atmospheric carbon dioxide concentration (e.g. 800 ppm), an effect that is more marked than that observed for changes in relative humidity. We model the likelihood of COVID-19 transmission on the ambient concentration of CO2, concluding that even this moderate increase in CO2 concentration results in a significant increase in overall risk. These observations confirm the critical importance of ventilation and maintaining low CO2 concentrations in indoor environments for mitigating disease transmission. Moreover, the correlation of increased CO2 concentration with viral aerostability need to be better understood when considering the consequences of increases in ambient CO2 levels in our atmosphere.

Quantifying the Impact of COVID‐19 Pandemic on the Spatiotemporal Changes of CO2 Concentrations in the Yangtze River Delta, China

AbstractWhile the reduction in anthropogenic emissions due to Coronavirus disease 2019 (COVID‐19) lockdown in China and its impact on air quality have been reported extensively, its impact on ambient carbon dioxide (CO2) concentrations is still yet to be assessed. In this study, the impact of emission reductions on spatiotemporal changes of CO2 concentrations during the COVID‐19 pandemic was quantified in the Yangtze River Delta region (YRD), using high‐resolution dynamic emission inventory and the Weather Research and Forecasting model coupled with the Vegetation Photosynthesis and Respiration Model (WRF‐VPRM). The simulated CO2 concentrations from dynamic emission inventory shows a better agreement with surface observations compared with the Open‐source Data Inventory for Anthropogenic CO2 and Emission Database for Global Atmospheric Research emission, providing confidence in the quantification of CO2 concentrations variations. Our results show that emission reductions during the COVID‐19 pandemic lead to a CO2 decrease by 4.6 ppmv (−1.1%) in Shanghai and 3.1 ppmv (−0.7%) in YRD region. For the column‐averaged CO2 concentrations (denoted as XCO2), it also decreases by 0.20 ppmv (−0.05%) in Shanghai and 0.15 ppmv (−0.04%) in YRD region. Furthermore, emission reductions from transportation and industry are major contributors to the decline in CO2 concentrations at the near surface, accounting for 45.8% (41.1%) and 34.9% (41.0%) in Shanghai (YRD). Our study deepens the understanding of the response of CO2 concentrations to different sectors, which is helpful for emission management and climate adaption policies.

Manipulating atmospheric CO2 concentration induces shifts in wheat leaf and spike microbiomes and in Fusarium pathogen communities.

Changing atmospheric composition represents a source of uncertainty in our assessment of future disease risks, particularly in the context of mycotoxin producing fungal pathogens which are predicted to be more problematic with climate change. To address this uncertainty, we profiled microbiomes associated with wheat plants grown under ambient vs. elevated atmospheric carbon dioxide concentration [CO2] in a field setting over 2 years. We also compared the dynamics of naturally infecting versus artificially introduced Fusarium spp. We found that the well-known temporal dynamics of plant-associated microbiomes were affected by [CO2]. The abundances of many amplicon sequence variants significantly differed in response to [CO2], often in an interactive manner with date of sample collection or with tissue type. In addition, we found evidence that two strains within Fusarium - an important group of mycotoxin producing fungal pathogens of plants - responded to changes in [CO2]. The two sequence variants mapped to different phylogenetic subgroups within the genus Fusarium, and had differential [CO2] responses. This work informs our understanding of how plant-associated microbiomes and pathogens may respond to changing atmospheric compositions.

Coupled effects of elevated CO2 and biochar on microbial communities of vegetated soil

Soil microbial communities are important for plant growth and establishing healthy ecosystems. Although biochar is widely adopted as a sustainable fertilizer, its influence on soil ecological functions is still unclear, especially under climate change such as elevated carbon dioxide concentration (eCO2). This study explores the coupled effects between eCO2 and biochar on microbial communities in soil planted with tree seedlings of Schefflera heptaphylla. Root characteristics and soil microbial communities were examined and interpreted with statistical analysis. Results show that biochar application at ambient carbon dioxide concentration (aCO2) always improves plant growth, which is further promoted under eCO2. Similarly, β-glucosidase, urease and phosphatase activities are enhanced by biochar at aCO2 (p < 0.05). In contrast, only urease activity increases with biochar added at eCO2 (p < 0.05). The beneficial effects of biochar on soil enzyme activities become less significant at eCO2. Depending on biochar type, biochar can increase bacterial diversity and fungal richness at aCO2. However, at eCO2, biochar does not significantly affect microbial richness (p > 0.05) while microbial diversity is reduced by peanut shell biochar (p < 0.05). Owing to better plant growth under biochar application and eCO2, plants are likely to become more dominant in specializing the microbial communities that are favourable to them. In such community, the abundance of Proteobacteria is the greatest and increases after biochar addition at eCO2. The most abundant fungus also shifts from Rozellomycota to Ascomycota and Basidiomycota. These microbes can improve soil fertility. Even though the microbial diversity is reduced, using biochar at eCO2 can further promote plant growth, which in turn enhances carbon sequestration. Thus, biochar application can be an effective strategy to facilitate ecological restoration under climate change and relieve the problem of eCO2.

Spatial Interpolation of the Concentrations of Particulate Matter and Carbon Dioxide of Some Selected Tourist Sites in Srinagar City, Jammu and Kashmir, India

This investigation was carried out to monitor and prepare thematic maps of the monthly spatial variability of the ambient concentrations of particulate matter (PM1, PM2.5, PM4, PM10, and TSP) and carbon dioxide (CO2) of some selected tourist sites (viz. Shalimar Garden, Chesmashahi Botanical Garden, Harwan Garden, Nishat Garden, Naseem Bagh, Lal Chowk, and Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir (SKUAST-K) Shalimar campus of Srinagar city, Kashmir valley from November 2019 to April 2020 using the Inverse Distance Weighting (IDW) interpolation technique in Quantum Geographical Information System (QGIS). Considering Srinagar city as a growing city in terms of population, construction, vehicles, etc., the Jammu and Kashmir State Pollution Control Board in a report on managing air quality in Srinagar city identified the pollution sources in the city with their estimated source proportion as follows: vehicular emission (65-75 %), dust from bad roads (10-15 %), biomass and garbage burning (10-20 %), construction and demolition emissions (5-8 %), minor industrial activities (7-8 %) and other sources (3 %). Thus, Srinagar city’s air quality is deteriorated by these sources. Therefore, this research attempts to reveal the monthly variation and spatial interpolation of particulate matter and CO2¬. The Aerocet 831-Aerosol Mass Monitor and CDM 901-CO2 Monitor were used fortnightly in each month to monitor the ambient concentration of particulate matter and CO2 in the morning, afternoon, and evening and the sampling was carried out by taking three replications. From the data, the average mean morning, afternoon and evening concentrations of each pollutant at all the monitoring sites were as follows respectively: PM1 (67.07, 55.87, 57.62 µg/m3); PM2.5 (129.49, 95.52, 112.50 µg/m3); PM4 (170.44, 121.09, 161.81 µg/m3); PM10 (315.49, 203.09, 383.97 µg/m3); TSP (376.43, 240.49,496.55 µg/m3); and CO2 (595.33, 557.94, 601.07 ppm) showing that the morning and evening concentrations of pollutants were highest in Srinagar city. Also, the data and IDW maps make it clear that there was a statistically significant (p ≤ 0.05) variation of the monthly mean and the average six months concentrations of the monitored pollutants between most of the monitoring sites. This informs us that the concentration of particulate matter and carbon dioxide varies on monthly basis with distance from one location to another in Srinagar city. The correlation of the monthly average of most locations was non-significantly positive between most parameters but significantly strongly positive between PM1, PM2.5, and PM4 at p ≤ 0.01 with each other. Also, there was a significantly strong positive correlation (p ≤ 0.05) between PM4 and PM10, and likewise PM10 and TSP. Thus, indicating that all the monitored parameters increase or decrease with each other simultaneously. It is therefore concluded that the poor air quality of Srinagar city varies with distance as depicted by the data and IDW maps with respect to the monitoring sites and the monitored pollutants. Thus, giving an idea of the pollutants blanket over the city.

Study on the effect of vehicular pollution on the ambient concentrations of particulate matter and carbon dioxide in Srinagar City.

The present study was carried out to monitor the ambient concentrations of particulate matter and carbon dioxide caused by vehicular pollution in Srinagar City of Jammu and Kashmir, India, for a period of 12 months from June 2019 to May 2020 as the major contributions in these areas are due to vehicular movement. Out of five, four locations (viz. Dalgate, Jehangir Chowk, Parimpora and Pantha Chowk) had highest traffic density in the city and the fifth location (Shalimar) had low traffic volume. The sampling was done on every fortnight using AEROCET 831—aerosol mass monitor and CDM 901—CO2 monitor with each sampling being carried out three times a day, i.e. morning (9:00 am–10:30 am), afternoon (1:00 pm–2:30 pm) and evening (4:30 pm–6:00 pm) with three replications at each site based on the peak traffic hours. The results show that during the whole period, average PM1 concentrations ranged from 15.10 to 108.9 µg/m3, PM2.5 (28.70–577.50 µg/m3), PM4 (44.50–780.87 µg/m3), PM10 (57.13–1225.53 µg/m3), total suspended particulates (77.77–1410.27 µg/m3) and CO2 (332.4–655.0 ppm). The average concentrations of these parameters showed that the maximum PM1 concentration was found at Dalgate (53.77 µg/m3) and PM2.5 had its maximum average concentration at Jehangir Chowk (140.13 µg/m3). Other parameters like PM4, PM10, TSP and CO2 had a maximum average values at Jehangir Chowk (240.23 µg/m3, 633.40 µg/m3, 853.50 µg/m3 and 533.20 ppm, respectively). The pollution load was observed to be maximum during winter season followed by autumn, summer and spring. The lowest concentration of all pollutants except CO2 was observed in April 2020 and this might be due to COVID-19 lockdown observed in the country during the same period.

AMF Inoculation Can Enhance Yield of Transgenic Bt Maize and Its Control Efficiency Against Mythimna separata Especially Under Elevated CO2.

The promotion and application of transgenic Bt crops provides an approach for the prevention and control of target lepidopteran pests and effectively relieves the environmental pressure caused by the massive usage of chemical pesticides in fields. However, studies have shown that Bt crops will face a new risk due to a decrease in exogenous toxin content under elevated carbon dioxide (CO2) concentration, thus negatively affecting the ecological sustainability of Bt crops. Arbuscular mycorrhizal fungi (AMF) are important beneficial microorganisms that can effectively improve the nutrient status of host plants and are expected to relieve the ecological risk of Bt crops under increasing CO2 due to global climate change. In this study, the Bt maize and its parental line of non-transgenic Bt maize were selected and inoculated with a species of AMF (Funneliformis caledonium, synonyms: Glomus caledonium), in order to study the secondary defensive chemicals and yield of maize, and to explore the effects of F. caledonium inoculation on the growth, development, and reproduction of the pest Mythimna separata fed on Bt maize and non-Bt maize under ambient carbon dioxide concentration (aCO2) and elevated carbon dioxide concentration (eCO2). The results showed that eCO2 increased the AM fungal colonization, maize yield, and foliar contents of jasmonic acid (JA) and salicylic acid (SA), but decreased foliar Bt toxin content and Bt gene expression in Bt maize leaves. F. caledonium inoculation increased maize yield, foliar JA, SA contents, Bt toxin contents, and Bt gene expression in Bt maize leaves, and positively improved the growth, development, reproduction, and food utilization of the M. separata fed on non-Bt maize. However, F. caledonium inoculation was unfavorable for the fitness of M. separata fed on Bt maize, and the effect was intensified when combined with eCO2. It is indicated that F. caledonium inoculation had adverse effects on the production of non-Bt maize due to the high potential risk of population occurrence of M. separata, while it was just the opposite for Bt maize. Therefore, this study confirms that the AMF can increase the yield and promote the expression levels of its endogenous (JA, SA) and exogenous (Bt toxin) secondary defense substances of Bt maize under eCO2, and finally can enhance the insect resistance capacity of Bt crops, which will help ensure the sustainable utilization and safety of Bt crops under climate change.

Greenhouse Carbon Dioxide Supplementation with Irrigation and Fertilization Management of Geranium and Fountain Grass

Increase in ambient carbon dioxide (CO2) concentration is beneficial for plant growth due to increased photosynthesis and water use efficiency. A greenhouse study was conducted to investigate how supplemented CO2 influences optimal irrigation and fertilization management for production of two ornamental plants. Two identical greenhouses were used, with one having CO2 supplementation and the other serving as the control with ambient CO2 concentration. Tensiometer-based irrigation treatments were applied at soil tensions of –5, –10, and –15 kPa with 0-, 3-, 6-, or 9-g controlled-release fertilizer rates applied in factorial with irrigation treatments. Plugs of geranium ‘Pinto Premium Rose Bicolor’ and fountain grass were grown under experimental conditions for 12 and 16 weeks, respectively. The results showed that CO2 supplementation increased the dry weight of geranium ‘Pinto Premium Rose Bicolor’ and fountain grass by 35% and 39%, respectively. Under the two driest irrigation regimes (–10 and –15 kPa), photosynthesis of geranium ‘Pinto Premium Rose Bicolor’ increased with CO2 supplementation compared with the ambient condition. Similarly, for fountain grass, the moderately watered (–10 kPa) treatment had a greater rate of photosynthesis with greater fertilizer rates of 6 or 9 g. CO2 supplementation resulted in increased water use efficiency of both species, whereas rate of transpiration was lower only in fountain grass. Among different fertilizer rates, 6- or 9-g fertilizer rates had greater values for dry weight, number of flowers, and stomatal conductance in both species. Therefore, it can be concluded that CO2 supplementation can help in efficient use of water for greenhouse production of ornamental plants.

Monitoring of ambient methane and carbon dioxide concentrations based on wavelength modulation-direct absorption spectroscopy

Wavelength modulation-direct absorption spectroscopy (WM-DAS) integrates the advantages of measuring absolute absorbance profile from calibration-free direct absorption spectrum (DAS) with the enhanced noise rejection and high sensitivity of wavelength modulation spectrum (WMS). This method can be used to precisely recover the crucial absorbance profile via the extraction of the characteristic frequency of the modulated transmitted light. In this paper, the WM-DAS method with non-calibration and high signal-to-noise ratio is integrated with a Herriott cell (about 128 m). Under the condition of atmospheric pressure and room temperature, the absorptance functions of two spectral lines of CO&lt;sub&gt;2&lt;/sub&gt; (6330.821 cm&lt;sup&gt;–1&lt;/sup&gt;) and CH&lt;sub&gt;4&lt;/sub&gt; (6046.964 cm&lt;sup&gt;–1&lt;/sup&gt;) in air are measured, and their standard deviations of spectral fitting residual are 5.6 × 10&lt;sup&gt;–5&lt;/sup&gt; and 7 × 10&lt;sup&gt;–5&lt;/sup&gt;, respectively. Subsequently, the concentration of CO&lt;sub&gt;2&lt;/sub&gt; and CH&lt;sub&gt;4&lt;/sub&gt; in air are monitored on-line by the WM-DAS method integrated with the Herriott cell, and compared with those by the highly sensitive continuous wave cavity ring down spectroscopy (CW-CRDS). The experimental results show that the measured results of the long optical path WM-DAS method are consistent with those by the CW-CRDS method, and the linear correlation between the two methods is above 0.99. The detection limit of CO&lt;sub&gt;2&lt;/sub&gt; and CH&lt;sub&gt;4&lt;/sub&gt; by the WM-DAS method are 170 ppb and 1.5 ppb respectively, which are slightly higher than those by the CW-CRDS. However, the measurement speed by WM-DAS is much higher than that by CW-CRDS, and possesses the advantages of simpler operation, lower environmental requirements, long-term stability, etc.

Responses of Angelica acutiloba Kitagawa Transplants to Elevated Ambient CO2 Concentration

Long-term exposure to an elevated ambient carbon dioxide (eCO2) concentration could weaken or diminish the enhancement of plant photosynthesis and growth. To monitor this response and offer references for growth management, the whole-plant photosynthetic rate (Pn,w) and dark respiration rate (Rd,w) of Angelica acutiloba Kitagawa transplants were monitored with a growth chamber. The results showed that eCO2 increased both the Pn,w and Rd,w by (79 ± 42) % and (126 ± 51) %. The dry weight of transplants under eCO2 was 33.6% greater than that under aCO2. However, the photosynthetic acclimation to eCO2 occurred. The increase in the Pn,w was maintained until the end of the experiment due to increased leaf area. Moreover, the increase in plant dry weight mainly occurred in the first 15 days of treatment. Furthermore, the dry weight estimated based on the Pn,w and Rd,w agreed well with the measured dry weight. The relative growth rate (RGR) calculated with the estimated dry weight demonstrated the response of transplant growth to eCO2. These results indicated that the proposed method can be used to monitor the response of plant growth to eCO2.

Fire deficits have increased drought sensitivity in dry conifer forests: Fire frequency and tree-ring carbon isotope evidence from Central Oregon.

A century of fire suppression across the Western United States has led to more crowded forests and increased competition for resources. Studies of forest thinning or stand conditions after mortality events have provided indirect evidence for how competition can promote drought stress and predispose forests to severe fire and/or bark beetle outbreaks. Here, we demonstrate linkages between fire deficits and increasing drought stress through analyses of annually resolved tree-ring growth, fire scars, and carbon isotope discrimination (Δ13 C) across a dry mixed-conifer forest landscape. Fire deficits across the study area have increased the sensitivity of leaf gas exchange to drought stress over the past >100years. Since 1910, stand basal area in these forests has more than doubled and fire-return intervals have increased from 25 to 140years. Meanwhile, the portion of interannual variation in tree-ring Δ13 C explained by the Palmer Drought Severity Index has more than doubled in ca. 300-500-year-old Pinus ponderosaas well as in fire-intolerant, ca. 90-190-year-old Abies grandis. Drought stress has increased in stands with a basal area of ≥25m2 /ha in 1910, as indicated by negative temporal Δ13 C trends, whereas stands with basal area ≤25m2 /ha in 1910, due to frequent or intense wildfire activity in decades beforehand, were initially buffered from increased drought stress and have benefited more from rising ambient carbon dioxide concentrations, [CO2 ], as demonstrated by positive temporal Δ13 C trends. Furthermore, the average Δ13 C response across all P.ponderosa since 1830 indicates that photosynthetic assimilation rates and stomatal conductance have been reduced by ~10% and ~20%, respectively, compared to expected trends due to increasing [CO2 ]. Although disturbance legacies contribute to local-scale intensity of drought stress, fire deficits have reduced drought resistance of mixed-conifer forests and made them more susceptible to challenges by pests and pathogens and other disturbances.

Urban land use regression models: can temporal deconvolution of traffic pollution measurements extend the urban LUR to suburban areas?

Land use regression (LUR) models that predict intra-urban variability of traffic-related air pollution are frequently used to inform exposure assessments in epidemiological studies. Spatially extending models built in city centres to unmeasured surrounding areas could be beneficial as it increases the size of area available for exposure assessment, which can improve the statistical power of health studies. However, past studies have shown poor performance when these models were transferred to unmeasured areas. In this study, ambient concentrations of black carbon (BC), ultrafine particles (UFP), nitric oxide (NO) and nitrogen dioxide (NO2) with response times ranging from 1 s to 20 s were measured in the summer using a mobile laboratory. These ambient concentrations were temporally deconvolved into local, neighbourhood- and regional-background time-series signals. The temporally resolved signals were used to develop resolved LUR models (i.e. local, neighbourhood-background and regional-background models) while unresolved LUR models were developed from total ambient concentrations (i.e., measurements that were not temporally resolved). Both resolved and unresolved LUR models displayed modest R2 values when compared to models developed from fixed sites which may be due to the mobile nature of our data. External validation of the resolved and unresolved models within the models' original geographic domain showed comparable performance for BC (R2 for resolved vs. unresolved: 0.44 vs. 0.47), UFP (0.34 vs. 0.35), NO (0.18 vs. 0.19) and NO2 (0.42 vs.0.40). However, the resolved models were better able to assess exposure than the unresolved models when they were spatially extended to suburban areas bordering the urban area: UFP (R2: 0.42 vs. 0.29), NO2 (0.36 vs 0.26), NO (0.21 vs 0.14) and BC (0.32 vs 0.30). Furthermore, the resolved models were better able to predict the observed variability in suburban areas with both similar and different land uses to the urban area.

Responses of Four Rice Varieties to Elevated CO2 and Different Salinity Levels

Abstract: This study was carried out in 2014 at Isfahan University of Technology, Iran, to evaluate the responses of four rice varieties (Neda, Deylamani, Shiroudi and Domsorkh) to ambient (360 ± 50 μmol/mol) and elevated (700 ± 50 μmol/mol) air carbon dioxide (CO2) concentrations under four salinity levels (0, 30, 60 and 90 mmol/L NaCl). There was significant variation among rice varieties in response to elevated CO2 concentration under the four salinity levels. Under non-saline condition, elevated CO2 increased the dry weight of Neda, Deylamani and Domsorkh by 8%, 50% and 8%, respectively, but reversely decreased that of Shiroudi by 34%. Increasing CO2 concentration significantly reduced the negative effects of salinity on Shiroudi, but these effects were even increased in Deylamani and Domsorkh under all the salinity levels and in Neda only under 30 and 60 mmol/L NaCl. Significant correlations were established between plant dry weight, SPAD value and leaf area under both CO2 levels. However, this trend was observed only at ambient CO2 concentration in the presence of soluble carbohydrates. The results revealed the genotype and salinity dependence of the effects of CO2 concentrations on the rice traits investigated.

Investigation of Growth Rate and Phycocolloid Content from Kappaphycus alvarezii (Rhodophyta, Solieriaceae) under Different Light Conditions Using Vibrational Spectroscopy

&lt;p&gt;&lt;em&gt;Kappa&lt;/em&gt;-carrageenan (&lt;em&gt;K&lt;/em&gt;-carrageenan) is an important phycocolloid which is a major constituent of the cell wall of &lt;em&gt;Kappaphycus alvarezii&lt;/em&gt;. The chemical structure of &lt;em&gt;K&lt;/em&gt;-carrageenan comprises a linear backbone of D-galactose residues linked with alternating α-(1,3) and β-(1,4) linkages which are substituted by one ester-sulphonic group per di-galactose repeating unit. The spectral qualities of light as well as the ambient carbon dioxide concentration, both play an important role in the photosynthetic pathway in plants and this investigation set forth to establish the effect of different wavelengths of light and carbon dioxide supplementation on the chemical structure of &lt;em&gt;K&lt;/em&gt;-carrageenan obtained from &lt;em&gt;K. alvarezii. &lt;/em&gt;Specimens were cultivated under a range of monochromatic light spectra and assessed for chemical composition using Fourier Transform Infrared (FTIR) spectroscopy.The &lt;em&gt;K. alvarezii&lt;/em&gt; control was irradiated with full light spectrum, treatments were carried out using blue (492-455 nm), green (577-492 nm) and red (780-622 nm)light. One experiment was carried out by supplementation with carbon dioxide. Samples were collected after 14 days. The effect of different wavelengths of light on the growth rates of experimental samples was determined. Red light had the most significant impact on the growth rate of &lt;em&gt;K. alvarezii &lt;/em&gt;as compared to those treated with blue light. The FTIR fingerprint of the ground seaweed was found to be identical to that of commercial &lt;em&gt;K&lt;/em&gt;-carrageenan (Sigma). Special emphasis was given to the 800-1300 cm&lt;sup&gt;-1 &lt;/sup&gt;region, which presents several vibrational modes. All the samples produced similar FTIR spectral profiles, suggesting that genes related to the carrageenan biosynthesis are not affected by different wavelengths of light or CO&lt;sub&gt;2&lt;/sub&gt;. The results obtained from FTIR spectroscopy demonstrated that different wavelengths of light and supplementation with CO&lt;sub&gt;2&lt;/sub&gt; have no influence to the chemical structure of &lt;em&gt;K&lt;/em&gt;-carrageenan in &lt;em&gt;K. alvarezii&lt;/em&gt;.&lt;/p&gt;

S-metolachlor and rainfall effects on sweetpotato (Ipomoea batatas L. [Lam]) growth and development

The herbicide S-metolachlor is used to control or suppress annual grasses, nutsedges and several broadleaf weeds in sweetpotato. However, a decline in storage root quality is suspected when an excessive rainfall occurs within 24h after application. A sunlit, controlled environment experiment was conducted to investigate sweetpotato response to five levels of S-metolachlor (0.00, 0.86, 1.72, 2.58 and 3.44kgha−1), and two levels of simulated rainfall (0 and 38mm at 51mmh−1) immediately after application. Sweetpotato slips were transplanted into white polyvinyl chloride pots filled with sandy loam soil. S-metolachlor treatments were applied to slips and a simulated rainfall treatment delivered immediately after transplanting and herbicide treatment. All pots were transferred to sunlit growth chambers that were maintained at 30/22°C, day/night temperatures and ambient carbon dioxide concentration (400μLL−1) for 60 days. An evapotranspiration-based irrigation system was used to supply water and nutrients. Plant biomass components and quality of storage roots were recorded 60 days after transplanting. There was no difference between rainfall treatments across S-metolachlor rates for vine lengths, leaf numbers and leaf area. These parameters, however, declined linearly and significantly with increase in S-metolachlor concentration. Total storage root weight declined linearly with increased S-metolachlor concentration; the decline was steeper with simulated rainfall. Yield of marketable storage roots declined by 18 and 31% in the absence of rainfall and 55 and 79% in the presence of rainfall with S-metolachlor at minimum (0.86kgha−1) and maximum (1.43kgha−1) recommended label rates, respectively, used to control weeds. Yield reduction was directly proportional to the rate of S-metolachlor applied in the absence or presence of rainfall; 77 and 123g fresh weight kg−1ha−1S-metolachlor for no-rainfall and rainfall treatment, respectively. These results can be used to improve management decisions to optimize yield under field conditions as well as to mitigate risk of injury that could be associated with the use of S-metolachlor in sweetpotato production systems.

Growth and physiological responses of creeping bentgrass (Agrostis stolonifera) to elevated carbon dioxide concentrations.

The atmospheric carbon dioxide level has increased and is predicted to continue increasing, which may affect various aspects of plant growth. The objective of this study was to investigate the effects of doubling the carbon dioxide level on the growth and physiological activities of a widely utilized cool-season turfgrass species, creeping bentgrass (Agrostis stolonifera L. ‘Penncross’). ‘Penncross’ plants were established in fritted clay medium and maintained under well-irrigated and well-fertilized conditions in growth chambers. The plants were exposed to either ambient carbon dioxide concentrations (400±10 µmol L−1) or elevated carbon dioxide concentrations (800±10 µmol L−1) for 12 weeks. Plants grown under elevated carbon dioxide displayed a significantly faster growth rate of their lateral stems (stolons) and increased shoot and root dry weight but a reduced specific leaf area compared to those plants at ambient carbon dioxide levels. Fast stolon growth is a highly desirable trait for turfgrass establishment and recovery from physical damage. The root length and surface area were also increased due to the elevated CO2, which may facilitate water uptake and serve critical drought-avoidance roles when irrigation water is limited. Elevated carbon dioxide caused an increase in the leaf net photosynthetic rate but a reduction in the stomatal conductance and transpiration rate, contributing to improved water use efficiency in creeping bentgrass. Efficient water use is especially important for turfgrass plant survival when irrigation water is limited. Our results suggested that cool-season turfgrass species may greatly benefit from increasingly elevated carbon dioxide concentrations via growth promotion and increasing water use efficiency.

Ambient carbon dioxide concentrations in industrial park areas: A monitoring and modeling study

Industrial parks are main sources for the fossil–fuel burning carbon dioxide (CO2) emissions. In this work we describe a monitoring and modeling study of ambient CO2 concentrations in two industrial park areas in Taiwan in 2011 and 2012. We used 1–minute high time resolution measurements to help better resolve time–varying plumes of air abundant in CO2 than the traditional one–hour average data. The inclusion of span–one and span–two CO2 calibration air traced back to the World Meteorological Organization (WMO) primary standards in the measurement system enabled us to persistently produce consistently calibrated CO2 measurements over various industrial parks. We use a small scale Lagrangian model and two–dimensional (2D) observational winds to associate ambient CO2 measurements with local emission sources. Given the closeness of our monitoring sites to the industrial parks, our 2D Lagrangian calculation can genuinely represent direction of pollution dispersion from the emission source. We focused on cases when vertical transport is weak and the emissions from the industrial parks are kept close to the surface. These much polluted cases were the targets of our 2D Lagrangian calculations. The model simulations with emissions from industrial park areas showed close resemblance between peak modeled results and observed CO2 levels at measurement sites. These comparisons revealed both the local and non–local effects on the dispersion of CO2 from industrial park areas. Our results vindicate the values of deploying high time–resolution CO2 analyzers combined with high resolution modeling to determine the relative importance of local and long–distance sources of CO2 emissions.

Low soil temperature inhibits the stimulatory effect of elevated [CO2] on height and biomass accumulation of white birch seedlings grown under three non‐limiting phosphorus conditions

White birch (Betula papyrifera Marsh.) seedlings were exposed to ambient or doubled ambient carbon dioxide concentration ([CO2]), three soil temperatures (Tsoil) (low, intermediate, high), and three phosphorus (P) regimes (low, medium, high) in environment‐controlled greenhouses. Height (H), root‐collar diameter (RCD), biomass, and leaf phosphorus concentration (leaf P) were determined four months after initiation of treatments. The low Tsoil reduced H, RCD, shoot biomass, root biomass and total seedling biomass whereas the high‐P level and the [CO2] elevation increased all the growth and biomass parameters. Elevated [CO2] significantly reduced leaf P. There were significant two‐factor interactions suggesting that the effect of elevated [CO2] on (1) H, total biomass, biomass of plant components, and leaf P was dependent on Tsoil, (2) total biomass was contingent on P regime. For instance, the positive response of H and total biomass to elevated [CO2] was limited to seedlings raised under the intermediate and high Tsoil, respectively. In addition, [CO2] elevation increased total biomass only at the high‐P regime but not at the low‐ or medium‐P level where the effect of [CO2] was statistically insignificant. No significant main effect of treatment or interaction was observed for root to shoot biomass ratio.

Farm-level Autonomous Adaptation of European Agricultural Supply to Climate Change

The impact of climate change on European agriculture is subject to a significant uncertainty, which reflects the intertwined nature of agriculture. This issue involves a large number of processes, ranging from field to global scales, which have not been fully integrated yet. In this study, we intend to help bridging this gap by quantifying the effect of farm-scale autonomous adaptations in response to changes in climate. To do so, we use a modelling framework coupling the STICS generic crop model to the AROPAj microeconomic model of European agricultural supply. This study provides a first estimate of the role of such adaptations, consistent at the European scale while detailed across European regions. Farm-scale autonomous adaptations significantly alter the impact of climate change over Europe, by widely alleviating negative impacts on crop yields and gross margins. They significantly increase European production levels. However, they also have an important and heterogeneous impact on irrigation water withdrawals, which exacerbate the differences in ambient atmospheric carbon dioxide concentrations among climate change scenarios.