Increasing CO2 Levels Research Articles

Anticipated atmospheric CO2 elevation differentially influenced the soil microbial diversities in crop, grassland, and forest: A meta-analysis

The increasing of atmospheric carbon dioxide (CO2) has a greater impact on soil microbial diversity and related soil nutrient dynamics under different ecology. In our study, a global database of 572 observations from 202 research publications analysed to explore the impacts of increased atmospheric CO2 on soil microbial diversities. The soil microbial biomass carbon (MBC), structural (microbial populations), and functional (enzymatic activities) microbial diversities were analysed across 22 nations and 108 crops (including forest, grassland and C3 plants). The impact of three elevated CO2 (eCO2) concentrations i.e., <25%, 25–50% and >50% over ambient in three-time scale (1970–1989, 1990–2009 and 2010–2020) and two region (tropical and temperate) on the above parameters were studied. Higher MBC contents were found under eCO2 level (>50%) followed by eCO2 level 25–50% and <25% over ambient in C3 plants and forest ecology, however, in grassland the average MBC content was higher under eCO2 level 25–50%. Soil enzymatic activities were higher under eCO2 (25–50%) than other elevated CO2 conditions in the forest and C3 plants, whereas in grasslands, the enzymatic activities decreased with an increase in CO2 concentrations. These findings suggested that grassland was more sensitive to elevated CO2 as such compared to the forest and C3 plants. Both the bacterial and fungal populations were higher only up to eCO2 level (25–50% over ambient) in all the vegetations. So, higher microbial populations and soil enzymatic activities were noticed up to 50% elevation of CO2 over ambient conditions irrespective of the vegetation and region indicating higher belowground soil activities. Therefore, the findings suggested that there would be higher belowground soil activities in increased CO2 levels (anticipated climate change scenario) in agriculture and forest crop up to a certain threshold elevation of CO2 which needs better water and nutrient management for getting sustainable yield. The finding also suggested region and vegetation-specific (crop/forest/grassland) management options are necessary for fetching advantage of CO2 fertilization and to tackle the abiotic stress management of crops.

Increased CO2 levels in the operating room correlate with the number of healthcare workers present: an imperative for intentional crowd control

The air in an operating room becomes more contaminated as the occupancy of the room increases. Individuals residing in a room can potentially emit infectious agents. In order to inhibit and better understand the epidemiology of surgical site infections, it is important to develop procedures to track room occupancy level and respiration. Exhaled CO2 provides a respiratory byproduct that can be tracked with IR light and is associated with human occupancy. Exhaled CO2 can also be used as an indirect measure of the potential release and level of infectious airborne agents. We show that non-dispersive infrared CO2 sensors can be used to detect CO2 in operating room air flow conditions of 20 air changes per hour and a positive pressure of 0.03 in. H2O. The CO2 concentration increased consecutively for occupation levels of one to four individuals, from approximately 65 ppm above the background level when one individual occupied the operating room for twenty minutes to approximately 300 ppm above the background when four individuals were present for twenty minutes. The amount of CO2 detected increases as the number of occupants increase, the activity level increases, the residency time increases and when the ventilation level is reduced.

Robotic assited perineal prostatectomy (RAPP) as a new era for anesthesiology: It's effects on hemodynamic parameters and respiratory mechanics.

Robotic-assisted perineal prostatactomy(RAPP) is a new alternative surgical technique, in prostate cancer patients especially with a history of intra-abdominal surgery. The aim of this study is to examine the effects of the challenging patient position and CO2 insufflation in perineal space during RAPP on both hemodynamic parameters and respiratory mechanics. Hemodynamic and respiratory parameters of 30 patients who underwent RAPP and 31 patients who underwent Robotic-assisted laparoscopic prostatectomy (RALP) for prostate cancer between 2017 and 2019 were retrospectively evaluated. Comparison between RAPP and RALP patients showed that anesthesia, surgery and insufflation times were shorter in RAPP patients (p < 0.05). Blood pCO2 level was higher, and the pH decrease was more prominent in the RAPP patients 30 and 60min after perineal CO2 insufflation (p < 0.05). The mean arterial pressures, driving pressure, Ppeak and Pplato values were statistically higher in the RALP patients and 60min after insufflation while static and dynamic lung compliance values were found to be lower. Our results showed that blood pCO2 level may severely increaseafter perineal CO2 insufflation. The fact that respiratory mechanics are less affected despite the difficult patient position for lungs in RAPP patients, the presence of higher CO2 level supports that the perineal CO2 insufflation plays a more important role in increased CO2 level. Considering these changes, especially the sudden increase in the risk of CO2 level, close follow-up and timely intervention by anesthesiology can ensure all changes remain in a clinically safe range.

Enhanced ZIF-8-enabled colorimetric CO2 sensing through dye-precursor synthesis

The accumulation of carbon dioxide (CO2) within enclosed spaces, along with volatile organic compounds, under certain humidity, temperature, and ventilation conditions is associated with detrimental human health symptoms such as fatigue. Color-based chemical sensing is a promising approach to detect CO2 levels relevant to indoor air quality through producing fast, quantifiable output visible to the naked eye. In a prior work, a colorimetric gas sensor was fabricated through synthesizing the metal-organic framework, ZIF-8, as the adsorbent, followed by post-synthetic mixing with a dye, phenol red (PSP), and primary amine, ethylenediamine (ED). While this sensor (termed PSP-ED/ZIF-8) maintained its structural integrity in atmospheric conditions and exhibited an increasing fuchsia-to-yellow color change with increasing CO2 levels in dry environment, the colorimetric response greatly suffered in the presence of humid CO2. In this work, a significantly improved colorimetric CO2 sensor (referred to as ED/PSP:ZIF-8) is accomplished through directly incorporating phenol red in the ZIF-8 metal and linker precursor solutions and then blending with ethylenediamine. MATLAB-generated color distributions and in-situ ultraviolet-visible (UV-Vis) spectroscopic studies quantitatively demonstrate an enhanced colorimetric gas response of ED/PSP:ZIF-8 compared to that of PSP-ED/ZIF-8 across an important range of CO2 for indoor air quality monitoring (500 – 3500 ppm) and across a range of humidity. The new sensor also exhibits high selectivity to CO2 compared to select volatile organic compounds, such as acetone and ethanol, which contribute to human health symptoms experienced indoors. The enhanced performance is attributed to the proposed incorporation of phenol red within ZIF-8, while maintaining the chemical stability of the MOF.

Quantification and uncertainty of root growth stimulation by elevated CO2 in a mature temperate deciduous forest

Increasing CO2 levels are a major global challenge, and the potential mitigation of anthropogenic CO2 emissions by natural carbon sinks remains poorly understood. The uptake of elevated CO2 (eCO2) by the terrestrial biosphere, and subsequent sequestration as biomass in ecosystems, remain hard to quantify in natural ecosystems. Here, we combine field observations of fine root stocks and flows, derived from belowground imaging and soil cores, with image analysis, stochastic modelling, and statistical inference, to elucidate belowground root dynamics in a mature temperate deciduous forest under free-air eCO2 to 150 ppm above ambient levels. eCO2 led to relatively faster root production (a peak volume fold change of 4.52 ± 0.44 eCO2 versus 2.58 ± 0.21 control), with increased root elongation relative to decay the likely causal mechanism for this acceleration. Physical analysis of 552 root systems from soil cores support this picture, with lengths and widths of fine roots significantly increasing under eCO2. Estimated fine root contributions to belowground net primary productivity increase under eCO2 (mean annual 204 ± 93 g dw m−2 yr−1 eCO2 versus 140 ± 60 g dw m−2 yr−1 control). This multi-faceted approach thus sheds quantitative light on the challenging characterisation of the eCO2 response of root biomass in mature temperate forests.

Effects of nitrogen addition on Eucalyptus globulus growth and carbon sequestration potential under various CO2 climatic conditions

ABSTRACT The catastrophic and enormous increase in atmospheric greenhouse gas levels leads to global climate change, and an immediate need to investigate the effects of increased CO2 levels on natural vegetation is complex. The goal of this study was to see how nitrogen addition affected Eucalyptus globulus Labill. species development in both ambient (408 ppm) and different elevated (450 ppm, 500 ppm, 550 ppm, and 600 ppm) carbon dioxide environments with OSC S-1000 L plant growth chamber. In this investigation, nitrogen was added in the form of potassium nitrate in various amounts (0, 25, 50, 100, and 200 mg/kg of soil). The plant’s growth responses (leaf length, leaf width, and shoot length) were investigated. To calculate the carbon content, a multiple regression equation was employed to fit the model. The maximum carbon content value 52.37 ± 0.03% was recorded at 200 mg/kg nitrogen addition level for an elevated CO2 condition of 600 ppm. The results of this study conclude that the nitrogen addition had a positive impact on the plant growth and carbon sequestration potential of Eucalyptus globulus under ambient as well as elevated CO2 conditions.

Mitochondrial and peroxisomal NAD+ uptake are important for improved photosynthesis and seed yield under elevated CO2 concentrations.

As sessile organisms, plants must adapt their physiology and developmental processes to cope with challenging environmental circumstances, such as the ongoing elevation in atmospheric carbon dioxide (CO2 ) levels. Nicotinamide adenine dinucleotide (NAD+ ) is a cornerstone of plant metabolism and plays an essential role in redox homeostasis. Given that plants impaired in NAD metabolism and transport often display growth defects, low seed production and disturbed stomatal development/movement, we hypothesized that subcellular NAD distribution could be a candidate for plants to exploit the effects of CO2 fertilization. We report that an efficient subcellular NAD+ distribution is required for the fecundity-promoting effects of elevated CO2 levels. Plants with reduced expression of either mitochondrial (NDT1 or NDT2) or peroxisomal (PXN) NAD+ transporter genes grown under elevated CO2 exhibited reduced total leaf area compared with the wild-type while PXN mutants also displayed reduced leaf number. NDT2 and PXN lines grown under elevated CO2 conditions displayed reduced rosette dry weight and lower photosynthetic rates coupled with reduced stomatal conductance. Interestingly, high CO2 doubled seed production and seed weight in the wild-type, whereas the mutants were less responsive to increases in CO2 levels during reproduction, producing far fewer seeds than the wild-type under both CO2 conditions. These data highlight the importance of mitochondrial and peroxisomal NAD+ uptake mediated by distinct NAD transporter proteins to modulate photosynthesis and seed production under high CO2 levels.

Evolution of Crassulacean acid metabolism in response to the environment: past, present, and future

Crassulacean acid metabolism (CAM) is a mode of photosynthesis that evolved in response to decreasing CO2 levels in the atmosphere some 20 million years ago. An elevated ratio of O2 relative to CO2 caused many plants to face increasing stress from photorespiration, a process exacerbated for plants living under high temperatures or in water-limited environments. Today, our climate is again rapidly changing and plants’ ability to cope with and adapt to these novel environments is critical for their success. This review focuses on CAM plant responses to abiotic stressors likely to dominate in our changing climate: increasing CO2 levels, increasing temperatures, and greater variability in drought. Empirical studies that have assessed CAM responses are reviewed, though notably these are concentrated in relatively few CAM lineages. Other aspects of CAM biology, including the effects of abiotic stress on the light reactions and the role of leaf succulence, are also considered in the context of climate change. Finally, more recent studies using genomic techniques are discussed to link physiological changes in CAM plants with the underlying molecular mechanism. Together, the body of work reviewed suggests that CAM plants will continue to thrive in certain environments under elevated CO2. However, how CO2 interacts with other environmental factors, how those interactions affect CAM plants, and whether all CAM plants will be equally affected remain outstanding questions regarding the evolution of CAM on a changing planet.

Digital Technology, Education, and Economic Growth in a Green Economy in Indonesia

This study investigates digital inclusion in the form of internet users, education, economic growth, and CO2 emissions to understand the digital economy and green economy in Indonesia. This research examines data from 2000 until 2020 to be able to produce "autoregressive vectors" that may be used to evaluate the causal link between variables. Based on secondary data from the World Bank, the following multivariate regression model was used to investigate the causal link between Internet Users, Economic Growth, Education, and Carbon dioxide expenditure in Indonesia. Carbon Dioxide encourages investment in Education to solve environmental problems so that the higher levels of CO2 in Indonesia's air encourage the Indonesian government to invest in education in terms of CO2 problems. Where education itself significantly increases public awareness so the relationship between education and CO2 has a significant negative correlation. And education drives future education and significantly boosts economic growth. High economic growth or a more established economy actually has a significant negative correlation with CO2 levels, which means that a green economy can be applied in Indonesia. The interesting thing is that there is a significant positive relationship between internet users and the increase in CO2 levels in the air in Indonesia. This is very interesting because the use of the internet in Indonesia has an impact on the business sector and ordering or online shopping increases the use of transportation for shipping goods which actually increases CO2 levels in Indonesia's air.

Recent advances in solar‐driven CO2 reduction over g‐C3N4‐based photocatalysts

AbstractThe persistent increase of CO2 levels in the atmosphere, already exceeding 400 ppm, urges the exploration of CO2 emission reduction and recycling technologies. Ideally, photocatalytic conversion of CO2 into valuable hydrocarbons realizes solar‐to‐chemical energy conversion, which is a desirable “kill two birds with one stone” strategy; namely, CO2 photoreduction can simultaneously tackle energy shortage and keep global carbon balance. Graphitic carbon nitride (g‐C3N4) working on CO2 reduction reaction deserves a highlight not only for the metal‐free feature that endows it with low cost, tunable electronic structure, and easy fabrication properties but also because of its strong reduction ability. The present review concisely summarizes the latest advances of g‐C3N4‐based photocatalysts toward CO2 reduction. It starts with the discussion of thermodynamics and dynamics aspects of the CO2 reduction process. Then the modification strategies to promote g‐C3N4‐based photocatalysts in CO2 photoreduction have been discussed in detail, including surface functionalization, molecule structure engineering, crystallization, morphology engineering, loading cocatalyst, and constructing heterojunction. Meanwhile, the intrinsic factors affecting CO2 reduction activity and selectivity are analyzed and summarized. In the end, the challenges and prospects for the future development of highly g‐C3N4‐based photocatalysts in CO2 reduction are also presented.

The Graphitic Carbon Nitride (g-C3N4): A Promising Material for Photocatalytic CO2 Reduction

The excess use of fossil fuel and rapid industrialization increase of CO2 level in the atmosphere. Efficient conversion of CO2 to value added chemicals and fuels are the best method to reduce CO2 level as well as to maintain sustainability. To overcome the kinetic and thermodynamic barrier in CO2, a suitable heterostructure composite is necessary. Among different types of materials carbon based materials and their composites are shown their suitability electrochemical, thermal and photo-assisted method of CO2 conversion. Among different carbon based materials, graphitic carbon nitrite (g-C3N4) is a sustainable, inexpensive photocatalyst for CO2 conversion. This present article tries to summarize recent works based on conversion of CO2 in presence of solar light using g-C3N4 based composites. This provides an outlook for the future development of new catalysts to reduce CO2 effectively and save our earth from CO2 pollution.

Efficient imidazolium ionic liquid as a tri-functional robust catalyst for chemical fixation of CO2 into cyclic carbonates

The recent increase in CO2 levels has had an extensive impact on the environment; hence an effective catalyst for chemical CO2 fixation into value-added products is demanded. This work demonstrates a simple approach towards the chemical fixation of CO2 to cyclic carbonates without solvent, metal and additives using one-pot synthesized tri-functional-imidazolium bromide ionic liquid. Herein, synthesized tri-functional-imidazolium-based ionic liquids, namely 3-(2-hydroxyethyl)-1-vinyl-1H-imidazole-3-ium bromide ([VIMEtOH][Br] (24 and 72 h)), 3-(2-hydroxyethyl)-1-vinyl-1H-imidazole-3-ium hydroxyl ([VIMEtOH][OH]) and poly 3-(2-hydroxyethyl)-1-vinyl-1H-imidazole-3-ium bromide (poly [VIMEtOH][Br]), were used for the comprehensive investigation of chemical fixation of CO2 into cyclic carbonates and their physiochemical properties. In case of [VIMEtOH][Br] ionic liquid, it displayed time-dependent synthesis dissolution in the reaction system. This study found that [VIMEtOH][Br]-72 ionic liquid is not dissolved in the reaction system. The effect on the catalytic efficiency of the presence of functional groups in ionic liquids such as N-vinyl (-CC–N), acidic proton of imidazolium (-C (2)-H) and hydroxyl (-OH) along with bromide anion and the reaction conditions are systematically investigated. For CO2 fixation, 99.6% conversion of propylene oxide with an excellent selectivity of propylene carbonate (≥99%) over [VIMEtOH][Br]-72 catalyst (at 120 °C, 2 MPa, 2 h) was observed without co-catalyst, metal and solvent. Also, it demonstrated an excellent wide substrates scope of epoxide and all reactions were performed on gram-scalable, which are potential prospects for industrial use.

Synergistic promoting effect of increasing aquatic ammonium and CO2 on Microcystis aeruginosa

Owing to climate change and intensive agricultural development, freshwater bodies have been affected by increases in both CO2 levels and chemically-reduced forms of N. However, little is known about how these changes affect cyanobacterial growth and blooms. This study explored a range of light conditions (30, 80, 130, or 200 μmol photons/m2/s) wherein Microcystis aeruginosa, a widespread bloom-forming species, was exposed to different concentrations of CO2 (400 parts per million (ppm) and 1000 ppm) in a medium containing NH4+ or NO3－. The interactive effects of N sources and CO2 levels on the C/N metabolic balance and energy balance were examined to assess changes in the growth of M. aeruginosa. When the light intensity was 80 μmol photons/m2/s, elevated CO2 could reduce intracellular reactive oxygen species (ROS) in NH4+-grown M. aeruginosa. Meanwhile, cell density and chlorophyll a (Chl a) increased with increasing CO2 levels, and the increase in Chl a was significantly greater in NH4+-grown M. aeruginosa than in NO3－-grown M. aeruginosa. Under light conditions of 200 μmol photons/m2/s, elevated CO2 concentration caused NO3－-grown M. aeruginosa to be affected by a large amount of ROS, and the growth of NO3－-grown M. aeruginosa was finally suppressed. However, NH4+-grown M. aeruginosa had a smaller amount of ROS and showed improved growth as CO2 was elevated. This difference can be attributed to the faster metabolic pathways in the NH4+ environment, which manifested in a lower accumulation of 2-oxoglutarate and fatty acids as CO2 was elevated. These findings suggest that the simultaneous increase in ammonium and CO2 in aquatic ecosystems confers cyanobacteria with greater advantages than the combination of nitrate and CO2, which may aggravate cyanobacterial blooms.

Variation in Carbon Sequestration and Soil Properties in Relation to Stand Age in Maple and Alder Plantations

ABSTRACT Increased CO2 levels caused by human activities (e.g., fossil fuel consumption and deforestation) has become a major concern for climate change and caused environmental problems. Afforestation/reforestation can help mitigate CO2 emission in the atmosphere by sequestering atmospheric carbon (C) in tree biomass. Herein, the above- and below-ground C sequestration of two pioneer tree species, including Acer velutinum Bioss and Alnus glutinosa L plantation stands of 25 (A25) and 35 (A35) years old were studied. The mean annual growth of diameter at breast height (cm/year) was significantly higher in A35 than A25, while the mean growth of height (m/year) was significantly higher in A25. The total and mean annual growth of the tree biomass and C storage (root and trunk) was significantly higher in A35. The amount of soil C sequestration in A35 was also significantly higher than in A25. The above-ground C sequestration and the annual average of C sequestration of the trees were positively correlated with soil moisture, pH, nitrogen, and phosphorus. Our study illustrates the benefits of considering stand age in the growth and developmental patterns of forest ecosystems in estimating terrestrial C stocks.

ASSESSMENT OF MORPHOLOGICAL CHANGES AMONG WHEAT AND ASSOCIATEDWEEDS UNDER HIGH CARBON DI-OXIDE ENVIRONMENT

Climate change and rising CO2 levels as well as weed control is disrupted in both natural and traditional biological ways. The effectiveness of bio-control agents will be compromised as a result of this CO2 -induced morphological, phenological, and physiological alterations. The present study was conducted for the assessment of the effects of elevated CO2 on morphology of wheat crop as well as two commonly associated weeds Phalaris minor and Avena ludoviciana. The plant height of wheat was found to be increased in wheat under elevated CO2 conditions in comparison to ambient environment at 30 DAS and 60 DAS. However, both of the weed species had opposite effect of elevated environment in terms of plant height trait. While taking observation on mean numbers of tillers in wheat crop, it was found to be reduced under elevated environment in comparison to ambient environment. However, both weeds had increment in mean numbers of tillers under elevated CO2 conditions at both 30 DAS and 60 DAS. Results of the present study confirm the effects of elevated CO2 on morphology of crop as well as weed species and indicate the need of research in this field because of alarming situations in the future due to expected increase in CO2 level in the environment.

Effects of Elevated CO2 on the Fitness of Three Successive Generations of Lipaphis erysimi.

Simple SummaryGlobal warming caused by the increase in atmospheric CO2 concentration is becoming a major environmental issue. Lipaphis erysimi is one of the most damaging pests of cruciferous crops worldwide, and L. erysimi has strong adaptability to the environment and reproductive capacity. The age-stage, two-sex life table is currently used by many researchers in place of the traditional age-specific life table, providing many details such as fitness and potential damage. In this study, the individual fitness and population dynamics parameters of three successive generations of L. erysimi were analyzed using the age-stage, two-sex life table. The results show that a high CO2 concentration had a cumulative effect on the survival rate and fecundity of L. erysimi, and elevated CO2 had a negative effect on the individual fitness parameters of L. erysimi. The life expectancy (exj) is significantly lower in elevated CO2 than that in ambient CO2 treatment in the three successive generations, indicating that L. erysimi was more sensitive to CO2 concentration and the life of L. erysimi was shortened under elevated CO2. Additionally, we can find that elevated CO2 has a short-term effect on the population parameters, including the intrinsic rate of increase (r) and finite rate of increase (λ) in L. erysimi. Through the data from this experiment, we believe that the individual and population fitness of L. erysimi will be decreased under elevated CO2, which indicates that the damage caused by L. erysimi may be reduced in the future with increasing CO2 levels.To assess the effect of elevated CO2 on the development, fecundity, and population dynamic parameters of L. erysimi, the age-stage, two-sex life table was used to predict the individual fitness and population parameters of three successive generations of L. erysimi in this study. The results show that a significantly longer total pre-adult stage before oviposition (TPOP) was observed in the third generation compared with the first generation of L. erysimi under the 800 μL/L CO2 treatment. The fecundity is significantly lower in the 800 μL/L CO2 treatment than that in the 400 μL/L CO2 treatment in the third generation of L. erysimi, which indicates that elevated CO2 had a negative effect on the individual fitness parameters of L. erysimi. Additionally, the life expectancy (exj) is significantly lower under the 800 μL/L CO2 treatment than that under the 400 μL/L CO2 treatment in the three successive generations. A significantly higher intrinsic rate of increase (r) and finite rate of increase (λ) were found in the second generation compared with those in the first and third generations of L. erysimi under the 800 μL/L CO2 treatment. Moreover, significantly lower r and λ were observed under the 800 μL/L CO2 treatment compared with those under the 400 μL/L and 600 μL/L CO2 treatments in the first generation of L. erysimi, which indicates that elevated CO2 has a short-term effect on the population parameters (r and λ) of L. erysimi. Our experiment can provide the data for the comprehensive prevention and control of L. erysimi in the future with increasing CO2 levels.

Is plastidic glutamine synthetase essential for C3 plants? A tale of photorespiratory mutants, ammonium tolerance and conifers.

SummaryAgriculture faces the considerable challenge of having to adapt to a progressively changing climate (including the increase in CO2 levels and temperatures); environmental impact must be reduced while at the same time crop yields need to be maintained or increased to ensure food security. Under this scenario, increasing plants’ nitrogen (N) use efficiency and minimizing the energy losses associated with photorespiration are two goals of crop breeding that are long sought after. The plastidic glutamine synthetase (GS2) enzyme stands at the crossroads of N assimilation and photorespiration, and is therefore a key candidate for the improvement of crop performance. The GS2 enzyme has long been considered essential for angiosperm survival under photorespiratory conditions. Surprisingly, in Arabidopsis GS2 is not essential for plant survival, and its absence confers tolerance towards ammonium stress, which is in conflict with the idea that NH4 + accumulation is one of the main causes of ammonium stress. Altogether, it appears that the ‘textbook’ view of this enzyme must be revisited, especially regarding the degree to which it is essential for plant growth under photorespiratory conditions, and the role of NH4 + assimilation during ammonium stress. In this article we open the debate on whether more or less GS2 is a desirable trait for plant productivity.

Simulating the impact of projected climate change on rice (Oryza sativa L.) yield and adaptation strategies in major rice growing regions of India

Global mean air temperatures are projected to increase by 1.8 to 4.0 oC by the end of this century. Higher temperatures coupled with increased CO2 levels could result in altered growth and productivity of crops. Since rice is sensitive to high temperatures, a simulation analysis was carried out to quantify the impact of increased temperatures (1, 2, 3, 4 and 5 oC) and elevated CO2 (369, 450,550 and 650ppm) alone and in combination on the yield using InfoCrop-RICE model. An assessment is also provided on the possible gains due to change in planting time and crop duration. Though elevated CO2 alone increased the rice yields, increase in temperature by 1oC (even at 369 ppm CO2 concentration) reduced irrigated rice yield by 6.6 to 11.1 % and rainfed rice yields by 4.6 % to 9.4 %. The combined impact of increased temperature and elevated CO2 resulted in net decline in yield in spite of CO2 fertilization. Planting cultivars in future with matching crop duration of current cultivars and change in planting time may reduce the adverse impacts of climate change on rice yields.

Shallow Sea Gas Manifestations in the Aegean Sea (Greece) as Natural Analogs to Study Ocean Acidification: First Catalog and Geochemical Characterization

The concepts of CO2 emission, global warming, climate change, and their environmental impacts are of utmost importance for the understanding and protection of the ecosystems. Among the natural sources of gases into the atmosphere, the contribution of geogenic sources plays a crucial role. However, while subaerial emissions are widely studied, submarine outgassing is not yet well understood. In this study, we review and catalog 122 literature and unpublished data of submarine emissions distributed in ten coastal areas of the Aegean Sea. This catalog includes descriptions of the degassing vents through in situ observations, their chemical and isotopic compositions, and flux estimations. Temperatures and pH data of surface seawaters in four areas affected by submarine degassing are also presented. This overview provides useful information to researchers studying the impact of enhanced seawater CO2 concentrations related either to increasing CO2 levels in the atmosphere or leaking carbon capture and storage systems.

İklim Değişikliğinin Bitki-Faydalı Mikroorganizma Etkileşimleri Üzerindeki Etkileri

Global climate is estimated to change drastically over the next century and the ecosystems will be affected in this changing environment. Plant-associated beneficial microorganisms can stimulate plant growth and increase resistance to biotic and abiotic stresses. Nowadays, the effects of climate change factors such as increased carbon dioxide (CO2), drought and warming on plant-beneficial microorganism interactions are increasingly being investigated in the scope of plant growth and health. Recent studies have shown that high CO2 level has a positive effect on the abundance of mycorrhizal fungi, whereas the effects on plant growth promoting bacteria and endophytic fungi are more variable. Elevated CO2 conditions lead to increased colonization of beneficial fungi. Additionally, the results of increasing CO2 levels, warming and drought, depend upon the plant and the microbial genotype. Also, plant growth promoting microorganisms, especially bacteria, positively affect plants exposed to drought stress. Altered communities of beneficial microorganisms depending on climate changes, might have to compete with different microbial communities and, therefore microbial activities may also get affected. This work presents that climate change is an important factor affecting microorganism and plant interactions, needs to take into consideration the adaptation processes in plants and microorganisms and might require the selection of adapted plant cultivars.