Rising CO2 Concentrations Research Articles

Impacts of land use change and elevated CO<sub>2</sub> on the interannual variations and seasonal cycles of gross primary productivity in China

Abstract. Climate change, rising CO2 concentration, and land use and land cover change (LULCC) are primary driving forces for terrestrial gross primary productivity (GPP), but their impacts on the temporal changes in GPP are uncertain. In this study, the effects of the three main factors on the interannual variation (IAV) and seasonal cycle amplitude (SCA) of GPP in China were investigated using 12 terrestrial biosphere models from the Multi-scale Synthesis and Terrestrial Model Intercomparison Project. The simulated ensemble mean value of China's GPP between 1981 and 2010, driven by common climate forcing, LULCC and CO2 data, was found to be 7.4±1.8 Pg C yr−1. In general, climate was the dominant control factor of the annual trends, IAV and seasonality of China's GPP. The overall rising CO2 led to enhanced plant photosynthesis, thus increasing annual mean and IAV of China's total GPP, especially in northeastern and southern China, where vegetation is dense. LULCC decreased the IAV of China's total GPP by ∼7 %, whereas rising CO2 induced an increase of 8 %. Compared to climate change and elevated CO2, LULCC showed less contributions to GPP's temporal variation, and its impact acted locally, mainly in southwestern China. Furthermore, this study also examined subregional contributions to the temporal changes in China's total GPP. Southern and southeastern China showed higher contributions to China's annual GPP, whereas southwestern and central parts of China explained larger fractions of the IAV in China's GPP.

Study on sulfur-fixation effects of cement raw meal during pulverized coal combustion under different atmospheres

For the sake of desulfurization in cement kiln industry, the research on sulfur-fixation efficiency of cement raw meal during pulverized coal combustion under different atmospheres was performed experimentally. In O2/N2 atmosphere, the highest sulfur-fixation efficiencies reach 66%, 83%, 89%, 95% and 97% at 800 °C at Ca/S molar ratios of 0.5, 1, 2, 3 and 4, respectively. At over 800–900 °C, the recrystallization of CaO, the decomposition of the sulfur fixation product, and the carbothermic reaction lead to lower sulfur-fixation efficiency. In the O2/N2/CO2 atmosphere, the maximum sulfur-fixation efficiency is 89% under 79% CO2 at 900 °C. The sulfur-fixation efficiency increases with the rising of CO2 concentration and it is higher than that in O2/N2 atmosphere at 1000–1200 °C, due to the porosity of CaSO4 and the inhibition of CO2. Besides, the sulfur-fixation efficiency of the cement raw meal shows superiority than that of CaCO3 at 600–1200 °C, with higher sulfur-fixation efficiency of 6–11%. Alkali metal minerals and oxides in the cement raw meal may improve the sulfur-fixation effect and stability at high temperature of desulfurization products.

Plant Cell Walls Tackling Climate Change: Insights into Plant Cell Wall Remodeling, Its Regulation, and Biotechnological Strategies to Improve Crop Adaptations and Photosynthesis in Response to Global Warming.

Plant cell wall (CW) is a complex and intricate structure that performs several functions throughout the plant life cycle. The CW of plants is critical to the maintenance of cells’ structural integrity by resisting internal hydrostatic pressures, providing flexibility to support cell division and expansion during tissue differentiation, and acting as an environmental barrier that protects the cells in response to abiotic stress. Plant CW, comprised primarily of polysaccharides, represents the largest sink for photosynthetically fixed carbon, both in plants and in the biosphere. The CW structure is highly varied, not only between plant species but also among different organs, tissues, and cell types in the same organism. During the developmental processes, the main CW components, i.e., cellulose, pectins, hemicelluloses, and different types of CW-glycoproteins, interact constantly with each other and with the environment to maintain cell homeostasis. Differentiation processes are altered by positional effect and are also tightly linked to environmental changes, affecting CW both at the molecular and biochemical levels. The negative effect of climate change on the environment is multifaceted, from high temperatures, altered concentrations of greenhouse gases such as increasing CO2 in the atmosphere, soil salinity, and drought, to increasing frequency of extreme weather events taking place concomitantly, therefore, climate change affects crop productivity in multiple ways. Rising CO2 concentration in the atmosphere is expected to increase photosynthetic rates, especially at high temperatures and under water-limited conditions. This review aims to synthesize current knowledge regarding the effects of climate change on CW biogenesis and modification. We discuss specific cases in crops of interest carrying cell wall modifications that enhance tolerance to climate change-related stresses; from cereals such as rice, wheat, barley, or maize to dicots of interest such as brassica oilseed, cotton, soybean, tomato, or potato. This information could be used for the rational design of genetic engineering traits that aim to increase the stress tolerance in key crops. Future growing conditions expose plants to variable and extreme climate change factors, which negatively impact global agriculture, and therefore further research in this area is critical.

Assessing the impact of global climate changes on irrigated wheat yields and water requirements in a semi-arid environment of Morocco

The present work aims to quantify the impact of climate change (CC) on the grain yields of irrigated cereals and their water requirements in the Tensift region of Morocco. The Med-CORDEX (MEDiterranean COordinated Regional Climate Downscaling EXperiment) ensemble runs under scenarios RCP4.5 (Representative Concentration Pathway) and RCP8.5 are first evaluated and disaggregated using the quantile-quantile approach. The impact of CC on the duration of the main wheat phenological stages based on the degree-day approach is then analyzed. The results show that the rise in air temperature causes a shortening of the development cycle of up to 50 days. The impacts of rising temperature and changes in precipitation on wheat yields are next evaluated, based on the AquaCrop model, both with and without taking into account the fertilizing effect of CO2. As expected, optimal wheat yields will decrease on the order of 7 to 30% if CO2 concentration rise is not considered. The fertilizing effect of CO2 can counterbalance yield losses, since optimal yields could increase by 7% and 13% respectively at mid-century for the RCP4.5 and RCP8.5 scenarios. Finally, water requirements are expected to decrease by 13 to 42%, mainly in response to the shortening of the cycle. This decrease is associated with a change in temporal patterns, with the requirement peak coming two months earlier than under current conditions.

Dark carbon fixation in the Arabian Sea oxygen minimum zone contributes to sedimentary organic carbon (SOM)

AbstractIn response to rising CO2 concentrations and increasing global sea surface temperatures, oxygen minimum zones (OMZ), or “dead zones”, are expected to expand. OMZs are fueled by high primary productivity, resulting in enhanced biological oxygen demand at depth, subsequent oxygen depletion, and attenuation of remineralization. This results in the deposition of organic carbon‐rich sediments. Carbon drawdown is estimated by biogeochemical models; however, a major process is ignored: carbon fixation in the mid‐ and lower water column. Here, we show that chemoautotrophic carbon fixation is important in the Arabian Sea OMZ; and manifests in a 13C‐depleted signature of sedimentary organic carbon. We determined the δ13C values of Corg deposited in close spatial proximity but over a steep bottom‐water oxygen gradient, and the δ13C composition of biomarkers of chemoautotrophic bacteria capable of anaerobic ammonia oxidation (anammox). Isotope mixing models show that detritus from anammox bacteria or other chemoautotrophs likely forms a substantial part of the organic matter deposited within the Arabian Sea OMZ (~17%), implying that the contribution of chemoautotrophs to settling organic matter is exported to the sediment. This has implications for the evaluation of past, and future, OMZs: biogeochemical models that operate on the assumption that all sinking organic matter is photosynthetically derived, without new addition of carbon, could significantly underestimate the extent of remineralization. Oxygen demand in oxygen minimum zones could thus be higher than projections suggest, leading to a more intense expansion of OMZs than expected.

Contributions of climate change, land use change and CO2 to changes in the gross primary productivity of the Tibetan Plateau

The ecosystems on the Tibetan Plateau (TP) are highly vulnerable to climate change, rising CO2 concentration, and land-use and land-cover change (LULCC), but their contributions to changes in the g...

Synthesis and characterization of amine-impregnated silica gel for potential carbon dioxide (CO2) absorption

The rising of CO2 concentration in atmosphere become global concern due to its effect to the global warming. One potentially economical for CO2 capture is through adsorption using solid sorbents. Silica gel has potential to adsorb carbon dioxide with modification of silica gel with amine groups which provide specific adsorption sides for carbon dioxide adsorption. Therefore, a study of impregnated silica gel with amine for carbon dioxide adsorption was done. A series of characterization was made between raw silica and impregnated silica with amine. Based on the results from Iodine Test Analysis and DSC characterization, it can be stated that the modification of Raw Desiccant Silica Gel (DSG) which had been modified with Aminopropyltrimethoxysilane (APMS), 95% had the highest possibilities of percentage to absorb CO2 from the environment with iodine value of 2736.85 mg/g that indicate the porosity and surface area of the adsorbent is higher. Amine 1A consist of 17.84 % of carbon, 5.41 % of hydrogen and 6.44 % of nitrogen. For FTIR result, Amine 1A has Si-O-Si stretching, C-C stretching, N-C stretching and C-N stretching due to the impregnation of amine to the raw silica gel. From DSC analysis, the higher the peak shows that water molecule bound to Amine 1A evaporated at a higher temperature of 92.4°C shows the highest porosity and have highest possibility as adsorbent for CO2 adsorption.

Effects of rising atmospheric CO2, climate change, and nitrogen deposition on aboveground net primary production in a temperate forest

Temperate forests regrowing from historical land use and land cover change in the eastern US serve as carbon (C) sinks. Environmental drivers have been significantly altered (e.g. rising atmospheric CO2 concentration, warmer temperature, and elevated nitrogen (N) deposition) and will have a wide range of impacts on future forest C sinks. However, the interactions among these environmental drivers are unclear and their effects are subject to uncertainty. We assessed the combined and interactive effects of rising CO2 concentration, climate change (temperature, precipitation), and N deposition on forest aboveground net primary production (ANPP) and their relative contribution to ANPP changes of a temperate forest in the eastern US. We used a process-based ecosystem model PnET-day to simulate coupled cycles of C, water, and N of forest ecosystems. We found that (1) climate change exerted negative effects on ANPP (−0.250 kg C m−2 yr−1) whereas rising CO2 and N deposition enhanced ANPP (+0.253, +0.014 kg C m−2 yr−1); (2) climate change interacted with rising CO2 and N deposition to decrease ANPP (−0.032, −0.018 kg C m−2 yr−1); rising CO2 and N deposition acted in synergy to increase ANPP (+0.014 kg C m−2 yr−1); (3) changes in ANPP were mainly attributed to rising CO2 and climate change whereas N deposition effects and any two- or three-factor interactive effects were relatively small. Our results suggest that the total negative effect sizes will not be offset by the total positive effect sizes, thus resulting in reductions in forest ANPP over the 21st century.

Can sugarcane cope with increasing atmospheric CO2 concentration?

Climate change is the one of the most emerging problem of today’s world. It is the most potent threat to the existence of mankind. These sudden abrupt changes in the climate are affecting all the crops to a great extent. High concentrations of CO2 are one of the leading reasons contributing to climate change due to the increasing level of green-house gases. The elevation in CO2 level is hampering crop production and productivity of different crops by causing effect on different physiological attributes. Unlike other crops, in sugarcane, several beneficial effects have been detected such as escalation in biomass, photosynthesis, leaf area, stalk juice volume, leaf dry weight and stem dry weight under such condition. Sugarcane crop is known to be one among those crops that is able to cope up with the increasing level of CO2 due to four natural endowments it possesses. Very low carbon dioxide compensation point and unique property of sequestering carbon in form of phytolith or planstone is some of the important natural endowment with respect to the rising CO2 concentration in atmosphere. Here, we have discussed the influence of atmospheric rising CO2 concentration on sugarcane crop.

The stomatal response to rising CO2 concentration and drought is predicted by a hydraulic trait-based optimization model.

Modeling stomatal control is critical for predicting forest responses to the changing environment and hence the global water and carbon cycles. A trait-based stomatal control model that optimizes carbon gain while avoiding hydraulic risk has been shown to perform well in response to drought. However, the model's performance against changes in atmospheric CO2, which is rising rapidly due to human emissions, has yet to be evaluated. The present study tested the gain-risk model's ability to predict the stomatal response to CO2 concentration with potted water birch (Betula occidentalis Hook.) saplings in a growth chamber. The model's performance in predicting stomatal response to changes in atmospheric relative humidity and soil moisture was also assessed. The gain-risk model predicted the photosynthetic assimilation, transpiration rate and leaf xylem pressure under different CO2 concentrations, having a mean absolute percentage error (MAPE) of 25%. The model also predicted the responses to relative humidity and soil drought with a MAPE of 21.9% and 41.9%, respectively. Overall, the gain-risk model had an MAPE of 26.8% compared with the 37.5% MAPE obtained by a standard empirical model of stomatal conductance. Importantly, unlike empirical models, the optimization model relies on measurable physiological traits as inputs and performs well in predicting responses to novel environmental conditions without empirical corrections. Incorporating the optimization model in larger scale models has the potential for improving the simulation of water and carbon cycles.

Observed and modelled historical trends in the water-use efficiency of plants and ecosystems.

Plant water-use efficiency (WUE, the carbon gained through photosynthesis per unit of water lost through transpiration) is a tracer of the plant physiological controls on the exchange of water and carbon dioxide between terrestrial ecosystems and the atmosphere. At the leaf level, rising CO2 concentrations tend to increase carbon uptake (in the absence of other limitations) and to reduce stomatal conductance, both effects leading to an increase in leaf WUE. At the ecosystem level, indirect effects (e.g. increased leaf area index, soil water savings) may amplify or dampen the direct effect of CO2 . Thus, the extent to which changes in leaf WUE translate to changes at the ecosystem scale remains unclear. The differences in the magnitude of increase in leaf versus ecosystem WUE as reported by several studies are much larger than would be expected with current understanding of tree physiology and scaling, indicating unresolved issues. Moreover, current vegetation models produce inconsistent and often unrealistic magnitudes and patterns of variability in leaf and ecosystem WUE, calling for a better assessment of the underlying approaches. Here, we review the causes of variations in observed and modelled historical trends in WUE over the continuum of scales from leaf to ecosystem, including methodological issues, with the aim of elucidating the reasons for discrepancies observed within and across spatial scales. We emphasize that even though physiological responses to changing environmental drivers should be interpreted differently depending on the observational scale, there are large uncertainties in each data set which are often underestimated. Assumptions made by the vegetation models about the main processes influencing WUE strongly impact the modelled historical trends. We provide recommendations for improving long-term observation-based estimates of WUE that will better inform the representation of WUE in vegetation models.

Feeding behavior, life history, and virus transmission ability of Bemisia tabaci Mediterranean species (Hemiptera: Aleyrodidae) under elevated CO2

The continuous rise of CO2 concentrations in the atmosphere is reducing plant nutritional quality for herbivores and indirectly affects their performance. The whitefly (Bemisia tabaci, Gennadius) is a major worldwide pest of agricultural crops causing significant yield losses. This study investigated the plant-mediated indirect effects of elevated CO2 on the feeding behavior and life history of B. tabaci Mediterranean species. Eggplants were grown under elevated and ambient CO2 concentrations for 3 weeks after which plants were either used to monitor the feeding behavior of whiteflies using the Electrical Penetration Graph technique or to examine fecundity and fertility of whiteflies. Plant leaf carbon, nitrogen, phenols and protein contents were also analyzed for each treatment. Bemisia tabaci feeding on plants exposed to elevated CO2 showed a longer phloem ingestion and greater fertility compared to those exposed to ambient CO2 suggesting that B. tabaci is capable of compensating for the plant nutritional deficit. Additionally, this study looked at the transmission of the virus Tomato yellow leaf curl virus (Begomovirus) by B. tabaci exposing source and receptor tomato plants to ambient or elevated CO2 levels before or after virus transmission tests. Results indicate that B. tabaci transmitted the virus at the same rate independent of the CO2 levels and plant treatment. Therefore, we conclude that B. tabaci Mediterranean species prevails over the difficulties that changes in CO2 concentrations may cause and it is predicted that under future climate change conditions, B. tabaci would continue to be considered a serious threat for agriculture worldwide.

Climate change and tropical marine ecosystems: A review with an emphasis on coral reefs

Climate change is usually associated with warming and weather extremes that impact the human environment and terrestrial systems, but it also has profound effects on the ocean, which is probably the most unique, life-supporting feature of planet Earth. The most direct consequence of rising CO2 concentration in the atmosphere is “ocean acidification,” a term that refers to the lowering of seawater pH, but encompasses a suite of chemical changes that affect marine organisms from shell formation, to reproduction, physiology, and behavior. The oceans are also warming in pace with the atmosphere, and in fact store the vast majority of the additional heat generated by rising CO2 and other greenhouse gases in the atmosphere. This warming is causing the more mobile marine species to redistribute poleward and deeper, and is causing high mortality in more sessile species such as those that build and habituate coral reefs. But warming is also leading to a decrease in dissolved oxygen in the oceans. For tropical marine ecosystems, the combination of ocean acidification, warming, and deoxygenation will continue to impact marine ecosystems in the future. The extent of these impacts depends on which energy pathway society follows, and our abilities to reduce other stressors and assist the rate at which species can adapt and migrate to more suitable environments.

Isotope ecology detects fine-scale variation in Svalbard reindeer diet: implications for monitoring herbivory in the changing Arctic

The Arctic is experiencing rapid climatic and environmental changes, which could alter diets of nonmigratory herbivores both within and between populations. Here, we used carbon and nitrogen stable isotope analysis (δ13C and δ15N) in hair to infer summer dietary differences of Rangifer tarandus platyrhynchus (nonmigratory reindeer) in Nordenskioldland, Svalbard and used regression models to predict how reindeer dietary intake depend on climatic variables. In linear regression models, current-year and last-year July temperatures positively correlated with both the δ13C and δ15N of reindeer hair, and were stronger predictors of isotopic signatures than July precipitation. δ13C and δ15N analysis indicated robust dietary differences between populations separated by less than 50 km and within these valley systems in the proportions of nonmycorrhizal vascular plants and mosses. Remote sensing (NDVI) and isotopic data together suggested an early-season switch from moss to vascular plant dependence in valleys closer to the sea, suggesting both high site fidelity and localized differences in forage availability related to the onset of the growing season. 13C photosynthetic discrimination increased with the rising atmospheric pCO2, indicating that Svalbard plants are already responding physiologically to rising CO2 concentrations. Calves were higher in δ13C and δ15N than adults, consistent with a weak trophic effect. We also determined how hair C:N correlated with δ13C and δ15N patterns. Overall, these data provide evidence that δ13C and δ15N measurements can detect dietary shifts over short time periods and fine spatial scales, indicating that isotopic studies can help monitor herbivory in the changing Arctic.

Supported Single Atoms as New Class of Catalysts for Electrochemical Reduction of Carbon Dioxide

AbstractCarbon dioxide (CO2) emitted from excess consumption of fossil fuels leads to the rise of CO2 concentrations in the atmosphere. One of the most attractive solutions to cut CO2 emission is the electrochemical reduction of CO2 to produce fuels and build a low carbon emission economy. However, the electrochemical CO2 reduction reaction (CO2RR) is a great challenge due to the activation of the highly stable, linear CO2 molecules, and the process involves proton‐coupled multi‐electron transfer with a high energy barrier. Thus, it is critical to develop efficient and highly stable catalyst materials for CO2RR. Nanoparticle‐based electrocatalysts have been extensively investigated, but the broad size distribution not only limits their activity due to the size‐dependent catalytic properties, but also constrains the selectivity and leads to undesired side reactions. Single‐atom catalysts (SACs), a rising star in the catalytic area, can combine the merits of heterogeneous and homogeneous catalysts, offering outstanding opportunities for CO2RR. The advent of SACs for CO2RR has attracted enormous attention recently, and great effort has been devoted into the area and significant advancements have been achieved in recent years. Here, this mini review updates the development of SACs for CO2RR, and their opportunities and challenges are discussed.

Earth system models underestimate carbon fixation by plants in the high latitudes

Most Earth system models agree that land will continue to store carbon due to the physiological effects of rising CO2 concentration and climatic changes favoring plant growth in temperature-limited regions. But they largely disagree on the amount of carbon uptake. The historical CO2 increase has resulted in enhanced photosynthetic carbon fixation (Gross Primary Production, GPP), as can be evidenced from atmospheric CO2 concentration and satellite leaf area index measurements. Here, we use leaf area sensitivity to ambient CO2 from the past 36 years of satellite measurements to obtain an Emergent Constraint (EC) estimate of GPP enhancement in the northern high latitudes at two-times the pre-industrial CO2 concentration (3.4 ± 0.2 Pg C yr−1). We derive three independent comparable estimates from CO2 measurements and atmospheric inversions. Our EC estimate is 60% larger than the conventionally used multi-model average (44% higher at the global scale). This suggests that most models largely underestimate photosynthetic carbon fixation and therefore likely overestimate future atmospheric CO2 abundance and ensuing climate change, though not proportionately.

Impact of climate change on disease scenario in crops

Climate change has posed a grim situation in front of us as global temperatures are rising unabated with imminent effect on production and productivity of crops. There is evidence that climate change has already negatively affected wheat and maize yields in many regions. Effect of climate change is also visible on plant-pathogens interactions generally in terms of their higher incidence, more severity and their wider geographical distribution. Pathogens still claim 10–16% of the global harvest. Climate models predict a gradual rise in CO2 concentration and temperature all over the world. Elevated levels of CO2 can directly affect the growth of pathogens. Changes in temperature and precipitation will alter the growth stage, development rate and pathogenicity of the plant pathogens and also physiology and resistance of the host plants. A change in temperature could directly affect the spread of infectious diseases and their survival between the seasons. Published observations on the distribution of 612 crop pests collected over the past 50 years indicate that crop pests have been spreading north and south a little less than 2 miles (3.2 km) a year since 1960. Specifically, losses from stripe rust of wheat were reported from just 11 of the 48 continental US states during the period 1960–1999, whereas during 2000–2014, the disease was reported in a total of 26 states in US and three Canadian provinces. Changing disease scenario with climate change emphasizes the need for developing regular monitoring, forecasting and early warning systems for important host-pathogens which have a direct bearing on the earnings of the farmers and food security at large. Further, adaptation through diversification will be required, which will produce changes in the crop profile that will have effects on disease incidence and severity.

Changes of alternative splicing in Arabidopsis thaliana grown under different CO2 concentrations

Atmospheric CO2 level is one of the most important factors which affect plant growth and crop production. Although many crucial genes and pathways have been identified in response to atmospheric CO2 changes, the integrated and precise mechanisms of plant CO2 response are not well understood. Alternative splicing (AS) is an important gene regulation process that affects many biological processes in plants. However, the AS pattern changes in plants in response to elevated CO2 levels have not yet been investigated. Here, we used RNA-Seq data of Arabidopsis thaliana grown under different CO2 concentration to analyze the global changes in AS. We found that AS increased with the rise in CO2 concentration. Additionally, we identified 345 differentially expressed (DE) genes and 251 differentially alternative splicing (DAS) genes under the elevated CO2 condition. Moreover, the results showed that the expression of most of the DAS genes did not change significantly, indicating that AS can serve as an independent mechanism for gene regulation in response to elevated CO2. Furthermore, our analysis of function categories revealed that the DAS genes were associated mainly with the stimulus response. Overall, this the first study to explore the changes of AS in plants in response to elevated CO2.

Contributions of Climate Change, CO2, Land-Use Change, and Human Activities to Changes in River Flow across 10 Chinese Basins

Abstract As an essential source of freshwater river flow comprises ~80% of the water consumed in China. Per capita water resources in China are only a quarter of the global average, and its economy is demanding in water resources; this creates an urgent need to quantify the factors that contribute to changes in river flow. Here, we used an offline process-based land surface model (ORCHIDEE) at high spatial resolution (0.1° × 0.1°) to simulate the contributions of climate change, rising atmospheric CO2 concentration, and land-use change to the change in natural river flow for 10 Chinese basins from 1979 to 2015. We found that climate change, especially an increase in precipitation, was responsible for more than 90% of the changes in natural river flow, while the direct effect of rising CO2 concentration and land-use change contributes at most 6.3%. Nevertheless, rising CO2 concentration and land-use change cannot be neglected in most basins as these two factors significantly change transpiration. From 2003 to 2015, the increase in water consumption offset more than 30% of the increase in natural river flow in northern China, especially in the Yellow River basin (~140%), but it had little effect on observed river flow in southern China. Although the uncertainties of rainfall data and the statistical water consumption data could propagate the uncertainties in simulated river flow, this study could be helpful for water planning and management in China under the context of global warming.

Changes in Growth Performance and Biochemical Composition of Nannochloropsis Oceanica in Response to Elevated CO2 Concentrations

We studied the growth performance and biochemical composition (including soluble carbohydrates, proteins, lipids, phenols, chlorophyll-a, carotenoid and the C/N-ratio) of Nannochloropsis oceanica under various CO2 concentrations. The cell density of N. oceanic increased with a rise in CO2 concentration and got the high level at a CO2 concentration of 1000ppm or 1500ppm. In addition, except the proteins all tested biochemical composition were significantly affected by CO2 concentration (0.01 <P< 0.05; one factorial ANOVA). However comparing with other biochemical components, the contents of phenols in N. oceanic showed the opposite trends (P<0.01; one factorial ANOVA). In general, the short-term stimulation of elevated CO2 concentration to N. oceanic can promote cell division and synthesis of most of biochemical components (expect proteins and phenols).