High CO2 Levels Research Articles

Frequent high-temperature volcanic combustion events delayed biotic recovery after the end-Permian mass extinction

The Early Triassic after the end-Permian mass extinction was a time of repeated environmental degradation, which delayed biotic recovery. Although repeated volcanic activity during the Early Triassic has been cited as the cause, the evidence for this hypothesis needs to be confirmed with convincing proxies. This study presents sedimentary molecular evidence for the continuity of volcanic combustion events into the Early Triassic. Geochemical analysis of combustion-derived organic molecules from the uppermost Permian to the Lower Triassic exposed in the Chaohu and Qingyan sections, South China, reveals multiple spikes of a polyaromatic hydrocarbon, coronene, formed by high-temperature organic matter combustion (>1200 K), in the transitions of the Permian–Triassic, Dienerian, Smithian–Spathian, and Olenekian–Anisian boundaries. The frequent high-temperature volcanic combustions ceased 2.7 Myr after the end-Permian mass extinction, and substantial biotic recovery began. The Earth's surface system has mechanisms to buffer high CO2 levels and global warming in the long term, as evidenced in the Cretaceous greenhouse period. Nevertheless, if volcanic activity is overly frequent, the Earth's surface buffering mechanisms cannot keep pace. A simple box model based on excess carbon input revealed by frequent combustion events reproduces the observed carbon isotopic record of carbonate. This model implies that combustion events impacted carbon cycle disturbances and the global climate (e.g., global warming and related environmental destruction). Frequent high-temperature volcanic combustion was a crucial mechanism of delayed biotic recovery during the Early Triassic.

Potential microbial mechanisms underlying the effects of rising atmospheric CO2 levels on the reduction and methylation processes of arsenic in the paddy soil

Many studies have demonstrated that climate change affects the biogeochemical cycle of pollutants, but the mechanisms of arsenic (As) biogeochemical processes under high CO2 levels are unknown. Here, rice pot experiments were carried out to explore the underlying mechanisms of the impacts of elevated CO2 on the reduction and methylation processes of As in paddy soils. The results revealed that elevated CO2 might increase As bioavailability and promote As(V)-to-As(III) transformation in the soil as well as higher As(III) and dimethyl arsenate (DMA) accumulation in rice grains, thus increasing health risk. In As-contaminated paddy soil, two key genes involved in the biotransformation of As (arsC and arsM) and associated host microbes were identified as being significantly promoted by increasing CO2 levels. Elevated CO2 enriched the soil microbes harboring arsC (Bradyrhizobiaceae and Gallionellaceae), which aided in the reduction of As(V) to As(III). Simultaneously, elevated CO2 enriched soil microbes harboring arsM (Methylobacteriaceae and Geobacteraceae), allowing As(V) to be reduced to As(III) and then methylated to DMA. The findings of the Incremental Lifetime Cancer Risk (ILTR) assessment suggested that elevated CO2 exacerbated the individual adult ILTR from rice food As(III) consumption by 9.0 % (p < 0.05). These findings show that elevated CO2 aggravates the exposure risk of As(III) and DMA in rice grains by changing microbial populations involved in As biotransformation in paddy soils.

Ocean acidification alters foraging behaviour in Dungeness crab through impairment of the olfactory pathway.

Crustacean olfaction is fundamental to most aspects of living and communicating in aquatic environments and more broadly, for individual- and population-level success. Accelerated ocean acidification from elevated CO2 threatens the ability of crabs to detect and respond to important olfactory-related cues. Here, we demonstrate that the ecologically and economically important Dungeness crab (Metacarcinus magister) exhibits reduced olfactory-related antennular flicking responses to a food cue when exposed to near-future CO2 levels, adding to the growing body of evidence of impaired crab behaviour. Underlying this altered behaviour, we find that crabs have lower olfactory nerve sensitivities (twofold reduction in antennular nerve activity) in response to a food cue when exposed to elevated CO2 . This suggests that near-future CO2 levels will impact the threshold of detection of food by crabs. We also show that lower olfactory nerve sensitivity in elevated CO2 is accompanied by a decrease in the olfactory sensory neuron (OSN) expression of a principal chemosensory receptor protein, ionotropic receptor 25a (IR25a) which is fundamental for odorant coding and olfactory signalling cascades. The OSNs also exhibit morphological changes in the form of decreased surface areas of their somata. This study provides the first evidence of the effects of high CO2 levels at multiple levels of biological organization in marine crabs, linking physiological and cellular changes with whole animal behavioural responses.

Light-independent regulation of algal photoprotection by CO2 availability

Photosynthetic algae have evolved mechanisms to cope with suboptimal light and CO2 conditions. When light energy exceeds CO2 fixation capacity, Chlamydomonas reinhardtii activates photoprotection, mediated by LHCSR1/3 and PSBS, and the CO2 Concentrating Mechanism (CCM). How light and CO2 signals converge to regulate these processes remains unclear. Here, we show that excess light activates photoprotection- and CCM-related genes by altering intracellular CO2 concentrations and that depletion of CO2 drives these responses, even in total darkness. High CO2 levels, derived from respiration or impaired photosynthetic fixation, repress LHCSR3/CCM genes while stabilizing the LHCSR1 protein. Finally, we show that the CCM regulator CIA5 also regulates photoprotection, controlling LHCSR3 and PSBS transcript accumulation while inhibiting LHCSR1 protein accumulation. This work has allowed us to dissect the effect of CO2 and light on CCM and photoprotection, demonstrating that light often indirectly affects these processes by impacting intracellular CO2 levels.

Primary cordierite with > 2.5 wt% CO2 from the UHT Bakhuis Granulite Belt, Surinam: CO2 fluid phase saturation during ultrahigh-temperature metamorphism

The Paleoproterozoic Bakhuis Granulite Belt (BGB) in Surinam, South America, shows ultrahigh-temperature metamorphism (UHTM) at temperatures of around 1000 °C which, unusually, produced peak-to-near-peak cordierite with sillimanite and, in some cases, Al-rich orthopyroxene on a regional scale. Mg-rich cordierite (Mg/(Mg + Fe) = 0.88) in a sillimanite-bearing metapelitic granulite has a maximum birefringence of second-order blue (ca. 0.020) indicative of a considerable amount of CO2 (> 2 wt%) within its structural channels. SIMS microanalysis confirms the presence of 2.57 ± 0.19 wt% CO2, the highest CO2 concentration found in natural cordierite. This high CO2 content has enabled the stability of cordierite to extend into UHT conditions at high pressures and very low to negligible H2O activity. Based on a modified calibration of the H2O–CO2 incorporation model of Harley et al. (J Metamorph Geol 20:71–86, 2002), this cordierite occupies a stability field that extends from 8.8 ± 0.6 kbar at 750 °C to 11.3 ± 0.65 kbar at 1050 °C. Volatile-saturated cordierite with 2.57 wt% CO2 and negligible H2O (0.04 wt%) indicates fluid-present carbonic conditions with a CO2 activity near 1.0 at peak or near-peak pressures of 10.5–11.3 kbar under UHT temperatures of 950–1050 °C. The measured H2O content of the cordierite in the metapelite is far too low to be consistent with partial melting at 1000–1050 °C, implying either that nearly all of any H2O originally in this cordierite under UHT conditions was lost during post-peak cooling or that the cordierite was formed after migmatization. The high level of CO2 required to ensure fluid saturation of the c. 11 kbar UHT cordierite is proposed to have been derived from an external, possibly mantle, source.

Monitoring of Subsurface Emissions and the Influence of Meteorological Factors on Landfill Gas Emissions: A Case Study of a South African Landfill

The government-accredited GA 2000 landfill gas analyzer was used to monitor the landfill gas (methane (CH4) and carbon dioxide (CO2)) generated from the subsurface of a landfill. Eighteen gas sample probes were constructed and placed approximately 100 m apart on the boundaries of the landfill site. The monitoring of the gases was conducted over a period of two years, taking into consideration the different seasons of the year. Results from the study show that as the LFG migrates toward the boundaries of the landfill in the subsurface, higher CO2 levels are recorded when compared to CH4. This could be a result of the oxidation process and some other factors present in the landfill. CH4 emissions ranged from 0.54 to 2.22% v/v in 2020. For the year 2021, the CH4 concentration ranged from 0.24% v/v to 2.33% v/v. In addition, the CO2 concentration for the year 2020 ranged from 4.66 to 6.37% v/v. In the year 2021, the CO2 concentration ranged from 3.5 to 6.56% v/v. Furthermore, higher gaseous concentrations were found in the surrounding active cells, where there is currently deposition of municipal solid waste (MSW). However, the monitoring probes situated in areas far away from the landfill recorded lower gaseous levels. This study recommends that there should be continuous monitoring of the LFG emission from the Thohoyandou landfill due to the different results obtained over the temporal variation. Frequent monitoring will help prevent the potential risk of fire hazards and pollution in the future.

An intelligent indicator for warning of short‐term high CO2 damage to garlic scapes

AbstractA pH‐sensitive indicator film based on CO2 change was prepared by mixing a water‐soluble indicator (bromocresol green and chlorophenol red sodium) with a film‐forming carrier (methyl cellulose (MC), polyvinyl alcohol (PVA) and glycerin). The innovation is not only to analyse the response characteristics of the colorimetric indicator to CO2, but also to optimise the preparation parameters of the film. The response experiment showed that CO2 dissolved rapidly in water and the pH value remained unchanged after reaching equilibrium, with a one‐to‐one relationship between pH and CO2 concentration. As the CO2 concentration rose from 18% to 20%, the colour of the indicator film changed from blue–purple to yellow–green in a different colour space, allowing the change to be easily distinguished by the naked eye. The optimum parameters (13 g‧L−1 MC, 5 g‧L−1 PVA, 10 g‧L−1 glycerin, 15 ml‧L−1 indicator and a casting amount of 0.2 ml‧cm−2) for preparing the intelligent film were optimised based on puncture strength (PS), water vapour permeability (WVP), water solubility (WS), casting time (CT) and colour performance. Evaluating this application using garlic scapes stored at 15°C revealed that the total colour difference was 34.23 as the CO2 concentration increased from 18.7% to 20.4%, and the colour of the indicator film changed from blue–purple to yellow–green. Therefore, the intelligent packaging film was able to effectively provide a warning when garlic scapes were exposed to damage from a short‐term high CO2 level.

A high concentration CO2 pool over the Indo-Pacific Warm Pool

Anthropogenic emissions have produced significant amount of carbon dioxide (CO2) in the atmosphere since the beginning of the industrial revolution. High levels of atmospheric CO2 increases global temperature as CO2 absorbs outgoing longwave radiation and re-emits. Though a well-mixed greenhouse gas, CO2 concentration is not uniform in the atmosphere across different altitudes and latitudes. Here, we uncover a region of high CO2 concentration (i.e. CO2 pool) in the middle troposphere (500–300 hPa) over the Indo-Pacific Warm Pool (IPWP, 40° E–140° W, 25° S–25° N), in which the CO2 concentration is higher than that of other regions in the same latitude band (20° N–20° S), by using CO2 satellite measurements for the period 2002–2017. This CO2 pool extends from the western Pacific to the eastern Indian Ocean. Much of the CO2 pool is over the western Pacific Ocean (74.87%), and the remaining lies over the eastern Indian Ocean (25.13%). The rising branch of Walker circulation acts as a “CO2 Chimney” that constantly transports CO2 released from the natural, human-induced and ocean outgassing processes to the middle and upper troposphere. The CO2 pool evolves throughout the year with an average annual trend of about 2.17 ppm yr−1, as estimated for the period 2003–2016. Our analysis further reveals that La Niña (El Niño) events strengthen (weaken) the CO2 pool in the mid-troposphere. The radiative forcing for the CO2 pool suggests more warming in the region and is a grave concern for global warming and climate change.

Effects of Increasing Indoor Negative Air Ions on Cognitive Performance and Health of High Pure CO2 Level-Exposed College Students

Cognitive performance is essential to foster learning. High CO2 concentrations are common in classrooms and can lead to reduced cognitive performance. Negative air ions (NAIs) can improve cognitive performance. This study explored the effects of indoor NAIs on the cognitive performance and health of college students exposed to a high pure CO2 environment. Forty college students were exposed to four sets of conditions (NAIs+500 ppm CO2, 500 ppm CO2, NAIs+2500 ppm CO2, and 2500 ppm CO2). Participants’ cognitive performance, including reasoning, short-term memory, concentration, and verbal ability, was assessed under each condition using the Cambridge Brain Sciences tool. Acute health symptoms were investigated using a subjective questionnaire, and simultaneously, participants’ blood pressure, heart rate, and lung function were tested. Analysis of variance (ANOVA) in a repeated-measures design was used to analyze the effects of different conditions on cognitive performance and health symptoms. The results revealed that the different levels of CO2 and NAIs had a significant effect on cognitive performance after one hour of exposure and had no significant effect after three hours of exposure. Compared with 500 ppm CO2, 500 ppm CO2+NAIs resulted in better reasoning skills, short-term memory, and verbal skills, and 2500 ppm CO2 led to poorer reasoning skills. The addition of NAIs to 2500 ppm CO2 improved reasoning skills, short-term memory, and verbal skills. The benefits of adding NAIs to high pure CO2 condition on cognitive performance are more noticeable than those to low CO2 condition. Moreover, adding NAIs can reduce nasal irritation or dryness, skin irritation or dryness, sleepiness symptoms, and heart rate elevation caused by pure CO2. However, the benefits of NAIs on health symptoms and physiology were not observed under the 500 ppm CO2 condition. Adding NAIs to a high pure CO2 level is an effective means to improve the cognitive performance and health of college students.

Tenrecs deal with poor air quality like reptiles

Dealing with dangerously high CO2 levels is a regular part of life for burrowing creatures. ‘Most animals that are able to tolerate such environments reduce their metabolic rate to re-balance their energy demands’, says Matthew Pamenter from the University of Ottawa, Canada. So, when he heard Frank van Breukelen of the University of Nevada, USA, talk about his burrowing tenrec (Tenrec ecaudatus) colony at a conference in 2019, he realised that the animals might also experience dangerous CO2 concentrations – up to 13.5%, compared with 0.04% in the atmosphere – when hibernating with burrow-mates for 8–9 months. Yet tenrecs are not regular mammals. They can remain active even when their body temperature plummets to 12°C; so how do they cope with the toxic air in their hibernation burrows?Pamenter contacted van Breukelen to suggest a collaboration, and in March 2020, Maiah Devereaux (University of Ottawa) joined Claudia Silva Rubio and van Breukelen at the University of Nevada to find out how tenrecs deal with excessive CO2 and low O2. ‘Our tenrecs are handled very frequently and so they are very docile. To be honest, they are kind of lazy!’ chuckles van Breukelen, who recalls that the animals were content to hang out in a respirometry chamber while Devereaux and Silva Rubio measured the tenrecs’ breath rate and O2 consumption to calculate their metabolic rate. The duo then modified the air mixture the tenrecs were breathing – first reducing the O2 content from 21% to 9% and 4%, before boosting the CO2 levels from 0% to 5% and 10% – at 28°C and 16°C, to find out how the mammals responded. ‘Trying to maintain a stable [gas] flow rate required some troubleshooting’, says van Breukelen.Even when the tenrecs were breathing normal air in the cooler conditions, the active animals’ metabolisms responded unconventionally. Some barely breathed at all – only consuming 2 ml O2 min−1 kg−1 – while others inhaled a colossal amount (23 ml O2 min−1 kg−1) relative to the warmer tenrecs, which only inhaled 12 ml O2 min−1 kg−1 at the most. Raising the CO2 levels in the air didn't affect the range of the cold tenrec's metabolic rates; however, when the team reduced the animals’ O2 supply, the chilly animals no longer had the wide range of metabolic rates they had when breathing normal air.The air temperature also had a major impact on the way the tenrecs breathed when their air was contaminated with CO2. The warmer animals began hyperventilating when the CO2 levels increased, in contrast to the cooler tenrecs, which were more like other burrowing mammals and did not hyperventilate.In short, the tenrecs’ breathing and metabolism were more affected by the environmental temperature than the build-up of toxic CO2 and quantity of O2 available. In addition, the animals in the colder conditions allowed their body temperatures to drift, with some cooling to 20°C while others remained at 32°C regardless of the air quality; all of the tenrecs in 28°C air maintained a warm body temperature (∼32°C) despite the air conditions. The physiological responses of the tenrecs were more like those of cold-blooded reptiles than those of warm-blooded burrowing mammals, probably because they don't have to maintain a high body temperature to survive. van Breukelen exclaims, ‘Many of the things that tenrecs do result in me saying, “How the heck do they do this?”’, and he is excited to find out how the animals cope with poor air quality when breathing as little as once every 45 min while hibernating.

Review on CeO2-Based Photocatalysts for Photocatalytic Reduction of CO2: Progresses and Perspectives

A promising approach is to transform carbon dioxide (CO2) into renewable, high value-added products with minimal environmental impact and maximum efficiency. Many problems, including energy shortages and environmental degradation, are caused by high CO2 levels, but this can help. Photocatalytic reduction methods are a promising technology for solving these problems. Cerium dioxide (CeO2) is one of the most important rare earth oxides, and cerium dioxide-based photocatalysts have gained a lot of attention in recent years due to their distinctive features, such as their tunable electronic structures and their excellent photocatalytic performances. However, the wide energy band of cerium oxide limits its utilization of light. This review provides various strategies for the modification of cerium oxide, encompassing external atom doping, heterostructure fabrication, defect fabrication, and crystal plane modulation, to improve the catalytic performance of CeO2. The fundamentals of the conversion of CeO2-based photocatalysts into high value-added products are also summarized. Finally, the challenges and prospects of CeO2-based catalysts for photocatalytic reduction of CO2 are presented.

A direct numerical simulation analysis of localised forced ignition in turbulent slot jets of CH4/CO2 blends

The early stages of flame evolution following successful localised forced ignition of different CH[Formula: see text]/CO[Formula: see text] blends in a slot jet configuration have been analysed using three-dimensional direct numerical simulations. The simulations have been conducted for three different concentration levels of CO[Formula: see text] in the fuel blend composed of CH[Formula: see text] and CO[Formula: see text] (ranging from 0% to 20% by volume). The effects of CO[Formula: see text] concentration have been analysed based on five different energy deposition scenarios which include situations where the mean mixture composition at the ignitor varies, but not its location in space, whereas other cases represent the scenarios where the mean mixture composition within the energy deposition region remains constant, but its spatial location changes with CO[Formula: see text] concentration. The most favourable region for successful flame development following thermal runaway, from the mixture composition standpoint (i.e. the highest flammability factor), has been found to be displaced close to the nozzle with an increase in CO[Formula: see text] concentration. The flame development following thermal runaway exhibits initial growth of hot gas kernel followed by downstream advection and eventual flame propagation along with radial expansion with a possibility of flame stabilisation irrespective of the level of CO[Formula: see text] concentration. The triple flame propagation has been found to play a key role in the upstream flame propagation and eventual stabilisation. The orientation of the local flame normal plays a key role in the flame stabilisation. The lift off height has been found to increase with increasing CO[Formula: see text] concentration which also adversely affect flame stabilisation for high levels of CO[Formula: see text] concentration.

Cell Plasticity of Marine Mediterranean Diazotrophs to Climate Change Factors and Nutrient Regimes

Ocean acidification and warming are current global challenges that marine diazotrophs must cope with. Little is known about the effects of pH and temperature changes at elevated CO2 levels in combination with different nutrient regimes on N2 fixers, especially on heterotrophic bacteria. Here, we selected four culturable diazotrophs, i.e., cyanobacteria and heterotrophic bacteria, found in association with the endemic Mediterranean seagrass Posidonia oceanica. We tested different pH (from pH 4 to 8) and temperature levels (from 12 to 30 °C), under different nutrient concentrations of both phosphorus, P (0.1 µM and 1.5 mM), and iron, Fe (2 nM and 1 µM). We also tested different CO2 concentrations (410 and 1000 particles per million (ppm)) under different P/Fe and temperature values (12, 18, and 24 °C). Heterotrophic bacteria were more sensitive to changes in pH, temperature, and CO2 than the cyanobacterial species. Cyanobacteria were resistant to very low pH levels, while cold temperatures stimulated the growth in heterotrophic bacteria but only under nutrient-limited conditions. High CO2 levels (1000 ppm) reduced heterotrophic growth only when cultures were nutrient-limited, regardless of temperature. In contrast, cyanobacteria were insensitive to elevated CO2 levels, independently of the nutrient and temperature levels. Changes in N2 fixation were mainly controlled by changes in growth. In addition, we suggest that alkaline phosphatase activity (APA) and reactive oxidative species (ROS) can be used as biomarkers to assess the plasticity of these communities to climate change factors. Unlike other studies, the novelty of this work lies in the fact that we compared the responses of cyanobacteria vs. heterotrophic bacteria, studying which changes occur at the cell plasticity level. Our results suggest that the responses of diazotrophs to climate change may depend on their P and Fe status and lifestyle, i.e., cyanobacteria or heterotrophic bacteria.

Multi-temporal variability forecast of particulate organic carbon in the Indonesian seas.

The current global condition characterized by high levels of CO2 is altering the carbon cycle and elemental biogeochemistry, resulting in subsequent global warming, climate change, ocean acidification, and the indirect response of deoxygenation. The features of Indonesia's coastal ecosystems and continental shelf waters also contribute to spatio-temporal ocean carbon variability. For instance, the level of particulate organic carbon (POC) will change annually, and thus, over a decadal period, ocean dynamics may affect the temporal variability of POC. Motivated by such conditions, future forecasting is needed to envision the productivity of Indonesian seas by predicting vital parameters such as POC. This research aimed to forecast the temporal variability of POC in Indonesian waters. The Seasonal Autoregressive Integrated Moving Average (SARIMA) forecasting model was used by considering the lowest value of the Akaike information criterion (AIC) and the mean absolute percentage error/MAPE (threshold < 10%). Using the highest correlation coefficient (threshold: 0.75), we obtained the best fit for forecasting POC temporal variability. Hindcast POC data (2002-2020/2021) was used to train the forecasting model. The result shows that forecasting of POC temporal variability can be conducted up to 2030. The validity of prediction is ensured for less than 5years forward after 2020 with correlation coefficients of 0.65 and 0.83 for seasonal and monthly POC, respectively. The hindcast and forecast estimates of POC in the Indonesian seas show a decreasing trend. The present study emphasizes the different forecasting results obtained using the different approaches of annual versus inter-annual variability. A sustained research effort is still required to assess POC forecasting for its potential benefits in marine system monitoring and assessment.

The decline of plant mineral nutrition under rising CO2: physiological and molecular aspects of a bad deal.

The elevation of atmospheric CO2 concentration has a strong impact on the physiology of C3 plants, far beyond photosynthesis and C metabolism. In particular, it reduces the concentrations of most mineral nutrients in plant tissues, posing major threats on crop quality, nutrient cycles, and carbon sinks in terrestrial agro-ecosystems. The causes of the detrimental effect of high CO2 levels on plant mineral status are not understood. We provide an update on the main hypotheses and review the increasing evidence that, for nitrogen, this detrimental effect is associated with direct inhibition of key mechanisms of nitrogen uptake and assimilation. We also mention promising strategies for identifying genotypes that will maintain robust nutrient status in a future high-CO2 world.

Score-driven threshold ice-age models: Benchmark models for long-run climate forecasts

Climate variables are known to be subject to abrupt changes when some threshold levels are surpassed. We use data for the last 798,000 years on global ice volume (Ice), atmospheric carbon dioxide level (CO2), and Antarctic land surface temperature (Temp) to model and measure those long-run nonlinear climate effects. The climate variables have very long and asymmetric cycles, created by periods of upward trends, followed by periods of downward trends driven by exogenous orbital variables. The exogenous orbital variables considered by the Milankovitch cycles are eccentricity of Earth’s orbit, obliquity, and precession of the equinox. We show that our new score-driven threshold ice-age models improve the statistical inference and forecasting performance of competing ice-age models from the literature. The drawback of using our 1000-year frequency observations, is that we cannot measure the nonlinear climate effects of humanity created during the last 250 years, which are known to have generated abrupt structural changes in the Earth’s climate, due to unprecedented high levels of CO2 and Temp, and low levels of Ice volume. On the other hand, the advantage of using low-frequency data is that they allow us to obtain long-run forecasts on what would have occurred if humanity had not burned fossil fuels since the start of the Industrial Revolution. These long-run forecasts can serve as benchmarks for the long-run evaluation of the impact of humanity on climate variables. Without the impact of humanity on climate, we predict the existence of turning points in the evolution of the three climate variables for the next 5,000 years: an upward trend in global ice volume, and downward trends in atmospheric CO2 level and Antarctic land surface temperature.

CO2 bee anaesthetic can cause complications

Most people don't really pay attention to the air they breathe. However, if you go up a mountain, where the oxygen levels are lower, you'll notice as you huff and puff while taking a normal walk around town. Changes in the amounts of the different gases that make up the air we breathe can have noticeable effects in other animals as well, especially insects. ‘Low concentrations of carbon dioxide (CO2) are often used as an attractant or repellent’, says Anna Cressman of Pennsylvania State University, USA; however, high concentrations can cause behavioural and physiological changes, and can even result in unconsciousness. Frequently, researchers use 100% CO2 to anaesthetize insects (called CO2 narcosis), but the side-effects of exposure to high levels of CO2 are often not considered. Working with Etya Amsalem, also of Pennsylvania State University, Cressman asked what is causing these side-effects in bumblebees (Bombus impatiens) – the lack of oxygen, or the high level of CO2 itself.Carbon dioxide is usually found at levels of around 0.04% in normal air, so the duo pumped either 100% CO2, 50% CO2, normal air with low oxygen, or 100% nitrogen gas (which means that there is no oxygen) into a chamber containing bees for 1 min, recording how many of the bees passed out, and then filmed the insects to monitor how they behaved once they awoke, as well as checking how the different gases affected bees with different roles, queens and workers, in the colony.Sure enough, when the team compared the effects of pure CO2 and 100% nitrogen, the bees’ responses were quite different. Even though both gases knocked the bees out, after recovering from the sedation, the bees that had inhaled 100% CO2 had different side-effects from the bees anaesthetised with pure nitrogen. The CO2-anaesthetised bees pumped their abdomens more and the queens took longer to regain consciousness. In addition, when Cressman compared the effects of the different gases on worker and queen bees, the workers produced smaller eggs after several doses of 100% CO2, whereas the queens produced larger eggs after a single dose of the pure gas. Cressman also compared the impact of the two gases on the expression of six specific genes – involved in egg production and protection from low oxygen levels – and she discovered that the genes reacted differently.The responses of the queen bees and workers to pure CO2 also differed: the queens seemed to be more vulnerable to the gas than the workers, only requiring one dose, to begin showing side-effects during their recovery, in contrast to the workers, which required multiple doses of the gas before the side-effects became apparent. ‘The fact that the physiological changes are different suggests that CO2 is not simply depriving the bees of oxygen but does something else and is likely to have a more direct impact on cells’, Amsalem concludes.So, inhaling CO2 can affect bees with different roles in the colony in different ways, and researchers should be aware of the potential complications that this may cause when using the gas to anaesthetize insects in their experiments.

AIRO: Development of an Intelligent IoT-based Air Quality Monitoring Solution for Urban Areas

Air pollution is the contamination of the atmosphere by any biological, physical, or chemical means. Bengaluru, the Silicon Valley of India, has air pollution levels that exceed WHO standards. Its air has high PM10, PM2.5, SO2, NO2, and CO2 levels, exposing residents to an increased risk of respiratory diseases. AIRO, a decentralised IoT-based air quality monitoring solution, is proposed to calculate the (Air Quality Index) AQI in real-time and notify the users of dangerous AQI levels. Unlike the city's fixed air quality monitoring stations, this portable system can easily be integrated into everyday items for computing real-time air quality at any given place. The proposed solution is then validated using a physical prototype incorporated into a water bottle. Using the Intel Edison development platform, this prototype is equipped with a GPS module, Wi-Fi module, PMS5003, MQ131, MQ135, MQ136, MQ7 sensors, and an LCD Display. The prototype records the air quality indicators, calculates the AQI, and sends the data to the AWS Cloud Server. After an in-depth analysis of the cloud data, the daily and weekly AQI is predicted for multiple locations in the city. A hybrid CNN-Bi-LSTM model is proposed for predicting AQI, which needs to be evaluated at the city scale for dependable results. Finally, a smartphone app is developed using Android Studio and Python to monitor the air quality and notify the users. The users also have an option to select a location and get the real-time and predicted AQI. In the future, this hybrid deep-learning model can be extended to other cities using the transfer learning approach.

Beneficial Impact of Hypercapnic Conditions During Early Incubation on Broiler Hatchability. Embryo Mortality and Postnatal Performance

We assessed the extent to which CO2 levels altered different hatching and chick parameters. In Experiments 1 and 2, a total of 16,184 eggs from Cobb 500 breeders were incubated in single stage incubators under three different conditions: (a) standard ventilated incubator (CON, Exp.1 and 2); (b) increasing CO2 levels during the first 10 days of incubation until 0.7% (V7000, Exp. 1) and (c) until 0.8% (V8000, Exp. 2). High levels of CO2 improved hatchability, possibly due to lower embryo mortality from ED18 to ED21. Internal and external pipping in experiment V8000 started later than in CON; nevertheless, the hatch still occurred before in V8000 as a result of the shorter durations of external pipping and hatch. In Experiment 3, a total of 12,138 eggs from Cobb 500 were incubated in single stage incubators under three different conditions: (a) standard ventilated incubator (CON); (b) increasing CO2 levels until 1.0% with ventilation (V10000); and (c) increasing CO2 levels until 1.0% without ventilation (NV10000). Hypercapnic conditions led to better hatchability and lower embryo mortality from ED18 to ED21. Internal pipping started earlier in NV10000, but only V10000 differed from CON in terms of the average time for hatch. Hypercapnic groups also showed shorter durations of external pipping and hatch when compared to CON. Post-hatch analysis revealed no differences among incubation conditions in terms of body weight gain, feed conversion ratio, mortality by sudden death syndrome, and production factor. Nevertheless, V10000 showed a lower mortality by ascites and a better viability when compared to CON, while NV10000 presented a higher mortality by other causes. Altogether, our findings indicate that in addition to not being detrimental to embryo survival, high CO2 levels reduce embryonic mortality at 18-21 days of incubation and increase hatchability.

The use of the news in predicting the clinical status of copd patients presenting to the emergency department with a the complaint of dyspnea

Aim: COPD (Chronic Obstructive Pulmonary Disease) is a lung disease that causes impairment in quality of life. NEWS (National Early Warning Score) is a scoring system that evaluates patients' general condition and mortality. We examined the utility of NEWS in predicting the clinical status of COPD patients. Materials and methods: COPD patients admitted to the emergency department were included in the study. Age, gender, comorbid diseases, occupational exposure status, smoking/tobacco intake, hematological and radiological examinations, vital values, and continuous drug use status of the patients were evaluated. The GCS (Glasgow Coma Scale), CCI (Charlson Comorbidity Index), and NEWS values of the patients were calculated. Chi-square, Fisher's exact, unpaired t-test, or Mann-Whitney U tests were applied according to the normal distribution. Values of p&lt;0.05 were considered statistically significant. Results: Of the patients, 82% (n=205) were male, and 18% (n=45) were female. Of the patients, 67% had comorbid diseases. Coronary artery disease was the most common comorbid disease (n=68, 27%). Low saturation, pH, mean blood pressure, low hemoglobin, high CO2, creatinine, urea, CRP, and INR levels were associated with mortality. In non-survival patients, the GCS was low, whereas the CCI and NEWS were high. Conclusions: The NEWS value should be considered in order to determine the clinical status of patients presenting with a COPD attack, to make the decision for hospitalization, and to predict their mortality. Keywords : Emergency department,COPD exacerbation,NEWS,mortality