Carbon Dioxide Levels Research Articles

The pervasive impact of global climate change on plant-nematode interaction continuum.

Pest profiles in today's global food production system are continually affected by climate change and extreme weather. Under varying climatic conditions, plant-parasitic nematodes (PPNs) cause substantial economic damage to a wide variety of agricultural and horticultural commodities. In parallel, their herbivory also accredit to diverse ecosystem services such as nutrient cycling, allocation and turnover of plant biomass, shaping of vegetation community, and alteration of rhizospheric microorganism consortium by modifying the root exudation pattern. Thus PPNs, together with the vast majority of free-living nematodes, act as ecological drivers. Because of direct exposure to the open environment, PPN biology and physiology are largely governed by environmental factors including temperature, precipitation, humidity, atmospheric and soil carbon dioxide level, and weather extremes. The negative effects of climate change such as global warming, elevated CO2, altered precipitation and the weather extremes including heat waves, droughts, floods, wildfires and storms greatly influence the biogeographic range, distribution, abundance, survival, fitness, reproduction, and parasitic potential of the PPNs. Changes in these biological and ecological parameters associated to the PPNs exert huge impact on agriculture. Yet, depending on how adaptable the species are according to their geo-spatial distribution, the consequences of climate change include both positive and negative effects on the PPN communities. While assorting the effects of climate change as a whole, it can be estimated that the changing environmental factors, on one hand, will aggravate the PPN damage by aiding to abundance, distribution, reproduction, generation, plant growth and reduced plant defense, but the phenomena like sex reversal, entering cryptobiosis, and reduced survival should act in counter direction. This seemingly creates a contraposition effect, where assessing any confluent trend is difficult. However, as the climate change effects will differ according to space and time it is apprehensible that the PPNs will react and adapt according to their location and species specificity. Nevertheless, the bio-ecological shifts in the PPNs will necessitate tweaking their management practices from the agri-horticultural perspective. In this regard, we must aim for a 'climate-smart' package that will take care of the food production, pest prevention and environment protection. Integrated nematode management involving precise monitoring and modeling-based studies of population dynamics in relation to climatic fluctuations with escalated reliance on biocontrol, host resistance, and other safer approaches like crop rotation, crop scheduling, cover cropping, biofumigation, use of farmyard manure (FYM) would surely prove to be viable options. Although the novel nematicidal molecules are target-specific and relatively less harmful to the environment, their application should not be promoted following the global aim to reduce pesticide usage in future agriculture. Thus, having a reliable risk assessment with scenario planning, the adaptive management strategies must be designed to cope with the impending situation and satisfy the farmers' need.

Global Change Factors Influence Plant-Epichloë Associations.

There is an increasing interest in determining the influence of global change on plant-microorganism interactions. We review the results of experiments that evaluated the effects of the global change factors carbon dioxide, ozone, temperature, drought, flooding, and salinity on plant symbioses with beneficial Epichloë endophytes. The factors affected the performance of both plants and endophytes as well as the frequency of plants symbiotic with the fungus. Elevated carbon dioxide levels and low temperatures differentially influenced the growth of plants and endophytes, which could compromise the symbioses. Furthermore, we summarise the plant stage in which the effects of the factors were quantified (vegetative, reproductive, or progeny). The factors ozone and drought were studied at all plant stages, but flooding and carbon dioxide were studied in just a few of them. While only studied in response to ozone and drought, evidence showed that the effects of these factors on symbiotic plants persisted trans-generationally. We also identified the putative mechanisms that would explain the effects of the factors on plant-endophyte associations. These mechanisms included the increased contents of reactive oxygen species and defence-related phytohormones, reduced photosynthesis, and altered levels of plant primary metabolites. Finally, we describe the counteracting mechanisms by which endophytes would mitigate the detrimental effects of the factors on plants. In presence of the factors, endophytes increased the contents of antioxidants, reduced the levels of defence-related phytohormones, and enhanced the plant uptake of nutrients and photosynthesis levels. Knowledge gaps regarding the effects of global change on plant-endophyte associations were identified and discussed.

Life Cycle Assessment of Innovative Carbon Dioxide Selective Membranes from Low Carbon Emission Sources: A Comparative Study.

Carbon capture has been an important topic of the twenty-first century because of the elevating carbon dioxide (CO2) levels in the atmosphere. CO2 in the atmosphere is above 420 parts per million (ppm) as of 2022, 70 ppm higher than 50 years ago. Carbon capture research and development has mostly been centered around higher concentration flue gas streams. For example, flue gas streams from steel and cement industries have been largely ignored due to lower associated CO2 concentrations and higher capture and processing costs. Capture technologies such as solvent-based, adsorption-based, cryogenic distillation, and pressure-swing adsorption are under research, but many suffer from higher costs and life cycle impacts. Membrane-based capture processes are considered cost-effective and environmentally friendly alternatives. Over the past three decades, our research group at Idaho National Laboratory has led the development of several polyphosphazene polymer chemistries and has demonstrated their selectivity for CO2 over nitrogen (N2). Poly[bis((2-methoxyethoxy)ethoxy)phosphazene] (MEEP) has shown the highest selectivity. A comprehensive life cycle assessment (LCA) was performed to determine the life cycle feasibility of the MEEP polymer material compared to other CO2-selective membranes and separation processes. The MEEP-based membrane processes emit at least 42% less equivalent CO2 than Pebax-based membrane processes. Similarly, MEEP-based membrane processes produce 34-72% less CO2 than conventional separation processes. In all studied categories, MEEP-based membranes report lower emissions than Pebax-based membranes and conventional separation processes.

A two-stage system proposal based on a type-2 fuzzy logic system for ergonomic control of classrooms and offices

For people who spend a long time indoors during the day, it is incredibly vital that their environmental conditions are ergonomically designed to provide comfort. However, keeping these comfort conditions at optimum limits during the day requires an important control activity. In this study, a two-stage system using type-2 fuzzy logic is proposed for the ergonomic control of indoor environments such as classrooms and offices. This system calculates the effective working time and time-dependent change in carbon dioxide levels in the first stage and evaluates the ergonomic comfort conditions in the second stage. To develop this system, temperature, humidity, and carbon dioxide levels were measured at different times of the day in university classrooms and the rooms of some faculty members. Based on the data obtained from these measurements, the proposed ergonomic control structure was modeled by using both type-1 and type-2 fuzzy logic systems. As a result, although it was seen that both fuzzy logic systems produced the same results in some examples, it was observed that the proposed type-2 fuzzy logic system produced better interpretations than type-1 in some of the others. Therefore, the type-2 fuzzy logic system is recommended for better ergonomic control in extremely fuzzy environments.

Simulating the Yield Responses of Sugar Beet to Different Climate Change Scenarios by LINTUL-MULTICROP Model

Sugar beet is an essential crop for the sugar industry that have a very crucial role in agro-industry of Türkiye and Konya ranks first in terms of total sugar beet production and harvested area. The predictions, that the world's human population will reach 9 billion by the end of the current century and that demand for food will increase, are forcing farmers for the decision to search for new areas for agriculture or choose the crops that will be most productive in already cultivated lands. The aim of this study was to apply the LINTUL-MULTICROP Model for investigating the adaptation of sugar beet for the current climatic conditions and for climate change scenarios to show the response of sugar beet to an increase level of carbon dioxide and temperature. Four different scenarios were compared to check the effects of the climate change on sugar beet farming in the semi-arid Konya Region as followings: i) scenario (a) is the current climate conditions; ii) scenario (b) is the average temperatures increased 2 °C, iii) scenario (c) is 200 ppm increasing atmospheric CO2; iv) scenario (d) new optimum sowing and harvest dates in sugar beet farming and increased temperatures and atmospheric CO2 amount were simulated together. The optimum sowing and harvesting dates of sugar beet were moved 13 days back for sowing, and 8 days forward for harvesting. The highest yield was estimated under conditions of 2 °C and 200 ppm increased atmosphere temperature and CO2 levels with new sowing and harvest dates. The yields under irrigated conditions varied between 74.4 t ha-1 and 111.2 t ha-1. The irrigation water requirements of sugar beet were ranged from 618.8 mm to 688.5 mm for different scenarios. In conclusion, the cultivation of sugar beet tends to alter in semi-arid Konya environment.

Neurological repercussions of changes in cerebral blood flow in neonates undergoing cardiovascular surgery.

Surgery for congenital heart disease can generate cerebral perfusion-associated alterations with neurological repercussions. To analyze the relationship of peri-surgical cerebrovascular resistance index (RI) with mediate neurological functions after congenital heart disease surgery. Prospective cohort study of 34 neonates in whom basilar artery RI, serum oxygen, carbon dioxide and lactate levels were determined before and after palliative or corrective procedures. We related pre-surgical RI with post-surgical ability to initiate the enteral route or to restore unassisted spontaneous breathing. Three groups were formed: 79 neonates with high RI (> 0.73), 73 with normal RI (0.63 to 0.73) and eight with low RI (< 0.63). In the former group, high RI persisted in the postoperative period, with persistent hyperlactatemia and hypoxia; in 86 %, the enteral route could not be initiated, and neither could assisted ventilation be withdrawn. In the second group, RI remained within normal values. In the third group, although RI, serum lactate and arterial oxygen pressure tended to normalize, 71 % had severe neurological damage. RI changes were common, although neurological damage appears to occur more commonly when RI remains high, possibly associated with low cerebral blood flow.

Bronchopulmonary Dysplasia and Carbon Dioxide Retention.

To determine the pre-discharge carbon dioxide (CO2 ) levels of preterm neonates with bronchopulmonary dysplasia (BPD) requiring ongoing nasal cannulae oxygen therapy and who were ready for discharge home. We studied a retrospective cohort of infants born <30 weeks gestational age (GA) at ≥36 weeks corrected GA who had established BPD requiring ongoing nasal cannulae oxygen therapy and were ready for discharge home. Neonates were born and admitted between May 2014 and Dec 2018. Demographic data at the time of birth and at the time of the last blood gas sampled was collected. 105 neonates with median GA 26.1 weeks and birth weight 775 g. Median (IQR) CO2 level was 54 (49-58) mmHg. 99 (94%) neonates had CO2 levels exceeding the normal range and 91 (87%) neonates had a CO2 between 45-65 mmHg. Ninety-four per cent of neonates <30 weeks GA at ≥36 weeks corrected GA requiring ongoing nasal cannulae oxygen therapy for established BPD, who were ready for discharge home, have CO2 levels outside of normocapnia (35-45 mmHg), with 87% having CO2 levels between 45-65 mmHg.

Improving the Clinical Interpretation of Transcutaneous Carbon Dioxide and Oxygen Measurements in the Neonatal Intensive Care Unit

Introduction: Transcutaneous blood gas monitoring allows for continuous non-invasive evaluation of carbon dioxide and oxygen levels. Its use is limited as its accuracy is dependent on several factors. We aimed to identify the most influential factors to increase usability and aid in the interpretation of transcutaneous blood gas monitoring. Methods: In this retrospective cohort study, transcutaneous blood gas measurements were paired to arterial blood gas withdrawals in neonates admitted to the neonatal intensive care unit. The effects of patient-related, microcirculatory, macrocirculatory, respiratory, and sensor-related factors on the difference between transcutaneously and arterially measured carbon dioxide and oxygen values (ΔPCO₂ and ΔPO₂) were evaluated using marginal models. Results: A total of 1,578 measurement pairs from 204 infants with a median [interquartile range] gestational age of 27³/₇ [26¹/₇–31³/₇] weeks were included. ΔPCO₂ was significantly associated with the postnatal age, arterial systolic blood pressure, body temperature, arterial partial pressure of oxygen (PaO₂), and sensor temperature. ΔPO₂ was, with the exception of PaO₂, additionally associated with gestational age, birth weight Z-score, heating power, arterial partial pressure of carbon dioxide, and interactions between sepsis and body temperature and sepsis and the fraction of inspired oxygen. Conclusion: The reliability of transcutaneous blood gas measurements is affected by several clinical factors. Caution is recommended when interpreting transcutaneous blood gas values with an increasing postnatal age due to skin maturation, lower arterial systolic blood pressures, and for transcutaneously measured oxygen values in the case of critical illness.

Blood chemistry and biliverdin differ according to reproduction and tourism in a free-living lizard.

Changes in the physiological health of species are an essential indicator of changing conditions and environmental challenges. Reponses to environmental challenges can often induce stress, influence physiology, and change metabolism in organisms. Here we tested blood chemistry parameters indicative of stress and metabolic activity using an i-STAT point-of-care blood analyzer in seven populations of free-ranging rock iguanas exposed to varying levels of tourism and supplemental feeding. We found significant differences in blood chemistry (glucose, oxygen, carbon dioxide, hematocrit, hemoglobin, calcium, potassium, and biliverdin levels) among populations exposed to varying levels of tourism, and some variation between sexes and reproductive states. However, different variables are not directly related to one another, suggesting that the causal physiological pathways driving tourism-induced differences are influenced by mechanisms that are not detected by common analyses of blood chemistry. Future work should investigate upstream regulators of these factors affected by tourism. Regardless, these blood metrics are known to be both stress sensitive and related to metabolic activity, suggesting that exposure to tourism and associated supplemental feeding by tourists are generally driven by stress-related changes in blood chemistry, biliverdin, and metabolism.

The plant response to high CO2 levels is heritable and orchestrated by DNA methylation.

Plant responses to abiotic environmental challenges are known to have lasting effects on the plant beyond the initial stress exposure. Some of these lasting effects are trans-generational, affecting the next generation. The plant response to elevated carbon dioxide (CO2 ) levels has been well studied. However, these investigations are typically limited to plants grown for a single generation in a high CO2 environment while trans-generational studies are rare. We aimed to determine trans-generational growth responses in plants after exposure to high CO2 by investigating the direct progeny when returned to baseline CO2 levels. We found that both the flowering plant Arabidopsis thaliana and seedless non-vascular plant Physcomitrium patens continue to display accelerated growth rates in the progeny of plants exposed to high CO2 . We used the model species Arabidopsis to dissect the molecular mechanism and found that DNA methylation pathways are necessary for heritability of this growth response. More specifically, the pathway of RNA-directed DNA methylation is required to initiate methylation and the proteins CMT2 and CMT3 are needed for the trans-generational propagation of this DNA methylation to the progeny plants. Together, these two DNA methylation pathways establish then maintain a cellular memory to high CO2 exposure.

Gigatonne Carbon Dioxide Removal Can Reverse Global Heating Trend

It is a surprising realization to many that a changing temperature tightly correlates with the carbon dioxide (CO2) levels worldwide in a linear, lockstep manner with a reversible but very short temporal feedback loop of only a few decades. A mapping of the past 400,000 years of earth’s climate history by Hansen, based on the Vostok ice core sampling, offers a glimpse into this remarkably tight relationship between CO2 and global temperature levels but also the average sea level over four ice ages that are clearly delineated in his historic depiction of all three quantities. As his Table accompanying the graph is analyzed, an equation linking the three variables has now been generated, yielding a fresh view into how past decades of hundreds of gigatons of atmospheric increase will continue to affect a worldwide temperature rise, also called “global warming.” The implication that is inescapable from such an analysis is that the presently stored CO2 level, far surpassing by over 40% those present in 1950, is the real cause of the physics “heat-trapping effect” seen worldwide. (Note: US tons are 0.907 of metric tonnes and both are used in this article.) Research accomplished in this review point to the heat-trapping property of CO2 as the major contributor to increasing heat worldwide and lead to the prediction of how much higher global temperature will rise if left unchecked, with the level of CO2 over 40% higher than it has ever been in more than 400,000 years. The proposed solution offered in this review is to initiate a 40 gigatonne carbon dioxide removal (CDR) annually in order to stabilize atmospheric CO2, to be followed by an expanded CDR effort toward a goal of 100 gigatonnes/year to begin reversing and lowering global temperature.

An integrated multi-level analysis reveals learning-memory deficits and synaptic dysfunction in the rat model exposure to austere environment

Austere environment existing in tank, submarine and vessel has many risk factors including high temperature and humidity, confinement, noise, hypoxia, and high level of carbon dioxide, which may cause depression and cognitive impairment. However, the underlying mechanism is not fully understood yet. We attempt to investigate the effects of austere environment (AE) on emotion and cognitive function in a rodent model. After 21 days of AE stress, the rats exhibit depressive-like behavior and cognitive impairment. Compared with control group, the glucose metabolic level of the hippocampus is significantly decreased using whole-brain positron emission tomography (PET) imaging, and the density of dendritic spines of the hippocampus is remarkably reduced in AE group. Then, we employ a label-free quantitative proteomics strategy to investigate the differentially abundant proteins in rats' hippocampus. It is striking that the differentially abundant proteins annotated by KEGG enrich in oxidative phosphorylation pathway, synaptic vesicle cycle pathway and glutamatergic synapses pathway. The synaptic vesicle transport related proteins (Syntaxin-1A, Synaptogyrin-1 and SV-2) are down-regulated, resulting in the accumulation of intracellular glutamate. Furthermore, the concentration of hydrogen peroxide and malondialdehyde is increased while the activity of superoxide dismutase and complex I and IV of mitochondria is decreased, indicating that oxidative damage to hippocampal synapses is associated with the cognitive decline. The results of this study offer direct evidence, for the first time, that austere environment can substantially cause learning and memory deficits and synaptic dysfunction in a rodent model via behavioral assessments, PET imaging, label-free proteomics, and oxidative stress tests. SignificanceThe incidence of depression and cognitive decline in military occupations (for example, tanker and submariner) is significantly higher than that of global population. In the present study, we first established novel model to simulate the coexisting risk factors in the austere environment. The results of this study offer the direct evidences, for the first time, that the austere environment can substantially cause learning and memory deficits by altering plasticity of the synaptic transmission in a rodent model via proteomic strategy, PET imaging, oxidative stress and behavioral assessments. These findings provide valuable information to better understand the mechanisms of cognitive impairment.

Supplemental oxygen and noninvasive ventilation.

The respiratory system attempts to maintain normal levels of oxygen and carbon dioxide. However, airflow limitation, parenchymal abnormalities and dysfunction of the respiratory pump may be compromised in individuals with advanced COPD, eventually leading to respiratory failure, with reduced arterial oxygen tension (hypoxaemia) and/or increased arterial carbon dioxide tension (P aCO2 ; hypercapnia). Hypoxaemia may persist in individuals with severe COPD despite smoking cessation and optimisation of pharmacotherapy. Long-term oxygen therapy (LTOT) can improve survival in those with severe daytime hypoxaemia, whereas those with less severe hypoxaemia may only have improved exercise capacity and dyspnoea. Changes in respiratory physiology that occur during sleep further predispose to hypoxaemia, particularly in individuals with COPD. However, the major cause of hypoxaemia is hypoventilation. Noninvasive ventilation (NIV) may reduce mortality and need for intubation in individuals with COPD and acute hypercapnic respiratory failure. However, NIV may also improve survival and quality of life in individuals with stable, chronic hypercapnia and is now suggested for those with prolonged hypercapnia (e.g. P aCO2 >55 mmHg 2-6 weeks after hospital discharge) when clinically stable and after optimisation of medical therapy including LTOT if indicated. Many questions remain about the optimal mode, settings and goal of NIV therapy.

Effects of acidification on nitrification and associated nitrous oxide emission in estuarine and coastal waters

In the context of an increasing atmospheric carbon dioxide (CO2) level, acidification of estuarine and coastal waters is greatly exacerbated by land-derived nutrient inputs, coastal upwelling, and complex biogeochemical processes. A deeper understanding of how nitrifiers respond to intensifying acidification is thus crucial to predict the response of estuarine and coastal ecosystems and their contribution to global climate change. Here, we show that acidification can significantly decrease nitrification rate but stimulate generation of byproduct nitrous oxide (N2O) in estuarine and coastal waters. By varying CO2 concentration and pH independently, an expected beneficial effect of elevated CO2 on activity of nitrifiers (“CO2-fertilization” effect) is excluded under acidification. Metatranscriptome data further demonstrate that nitrifiers could significantly up-regulate gene expressions associated with intracellular pH homeostasis to cope with acidification stress. This study highlights the molecular underpinnings of acidification effects on nitrification and associated greenhouse gas N2O emission, and helps predict the response and evolution of estuarine and coastal ecosystems under climate change and human activities.

Late permissive hypercapnia and respiratory stability among very preterm infants: a pilot randomised trial

ObjectiveDetermine if targeting higher transcutaneous carbon dioxide improves respiratory stability among very preterm infants on ventilatory support.DesignSingle-centre pilot randomised clinical trial.SettingThe University of Alabama at Birmingham.PatientsVery preterm infants on ventilatory...

Association between intraoperative end-tidal carbon dioxide and postoperative organ dysfunction in major abdominal surgery: A cohort study.

Data on the effects of intraoperative end-tidal carbon dioxide (EtCO2) levels on postoperative organ dysfunction are limited. Thus, this study was designed to investigate the relationship between the intraoperative EtCO2 level and postoperative organ dysfunction in patients who underwent major abdominal surgery under general anesthesia. We conducted a cohort study involving patients who underwent major abdominal surgery under general anesthesia at Kyoto University Hospital. We classified those with a mean EtCO2 of less than 35 mmHg as low EtCO2. The time effect was determined as the minutes when the EtCO2 value was below 35 mmHg, whereas the cumulative effect was evaluated by measuring the area below the 35-mmHg threshold. The outcome was postoperative organ dysfunction, defined as a composite of at least one organ dysfunction among acute renal injury, circulatory dysfunction, respiratory dysfunction, coagulation dysfunction, and liver dysfunction within 7 days after surgery. Of the 4,171 patients, 1,195 (28%) had low EtCO2, and 1,428 (34%) had postoperative organ dysfunction. An association was found between low EtCO2 and increased postoperative organ dysfunction (adjusted risk ratio, 1.11; 95% confidence interval [CI], 1.03-1.20; p = 0.006). Additionally, long-term exposure to EtCO2 values of less than 35 mmHg (≥224 min) was associated with postoperative organ dysfunction (adjusted risk ratio, 1.18; 95% CI, 1.06-1.32; p = 0.003) and low EtCO2 severity (area under the threshold) (adjusted risk ratio, 1.13; 95% CI, 1.02-1.26; p = 0.018). Intraoperative low EtCO2 of below 35 mmHg was associated with increased postoperative organ dysfunction.

Do Environmental Taxes Improve Environmental Quality? Evidence from OECD Countries

This article investigates the relationship between environmentally related taxes introduced in OECD countries and air pollution, represented by carbon dioxide and greenhouse gas emission levels in the atmosphere. The article makes a statistical analysis of data on environmental taxes, specifically energy and transport taxes, and other variables that might affect air quality in the OECD member countries. The ARDL model used on the panel data of all OECD member countries shows statistical significance in only one out of five models. A subsequent comparative analysis of the reduced sample of OECD countries that are members of the EU exhibits a statistically significant effect of environmentally related tax revenues on the air emission levels, indicating that this relationship is present in the reduced sample.

The Tissue Response to Hypoxia: How Therapeutic Carbon Dioxide Moves the Response toward Homeostasis and Away from Instability

Sustained tissue hypoxia is associated with many pathophysiological conditions, including chronic inflammation, chronic wounds, slow-healing fractures, microvascular complications of diabetes, and metastatic spread of tumors. This extended deficiency of oxygen (O2) in the tissue sets creates a microenvironment that supports inflammation and initiates cell survival paradigms. Elevating tissue carbon dioxide levels (CO2) pushes the tissue environment toward "thrive mode," bringing increased blood flow, added O2, reduced inflammation, and enhanced angiogenesis. This review presents the science supporting the clinical benefits observed with the administration of therapeutic CO2. It also presents the current knowledge regarding the cellular and molecular mechanisms responsible for the biological effects of CO2 therapy. The most notable findings of the review include (a) CO2 activates angiogenesis not mediated by hypoxia-inducible factor 1a, (b) CO2 is strongly anti-inflammatory, (c) CO2 inhibits tumor growth and metastasis, and (d) CO2 can stimulate the same pathways as exercise and thereby, acts as a critical mediator in the biological response of skeletal muscle to tissue hypoxia.

Modeling carbon export mediated by biofouled microplastics in the Mediterranean Sea

AbstractMarine microplastics can be colonized by biofouling microbial organisms, leading to a decrease in microplastics' buoyancy. The sinking of biofouled microplastics could therefore represent a novel carbon export pathway within the ocean carbon cycle. Here, we model how microplastics are biofouled by diatoms, their consequent vertical motion due to buoyancy changes, and the interactions between particle‐attached diatoms and carbon pools within the water column. We initialize our Lagrangian framework with biogeochemical data from NEMO‐MEDUSA‐2.0 and estimate the amount of organic carbon exported below 100 m depth starting from different surface concentrations of 1‐mm microplastics. We focus on the Mediterranean Sea that is characterized by some of the world's highest microplastics concentrations and is a hotspot for biogeochemical changes induced by rising atmospheric carbon dioxide levels. Our results show that the carbon export caused by sinking biofouled microplastics is proportional to the concentration of microplastics in the sea surface layer, at least at modeled concentrations. We estimate that, while current concentrations of microplastics can modify the natural biological carbon export by &lt; 1%, future concentrations projected under business‐as‐usual pollution scenarios may lead to carbon exports up to 5% larger than the baseline (1998–2012) by 2050. Areas characterized by high primary productivity, that is, the Western and Central Mediterranean, are those where microplastics‐mediated carbon export results to be the highest. While highlighting the potential and quantitatively limited occurrence of this phenomenon in the Mediterranean Sea, our results call for further investigation of a microplastics‐related carbon export pathway in the global ocean.

The effect of gas composition on the color Doppler ultrasound twinkling artifact

The twinkling artifact, or twinkling, appears when imaging kidney stones and other mineralizations with Doppler ultrasound and is caused by scattering off crevice microbubbles. Previous work found that twinkling on in vivo kidney stones increased or decreased with elevated oxygen or carbon dioxide, respectively. However, it is unclear whether these results are from biological adaptions to the changing respiratory gas and thus if in vitro mineralizations are similarly affected. Here, cholesterol, calcium phosphate, and uric acid crystals were grown in vitro and imaged in deionized water using a Vantage-128 research ultrasound system with a Philips/ATL L7-4 transducer. Five of each crystal composition were imaged for one minute at different dissolved gas concentrations. By bubbling gas through water, dissolved oxygen ranged from 2 to 20 mg/L while dissolved carbon dioxide ranged from 30 to 290 mg/L. Twinkling on cholesterol crystals increased by 70% and 140% when oxygen and carbon dioxide levels were maximized, respectively. In contrast, twinkling on calcium phosphate and uric acid was not significantly affected by either gas. These results suggest that changes in twinkling from increased gas concentrations are dependent on crystal composition and are likely affected by biological adaptations in vivo. [Work supported by NSF-CAREER-1943937 and NSF-GRFP-DGE1255832.]