Increase In HCO3 Research Articles

Tomato yield and soil chemical properties influenced by low–molecular–weight organic acids in calcareous soil

<p>Calcareous soils have restrictive characteristics that limit and pose a challenge for crop production; in this environment, plants can exude low-molecular-weight organic acids (LMWOAs). This study aimed to verify the influence of exogenously applied LMWOAs in calcareous soils on tomato yield and the chemical characteristics of soil and leachate. <em>Solanum lycopersicum</em> L. seedlings were grown in pots containing calcareous soil in a greenhouse, fertilized by drip irrigation with Steiner nutrient solution in which the treatments 0.1 mM citric acid (CA), 0.1 mM oxalic acid (OA), 0.01 mM salicylic acid (SA) and a control without LMWOAs (T0) were prepared, applied during the whole growth cycle. The experiment was repeated four times, with twenty replicates per treatment, under a completely randomized design. The yield per plant was quantified, while pH and microbial respiration (RMS) were measured in the soil. The pH, electrical conductivity (EC), oxidation-reduction potential (ORP), carbonate (CO<sub>3</sub><sup>2–</sup>), and bicarbonate (HCO<sub>3</sub><sup>–</sup>) contents were quantified in the leachates. SA application reduced the soil pH (8.75). SA and CA improved the fruit yield per plant by 11% and 33%, respectively (p < 0.05). CA induced a 1.7% reduction in leachate pH (p < 0.05) and a 15.9% increase in HCO<sub>3</sub><sup>–</sup> content (p < 0.05). SA decreased EC and CO<sub>3</sub><sup>2–</sup> concentrations by 8.9 and 23.1% (p < 0.05), but increased HCO<sub>3</sub><sup>–</sup> content by 23.1 % (p < 0.05). The use of LMWOAs as a strategy in the management of calcareous soils can promote favorable conditions for tomato yield per plant.</p>

Thermodynamic Stability and Dissolution of Calcium Fluoride of Phosphogypsum Solidified in Cement-Based Cementing Materials in Bicarbonate Solution

Cement-based cementitious materials present an alkaline environment and mainly exist in the form of Ca(OH)2. Phosphogypsum, as a retarder of cementitious materials, is often added to cement instead of gypsum, and the fluorine by-product of phosphogypsum is also fixed in the form of CaF2. These cement-based materials often serve in environments containing carbonate groundwater, which changes the stability of solidified CaF2. This paper studied the solid and liquid changes in Ca(OH)2-CaF2, Ca(OH)2-CaF2-HCO3, CaF2-HCO3-OH systems, and therefore studied the solubility of the by-product CaF2 of phosphogypsum in the groundwater containing HCO3- anion after curing in the cement-based cementitious system through experiments and thermodynamic equation simulation. The results showed that the dissolved Ca2+ of Ca(OH)2 led to the dissolution of CaF2, which led to a significant reduction in the F- anion concentration. However, with the increase of HCO3- concentration in groundwater, the F- anion concentration of Ca(OH)2-CaF2-HCO3 system increased, and the main product formed in the solid phase was calcium carbonate; The dissolution of F- anions in CaF2-HCO3-OH system also increased with the increase of HCO3- concentration. Therefore, the influence of HCO3- in groundwater should be considered when using phosphogypsum instead of gypsum as a retarder in cement-based cementitious materials.

ВЛИЯНИЕ ГЕМОСОРБЦИИ С ЭКCТРАКОРПОРАЛЬНОЙ АУТОГЕМОМАГНИТОТЕРАПИЕЙ В СРАВНЕНИИ С МЕДИКАМЕНТОЗНОЙ ТЕРАПИЕЙ АНТАГОНИСТАМИ РЕЦЕПТОРОВ ИЛ-6 НА КЛИНИКО-ЛАБОРАТОРНЫЕ ПАРАМЕТРЫ ПАЦИЕНТОВ С ТЯЖЕЛЫМ ТЕЧЕНИЕМ COVID-19

Background: SARS-CoV-2 infection in 10-20% of cases is characterized by hypercytokinemia, and in this context, the use of interleukin-6 (IL-6) receptor blockers, in particular tocilizumab and levilimab, is pathogenetically justified, but anticytokine hemosorption is also used in such cases. It is impossible to determine which method is preferable in patients with severe COVID-19 due to the lack of large comparative studies of medical and extracorporeal anticytokine therapies. Purpose: To evaluate the effect of hemosorption through the Нemo-Рroteasosorb hemorosorbent in combination with extracorporeal autohemomagnetic therapy and medical therapy with IL-6 receptor antagonists on the respiratory status, hemostasis, acid-base state of the blood, the detoxification function of the liver and kidneys in patients with severe COVID-19 infection. Material and methods: The clinical and laboratory findings of 102 patients with a severe course of coronavirus infection, who developed cytokine storm, were evaluated. All patients were divided into three groups: hemosorption with magnetic blood treatment («HS+MBT») (41 patients), Tocilizumab group (40 patients) and Levilimab group (20 patients). The following indicators were studied: erythrocyte count and platelet count; hemoglobin level; concentration of total protein, creatinine, urea, total bilirubin, aspartate aminotransferase (AST), alanine aminotransferase (ALT), fibrinogen, D-dimers; acid-base state and blood gas composition. To assess the respiratory status, the respiratory index (RI), ROX index, total oxygen flow, and dynamics of the level of respiratory support were evaluated. To assess hemodynamics, mean arterial pressure and heart rate were determined, the body temperature of the patients was also measured. Results: The results obtained demonstrate that with the combined use of MBT and hemosorption through the Hemo-Proteasosorb sorbent in patients with severe COVID-19, there were no significant fluctuations in hemodynamic parameters, levels of urea, creatinine, total bilirubin, AST and ALT. At the same time, the use of tocilizumab was associated with an increase in the levels of urea, total bilirubin and ALT. In the Levilimab group there was an increase in the concentration of urea. The use of HS+MBT was associated with a decrease in the level of fibrinogen, which was noted on the next day, as well as a tendency to a decrease in D-dimers. At the same time, during the treatment with IL-6 receptor blockers, a significant decrease in the level of fibrinogen was noted only on days 6-8. The number of thromboembolic complications was also lower in the patients with extracorporeal detoxification. With HS+MBT, an increase in the respiratory status indicators (RI, ROX-index, decrease in total oxygen flow) was observed already on the next day, while in the Tocilizumab and Levilimab groups, an increase in these indicators was noted only on days 6-8. A decrease in the ROX index and the absence of dynamics in the total oxygen flow were found on the next day in both groups. In the HS+MBT group, the obtained results indicated that the given technique both prevents more significantly the transition to the next level of respiratory support and contributes to its decrease as compared to IL-6 receptor blockers. Analysis of the acid-base state of the blood following HS + MBT showed a decrease in the level of lactate and an increase in HCO3, as well as deficiency/excess of bases, which indicated compensation for metabolic acidosis. Similar results with the use of IL-6 receptor blockers were obtained only on the 6th-8th day of the study, but no normalization of the lactate concentration in the blood of patients was found at any stage. Conclusion: The use of HS+MBT has a number of advantages over the treatment with IL-6 receptor blockers, which is manifested by the absence of cardio, hepato- and nephrotoxicity, as well as more significant positive effect on hemostasis, respiratory status and acid-base status of patients.

Solute transport through undisturbed carbonatic clay soils in dry regions under differing water quality and irrigation patterns

The often-indispensable use of poor-quality irrigation water in drylands instigates diverse physicochemical dynamics leading to soil salinization and sodicity which are recognized as major contributors to land degradation. This study aimed to examine the effects of water quality and irrigation mode on solute transport conditions in terms of ion exchange of colloidal particles. Laboratory studies with undisturbed soil columns were carried out with two water treatments - tap and sodic waters - as well as two water flow velocities: fast leaching which corresponds to Darcy velocity equal to the saturated hydraulic conductivity and slow leaching equal to half the fast-leaching case. Results indicated that the flow velocities did not significantly influence pH, EC and ion concentrations due to the high calcium carbonate and clay contents of the soil which make the soil less permeable. However, flow velocity rapidly decreased in the fast leaching compared to that in slow leaching as the sodic water was applied. This reveals the destructive effect of Na+ in the soil. The EC rapidly dropped at the beginning of leaching for both water qualities opposite to pH, then became steady. All sodic applications caused an increase in Na+ till the end of treatments. This also resulted in variations in measured soluble anions. In general, sharp decreases in highly soluble anions were observed in all treatments, leading to an increase in HCO3–, especially for sodic treatments. Overall, sodicity caused significant changes in flow dynamics and ion concentrations and created favorable conditions for secondary salinization in this low permeable soil system.

Analysis of Correlations between Selected Blood Markers of Acid-Base Balance, Blood Electrolytes, and Milk Components in Dairy Cows during Late Lactation

The aim of the study was to assess the values of and correlations between selected markers of acid-base balance and electrolytes in the blood of late lactation cows, such as pH, pCO2, pO2, HCO3 –, BE, BE(B), Na+, K+, Cl–, as well as selected parameters of milk, such as the number of somatic cells (SCC), colony forming units (CFU), milk fat (MF), milk protein (MP), milk lactose (ML), milk solids, milk solids non-fat (SNF), and current milk production. Blood and milk samples were collected at the same time from 11 clinically healthy milking cows in the later lactation period. Those 11 selected cows were examined once a day for 3 consecutive days resulting in 33 sets of blood and milk samples used for laboratory and statistical analyses. Significant positive correlations were observed between pH and HCO3 –, pH and BE, pH and BE(B), pCO2 and HCO3 –, pCO2 and BE, pCO2 and BE(B), HCO3 – and BE, HCO3 – and BE(B), BE and BE(B), Na+ and Cl–, Na+ and milk production, Cl– and milk production, and Cl– and MP. Significant negative correlations were observed between pH and K+, pH and Cl–, pCO2 and Cl–, HCO3 – and Cl–, BE and Cl–, and BE(B) and Cl–. The increase in blood pH was significantly negatively correlated with the current milk production, while the increase in HCO3 – or pCO2 was associated with a significant decrease in the amount of protein in milk. These relations can indicate a significant negative influence of blood acid-base imbalance on the quantity and quality of cow’s milk. The repeatable diagnostic model presented here proved to be a very useful tool for a detailed assessment of selected higly sensitive parameters of internal homeostasis in productive dairy cows.

Hydrogeochemical processes regulating the enrichment and migration of As and B from the river sediments in the Singe Tsangpo River Bain, Western Tibetan plateau

Although the enrichment of arsenic (As) and boron (B) has been extensively observed in the major river basin within the Tibetan Plateau, little is known about the hydrogeochemical processes regulating the enrichment and mobility of As and B within river sediments. The present study conducted geochemical investigations of river sediments along the river flow path of the Singe Tsangpo River (STR) basin, and examined the mobility of As and B within river sediments under various environmental conditions through incubation experiments. The results suggested that the weathering of Cs-bearing silicate minerals could be a potential origin for As in the river sediments, which was evidenced by the corresponding variations between Cs and As (R = 0.60, P < 0.01). In contrast, carbonate weathering has contributed to the B enrichment, supported by the correlation between CaO and B concentrations (R = 0.60, P < 0.01). The incubation experiments showed intense mobilizations of As and B (∼12 mg/kg) under varying environmental conditions, where the increases in HCO3− concentration and temperature could enhance both As and B mobilization. Additionally, the As mobilization was enhanced by the anaerobic and alkaline conditions. These scenarios are relevant to the hydrogeochemical processes that regulate the As and B enrichment in both river water and groundwater from the STR basin, including the redox fluctuations that resulted from flood and draught cycling and the variations in the water/sediment particle ratios. The present study thus provided new insights into the hydrogeochemical control on the enrichment and mobility of As and B in the river sediments from the STR basin, which is also applicable in other riverine systems under similar conditions.

Isotope and chemical studies of groundwater in the Kurobe River alluvial fan, Toyama, Japan, for the efficient utilization of groundwater heat

The source of groundwater and its flow pattern were investigated by analyzing hydrogen and oxygen isotope ratios and chemical compositions for efficient heat utilization of groundwater in the Kurobe River alluvial fan area in eastern Toyama Prefecture for indoor heating and cooling and greenhouse cultivation. Forty-five groundwater and five river water samples were taken in July 2012, and additional samples were also taken in August and September 2013 to analyze annual changes in the water's chemical composition. The isotope composition analyses revealed that the contribution of river water was large near the Kurobe River, but precipitation was also mixed in. The contribution of river water decreases from the Kurobe River to the central part of the alluvium fan, and the contribution of precipitation increases. The dissolved chemical constituents in the groundwater did not change significantly over time. The electric conductivity (EC) of the groundwater tended to increase with distance from the Kurobe River, which was attributed to the increase in HCO3− and Ca2+ concentrations. When groundwater is used as a heat source in a geothermal heat pump system, it is necessary to investigate the behavior of its precipitates (scales), which can reduce the heat exchange rate. The saturation indices of common scale components—calcite/aragonite (CaCO3) and iron (FeOOH, Fe(OH)3) compounds—were calculated based on the chemical composition of the groundwater. All groundwater was undersaturated for CaCO3, and FeOOH and Fe(OH)3 precipitated in all regions except for some areas; however, the amount of precipitation was not expected to be significant due to the low iron concentration.

Co-Deposition Mechanisms of Calcium Sulfate and Calcium Carbonate Scale in Produced Water

Co-precipitation of mineral-based salts during scaling remains poorly understood and thermodynamically undefined within the water industry. This study focuses on investigating calcium carbonate and calcium sulfate mixed precipitation in scaling. Scaling is often observed in the produced water supply as a result of treatment processes. Co-precipitation results were compared with experimental results of a single salt crystallization. Several parameters were carefully monitored, including the electrical conductivity, pH value, crystal morphology and crystal form. The existence of the calcium carbonate scale in the mixed system encourages the loose calcium sulfate scale to become more tightly packed. The mixed scale was firmly adhered to the beaker, and the adhesion of the co-deposition product was located between the pure calcium sulfate scale and the pure calcium carbonate scale. The crystalline form of calcium sulfate was gypsum in both pure material deposition and mixed deposition, while the calcium carbonate scale was stable in calcite form in the pure material deposition. In the co-deposition, apart from calcite form, some calcium carbonate scale crystals had metastable vaterite form. This indicated that the presence of SO42− ions reduced the energy barrier of the calcium carbonate scale and hindered its transformation from a vaterite form to a calcite one, and the increase in HCO3− content inhibited the formation of calcium sulfate scale.

CHANGES IN HYDROGEN INDEX AND BLOOD ELECTROLYTES DURING RECOVERY PERIOD AFTER BLOOD LOSS WITH FOLLOWING ADMINISTRATION OF MAGNETITE NANOPARTICLES

Magnetite nanoparticles are one of the extensively investigated and implemented into medical practice. They are known as having significant therapeutic potential in providing rapid recovery of hematological parameters after acute blood loss. Since the pathogenesis of acute blood loss, except of anaemia, includes other components (hypoxia, hypovolemia, acidosis), it is important to know how magnetite nanoparticles affect the parameters of these processes.&#x0D; The aim of this study was to investigate the effect of magnetite nanoparticles on changes in hydrogen index (pH) and blood electrolytes induced by acute blood loss. Materials and methods. The experiment was performed on 47 white male rats. Blood loss (25% of circulating blood) was simulated by puncture of the heart under the ether anesthesia. The nanoparticles’ solution (5-8 nm) was administered intraperitoneally immediately after the blood loss in a dose of 6.75 mg Fe/kg in a volume of at least 1 ml. In 3, 24 and 72 hours, and in 5 day interval, the blood pH and content of HCO3–, Na+, K+ and Ca2+ were checked. The data obtained were processed using one-way variance analysis ANOVA (Statistica for Windows 8.0). Results and discussion. It is shown that magnetite nanoparticles elevated the pH level in 3 hours, reduced in 24 hours and did not affect it in 72 hours and 5 days as compared to the control pathology. The administration of magnetite nanoparticles after 3 hours, 24 hours and 5 days resulted in increase in Na+ content compared to that in blood loss. An increase in the content of K+ took place after 24 hours as compared to the control pathology. Magnetite nanoparticles contributed to the normalization of Ca2+ after 72 hours. The content of HCO3– in all terms of observations ranged within normal limits, except for that in blood loss with magnetite nanoparticles introduced after 24 hours caused the increase of HCO3–in 1.2 times compared to the control pathology. Conclusion. Magnetite nanoparticles, administered to manage the acute blood loss syndrome, are able to modify the acid-base balance and electrolyte content in the blood for 5 days of recovery period that largely depends on the ability of non-iron to accelerate erythropoiesis and thus to restrain other components in the pathogenesis.

The influence mechanism of HCO3− on fluoride removal by different types of aluminum salts

In order to study the influence mechanism of HCO3− on the fluoride removal by AlCl3 and Al13, the residual fluoride concentration, residual aluminum concentration and pH value in coagulation effluent were measured at different HCO3− concentrations. Electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS) was used to analyze the aluminum species in the supernatant after coagulation, and the flocs collected were analyzed by nuclear magnetic resonance (NMR) and X-ray photoelectron spectra (XPS). The results show that AlCl3 is used as a coagulant, when the concentration of HCO3− increases from 100 mg/L to 300 mg/L, Al3+ and HCO3− are double hydrolyzed to form Al(OH)3 alum flower after adding AlCl3, and the removal rate of fluoride rapidly increases from 9.55 % to 78.0 %. When the concentration of HCO3− increases from 300 mg/L to 1000 mg/L, the precipitation of Al(OH)3 will gradually dissolve to form Al(OH)4− and the removal rate of fluoride drops from 78.0 % to 56.2 %. When Al13 is used as a coagulant, with the increase of HCO3− from 100 mg/L to 1000 mg/L, its double hydrolysis with Al-F complexes is enhanced, resulting in the formed Al6F2, Al7F2 and Al9F3 gradually dissociate, and the removal rate of fluorine decreases from 78.8 % to 59.4 %.

Study on Hydrochemical Ion Characteristics in the Upper Reach of Tao River

In this paper, the water in the upper reach of the Tao River was selected as the research object, the chemical characteristics of water environment in the upper reach of Tao River were studied and the water quality was evaluated based on the comparative analysis of the data of two monitoring stations for one year. The results show that the contents of HCO3-, SO4 2- and Ca2+are high in the upper reach of the Tao River, and the water quality belongs to alkaline medium salinity water, and the salinity increases with the increase of HCO3 -.

Study on the Chemical Characteristics of the Water Environment in the Middle and Lower Reaches of the Tao River

In this paper, the water in the middle and lower reaches of the Tao River was selected as the research object, the chemical characteristics of water environment in the middle and lower reaches of Tao River were studied and the water quality was evaluated based on the comparative analysis of the data of three monitoring stations for one year. The results show that the contents of HCO3−, SO42− and Ca2+are high in the middle and lower reaches of Tao River, and the water quality belongs to alkaline medium salinity water, and the salinity increases with the increase of HCO3−. The pH value, total hardness, salinity and main ion content in the middle and lower reaches of the river reach the requirements of the GB5749-2006 Sanitary Standard for Drinking Water or the Class III water quality standard of the surface water environment of GB3838-2002, and which proves the water quality is good.

Carbon capture induced changes in Deccan basalt: a mass‐balance approach

AbstractPrevious studies on the Deccan basalt–water–CO2 interaction were focused on numerical simulations and experimental validation that revealed carbonate formation, but restricted to low temperatures and for a shorter period. However, during prolonged interactions, silicates restricted carbonates from forming, and thus necessitated for comparative mass‐balance calculations of parent basalt, neo‐formed mineral and dissolution products to understand apposite parameters that control the reaction extent and optimal geochemical conditions. To examine these interactions, mass‐balance calculations have been attempted. A gradual increase in HCO3− concentration and basalt dissolution is concomitant with the increase in experimental run time; thus, the pH of the solution is affected. X‐ray diffraction and scanning electron microscope–energy dispersive X‐ray spectrometer analyses revealed the presence of carbonates in the post‐experiment residue (run for a shorter period). Owing to gradual carbonate decrease in the residue, Ca2+, Fe2+ and Mg2+ released from basalt gradually increased in the leachate at 100°C. But with the progression of time at 200°C, more secondary silicates were formed and incorporated Mg2+ and Si4+, which led to a decrease in Mg2+ and Si4+ concentrations in the leachate. Mass‐balance calculations revealed that the maximum amount of CO2 is mineralized (22.88 mol%) from the ions derived from the parent basalt at 100°C under 5 bar CO2 and 70 h of experiment running time. But, for longer periods of experiments, the rate of ionic interactions as well as CO2 mineralization is almost ceased. Thus, the rate of dissolution is affected by temperature, but the amount of CO2 mineralization is directly a function of the basalt–water–CO2 interaction time. © 2019 Society of Chemical Industry and John Wiley &amp; Sons, Ltd.

Sensitivity to near-future CO2 conditions in marine crabs depends on their compensatory capacities for salinity change

Marine crabs inhabit shallow coastal/estuarine habitats particularly sensitive to climate change, and yet we know very little about the diversity of their responses to environmental change. We report the effects of a rarely studied, but increasingly prevalent, combination of environmental factors, that of near-future pCO2 (~1000 µatm) and a physiologically relevant 20% reduction in salinity. We focused on two crab species with differing abilities to cope with natural salinity change, and revealed via physiological and molecular studies that salinity had an overriding effect on ion exchange in the osmoregulating shore crab, Carcinus maenas. This species was unaffected by elevated CO2, and was able to hyper-osmoregulate and maintain haemolymph pH homeostasis for at least one year. By contrast, the commercially important edible crab, Cancer pagurus, an osmoconformer, had limited ion-transporting capacities, which were unresponsive to dilute seawater. Elevated CO2 disrupted haemolymph pH homeostasis, but there was some respite in dilute seawater due to a salinity-induced metabolic alkalosis (increase in HCO3− at constant pCO2). Ultimately, Cancer pagurus was poorly equipped to compensate for change, and exposures were limited to 9 months. Failure to understand the full spectrum of species-related vulnerabilities could lead to erroneous predictions of the impacts of a changing marine climate.

Imaging the water snowline in a protostellar envelope with H13CO+

Context. Snowlines are key ingredients for planet formation. Providing observational constraints on the locations of the major snowlines is therefore crucial for fully connecting planet compositions to their formation mechanism. Unfortunately, the most important snowline, that of water, is very difficult to observe directly in protoplanetary disks because of the close proximity of this snowline to the central star. Aims. Based on chemical considerations, HCO+ is predicted to be a good chemical tracer of the water snowline because it is particularly abundant in dense clouds when water is frozen out. This work aims to map the optically thin isotopolog H13CO+ toward the envelope of the low-mass protostar NGC 1333-IRAS2A, where the snowline is at a greater distance from the star than in disks. Comparison with previous observations of H218O show whether H13CO+ is indeed a good tracer of the water snowline. Methods. NGC 1333-IRAS2A was observed using the NOrthern Extended Millimeter Array (NOEMA) at ~0.′′9 resolution, targeting the H13CO+ J = 3 − 2 transition at 260.255 GHz. The integrated emission profile was analyzed using 1D radiative transfer modeling of a spherical envelope with a parametrized abundance profile for H13CO+. This profile was validated with a full chemical model. Results. The H13CO+ emission peaks ~ 2′′ northeast of the continuum peak, whereas H218O shows compact emission on source. Quantitative modeling shows that a decrease in H13CO+ abundance by at least a factor of six is needed in the inner ~360 AU to reproduce the observed emission profile. Chemical modeling indeed predicts a steep increase in HCO+ just outside the water snowline; the 50% decrease in gaseous H2O at the snowline is not enough to allow HCO+ to be abundant. This places the water snowline at 225 AU, further away from the star than expected based on the 1D envelope temperature structure for NGC 1333-IRAS2A. In contrast, DCO+ observations show that the CO snowline is at the expected location, making an outburst scenario unlikely. Conclusions. The spatial anticorrelation of H13CO+ and H218O emission provide proof of concept that H13CO+ can be used as a tracer of the water snowline.

Inorganic carbon and pH dependency of photosynthetic rates in Trichodesmium.

Increasing atmospheric CO2 concentrations are leading to increases in dissolved CO2 and HCO3- concentrations and decreases in pH and CO32- in the world's oceans. There remain many uncertainties as to the magnitude of biological responses of key organisms to these chemical changes. In this study, we established the relationship between photosynthetic carbon fixation rates and pH, CO2, and HCO3- concentrations in the diazotroph, Trichodesmium erythraeum IMS101. Inorganic 14C-assimilation was measured in TRIS-buffered artificial seawater medium where the absolute and relative concentrations of CO2, pH, and HCO3- were manipulated. First, we varied the total dissolved inorganic carbon concentration (TIC) (<0 to ~5 mM) at constant pH, so that ratios of CO2 and HCO3- remained relatively constant. Second, we varied pH (~8.54 to 7.52) at constant TIC, so that CO2 increased whilst HCO3- declined. We found that 14C-assimilation could be described by the same function of CO2 for both approaches, but it showed different dependencies on HCO3- when pH was varied at constant TIC than when TIC was varied at constant pH. A numerical model of the carbon-concentrating mechanism (CCM) of Trichodesmium showed that carboxylation rates are modulated by HCO3- and pH. The decrease in assimilation of inorganic carbon (Ci) at low CO2, when TIC was varied, was due to HCO3- uptake limitation of the carboxylation rate. Conversely, when pH was varied, Ci assimilation declined due to a high-pH mediated increase in HCO3- and CO2 leakage rates, potentially coupled to other processes (uncharacterised within the CCM model) that restrict Ci assimilation rates under high-pH conditions.

Evaluation of Different Oral Rehydration Solutions for Diarrheic Dairy Calves

Regardless of the causative agent, diarrhea results in large loss of water and electrolytes, which leads to reduced performance and mortality. The aim of this study was to evaluate oral rehydration solutions in order to determine the most effective in restoring electrolytes and water while maintaining animal performance. Forty two calves (14 per treatment) were distributed in one of three treatments (1) Common electrolytes solution (dextrose, sodium bicarbonate and sodium chloride; 507±2 mOsm), (2) Glutellac® (sodium acetate, glucose and sodium and potassium chloride; 665±1 mOsm); and (3) Common electrolytes solution + Aminogut® (glutamate and glutamine; 575±2 mOsm). Treatments were administered when fecal score ≥3, in a scale of 1 to 5. During diarrhea daily water intake was registered and blood sample was taken for metabolites, electrolytes and gases determination. Animals did not differ in days in diarrhea, fecal score or hematocrit. Calves receiving Glutellac® presented higher voluntary water intake. There was no effect of treatment for animal performance and starter feed intake. Concentrations of Na+ and HCO3 tended to be higher for animals rehydrated with Glutellac®. While there was an increase in HCO3 from the first to the second day, K+ and glucose decreased. The increased voluntary water intake in animals rehydrated with Glutellac®, which shows greater simplicity of use, are the main advantages of this solution.

Utility of arterial blood gas, CBC, biochemistry and cardiac hormones as evaluation parameters of cardiovascular disease in nonhuman primates.

Cardiovascular disease (CVD) has a tremendous impact on the quality of life of humans. While experimental animals are valuable to medical research as models of human diseases, cardiac systems differ widely across various animal species. Thus, we examined a CVD model in cynomolgus monkeys. Laboratory primates are precious resources, making it imperative that symptoms of diseases and disorders are detected as early as possible. Thus, in this study we comprehensively examined important indicators of CVD in cynomolgus monkeys, including arterial blood gas, complete blood count (CBC), biochemistry and cardiac hormones. The control group included 20 healthy macaques showing non-abnormal findings in screening tests, whereas the CVD group included 20 macaques with valvular disease and cardiomyopathy. An increase of red blood cell distribution width was observed in the CBC, indicating chronic inflammation related to CVD. An increase of HCO3 was attributed to the correction of acidosis. Furthermore, development of the CVD model was supported by significant increases in natriuretic peptides. It is suggested that these results indicated a correlation between human CVD and the model in monkeys. Moreover, blood tests including arterial blood gas are non-invasive and can be performed more easily than other technical tests. CVD affected animals easily change their condition by anesthesia and surgical invasion. Pay attention to arterial blood gas and proper respond to their condition are important for research. This data may facilitate human research and aid in the management and veterinary care of nonhuman primates.

Variations to calcareous nannofossil CaCO3 content during the middle Eocene C21r-H6 hyperthermal event (~ 47.4 Ma) in the Gorrondatxe section (Bay of Biscay, western Pyrenees)

The carbonate content of calcareous nannofossils is dependent on seawater composition. One of the factors that affect seawater chemistry and consequently the degree of calcification in coccolithophores is temperature, as seen in present day warming oceans. The depth at which carbonates are dissolved (Calcite Compensation depth, CCD) can rise due to an increase in HCO3– and decrease in pH, leading to a major dissolution on the seabed and burndown. Similar processes have also been deduced for Eocene hyperthermal events, such as the PETM and ETM2. This study reports changes in coccolith carbonate mass from a hemipelagic setting (Gorrondatxe, at 1500m paleodepth) during the core of a minor Eocene hyperthermal event, namely the C21r-H6 event (47.44–47.32Ma). Image analysis techniques were used to determine differences in the carbonate mass of selected calcareous nannofossil taxa, revealing species-specific patterns. The CaCO3 mass of Chiasmolithus solitus decreased by 50% over the course of the C21r-H6 event, and many specimens also lost their crossed central bars, an additional indication of mass loss; Reticulofenestra sp. (3–5μm) showed a similar trend, but the percentage of mass lost was lower; Toweius pertusus, interpreted as being reworked, mirrored the behaviour of Chiasmolithus solitus, suggesting that the CaCO3 mass loss may have occurred on the seabed, rather than in the water column. In general, it can be concluded that the lysocline rose to 1500m paleobathymetry in the Bay of Biscay during the C21r-H6 event. Formation of corrosive bottom water in the North Atlantic Ocean is regarded as being responsible for the rise in the lysocline.

Seasonal variations in the vertical structure of pelagian water stratum in the Southern Baikal

For the first time, T,S-analysis was used to determine the specifics of seasonal variations in the vertical structure of Lake Baikal active layer. In the under-ice period, the active layer includes the under-ice, top winter, and upper intermediate water masses. The under-ice water mass, unlike other masses, shows an increase in mineralization to 100.74 mg/kg, which corresponds to a release of 71.1 g salt under 1 m2 of water surface in a layer 0–40 m in the process of salt freezing out during ice cover formation and accretion. In the phases of mixing (homothermy), the water masses of the active layer transform into a surface homogeneous mass. In summer and autumn, surface and upper intermediate water masses, separated by a water mass of summer thermocline can be identified. A specific feature of the summer thermocline water mass is the increased sum of ions because of an increase in HCO 3 - concentration at the decay of organic matter accumulating in the bottom part of the thermocline. The existence of the under-ice water mass and the water mass of summer thermocline was established in Lake Baikal for the first time. In the deep-water zone (>250 m), except for the bottom parts, the lower water masses (the lower intermediate and the deep) are permanent, their characteristics remaining stable during the year. The changes in the bottom water mass are due to the character of the processes of bottom water renewal.