Dissolved CO2 Research Articles

Radiocarbon Analyses Quantify Peat Carbon Losses With Increasing Temperature in a Whole Ecosystem Warming Experiment

AbstractClimate warming is expected to accelerate peatland degradation and release rates of carbon dioxide (CO2) and methane (CH4). Spruce and Peatlands Responses Under Changing Environments is an ecosystem‐scale climate manipulation experiment, designed to examine peatland ecosystem response to climate forcings. We examined whether heating up to +9 °C to 3 m‐deep in a peat bog over a 7‐year period led to higher C turnover and CO2 and CH4 emissions, by measuring 14C of solid peat, dissolved organic carbon (DOC), CH4, and dissolved CO2 (DIC). DOC, a major substrate for heterotrophic respiration, increased significantly with warming. There was no 7‐year trend in the DI14 C of the ambient plots which remained similar to their DO14 C. At +6.75 °C and +9 °C, the 14C of DIC, a product of microbial respiration, initially resembled ambient plots but became more depleted over 7 years of warming. We attributed the shifts in DI14 C to the increasing importance of solid phase peat as a substrate for microbial respiration and quantified this shift via the radiocarbon mass balance. The mass‐balance model revealed increases in peat‐supported respiration of the catotelm depths in heated plots over time and relative to ambient enclosures, from a baseline of 20%–25% in ambient enclosures, to 35%–40% in the heated plots. We find that warming stimulates microorganisms to respire ancient peat C, deposited under prior climate (cooler) conditions. This apparent destabilization of the large peat C reservoir has implications for peatland‐climate feedbacks especially if the balance of the peatland is tipped from net C sink to C source.

P1120QUANTIFICATION OF ACID-BASE TRANSPORT IN HEMODIALYZERS

Abstract Background and Aims Quantification of bicarbonate and dissolved carbon dioxide (CO2) transport in hemodialyzers can be described by the product of a dialysance (D) and their respective concentration differences between dialysate and plasma. It is typically assumed that D values are constant for a given hemodialyzer and flow conditions; however, this approach neglects the chemical interconversion of bicarbonate and dissolved CO2 within blood. We assessed the validity of this approach by developing a comprehensive mathematical model of acid-base transport in hemodialyzers. Method Mass balance relationships in a hemodialyzer were defined using a one-dimensional model with counter-current flows of blood and dialysate. The molecular biochemistry of bicarbonate, dissolved CO2, and non-bicarbonate buffer in both plasma and erythrocytes, together with carbaminohemoglobins within erythrocytes, was assumed to be in equilibrium as described by Rees and Andreassen (Crit Rev Biomed Eng 2005). The model equations were solved numerically, and optimal mass transfer-area coefficients for bicarbonate and dissolved CO2 were determined by comparing model predictions with the data from Sombolos et al (Artif Organs 2005). The latter data included measured concentrations of bicarbonate and dissolved CO2 in plasma and dialysate inlet and outlet flows at a blood flow rate of 300 mL/min, dialysate flow rate of 700 mL/min, and dialysate bicarbonate concentration of 32.5 mEq/L. Base excess of blood was assumed as -5 mEq/L. Model simulations then evaluated the effect of the plasma bicarbonate concentration at the blood inlet (assuming constant mass transfer-area coefficients and flow rates) on D for both bicarbonate (Dbic) and dissolved CO2 (DCO2). D values were calculated as the loss of the molecule from the dialysate divided by the difference in inlet concentrations of dialysate and plasma. Results Optimal mass transfer-area coefficients for bicarbonate and dissolved CO2 were 396 and 1360 mL/min, respectively. Simulation results at different plasma bicarbonate concentrations at the blood inlet ([Bicarbonate]) as expected during a typical hemodialysis treatment are tabulated: Conclusion Quantification of acid-base transport in hemodialyzers requires dialysance values for bicarbonate and dissolved CO2 that are not constant but instead are dependent on the plasma bicarbonate concentration at the blood inlet for a given hemodialyzer at fixed blood and dialysate flow rates.

Appropriate Location and Deployment Method for Successful Iron Fertilization

“High nutrient, low chlorophyll (HNLC)” regions were created by locking iron into sedimentary iron sulfides with hydrogen sulfide available from volcanic eruptions in surrounding oceans. Appropriate locations and deployment methods for the iron fertilization were far from volcanoes, earthquakes and boundaries of tectonic plates to reduce the chance of iron-locking by volcanic sulfur compounds. The appropriate locations for the large-scale iron fertilization are proposed as Shag Rocks in South Georgia and the Bransfield Strait in Drake Passage in the Southern Ocean due to their high momentum flux causing efficient iron deployment. The iron (Fe) replete compounds, consisting of natural clay, volcanic ash, agar, N2-fixing mucilaginous cyanobacteria, carbon black, biodegradable plastic foamed polylactic acid, fine wood chip, and iron-reducing marine bacterium, are deployed in the ocean to stay within a surface depth of 100 m for phytoplankton digestion. The deployment method of Fe-replete composite with a duration of at least several years for the successful iron fertilization, is configured to be on the streamline of the Antarctic Circumpolar Current (ACC). This will result in high momentum flux for its efficient dispersion on the ocean surface where diatom, copepods, krill and humpback whale stay together (~100 m). Humpback whales are proposed as a biomarker for the successful iron fertilization in large-scale since humpback whales feed on krill, which in turn feed on cockpods and diatoms. The successful large-scale iron fertilization may be indicated by the return of the humpback whales if they could not be found for a long period before the iron fertilization. On-line monitoring for the successful iron fertilization focuses on the simultaneous changes of the following two groups; the increase concentration group (chlorophyll, O2, Dissolved Oxygen (DO), Di Methyl Sulfide (DMS)) and the decrease concentration group (nitrate, phosphate, silicate, CO2, Dissolved CO2 (DCO2)). The monitoring of chlorophyll-a, nitrate phosphate, and silicate concentrations after deploying the Fe-replete complex is carried out throughout the day and night for the accurate measurement of algal blooms.

Dynamics of Dissolved Inorganic Carbon and CO2 Fluxes between the Water and the Atmosphere in the Main Channel of the Ob River

Dynamics of Dissolved Inorganic Carbon and CO2 Fluxes between the Water and the Atmosphere in the Main Channel of the Ob River

Diurnal Variations of Concentration of Porewater Dissolved CH4 and CO2 in a Brackish Marsh Dominated by Cyperus malaccensis and Phragmites australis During Neap and Spring Tidal Days in the Minjiang River Estuary

Understanding of diurnal variation of soil porewater dissolved CO2 and CH4 concentration plays an important role in revealing carbon cycling in estuarine wetlands.During neap and spring tidal days in April and September 2010,the diurnal variations of soil porewater dissolved CO2 and CH4 concentrations and main impacting factors in a brackish marsh ecosystem dominated by two species of Cyperus malaccensis(brevifolius) and Phragmites australis(common reed) were determined in the ShanYutan in the Min River estuary,southeast China.The results showed that:① the soil porewater dissolved CH4 concentration during the spring and neap tidal days in April and September ranged from 88.20 to 190.74,53.42 to 141.24,16.27 to 81.89 and 44.90 to 88.53 μmol·L-1,respectively.The mean of dissolved CH4 concentration was higher at nighttime than at daytime during the spring and neap tidal days in April,but the mean of dissolved CH4 concentration was higher at daytime than at nighttime during the spring and neap tidal tidal days in September.② the soil porewater dissolved CO2 concentration during the spring and neap tidal days in September ranged from 19.33 to 40.1 μmol·L-1 and 9.69 to 29.96 μmol·L-1,respectively,and the dissolved CO2 concentration during daytime was lower than that at night;③ the mean of dissolved CO2 concentration was lower during the inundation period than in the exposed soil surface period,but the mean of dissolved CH4 concentration was higher during the inundation period than in the exposed soil surface period.

Anabaena sp. mediated bio-oxidation of arsenite to arsenate in synthetic arsenic (III) solution: Process optimization by response surface methodology

Blue green algae Anabaena sp. was cultivated in synthetic arsenite solution to investigate its bio-oxidation potential for arsenic species. Response surface methodology (RSM) was employed based on a 3-level full factorial design considering four factors, viz. initial arsenic (III) concentration, algal dose, temperature and time. Bio-oxidation (%) of arsenic (III) was considered as response for the design. The study revealed that about 100% conversion of As (III) to As (V) was obtained for initial As (III) concentration of 2.5–7.5mg/L at 30°C for 72h of exposure using 3g/L of algal dose signifying a unique bio-oxidation potential of Anabaena sp. The dissolved CO2 (DCO2) and oxygen (DO) concentration in solution was monitored during the process and based on the data, a probable mechanism was proposed wherein algal cell acts like a catalytic membrane surface and expedites the bio-oxidation process. Bioaccumulation of arsenic, as well as, surface adsorption on algal cell was found considerably low.Lipid content of algal biomass grown in arsenite solution was found slightly lower than that of algae grown in synthetic media. Toxicity effects on algal cells due to arsenic exposure were evaluated in terms of comet assay and chlorophyll a content which indicated DNA damage to some extent along with very little decrease in chlorophyll a content. In summary, the present study explored the potential application of Anabaena sp. as an ecofriendly and sustainable option for detoxification of arsenic contaminated natural water with value-added product generation.

Modeling geochemical factors controlling fluoride concentration in groundwater

The fluoride in groundwater can affect human health. The concentration of fluoride ions in groundwater is influenced by geogenic processes and is limited by the solubility of fluoride-containing minerals, especially fluorite. In this work, we summarize and assess fluorite solubility and the Pitzer interaction model parameters of related species, by which a quantitative model for calculation of the phases and chemical speciation in the Na–Ca–H–F–Cl–SO4–OH–HCO3–CO3–CO2–H2O aqueous system for temperatures 0–100 °C, and a pressure of 1 bar was established. Based on this model, we evaluate factors that govern the levels of fluoride, e.g. temperature, solution composition, pH, CO2 partial pressure, and concentration of carbonate minerals in the aquifer. The fluorite solubility increases with temperature and varies in different aqueous solutions. The fluoride concentration is highest in NaHCO3 type aqueous solutions. In acidic solution, HF is the dominant species, and free fluoride becomes dominant with increasing pH. Dissolved CO2 in solution slightly increases the concentration of fluoride in non-bicarbonate aqueous solution and non-calcite-bearing aquifer systems. In contrast, it has a significant negative effect in calcite and bicarbonate-bearing aquifer systems, where it greatly decreases the fluoride concentration. In calcite-bearing aquifer systems, the fluoride concentration is lower than in non-calcite mineral aquifer systems.

CO2-DISSOLVED: a Novel Concept Coupling Geological Storage of Dissolved CO2 and Geothermal Heat Recovery – Part 3: Design of the MIRAGES-2 Experimental Device Dedicated to the Study of the Geochemical Water-Rock Interactions Triggered by CO2 Laden Brine Injection.

The CO2-DISSOLVED project aims at assessing the feasibility of the coupling between dissolved CO2 storage in aquifer and geothermal heat recovery. The MIRAGES-2 experimental setup has been designed to study, at the centimeter scale and under relevant conditions of pressure and temperature, the chemical interactions in the near-injection well area between the reservoir rock, the cement phases, and the corrosive CO2-rich solution. This original experimental setup allows performing flow-through experiments with continuous in-situ data acquisition of pressure, temperature, flow rate, pH, and dissolved CO2 concentration. The datasets acquired will be further interpreted with the help of geochemical models, in order to better understand the effects of the key physical-chemical processes involved.

CO2-DISSOLVED: a Novel Concept Coupling Geological Storage of Dissolved CO2 and Geothermal Heat Recovery – Part 1: Assessment of the Integration of an Innovative Low-cost, Water- based CO2 Capture Technology

Abstract The CO 2 -DISSOLVED project evaluates the feasibility of coupling capture and storage in saline aquifer of dissolved CO 2 , and geothermal heat recovery. The proposed system basically relies on the integration of a patented water-based in-well CO 2 capture facility (Pi-CO 2 ) in a classical low-enthalpy geothermal doublet. The results of this preliminary engineering design study demonstrated that (1) the use of composite materials for the wells casings would be compatible with the injection of the corrosive CO 2 -rich brine; (2) the housing of the Pi-CO 2 system in a separate large diameter well associated with a dedicated CO 2 injection line integrated in the doublet injection well is the best option for efficient CO 2 capture and dissolution in brine.

CO2-DISSOLVED: a Novel Concept Coupling Geological Storage of Dissolved CO2 and Geothermal Heat Recovery – Part 2: Assessment of the Potential Industrial Applicability in France, Germany, and the U.S.A

Abstract The CO 2 -DISSOLVED project aims at assessing the technical-economic feasibility of coupling dissolved CO 2 storage in a saline aquifer and geothermal heat recovery. It targets specifically low-medium tonnage CO 2 emitters (ca. 10-150 kt/yr) because the amount of dissolved CO 2 that can be injected into a geothermal saline aquifer is physically limited by the solubility of CO 2 in brine. This work makes an inventory of the potential candidates to the CO 2 -DISSOLVED concept in France, Germany, and the U.S.A. The results evidenced that relatively large geothermal areas match the presence of many industrial sources emitting low rates of CO 2 , allowing us to conclude on the potential applicability of the concept in these three countries.

CO2-DISSOLVED: a Novel Concept Coupling Geological Storage of Dissolved CO2 and Geothermal Heat Recovery – Part 4: Preliminary Thermo-Hydrodynamic Simulations to Assess the CO2 Storage Efficiency

The CO2-DISSOLVED project aims at assessing the technical-economic feasibility of coupling CO2 storage in a saline aquifer and geothermal heat recovery. The proposed infrastructure basically relies on a standard geothermal doublet where CO2 would be injected after having been entirely dissolved in the cooled brine. The objective of this preliminary thermo-hydrodynamic modeling study was to quantify the expected CO2 storage lifetime and efficiency. The results first confirmed that CO2 will inevitably be produced in the extracted brine after 2-15 years of continuous injection, depending on the operating parameters. However, mass balance calculations evidenced that after a 30 year injection period, 37-85% of the total CO2 injected should remain stored in the aquifer.

Underwater sinkhole sediments sequester Lake Huron’s carbon

Lake Huron’s submerged sinkhole habitats are impacted by high-conductivity groundwater that allows photosynthetic cyanobacterial mats to form over thick, carbon-rich sediments. To better understand nutrient cycling in these habitats, we measured the stable isotopic content of carbon and nitrogen in organic and inorganic carbon pools in Middle Island sinkhole, a ~23 m deep feature influenced by both groundwater and overlying lake water. Two distinct sources of dissolved CO2 (DIC) were available to primary producers. Lake water DIC (δ 13C = −0.1 ‰) differed by +5.9 ‰ from groundwater DIC (δ 13C = −6.0 ‰). Organic carbon fixed by primary producers reflected the two DIC sources. Phytoplankton utilizing lake water DIC were more enriched in 13C (δ 13C = −22.2 to −23.2 ‰) than mat cyanobacteria utilizing groundwater DIC (δ 13C = −26.3 to −30.0 ‰). Sinkhole sediments displayed an isotopic signature (δ 13C = −23.1 ‰) more similar to sedimenting phytoplankton than the cyanobacterial mat. Corroborated by sediment C/N ratios, these data suggest that the carbon deposited in sinkhole sediments originates primarily from planktonic rather than benthic sources. 210Pb/137Cs radiodating suggests rapid sediment accumulation and sub-bottom imaging indicated a massive deposit of organic carbon beneath the sediment surface. We conclude that submerged sinkholes may therefore act as nutrient sinks within the larger lake ecosystem.

Numerical prediction of the dilution process and its biological impacts in CO 2 ocean sequestration

In order to investigate the biological impacts of the ocean sequestration of CO2 (carbon dioxide), the dilution processes of CO2 were investigated near injection points in the deep ocean. From a combined fluid-dynamics, chemical, and biological approach, a two-phase computational fluid dynamics (CFD) method with mass transfer was developed to predict droplet plume flow, the dissolution of CO2 from droplets into seawater, and the advection–diffusion of dissolved CO2 (DCO2) in the deep ocean. Changes in pH due to the concentration of DCO2 were also calculated. In addition, the isomortality concept of Auerbach et al. was incorporated to predict the lethal damage to marine organisms caused by DCO2. The simulation results suggested that the biological impacts of CO2 sequestration were insignificant in terms of mortality in both small-scale field experiments and the real-life cases we propose.

Continuous, On-Line Stream Analyzer for Dissolved CO2 in Beer

(1968). Continuous, On-Line Stream Analyzer for Dissolved CO2 in Beer. Proceedings. Annual meeting - American Society of Brewing Chemists: Vol. 26, Proceedings of the Annual Meeting 1968, pp. 120-124.