The present lab-scale research reveals the enrichment of anaerobic ammonium oxidation microorganism from methanogenic anaerobic granular sludge and the effect of inorganic carbon(sodium bicarbonate)on anaerobic ammoni...The present lab-scale research reveals the enrichment of anaerobic ammonium oxidation microorganism from methanogenic anaerobic granular sludge and the effect of inorganic carbon(sodium bicarbonate)on anaerobic ammonium oxidation.The enrichment of anammox bacteria was carried out in a 7.0-L sequencing batch reactor(SBR)and the effect of bicarbonate on anammox was conducted in a 3.0-L SBR.Research results,especially the biomass,showed first signs of anammox activity after 54 d cultivation with synthetic w...展开更多
To assess the effects of river damming on dissolved inorganic carbon in the Jialing River, a total of 40 water samples, including inflow, outflow, and stratified water in four cascade reservoirs(Tingzikou, Xinzheng,Do...To assess the effects of river damming on dissolved inorganic carbon in the Jialing River, a total of 40 water samples, including inflow, outflow, and stratified water in four cascade reservoirs(Tingzikou, Xinzheng,Dongxiguan, Caojie) were collected in January and July,2016. The major cations, anions, and δ^(13)C_(DIC) values were analyzed. It was found that the dissolved compositions are dominated by carbonate weathering, while sulfuric acids may play a relatively important role during carbonate weathering and increasing DIC concentration. Different reservoirs had variable characteristics of water physiochemical stratification. The DIC concentrations of reservoir water were lower in summer than those in winter due to the dilute effects and intensive aquatic photosynthesis, as well as imported tributaries. The δ^(13)C_(DIC) values in Tingzikou Reservoir were higher during summer than those in winter,which indicated that intensive photosynthesis increased the δ^(13)C_(DIC) values in residual water, but a similar trend was not obvious in other reservoirs. Except for in Xinzheng Reservoir, the δ^(13)C_(DIC) values in inflow and outflow reservoir water were lower than those in the surface water of stratified sampling in summer. For stratified sampling, it could be found that, in summer, the Tingzikou Reservoir δ^(13)C_(DIC) values significantly decreased with water depthdue to the anaerobic breakdown of organic matter. The significant correlation(p<0.01 or 0.05) between the DIC concentrations, the δ^(13)C_(DIC) values and anthropogenic species(Na^++K^+, Cl~–, SO_4^(2-) and NO_3^-) showed that the isotope composition of DIC can be a useful tracer of contaminants. In total, Tingzikou Reservoir showed lacustrine features, Xinzheng Reservoir and Dongxiguan Reservoir had "transitional'' features, and Caojie Reservoir had a total of "fluvial'' features. Generally, cascade reservoirs in the Jialing River exhibited natural river features rather than typical lake features due to characteristics of reservoir water in physiochemical stratification, spatiotemporal variations of DIC concentrations and isotopic compositions. It is evident that the dissolved inorganic carbon dynamics of natural rivers had been partly remolded by dam building.展开更多
Organic and inorganic carbon contents of marine sediments are important to reconstruct marine productivity,global carbon cycle, and climate change. A proper method to separate and determine organic and inorganic carbo...Organic and inorganic carbon contents of marine sediments are important to reconstruct marine productivity,global carbon cycle, and climate change. A proper method to separate and determine organic and inorganic carbons is thus of great necessity. Although the best method is still disputable, the acid leaching method is widely used in many laboratories because of its ease-of-use and high accuracy. The results of the elemental analysis of sediment trap samples reveal that organic and inorganic carbon contents cannot be obtained using the acid leaching method, causing an infinitely amplified error when the carbon content of the decarbonated sample is 12%±1% according to a mathematical derivation. Acid fumigation and gasometric methods are used for comparison, which indicates that other methods can avoid this problem in organic carbon analysis. For the first time, this study uncovers the pitfalls of the acid leaching method, which limits the implication in practical laboratory measurement, and recommends alternative solutions of organic/inorganic carbon determination in marine sediments.展开更多
Based on long-term dynamic tracing of dissolved inorganic carbon(DIC)and stable carbon isotope(δ13CDIC)in produced water from 20 coalbed methane(CBM)wells in western Guizhou,the spatial-temporal dynamic variations of...Based on long-term dynamic tracing of dissolved inorganic carbon(DIC)and stable carbon isotope(δ13CDIC)in produced water from 20 coalbed methane(CBM)wells in western Guizhou,the spatial-temporal dynamic variations ofδ13CDIC of the GP well group produced in multi-layer commingled manner were analyzed,and the relationship between the value ofδ13CDIC and CBM productivity was examined.The produced water samples of typical wells in the GP well group were amplified and sequenced using 16S rDNA,and a geological response model ofδ13CDIC in produced water from CBM wells with multi-coal seams was put forward.The research shows that:δ13CDIC in produced water from medium-rank coal seams commonly show positive anomalies,the produced water contains more than 15 species of methanogens,and Methanobacterium is the dominant genus.The dominant methanogens sequence numbers in the produced water are positively correlated withδ13CDIC,and the positive anomaly of v is caused by reduction of methanogens,and especially hydrogenotrophic methanogens.Vertical segmentation of sedimentary facies and lithology in stratum with multi-coal seams will result in permeability and water cut segmentation,which will lead to the segmentation ofδ13CDIC and archaea community in produced water,so in the strata with better permeability and high water cut,theδ13CDIC of the produced water is abnormally enriched,and the dominant archaea is mainly Methanobacterium.In the strata with weak permeability and low water cut,theδ13CDIC of the produced water is small,and the microbial action is weak.The shallow layer close to the coal seam outcrop is likely to be affected by meteoric precipitation,so theδ13CDIC of the produced water is smaller.The geological response model ofδ13CDIC in produced water from multi-coal seams CBM wells in the medium-rank coal reveals the geological mechanism and microbial action mechanism of theδ13CDIC difference in the produced water from the multi-coal seams CBM wells.It also provides effective geochemical evidence for the superimposed fluid system controlled by sedimentary facies,and can also be used for the contribution analysis of the produced gas and water by the multi-layer CBM wells.展开更多
To explore variation of dissolved inorganic carbon content( DIC) caused by cyanobacterial blooms and provide a basis for formulating effective preventive and control measures of cyanobacterial blooms,the concentration...To explore variation of dissolved inorganic carbon content( DIC) caused by cyanobacterial blooms and provide a basis for formulating effective preventive and control measures of cyanobacterial blooms,the concentration of inorganic carbon and the concentration of planktonic algae were studied by sampling method,and the distribution and variation of the DIC and physicochemical factors in the ecological restoration area of Fubao Bay of Dianchi Lake were analyzed. Results indicated that the distribution of chlorophyll-a was significantly positive correlated with CO_3^(2-)( P < 0. 01) and pH values( P < 0. 05); and the distribution of chlorophyll-a was significantly negative correlated with CO_2( P <0. 01),DIC and HCO_3^-( P < 0. 05). In conclusion,the outbreak and extinction of cyanobacterial blooms is one of the important reasons for the variation of inorganic carbon form and concentration.展开更多
The amount of bicarbonate utilised by plants is usually ignored because of limited measurement methods.Accordingly, this study quantified the photosynthetic assimilation of inorganic carbon(CO_2and HCO_3^-) by plants....The amount of bicarbonate utilised by plants is usually ignored because of limited measurement methods.Accordingly, this study quantified the photosynthetic assimilation of inorganic carbon(CO_2and HCO_3^-) by plants. The net photosynthetic CO_2assimilation(PN), the photosynthetic assimilation of CO_2 and bicarbonate(PN'),the proportion of increased leaf area(fLA) and the stable carbon isotope composition(δ^(13)C) of Orychophragmus violaceus(Ov) and Brassica juncea(Bj)under three bicarbonate levels(5, 10 and 15 mm NaHCO_3)were examined to determine the relationship among PN,PN' and fLA. PN', not PN,changed synchronously with fLA.Moreover, the proportions of exogenous bicarbonate and total bicarbonate(including exogenous bicarbonate and dissolved CO_2-generated bicarbonate) utilised by Ov were 2.27 % and 5.28 % at 5 mm bicarbonate, 7.06 % and13.28 % at 10 mm bicarbonate, and 8.55 % and 17.31 % at15 mm bicarbonate, respectively. Meanwhile, the proportions of exogenous bicarbonate and total bicarbonate utilised by Bj were 1.77 % and 3.28 % at 5 mm bicarbonate,2.11 % and 3.10 % at 10 mm bicarbonate, and 2.36 % and3.09 % at 15 mm bicarbonate, respectively. Therefore, the dissolved CO_2-generated bicarbonate and exogenous bicarbonate are important sources of inorganic carbon for plants.展开更多
This paper reports a Lower Triassic inorganic carbon isotope profile from the North Pingdingshan Section in Chaohu, Anhui Province, China, which was situated in a deep part of the Lower Yangtze carbonate ramp. The δ ...This paper reports a Lower Triassic inorganic carbon isotope profile from the North Pingdingshan Section in Chaohu, Anhui Province, China, which was situated in a deep part of the Lower Yangtze carbonate ramp. The δ ( 13 C) excursion shows two periods from the Permian Triassic boundary to the lower Spathian substage, corresponding to the ecosystem undergoing evolution and recovery after the end Permian mass extinction and related events. The first period starts at the δ ( 13 C) depletion caused by the mass extinction and evolves with a gradual δ ( 13 C) increase resulting from the development of some disaster taxa during the Induan. The strong Smithian δ ( 13 C) depletion in the second period might be formed by the collapse of the disaster ecosystem and the biotic recovery occurred with the explosive increase of bioproductivity in the Spathian. Thus the δ ( 13 C) excursion in the Lower Triassic expresses patterns of biotic evolution and recovery during the erratic ecosystem that followed the great end Permian mass extinction.展开更多
The photochemical mineralization of dissolved organic carbon(DOC) to dissolved inorganic carbon(DIC) is a key process in carbon cycling.Using a Suntest CPS solar simulator,Suwannee River humic acid(SRHA) was photooxid...The photochemical mineralization of dissolved organic carbon(DOC) to dissolved inorganic carbon(DIC) is a key process in carbon cycling.Using a Suntest CPS solar simulator,Suwannee River humic acid(SRHA) was photooxidated to examine the effects of O2 levels,the wavelength of incident light,and the concentration of Fe on the photoproduction of DIC.Increasing the O2 abundance enhanced photodegradation of SRHA.The rate of DIC photoproduction under air saturation in the first 24 h(4.40 μmol/(L h)) was increased by a factor of 1.56 under O2 saturation,but fell by only 36% under N2 saturation.To evaluate the relative importance of UV-B,UV-A,and visible radiation in the photodegradation,we examined the above process using Mylar-d films and UF-3 and UF-4 plexiglass filters.The results indicated that the UV-B,UV-A and visible wavelengths accounted for 31.8%,32.6% and 25.6%,respectively,of DIC production with simulated sunlight irradiation.The above results also indicated that photoproduction of DIC could take place in natural water at depths greater than those that UV light can reach.When 20 μmol/L desferrioxamine mesylate(DFOM,a strong Fe complexing ligand) was added,the rate of DIC photoproduction fell to 55.6% that of the original SRHA samples with 5.46 μmol/L Fe.展开更多
The eutrophication,hypoxia and coastal acidification are attracting more and more attention.In this study,inorganic carbon parameters,including dissolved inorganic carbon (DIC) ,total alkalinity (TA) and calculated pa...The eutrophication,hypoxia and coastal acidification are attracting more and more attention.In this study,inorganic carbon parameters,including dissolved inorganic carbon (DIC) ,total alkalinity (TA) and calculated partial pressure of CO2 (pCO2) ,obtained from a summer cruise in August,2009,were used to investigate their integrated response to biological processes accompanying the oxygen depletion in the areas off the Changjiang Estuary.According to the observations,the typical hypoxia occurred in the bottom water just outside the Changjiang Estuary with Dissolved Oxygen (DO) lower than 2.00 mg L 1.The biological uptake in the surface water and the decomposition of organic matter in the bottom water were fully coupled with each other.The high concentration of Chl_a (Chl_a=10.9μg L 1) and DO (9.25 mg L 1) ,profoundly decreased DIC concentration (1828μmol kg 1) and elevated pH (8.42) was observed in the surface water.The correspondingly increased DIC and depletion of oxygen were observed in the bottom water.The semi-quantitative analysis proved that the locally-produced phytoplankton,determined by primary productivity,was deposited to the bottom and contributed about 76%of total amount of the organic carbon decomposition in the bottom.However,in the bottom hypoxia (DO=2.05 mg L 1) area observed in the Southern Zhejiang coastal water,the responding patterns of inorganic carbon parameters deviated from the previous one.The expanding of Changjiang Diluted Water (CDW) ,the adding of Hangzhou Bay water (with high DIC concentration) and Coastal Current together modify the DIC background value in this area,and the local degeneration and upwelling process may also help to offset the local DIC removed by net biological uptake in surface water.In addition,when the mixing occurring in autumn,which may break the summer stratification,the excess release of high DIC in the bottom water to the subsurface water could have an important influence on coastal acidification and the CO2uptake capacity in this area.展开更多
The isotopic composition of dissolved inorganic carbon (DIC) in marine and estuarine environments has been studied in some detail because of its role in determining the isotopic composition of inorganic/organic matter...The isotopic composition of dissolved inorganic carbon (DIC) in marine and estuarine environments has been studied in some detail because of its role in determining the isotopic composition of inorganic/organic matter and its applications to the study of various natural processes. The δ13CDIC values of sea water are controlled by the sources and sinks of carbon and the results from isotope fractionation among solid, dissolved and gaseous phases. In this paper, based on the description of the stable isotope geochemical characteristics of dissolved inorganic carbon in northern South China Sea, the following conclusions were drawn: 1) the δ13CDIC values of natural waters are controlled by the sources and sinks of carbon and the results from isotope fractionation among solid, dissolved and gaseous phases. And the low seawater δ13CDIC values of northern South China Sea are accompanied by a low level of sea primary productivity in this region; 2) according to the parameter relationship (δ13CDIC-1.1 PO4) between δ13CDIC and PO4, it is indicated that northern South China Sea is the source of atmospheric CO2; and 3) nitrogen (N) and phosphorus (P) are the elements which are the basis for phytoplankton growth. Based on the analysis of seawater δ13CDIC values and PO4 and NO3+NO2 concentrations, our data show that N is a limiting nutrient in northern South China Sea.展开更多
The isotopic composition of dissolved inorganic carbon(DIC) in estuarine environments has been studied for its significant role in determining the isotopic composition of inorganic/organic matter and its applications ...The isotopic composition of dissolved inorganic carbon(DIC) in estuarine environments has been studied for its significant role in determining the isotopic composition of inorganic/organic matter and its applications to the study of various natural processes. In this paper, based on the stable isotope geochemical characteristics of dissolved inorganic carbon in the Jiulong River Estuary, the following conclusions are drawn:(1) δ13CDIC values are mainly controlled by the mixing ratio of fresh water and sea water;(2) δ13Cphytoplankton values are linearly related to the δ13CDIC values;(3) δ13CPOM values for the Jiulong River Estuary are affected by anthropogenic pollution significantly; and(4) the comprehensive analysis of δ13Cphytoplankton, δ13CPOM and δ13CDIC shows that along with increasing salinity, the proportion of POM derived from the degradation of phytoplanktons gradually increases.展开更多
Data on the distribution of dissolved inorganic carbon (DIC) were obtained from two cruises in the North Yellow Sea (NYS) and off the Qingdao Coast (QC) in October, 2007. Carbonate parameters were calculated. The conc...Data on the distribution of dissolved inorganic carbon (DIC) were obtained from two cruises in the North Yellow Sea (NYS) and off the Qingdao Coast (QC) in October, 2007. Carbonate parameters were calculated. The concentrations of DIC are from 1.896-2.229 mmolL-1 in the NYS and from 1.939-2.032 mmolL-1 off the QC. In the southwest of the NYS, DIC in the upper layers decreases from the north of the SP (Shandong Peninsula) shelf to the center of the NYS; whereas in the lower layers DIC increases from the north of the SP shelf to the center of the NYS and South Yellow Sea. In the northeast of the NYS, DIC in all layers in- creases from the YR (Yalu River) estuary to the centre of the NYS. The distribution of DIC in NYS can be used as an indicator of Yellow Sea Cold Water Mass (YSCWM). Air-sea CO2 fluxes were calculated using three models and the results suggest that both the NYS and the QC waters are potential sources of atmospheric CO2 in October.展开更多
Major elements and carbon isotopes of dissolved inorganic carbon(DIC)have been measured in the waters of Changbaishan mountain,a volcanic area in northeastern China,between June and September 2016 to decipher the orig...Major elements and carbon isotopes of dissolved inorganic carbon(DIC)have been measured in the waters of Changbaishan mountain,a volcanic area in northeastern China,between June and September 2016 to decipher the origin of the CO_2 involved in chemical weathering reactions.Spatial variations of major elements ratios measured in water samples can be explained by a change of the chemical composition of the volcanic rocks between the volcanic cone(trachytes)and the basaltic shield as evidenced by the variations in the composition of these rocks.Hence,DIC results from the neutralization of CO_2 by silicate rocks.DIC concentrations vary from 0.3 to 2.5 mmol/L and carbon isotopic compositions of DIC measured in rivers vary from-14.2‰to 3.5‰.At a first order,the DIC transported by rivers is derived from the chemical weathering’s consumption of CO_2 with a magmatic origin,enriched in^(13)C(-5%)and biogenic soil CO_2 with lower isotopic compositions.The highest δ^(13)C values likely result from C isotopes fractionation during CO_2 degassing in rivers.A mass balance based on carbon isotopes suggest that the contribution of magmatic CO_2 varied from less than 20%to more than 70%.Uncertainties in this calculation associated with CO_2 degassing in rivers are difficult to quantify,and the consequence of CO_2 degassing would be an overestimation of the contribution of DIC derived from the neutralization of magmatic CO_2 by silicate rocks.展开更多
Iron in seawater is an essential trace metal for phytoplankton that plays an important role in the marine carbon cycle. But most studies focused on oceanic iron fertilization in high nutrient low chlorophyll (HNLC) se...Iron in seawater is an essential trace metal for phytoplankton that plays an important role in the marine carbon cycle. But most studies focused on oceanic iron fertilization in high nutrient low chlorophyll (HNLC) seawaters. A study of inorganic carbon (IC) forms and its influencing factors was presented in Liaodong Gulf sediments, and especially the influence of iron was discussed in detail. Inorganic carbon in Liaodong Gulf sediments was divided into five forms: NaCl, NH_ 3·H_ 2O, NaOH, NH_ 2OH·HCl and HCl. The concentration of NaCl and NaOH forms were similar and they only occupied the minority of total inorganic carbon (TIC). However, NH_ 3·H_ 2O, NH_ 2OH·HCl and HCl forms were the principal forms of TIC and accounted for more than 80% of TIC. Especially, the percentage of NH_ 3·H_ 2O form was much higher than that in the Changjiang River Estuary and Jiaozhou Bay sediments. All forms of inorganic carbon were influenced by organic carbon,pore water, iron, pH, redox potential(Eh) and sulfur potential(Es) in sediments, moreover, the influences had different characteristics for different IC forms. However, the redox reactions of iron affected mainly active IC forms. Iron had little effect on NH_ 2OH·HCl and HCl forms of IC which were influenced mainly by pH. Iron had a stronger influence on NaCl, NaOH and NH_ 3·H_ 2O forms of IC; the influence of Fe 2+ was higher than Fe 3+ and its effect on NH_ 3·H_ 2O form was stronger than on NaCl and NaOH forms.展开更多
Inorganic carbon forms and their influencing factors,mutual transformation and contribution to carbon cycling in the Jiaozhou Bay sediments were discussed.The results show that inorganic carbon in sediments could be d...Inorganic carbon forms and their influencing factors,mutual transformation and contribution to carbon cycling in the Jiaozhou Bay sediments were discussed.The results show that inorganic carbon in sediments could be divided into five forms:NaCl form,NH3·H2O form,NaOH form,NH2OH·HCl form and HCl form.Thereinto,NH2OH·HCl form and HCl form account for more than 70% of total inorganic carbon.There was close relationship among every form of inorganic carbon and their correlativity was clearly different with different sedimentary environment except the similar strong positive correlation among NH2OH·HCl form,HCl form and total inorganic carbon in all regions of the Jiaozhou Bay.All forms of inorganic carbon were influenced by organic carbon,pH,Eh,Es,nitrogen and phosphorus in sediments,but their influence had different characteristics in different regions.Every form of inorganic carbon transformed into each other continuously during early diagenesis of sediments and the common phenomenon was that NaCl form,NH3·H2O form,NaOH form and NH2OH·HCl form might transform into steady HCl form.NaCl form,NH3·H2O form,NaOH form and NH2OH·HCl form could participate in carbon recycle and they are potential carbon source;HCl form may be buried for a long time in sediments,and it may be one of the final resting places of atmospheric CO2.Inorganic carbon which entered into sediments was about 4.98×1010 g in the Jiaozhou Bay every year,in which about 1.47×1010 g of inorganic carbon might be buried for a long time and about 3.51×1010 g of inorganic carbon might return into seawater and take part in carbon recycling.展开更多
Soil acidification is a major global issue of sustainable development for ecosystems. The increasing soil acidity induced by excessive nitrogen(N) fertilization in farmlands has profoundly impacted the soil carbon dyn...Soil acidification is a major global issue of sustainable development for ecosystems. The increasing soil acidity induced by excessive nitrogen(N) fertilization in farmlands has profoundly impacted the soil carbon dynamics. However, the way in which changes in soil p H regulating the soil carbon dynamics in a deep soil profile is still not well elucidated. In this study, through a 12-year field N fertilization experiment with three N fertilizer treatments(0, 120, and 240 kg N/(hm^2·a)) in a dryland agroecosystem of China, we explored the soil p H changes over a soil profile up to a depth of 200 cm and determined the responses of soil organic carbon(SOC) and soil inorganic carbon(SIC) to the changed soil p H. Using a generalized additive model, we identified the soil depth intervals with the most powerful statistical relationships between changes in soil p H and soil carbon dynamics. Hierarchical responses of SOC and SIC dynamics to soil acidification were found. The results indicate that the changes in soil p H explained the SOC dynamics well by using a non-linear relationship at the soil depth of 0–80 cm(P=0.006), whereas the changes in soil p H were significantly linearly correlated with SIC dynamics at the 100–180 cm soil depth(P=0.015). After a long-term N fertilization in the experimental field, the soil p H value decreased in all three N fertilizer treatments. Furthermore, the declines in soil p H in the deep soil layer(100–200 cm) were significantly greater(P=0.035) than those in the upper soil layer(0–80 cm). These results indicate that soil acidification in the upper soil layer can transfer excess protons to the deep soil layer, and subsequently, the structural heterogeneous responses of SOC and SIC to soil acidification were identified because of different buffer capacities for the SOC and SIC. To better estimate the effects of soil acidification on soil carbon dynamics, we suggest that future investigations for soil acidification should be extended to a deeper soil depth, e.g., 200 cm.展开更多
Inorganic carbon utilization in the non calcifying marine microalgae, Nannochloropsis oculata, Phaeodactylum tricornutum and Porphyridium purpureum was compared with high and low calcifying strains of Emiliania huxley...Inorganic carbon utilization in the non calcifying marine microalgae, Nannochloropsis oculata, Phaeodactylum tricornutum and Porphyridium purpureum was compared with high and low calcifying strains of Emiliania huxleyi grown in artificial seawater medium aerated with either air (0.03% V/V CO 2) or CO 2 free air. For high calcifying strain of E. oculata and P. tricornutem , similar growth patterns were observed in air and CO 2 free air grown cultures. P. purpureum showed a less final cell density in CO 2 free air than in air grown culture. However, low calcifying strain of E. huxleyi was able to grow only in air grown culture, but not in CO 2 free air grown culture. Measurements of alkalinity, pH, concentration of dissolved inorganic carbon (DIC) and free CO 2 showed different patterns of DIC utilization. With N. oculata, P. tricornutum and P. purpureum the pattern of DIC utilization was characterized by an increase of pH and a decrease of DIC but a constant alkalinity in the cultures aerated with air or CO 2 free air, suggesting that bicarbonate utilization was concomitant with an efflux of OH -. Both alkalinity and pH were maintained rather constant in air grown culture of low calcifying strain of E. huxleyi, suggesting that diffusive entry of CO 2 could meet the requirement of DIC for its photosynthesis and growth. High calcifying strain of E.huxleyi , however, showed a pattern of decrease of alkalinity and DIC but an almost constant pH , indicating that bicarbonate was the major form of inorganic carbon utilised by this organism and bicarbonate uptake is unlikely to be accompanied by an efflux of OH -. The final pH values reached by N. oculata, P. tricornutum and P. purpureum in a closed system were 10.75, 10.60 and 9.85 respectively, showing that bicarbonate utilisation is concomitant with an efflux of OH . While the final pH of 8.4 in high calcifying E. huxleyi suggests that bicarbonate utilization was not accompanied by an efflux of OH -.展开更多
The influence of macronitrogen (NO - 3 and NH + 4 ) addition with Ulva pertusa on dissolved inorganic carbon system in seawater was studied. The results indicate that p(CO 2 ) and HCO 3 concentration decrease signific...The influence of macronitrogen (NO - 3 and NH + 4 ) addition with Ulva pertusa on dissolved inorganic carbon system in seawater was studied. The results indicate that p(CO 2 ) and HCO 3 concentration decrease significantly, while pH and CO 2- 3 concentration increase significantly. When the concentration of NO 3 was less than 71 μmol/dm 3 or NH + 4 was less than 49.7 μmol/dm 3 , dissolved inorganic carbon (DIC) absorption rates by Ulva pertusa generally increased with the increasing of nitrogen concentration. The DIC decreased 151 μmol/dm 3 with the addition of 71 μmol/dm 3 NO 3 and decreased 232 μmol/dm 3 with the addition of 49.7 μmol/dm 3 NH + 4 after the experiment compared with DIC measured without nitrogen addition. A significant negative-correlation was found between c(DIC) and growth rate (μ) of Ulva pertusa (r = -0.91, P <0.000 1, n=11). NH + 4 had more influence on the species of inorganic carbon system than NO 3 .展开更多
The third Chinese National Arctic Research Expedition (3rd CHINARE-Arctic in 2008) was carried out from July to September 2008. During the survey, numerous sea water samples were taken for CO2 parameter measurement (i...The third Chinese National Arctic Research Expedition (3rd CHINARE-Arctic in 2008) was carried out from July to September 2008. During the survey, numerous sea water samples were taken for CO2 parameter measurement (including total alkalinity TA and total dissolved inorganic carbon DIC).The distribution of CO2 parameters in the Western Arctic Ocean was determined, and the controlling factors are addressed. The ranges of summertime TA, normalized TA (nTA), DIC and normalized DIC (nDIC) in the surface seawater were 1 757-2 229 μmol·kg 1, 2 383-2 722 μmol·kg 1, 1 681-2 034 μmol·kg 1, 2 119-2 600 μmol·kg 1, respectively. Becauseof dilution from ice meltwater, the surface TA and DIC concentrations were relatively low. TA in the upper 100m to the south of 78 N had good correlation with salinity, showing a conservative behavior. The distribution followed the seawater-river mixing line at salinity >30, then followed the seawater mixing line (diluted by river water to salinity = 30) with the ice meltwater. The DIC distribution in the Chukchi Sea was dominated by biological production or respiration of organic matter, whereas conservative mixing dominated the mixed layer TA distribution in the ice-free Canada Basin.展开更多
文摘The present lab-scale research reveals the enrichment of anaerobic ammonium oxidation microorganism from methanogenic anaerobic granular sludge and the effect of inorganic carbon(sodium bicarbonate)on anaerobic ammonium oxidation.The enrichment of anammox bacteria was carried out in a 7.0-L sequencing batch reactor(SBR)and the effect of bicarbonate on anammox was conducted in a 3.0-L SBR.Research results,especially the biomass,showed first signs of anammox activity after 54 d cultivation with synthetic w...
基金financially supported by the National Key Research and Development Program of China(2016YFA0601000)the National Natural Science Foundation of China(Grant No.41373136)
文摘To assess the effects of river damming on dissolved inorganic carbon in the Jialing River, a total of 40 water samples, including inflow, outflow, and stratified water in four cascade reservoirs(Tingzikou, Xinzheng,Dongxiguan, Caojie) were collected in January and July,2016. The major cations, anions, and δ^(13)C_(DIC) values were analyzed. It was found that the dissolved compositions are dominated by carbonate weathering, while sulfuric acids may play a relatively important role during carbonate weathering and increasing DIC concentration. Different reservoirs had variable characteristics of water physiochemical stratification. The DIC concentrations of reservoir water were lower in summer than those in winter due to the dilute effects and intensive aquatic photosynthesis, as well as imported tributaries. The δ^(13)C_(DIC) values in Tingzikou Reservoir were higher during summer than those in winter,which indicated that intensive photosynthesis increased the δ^(13)C_(DIC) values in residual water, but a similar trend was not obvious in other reservoirs. Except for in Xinzheng Reservoir, the δ^(13)C_(DIC) values in inflow and outflow reservoir water were lower than those in the surface water of stratified sampling in summer. For stratified sampling, it could be found that, in summer, the Tingzikou Reservoir δ^(13)C_(DIC) values significantly decreased with water depthdue to the anaerobic breakdown of organic matter. The significant correlation(p<0.01 or 0.05) between the DIC concentrations, the δ^(13)C_(DIC) values and anthropogenic species(Na^++K^+, Cl~–, SO_4^(2-) and NO_3^-) showed that the isotope composition of DIC can be a useful tracer of contaminants. In total, Tingzikou Reservoir showed lacustrine features, Xinzheng Reservoir and Dongxiguan Reservoir had "transitional'' features, and Caojie Reservoir had a total of "fluvial'' features. Generally, cascade reservoirs in the Jialing River exhibited natural river features rather than typical lake features due to characteristics of reservoir water in physiochemical stratification, spatiotemporal variations of DIC concentrations and isotopic compositions. It is evident that the dissolved inorganic carbon dynamics of natural rivers had been partly remolded by dam building.
基金The National Natural Science Foundation of China under contract Nos 41530964,41776047,41876048 and 91528304。
文摘Organic and inorganic carbon contents of marine sediments are important to reconstruct marine productivity,global carbon cycle, and climate change. A proper method to separate and determine organic and inorganic carbons is thus of great necessity. Although the best method is still disputable, the acid leaching method is widely used in many laboratories because of its ease-of-use and high accuracy. The results of the elemental analysis of sediment trap samples reveal that organic and inorganic carbon contents cannot be obtained using the acid leaching method, causing an infinitely amplified error when the carbon content of the decarbonated sample is 12%±1% according to a mathematical derivation. Acid fumigation and gasometric methods are used for comparison, which indicates that other methods can avoid this problem in organic carbon analysis. For the first time, this study uncovers the pitfalls of the acid leaching method, which limits the implication in practical laboratory measurement, and recommends alternative solutions of organic/inorganic carbon determination in marine sediments.
基金Supported by the National Natural Science Foundation of China(41772155)the National Science and Technology Major Project of China(2016ZX05044-002)
文摘Based on long-term dynamic tracing of dissolved inorganic carbon(DIC)and stable carbon isotope(δ13CDIC)in produced water from 20 coalbed methane(CBM)wells in western Guizhou,the spatial-temporal dynamic variations ofδ13CDIC of the GP well group produced in multi-layer commingled manner were analyzed,and the relationship between the value ofδ13CDIC and CBM productivity was examined.The produced water samples of typical wells in the GP well group were amplified and sequenced using 16S rDNA,and a geological response model ofδ13CDIC in produced water from CBM wells with multi-coal seams was put forward.The research shows that:δ13CDIC in produced water from medium-rank coal seams commonly show positive anomalies,the produced water contains more than 15 species of methanogens,and Methanobacterium is the dominant genus.The dominant methanogens sequence numbers in the produced water are positively correlated withδ13CDIC,and the positive anomaly of v is caused by reduction of methanogens,and especially hydrogenotrophic methanogens.Vertical segmentation of sedimentary facies and lithology in stratum with multi-coal seams will result in permeability and water cut segmentation,which will lead to the segmentation ofδ13CDIC and archaea community in produced water,so in the strata with better permeability and high water cut,theδ13CDIC of the produced water is abnormally enriched,and the dominant archaea is mainly Methanobacterium.In the strata with weak permeability and low water cut,theδ13CDIC of the produced water is small,and the microbial action is weak.The shallow layer close to the coal seam outcrop is likely to be affected by meteoric precipitation,so theδ13CDIC of the produced water is smaller.The geological response model ofδ13CDIC in produced water from multi-coal seams CBM wells in the medium-rank coal reveals the geological mechanism and microbial action mechanism of theδ13CDIC difference in the produced water from the multi-coal seams CBM wells.It also provides effective geochemical evidence for the superimposed fluid system controlled by sedimentary facies,and can also be used for the contribution analysis of the produced gas and water by the multi-layer CBM wells.
基金Supported by the National Major Science and Technology Program for Water Pollution Control and Treatment(2012ZX07103-003 and 2012ZX07103-004)
文摘To explore variation of dissolved inorganic carbon content( DIC) caused by cyanobacterial blooms and provide a basis for formulating effective preventive and control measures of cyanobacterial blooms,the concentration of inorganic carbon and the concentration of planktonic algae were studied by sampling method,and the distribution and variation of the DIC and physicochemical factors in the ecological restoration area of Fubao Bay of Dianchi Lake were analyzed. Results indicated that the distribution of chlorophyll-a was significantly positive correlated with CO_3^(2-)( P < 0. 01) and pH values( P < 0. 05); and the distribution of chlorophyll-a was significantly negative correlated with CO_2( P <0. 01),DIC and HCO_3^-( P < 0. 05). In conclusion,the outbreak and extinction of cyanobacterial blooms is one of the important reasons for the variation of inorganic carbon form and concentration.
基金supported by the National Key Basic Research Program of China(2013CB956701)the National Natural Science Foundation of China (No.31070365)+1 种基金the project on social development of Guizhou Province (SY[2010]3043)the State Key Laboratory of Environmental Geochemistry (SKLEG2014909)
文摘The amount of bicarbonate utilised by plants is usually ignored because of limited measurement methods.Accordingly, this study quantified the photosynthetic assimilation of inorganic carbon(CO_2and HCO_3^-) by plants. The net photosynthetic CO_2assimilation(PN), the photosynthetic assimilation of CO_2 and bicarbonate(PN'),the proportion of increased leaf area(fLA) and the stable carbon isotope composition(δ^(13)C) of Orychophragmus violaceus(Ov) and Brassica juncea(Bj)under three bicarbonate levels(5, 10 and 15 mm NaHCO_3)were examined to determine the relationship among PN,PN' and fLA. PN', not PN,changed synchronously with fLA.Moreover, the proportions of exogenous bicarbonate and total bicarbonate(including exogenous bicarbonate and dissolved CO_2-generated bicarbonate) utilised by Ov were 2.27 % and 5.28 % at 5 mm bicarbonate, 7.06 % and13.28 % at 10 mm bicarbonate, and 8.55 % and 17.31 % at15 mm bicarbonate, respectively. Meanwhile, the proportions of exogenous bicarbonate and total bicarbonate utilised by Bj were 1.77 % and 3.28 % at 5 mm bicarbonate,2.11 % and 3.10 % at 10 mm bicarbonate, and 2.36 % and3.09 % at 15 mm bicarbonate, respectively. Therefore, the dissolved CO_2-generated bicarbonate and exogenous bicarbonate are important sources of inorganic carbon for plants.
基金ThisresearchissupportedbytheChinese" 973Program" (No .G2 0 0 0 0 7770 5 ) theNationalNaturalScienceFoundationofChina (No .40 0 72 0 11) theChinaNationalCommissiononStratigraphyandtheYichangCenterofStratigraphyandPaleontology .
文摘This paper reports a Lower Triassic inorganic carbon isotope profile from the North Pingdingshan Section in Chaohu, Anhui Province, China, which was situated in a deep part of the Lower Yangtze carbonate ramp. The δ ( 13 C) excursion shows two periods from the Permian Triassic boundary to the lower Spathian substage, corresponding to the ecosystem undergoing evolution and recovery after the end Permian mass extinction and related events. The first period starts at the δ ( 13 C) depletion caused by the mass extinction and evolves with a gradual δ ( 13 C) increase resulting from the development of some disaster taxa during the Induan. The strong Smithian δ ( 13 C) depletion in the second period might be formed by the collapse of the disaster ecosystem and the biotic recovery occurred with the explosive increase of bioproductivity in the Spathian. Thus the δ ( 13 C) excursion in the Lower Triassic expresses patterns of biotic evolution and recovery during the erratic ecosystem that followed the great end Permian mass extinction.
基金Supported by the National Science and Engineering Research Committee of Canada (No213327)
文摘The photochemical mineralization of dissolved organic carbon(DOC) to dissolved inorganic carbon(DIC) is a key process in carbon cycling.Using a Suntest CPS solar simulator,Suwannee River humic acid(SRHA) was photooxidated to examine the effects of O2 levels,the wavelength of incident light,and the concentration of Fe on the photoproduction of DIC.Increasing the O2 abundance enhanced photodegradation of SRHA.The rate of DIC photoproduction under air saturation in the first 24 h(4.40 μmol/(L h)) was increased by a factor of 1.56 under O2 saturation,but fell by only 36% under N2 saturation.To evaluate the relative importance of UV-B,UV-A,and visible radiation in the photodegradation,we examined the above process using Mylar-d films and UF-3 and UF-4 plexiglass filters.The results indicated that the UV-B,UV-A and visible wavelengths accounted for 31.8%,32.6% and 25.6%,respectively,of DIC production with simulated sunlight irradiation.The above results also indicated that photoproduction of DIC could take place in natural water at depths greater than those that UV light can reach.When 20 μmol/L desferrioxamine mesylate(DFOM,a strong Fe complexing ligand) was added,the rate of DIC photoproduction fell to 55.6% that of the original SRHA samples with 5.46 μmol/L Fe.
基金supported by the National Basic Research Program of China(973 program,No.2010CB428903)Public Science and Technology Research Funds the Projects of Ocean(No.201105014)+1 种基金National Natural Science Foundation of China(No.41203085)the Fundamental Research Funds for the Second Institute of Oceanography,SOA(JT0906)
文摘The eutrophication,hypoxia and coastal acidification are attracting more and more attention.In this study,inorganic carbon parameters,including dissolved inorganic carbon (DIC) ,total alkalinity (TA) and calculated partial pressure of CO2 (pCO2) ,obtained from a summer cruise in August,2009,were used to investigate their integrated response to biological processes accompanying the oxygen depletion in the areas off the Changjiang Estuary.According to the observations,the typical hypoxia occurred in the bottom water just outside the Changjiang Estuary with Dissolved Oxygen (DO) lower than 2.00 mg L 1.The biological uptake in the surface water and the decomposition of organic matter in the bottom water were fully coupled with each other.The high concentration of Chl_a (Chl_a=10.9μg L 1) and DO (9.25 mg L 1) ,profoundly decreased DIC concentration (1828μmol kg 1) and elevated pH (8.42) was observed in the surface water.The correspondingly increased DIC and depletion of oxygen were observed in the bottom water.The semi-quantitative analysis proved that the locally-produced phytoplankton,determined by primary productivity,was deposited to the bottom and contributed about 76%of total amount of the organic carbon decomposition in the bottom.However,in the bottom hypoxia (DO=2.05 mg L 1) area observed in the Southern Zhejiang coastal water,the responding patterns of inorganic carbon parameters deviated from the previous one.The expanding of Changjiang Diluted Water (CDW) ,the adding of Hangzhou Bay water (with high DIC concentration) and Coastal Current together modify the DIC background value in this area,and the local degeneration and upwelling process may also help to offset the local DIC removed by net biological uptake in surface water.In addition,when the mixing occurring in autumn,which may break the summer stratification,the excess release of high DIC in the bottom water to the subsurface water could have an important influence on coastal acidification and the CO2uptake capacity in this area.
基金National Natural Science Foundation of China, No.40671027 No.40471120+2 种基金 Guangdong Provincial Natural Science Foundation, No.7003669 Specialized Research Fund for the Doctoral Program of Higher Education, No.20040558025 The Program for New Century Excellent Talents in University
基金supported jointly by the National Natural Science Foundation of China (Grant Nos. 902011020, 40576036, 40771185)the Fujian Provincial Natural Science Foundation (D0710021)
文摘The isotopic composition of dissolved inorganic carbon (DIC) in marine and estuarine environments has been studied in some detail because of its role in determining the isotopic composition of inorganic/organic matter and its applications to the study of various natural processes. The δ13CDIC values of sea water are controlled by the sources and sinks of carbon and the results from isotope fractionation among solid, dissolved and gaseous phases. In this paper, based on the description of the stable isotope geochemical characteristics of dissolved inorganic carbon in northern South China Sea, the following conclusions were drawn: 1) the δ13CDIC values of natural waters are controlled by the sources and sinks of carbon and the results from isotope fractionation among solid, dissolved and gaseous phases. And the low seawater δ13CDIC values of northern South China Sea are accompanied by a low level of sea primary productivity in this region; 2) according to the parameter relationship (δ13CDIC-1.1 PO4) between δ13CDIC and PO4, it is indicated that northern South China Sea is the source of atmospheric CO2; and 3) nitrogen (N) and phosphorus (P) are the elements which are the basis for phytoplankton growth. Based on the analysis of seawater δ13CDIC values and PO4 and NO3+NO2 concentrations, our data show that N is a limiting nutrient in northern South China Sea.
基金financially supported jointly by the National Natural Science Foundation of China(Grant Nos.40771185 and 51004053)the Fujian Province Natural Science Foundation(D0710021)the Li Shangda Scientific Research Foundation of Jimei University,China(No.ZC2011015)
文摘The isotopic composition of dissolved inorganic carbon(DIC) in estuarine environments has been studied for its significant role in determining the isotopic composition of inorganic/organic matter and its applications to the study of various natural processes. In this paper, based on the stable isotope geochemical characteristics of dissolved inorganic carbon in the Jiulong River Estuary, the following conclusions are drawn:(1) δ13CDIC values are mainly controlled by the mixing ratio of fresh water and sea water;(2) δ13Cphytoplankton values are linearly related to the δ13CDIC values;(3) δ13CPOM values for the Jiulong River Estuary are affected by anthropogenic pollution significantly; and(4) the comprehensive analysis of δ13Cphytoplankton, δ13CPOM and δ13CDIC shows that along with increasing salinity, the proportion of POM derived from the degradation of phytoplanktons gradually increases.
文摘Data on the distribution of dissolved inorganic carbon (DIC) were obtained from two cruises in the North Yellow Sea (NYS) and off the Qingdao Coast (QC) in October, 2007. Carbonate parameters were calculated. The concentrations of DIC are from 1.896-2.229 mmolL-1 in the NYS and from 1.939-2.032 mmolL-1 off the QC. In the southwest of the NYS, DIC in the upper layers decreases from the north of the SP (Shandong Peninsula) shelf to the center of the NYS; whereas in the lower layers DIC increases from the north of the SP shelf to the center of the NYS and South Yellow Sea. In the northeast of the NYS, DIC in all layers in- creases from the YR (Yalu River) estuary to the centre of the NYS. The distribution of DIC in NYS can be used as an indicator of Yellow Sea Cold Water Mass (YSCWM). Air-sea CO2 fluxes were calculated using three models and the results suggest that both the NYS and the QC waters are potential sources of atmospheric CO2 in October.
基金supported by the National Natural Science Foundation of China through Grant No.41473023
文摘Major elements and carbon isotopes of dissolved inorganic carbon(DIC)have been measured in the waters of Changbaishan mountain,a volcanic area in northeastern China,between June and September 2016 to decipher the origin of the CO_2 involved in chemical weathering reactions.Spatial variations of major elements ratios measured in water samples can be explained by a change of the chemical composition of the volcanic rocks between the volcanic cone(trachytes)and the basaltic shield as evidenced by the variations in the composition of these rocks.Hence,DIC results from the neutralization of CO_2 by silicate rocks.DIC concentrations vary from 0.3 to 2.5 mmol/L and carbon isotopic compositions of DIC measured in rivers vary from-14.2‰to 3.5‰.At a first order,the DIC transported by rivers is derived from the chemical weathering’s consumption of CO_2 with a magmatic origin,enriched in^(13)C(-5%)and biogenic soil CO_2 with lower isotopic compositions.The highest δ^(13)C values likely result from C isotopes fractionation during CO_2 degassing in rivers.A mass balance based on carbon isotopes suggest that the contribution of magmatic CO_2 varied from less than 20%to more than 70%.Uncertainties in this calculation associated with CO_2 degassing in rivers are difficult to quantify,and the consequence of CO_2 degassing would be an overestimation of the contribution of DIC derived from the neutralization of magmatic CO_2 by silicate rocks.
文摘Iron in seawater is an essential trace metal for phytoplankton that plays an important role in the marine carbon cycle. But most studies focused on oceanic iron fertilization in high nutrient low chlorophyll (HNLC) seawaters. A study of inorganic carbon (IC) forms and its influencing factors was presented in Liaodong Gulf sediments, and especially the influence of iron was discussed in detail. Inorganic carbon in Liaodong Gulf sediments was divided into five forms: NaCl, NH_ 3·H_ 2O, NaOH, NH_ 2OH·HCl and HCl. The concentration of NaCl and NaOH forms were similar and they only occupied the minority of total inorganic carbon (TIC). However, NH_ 3·H_ 2O, NH_ 2OH·HCl and HCl forms were the principal forms of TIC and accounted for more than 80% of TIC. Especially, the percentage of NH_ 3·H_ 2O form was much higher than that in the Changjiang River Estuary and Jiaozhou Bay sediments. All forms of inorganic carbon were influenced by organic carbon,pore water, iron, pH, redox potential(Eh) and sulfur potential(Es) in sediments, moreover, the influences had different characteristics for different IC forms. However, the redox reactions of iron affected mainly active IC forms. Iron had little effect on NH_ 2OH·HCl and HCl forms of IC which were influenced mainly by pH. Iron had a stronger influence on NaCl, NaOH and NH_ 3·H_ 2O forms of IC; the influence of Fe 2+ was higher than Fe 3+ and its effect on NH_ 3·H_ 2O form was stronger than on NaCl and NaOH forms.
基金The opening foundation of the Key Laboratory of Marine Sedimentology & Environmental Geology,SOA under contract No. MASEG200606Creative Research Groups by NSFC under contract No.40821004+1 种基金the National Key Project for Basic Research of China under contract No. 2007CB407305the "100 Talents Project" of the Chinese Academy of Sciences
文摘Inorganic carbon forms and their influencing factors,mutual transformation and contribution to carbon cycling in the Jiaozhou Bay sediments were discussed.The results show that inorganic carbon in sediments could be divided into five forms:NaCl form,NH3·H2O form,NaOH form,NH2OH·HCl form and HCl form.Thereinto,NH2OH·HCl form and HCl form account for more than 70% of total inorganic carbon.There was close relationship among every form of inorganic carbon and their correlativity was clearly different with different sedimentary environment except the similar strong positive correlation among NH2OH·HCl form,HCl form and total inorganic carbon in all regions of the Jiaozhou Bay.All forms of inorganic carbon were influenced by organic carbon,pH,Eh,Es,nitrogen and phosphorus in sediments,but their influence had different characteristics in different regions.Every form of inorganic carbon transformed into each other continuously during early diagenesis of sediments and the common phenomenon was that NaCl form,NH3·H2O form,NaOH form and NH2OH·HCl form might transform into steady HCl form.NaCl form,NH3·H2O form,NaOH form and NH2OH·HCl form could participate in carbon recycle and they are potential carbon source;HCl form may be buried for a long time in sediments,and it may be one of the final resting places of atmospheric CO2.Inorganic carbon which entered into sediments was about 4.98×1010 g in the Jiaozhou Bay every year,in which about 1.47×1010 g of inorganic carbon might be buried for a long time and about 3.51×1010 g of inorganic carbon might return into seawater and take part in carbon recycling.
基金supported by the National Basic Research Program of China(2014CB954204)the National Natural Science Foundation of China(41701099,31770765)
文摘Soil acidification is a major global issue of sustainable development for ecosystems. The increasing soil acidity induced by excessive nitrogen(N) fertilization in farmlands has profoundly impacted the soil carbon dynamics. However, the way in which changes in soil p H regulating the soil carbon dynamics in a deep soil profile is still not well elucidated. In this study, through a 12-year field N fertilization experiment with three N fertilizer treatments(0, 120, and 240 kg N/(hm^2·a)) in a dryland agroecosystem of China, we explored the soil p H changes over a soil profile up to a depth of 200 cm and determined the responses of soil organic carbon(SOC) and soil inorganic carbon(SIC) to the changed soil p H. Using a generalized additive model, we identified the soil depth intervals with the most powerful statistical relationships between changes in soil p H and soil carbon dynamics. Hierarchical responses of SOC and SIC dynamics to soil acidification were found. The results indicate that the changes in soil p H explained the SOC dynamics well by using a non-linear relationship at the soil depth of 0–80 cm(P=0.006), whereas the changes in soil p H were significantly linearly correlated with SIC dynamics at the 100–180 cm soil depth(P=0.015). After a long-term N fertilization in the experimental field, the soil p H value decreased in all three N fertilizer treatments. Furthermore, the declines in soil p H in the deep soil layer(100–200 cm) were significantly greater(P=0.035) than those in the upper soil layer(0–80 cm). These results indicate that soil acidification in the upper soil layer can transfer excess protons to the deep soil layer, and subsequently, the structural heterogeneous responses of SOC and SIC to soil acidification were identified because of different buffer capacities for the SOC and SIC. To better estimate the effects of soil acidification on soil carbon dynamics, we suggest that future investigations for soil acidification should be extended to a deeper soil depth, e.g., 200 cm.
文摘Inorganic carbon utilization in the non calcifying marine microalgae, Nannochloropsis oculata, Phaeodactylum tricornutum and Porphyridium purpureum was compared with high and low calcifying strains of Emiliania huxleyi grown in artificial seawater medium aerated with either air (0.03% V/V CO 2) or CO 2 free air. For high calcifying strain of E. oculata and P. tricornutem , similar growth patterns were observed in air and CO 2 free air grown cultures. P. purpureum showed a less final cell density in CO 2 free air than in air grown culture. However, low calcifying strain of E. huxleyi was able to grow only in air grown culture, but not in CO 2 free air grown culture. Measurements of alkalinity, pH, concentration of dissolved inorganic carbon (DIC) and free CO 2 showed different patterns of DIC utilization. With N. oculata, P. tricornutum and P. purpureum the pattern of DIC utilization was characterized by an increase of pH and a decrease of DIC but a constant alkalinity in the cultures aerated with air or CO 2 free air, suggesting that bicarbonate utilization was concomitant with an efflux of OH -. Both alkalinity and pH were maintained rather constant in air grown culture of low calcifying strain of E. huxleyi, suggesting that diffusive entry of CO 2 could meet the requirement of DIC for its photosynthesis and growth. High calcifying strain of E.huxleyi , however, showed a pattern of decrease of alkalinity and DIC but an almost constant pH , indicating that bicarbonate was the major form of inorganic carbon utilised by this organism and bicarbonate uptake is unlikely to be accompanied by an efflux of OH -. The final pH values reached by N. oculata, P. tricornutum and P. purpureum in a closed system were 10.75, 10.60 and 9.85 respectively, showing that bicarbonate utilisation is concomitant with an efflux of OH . While the final pH of 8.4 in high calcifying E. huxleyi suggests that bicarbonate utilization was not accompanied by an efflux of OH -.
基金The Key Laboratory of State Oceanic Administration for Marine Ecology and Environmental Science and Engineering,State Oceanic Administration under contract No.MESE-2008-07the Open Fund of North China Sea Branch,State Oceanic Administration under contract No.2010A01+1 种基金the Open Fund of State Oceanic Administration of China under contract No.2010503the Open Fund of Key Laboratory of Marine Ecology and Environmental Science,Institute of Oceanology,Chinese Academy of Sciences under contract No.KLMEES201003
文摘The influence of macronitrogen (NO - 3 and NH + 4 ) addition with Ulva pertusa on dissolved inorganic carbon system in seawater was studied. The results indicate that p(CO 2 ) and HCO 3 concentration decrease significantly, while pH and CO 2- 3 concentration increase significantly. When the concentration of NO 3 was less than 71 μmol/dm 3 or NH + 4 was less than 49.7 μmol/dm 3 , dissolved inorganic carbon (DIC) absorption rates by Ulva pertusa generally increased with the increasing of nitrogen concentration. The DIC decreased 151 μmol/dm 3 with the addition of 71 μmol/dm 3 NO 3 and decreased 232 μmol/dm 3 with the addition of 49.7 μmol/dm 3 NH + 4 after the experiment compared with DIC measured without nitrogen addition. A significant negative-correlation was found between c(DIC) and growth rate (μ) of Ulva pertusa (r = -0.91, P <0.000 1, n=11). NH + 4 had more influence on the species of inorganic carbon system than NO 3 .
基金funded from the National Natural Science Foundation of China (Grant no. 40976116)the Scientific Research Foundation of Third Institute of Oceanography,SOA (Grant nos. 2010011, 2010001)+1 种基金sponsored by the China Program for International Polar Year 2007–2008the Special Research Foundation for Public Welfare Marine Program(Grant no. 201105022–2)
文摘The third Chinese National Arctic Research Expedition (3rd CHINARE-Arctic in 2008) was carried out from July to September 2008. During the survey, numerous sea water samples were taken for CO2 parameter measurement (including total alkalinity TA and total dissolved inorganic carbon DIC).The distribution of CO2 parameters in the Western Arctic Ocean was determined, and the controlling factors are addressed. The ranges of summertime TA, normalized TA (nTA), DIC and normalized DIC (nDIC) in the surface seawater were 1 757-2 229 μmol·kg 1, 2 383-2 722 μmol·kg 1, 1 681-2 034 μmol·kg 1, 2 119-2 600 μmol·kg 1, respectively. Becauseof dilution from ice meltwater, the surface TA and DIC concentrations were relatively low. TA in the upper 100m to the south of 78 N had good correlation with salinity, showing a conservative behavior. The distribution followed the seawater-river mixing line at salinity >30, then followed the seawater mixing line (diluted by river water to salinity = 30) with the ice meltwater. The DIC distribution in the Chukchi Sea was dominated by biological production or respiration of organic matter, whereas conservative mixing dominated the mixed layer TA distribution in the ice-free Canada Basin.
