首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 15 毫秒
1.
We provide an expert quality assessment of the data for 1932–1993 and used these data to perform the numerical analysis of the carbonate system of the aerobic zone in the Black Sea. The intraannual and long-term variations of the carbonate system are studied in the abyssal part of the sea for 1960–1993. We propose explanations of the intraannual variations of the analyzed system for various layers of the aerobic zone and reveal long-term variations of the pH values, total alkalinity, and the ratios of the components of the carbonate system. We discover and explain the observed increase in the concentrations of TCO2 and CO2 and the partial pressure of carbon dioxide pCO2, as well as a decrease in pH values and the concentration of CO32− in waters of the aerobic zone of the Black Sea.  相似文献   

2.
A study of the diurnal and seasonal variation in the physico-chemical conditions within intertidal rock pools on the West coast of Scotland was undertaken to provide data on the environmental conditions experienced by animals inhabiting these pools. The temperature, pH, partial pressure of oxygen (PO2) and salinity were measured every hour for 24 h and the total alkalinity, partial pressure of carbon dioxide (PCO2) and carbon dioxide content (CCO2) calculated. This sampling regime was carried out once a month for 12 months to determine the extent of seasonal variation in conditions within temperate pools.Large diurnal variations were recorded in nearly all the physico-chemical parameters measured. The greatest variation was recorded in the temperature and PO2 of the water but significant changes in pH and PCO2 were also recorded. Total alkalinity varied little during any 24 h period but carbonate alkalinity, which was always lower than total alkalinity, showed slightly greater variation. There was also considerable variation in the magnitude of these diurnal changes between pools at different heights on the shore.Diurnal variation in the physico-chemical conditions within the pools were observed throughout the year although the magnitude of these changes varied seasonally. Detailed studies on individual pools demonstrated that appreciable local variation existed in the physico-chemical conditions within each pool.  相似文献   

3.
This article presents the results of long-term studies of the dynamics of carbonate parameters and air–sea carbon dioxide fluxes on the Chukchi Sea shelf during the summer. As a result of the interaction of physical and biological factors, the surface waters on the west of Chukchi Sea were undersaturated with carbon dioxide when compared with atmospheric air; the partial pressure of CO2 varied in the range from 134 to 359 μatm. The average value of CO2 flux in the Chukchi Sea per unit area varied in the range from–2.4 to–22.0 mmol /(m2 day), which is significantly higher than the average value of CO2 flux in the World Ocean. It has been estimated that the minimal mass of C absorbed by the surface of Chukchi Sea from the atmosphere during ice-free season is 13 × 1012 g; a great part of this carbon is transported to the deeper layers of sea and isolated from the atmosphere for a long period of time. The studies of the carbonate system of the Chukchi Sea, especially of its western part, will provide some new data on the fluxes of carbon dioxide in the Arctic Ocean and their changes. Our analysis can be used for an interpretation of the satellite assessment of CO2 fluxes and dissolved CO2 distribution in the upper layers of the ocean.  相似文献   

4.
The intermediate and deep waters of the Labrador Sea are dominated by recently ventilated water masses (ventilation ages <20 yr). Atmospheric gases such as CO2 and chlorofluorocarbons are incorporated into these water masses at the time of formation and subsequently transported via boundary currents into the North Atlantic interior. Recent measurements of total carbonate were used in tandem with total alkalinity and oxygen to estimate the levels of anthropogenic carbon dioxide in the Labrador Sea region. Upper water column anthropogenic CO2 estimated in this manner showed good agreement with levels calculated from CO2 increase in the atmosphere. In spring 1997, anthropogenic contributions to total carbonate (CTant) were 40±3 μmol/kg in water penetrated by deep convection the previous winter and slightly lower (37±2 μmol/kg) in the deeper convective layer formed in the winters of 1992–1994. Consistent with the concurrent profiles of CFC-11, levels decrease into the older NEADW (North East Atlantic Deep Water) with levels of 30±3 μmol/kg and then increase near bottom within the layer of DSOW (Denmark Strait Overflow Water). The distribution of CTant shows the flow of new LSW southwards with the western boundary current and also eastwards into the Irminger Sea. We estimate that 0.15–0.35 Gt carbon of anthropogenic origin flow through the Labrador Sea within the Western Boundary Undercurrent per year.  相似文献   

5.
A study has been made of the effect of error in the measurement of the determinable parameters of the marine CO2 system on the calculation of the remaining parameters from equations such as those of Park (1969). This approach can be used either to assess and compare experimental data, or to aid in the choice of suitable combinations of determinable parameters for solving any particular problem. Now that the total alkalinity and total inorganic carbon (CT) can be determined extremely accurately by titration, a combination of carbonate alkalinity and CT is the most satisfactory combination for the majority of applications. If, however, PCO2 is required it should be measured directly.  相似文献   

6.
The carbon dioxide in seawater (pCO2) was measured in the Seto Inland Sea of Japan using newly developed equilibrator instrument designed to be free from the correction for addition or extraction of the carbon dioxide from carrier gas. The temperature dependence of pCO2 was about 4.5%pCO2/°C for a single seawater sample which was processed as free from biological activity and change in total carbon dioxide content during an experiment. The decrease in pCO2 during daylight hours due to the photosynthetic fixation was about 30% of the daily mean of pCO2 during warm months and about 15% during cold months. The effect of carbon dioxide exchange between air and seawater on pCO2 was about 0.6 ppm in August and about 0.1 ppm in March. This is negligible small compared with the daily oscillation of carbon dioxide in seawater.  相似文献   

7.
A preliminary study of carbon system in the East China Sea   总被引：1，自引：0，他引：1  
In the central part of the East China Sea, the activity of CO2 in the surface water and total carbonate, pH and alkalinity in the water column were determined in winter and autumn of 1993. The activity of CO2 in the continental shelf water was about 50 ppm lower than that of surface air. This decrease corresponds to the absorption of about 40 gC/m2/yr of atmospheric CO2 in the coastal zone or 1 GtC/yr in the global continental shelf, if this rate is applicable to entire coastal seas. The normalized total carbonate contents were higher in the water near the coast and near the bottom. This increase toward the bottom may be due to the organic matter deposited on the bottom. This conclusion is supported by the distribution of pH. The normalized alkalinity distribution also showed higher values in the near-coast water, but in the surface water, indicating the supply of bicarbonate from river water. The residence time of the East China Sea water, including the Yellow Sea water, has been calculated to be about 0.8 yr from the excess alkalinity and the alkalinity input. Using this residence time and the excess carbonate, we can estimate that the amount of dissolved carbonate transported from the coastal zone to the oceanic basin is about 70 gC/m2/yr or 2 GtC/yr/area-of-global-continental-shelf. This also means that the rivers transport carbon to the oceans at a rate of 30 gC/m2/yr of the coastal sea or 0.8 GtC/yr/ area-of-global shelf, the carbon consisting of dissolved inorganic carbonate and terrestrial organic carbon decomposed on the continental shelf.  相似文献   

8.
The TCO2, O2, TA and δ13C data of the 1969 Geosecs Intercalibration Cruise was analyzed and found to be consistent with a vertical mixing model which assumes that each point along a vertical profile is a mixture of the upper and lower boundaries. Calculated regression coefficients are in agreement with the model of Redfield et al. (1963) and with the assumption that TA variation is due to carbonate reaction. Oxygen consumption and TCO2 production decrease exponentially with depth and approximately 80% of ΔCO2 can be accounted for, on average, by O2 consumption. The remaining 20% are probably due to carbonate solution which seems to take place at depths below 2,500 m. The present study suggests that the isotopic composition (δ13C) of the carbon source, required to account for most of the oxygen consumed, may be heavier than the value of −23%. assigned to dissolved organic carbon and particulate organic carbon.  相似文献   

9.
CO2是引起全球气候变暖的最重要温室气体。大气中过量CO2被海水吸收后将改变海水中碳酸盐体系的组成,造成海水酸化,危害海洋生态环境。本文采用局部近似回归法对2013年12月—2014年11月期间西沙海洋大气CO2浓度连续监测数据进行筛分,得到西沙大气CO2区域本底浓度。结果表明,西沙大气CO2区域浓度具有明显的日变化和季节变化特征。4个季节西沙大气CO2区域本底浓度日变化均表现为白天低、夜晚高,最高值405.39×10-6(体积比),最低值399.12×10-6(体积比)。西沙大气CO2区域本底浓度季节变化特征表现为春季和冬季高,夏季和秋季低。CO2月平均浓度最高值出现在2013年12月,为406.22×10-6(体积比),最低值出现在2014年9月,为398.68×10-6(体积比)。西沙大气CO2区域本底浓度日变化主要受本区域日照和温度控制。季节变化主要控制因素是南海季风和大气环流,南海尤其是北部海域初级生产力变化和海洋对大气CO2的源/汇调节作用。  相似文献   

10.
An experimental method for the continuous determination of the partial pressure of carbon dioxide was attempted during a cruise in the Mediterranean Sea. The method, which uses infrared analysis of air continuously equilibrated with pumped seawater, is described. Calculations to obtain pCO2 in seawater from measured pCO2 are given with an example of the results.  相似文献   

11.
In the Mediterranean Sea the carbon chemistry is poorly known. However, the impact of the regional and large-scale anthropogenic pressures on this fragile environment rapidly modifies the distribution of the carbonate system key properties like CT (total dissolved inorganic carbon), AT (total alkalinity), CANT (anthropogenic CO2), and pH. This leads inexorably to the acidification of its waters. In order to improve our knowledge, we first develop interpolation procedures to estimate CT and AT from oxygen, salinity, and temperature data using all available data from the EU/MEDAR/MEDATLAS II database. The acceptable levels of precision obtained for these estimates (6.11 ??mol-kg−1 for CT and 6.08 ??mol kg−1 for AT) allow us to draw the distribution of CANT (with an uncertainty of 6.75 ??mol kg−1) using the Tracer combining Oxygen, inorganic Carbon, and total Alkalinity (TrOCA) approach. The results indicate that: 1) all Mediterranean water bodies are contaminated by anthropogenic carbon; 2) the lowest concentration of CANT is 37.5 ??mol kg−1; and 3) the western basin is more contaminated than the Eastern basin. After reconstructing the distribution of key properties (CT, AT, CANT) for four periods of time (between 1986 and 2001) along a west-east section throughout the whole Mediterranean Sea, we analyze the impact of the Eastern Mediterranean Transient (EMT). Not only has the concentration of CANT increased (especially in the intermediate and the bottom layers of the eastern basin, during and after the EMT), but also the distribution of all properties has been considerably perturbed. This is discussed in detail. For the first time, the level of acidification is estimated for the Mediterranean Sea. Our results indicate that for the year 2001 all waters (even the deepest) have been acidified by values ranging from −0.14 to −0.05 pH unit since the beginning of the industrial era, which is clearly higher than elsewhere in the open ocean. Given that the pH of seawater may affect a very large number of chemical and biological processes, our results stress the necessity to develop new programs of research to understand and then predict the evolution of the carbonate system properties in the Mediterranean Sea.  相似文献   

12.
  相似文献   

13.
Data on the carbonate system of the Northwestern Indian Ocean obtained on a cruise of F.S. Meteor during SW monsoon in July/August 1995 were compared with those of George et al. [George, M.D., Kumar, M.D., Naqvi, S.W.A., Banerjee, S., Narvekar, P.V., de Sousa, S.N., Jayakumar, D.A., 1994. A study of the carbon dioxide system in the northern Indian Ocean during premonsoon. Mar. Chem. 47, 243–254] collected during intermonsoon. In general, deep water values agreed well between the two expeditions. Surface waters, however, showed a substantial increase in dissolved inorganic carbon (CT) in the coastal regions due to strong upwelling in the SW monsoon. This was also accompanied by very high CO2 partial pressures in surface waters. The north–south gradients in vertical profiles of the measured parameters in the Arabian Sea are discussed by comparing profiles from the oligotrophic equatorial region with those from the highly productive central Arabian Sea. The effect of denitrification on regenerated CT and AT is minor, with contributions of <9 and <8 μmol kg−1, respectively, to the total amount regenerated also utilizing oxygen. The dissolution of biogenic carbonates is discussed; different approaches to define the depth, where the dissolution starts (lysocline(s), carbonate critical depth (CCrD)), are compared together with the calculation of saturation depth from carbonate concentrations. It is shown, that small differences in measured CT and AT (found between our data and those measured during GEOSECS) and different calculation approaches to the CO2 system (different dissociation constants for species involved and taking into account phosphate and silicate concentrations) can produce pronounced differences in the calculated saturation depths. However, CT and AT data suggest substantial dissolution of biogenic carbonate in the water column even above the calcite lysocline, irrespective of the procedures followed to calculate this horizon.  相似文献   

14.
Detection and attribution of hydrographic and biogeochemical changes in the deep ocean are challenging due to the small magnitude of their signals and to limitations in the accuracy of available data. However, there are indications that anthropogenic and climate change signals are starting to manifest at depth. The deep ocean below 2000 m comprises about 50% of the total ocean volume, and changes in the deep ocean should be followed over time to accurately assess the partitioning of anthropogenic carbon dioxide (CO2) between the ocean, terrestrial biosphere, and atmosphere. Here we determine the changes in the interior deep-water inorganic carbon content by a novel means that uses the partial pressure of CO2 measured at 20 °C, pCO2(20), along three meridional transects in the Atlantic and Pacific oceans. These changes are measured on decadal time scales using observations from the World Ocean Circulation Experiment (WOCE)/World Hydrographic Program (WHP) of the 1980s and 1990s and the CLIVAR/CO2 Repeat Hydrography Program of the past decade. The pCO2(20) values show a consistent increase in deep water over the time period. Changes in total dissolved inorganic carbon (DIC) content in the deep interior are not significant or consistent, as most of the signal is below the level of analytical uncertainty. Using an approximate relationship between pCO2(20) and DIC change, we infer DIC changes that are at the margin of detectability. However, when integrated on the basin scale, the increases range from 8–40% of the total specific water column changes over the past several decades. Patterns in chlorofluorocarbons (CFCs), along with output from an ocean model, suggest that the changes in pCO2(20) and DIC are of anthropogenic origin.  相似文献   

15.
桑沟湾养殖海域沉积物中碳埋藏通量的长期记录   总被引：1，自引：0，他引：1  
刘赛  杨茜  杨庶  孙耀  杨桂朋 《海洋学报》2014,36(8):30-38
对取自桑沟湾北部和南部养殖海域2个站位柱状沉积物样品进行研究,测定了它们的总碳(TC)、有机碳(TOC)、无机碳(TIC)含量,估算了海源有机碳(Ca),结合沉积物年代序列测定,对碳的来源和埋藏通量(BF)进行分析。结果表明:从19世纪到20世纪初,桑沟湾碳埋藏基本处于平稳期;20世纪初开始,伴随着中国工业革命兴起,湾内营养水平提高,大量天然小型贝类繁殖及残骸埋藏使桑沟湾碳埋藏量有大幅度突跃;20世纪60年代以来人工养殖活动兴起及到90年代大规模养殖后,天然贝类繁殖受抑制且伴随养殖产品的不断收获,使此期间碳埋藏量又处于平稳期。20世纪60年代前BFCa/BFTOC和BFCa/BFTC的比值分别在20%和4%以下波动,其后随养殖活动增加呈显著增大趋势;但BFTOC/BFTC比值基本在40%以下范围内波动。并将该区与取自黄海中部一柱状沉积物的BFTIC/BFTC比值作对比,桑沟湾BFTIC/BFTC比值基本在60%~98%之间远高于黄海中部(约15%)的比值,桑沟湾TIC与TC含量高比值使仅应用TOC或Ca含量估算碳埋藏通量可能带来巨大误差。  相似文献   

16.
In the course of the expedition of the Pacific Oceanological Institute in August 2007, extensive hypoxia was found in the near-bottom layer of the Amur Bay water mass. The hypoxia’s formation was immediately reflected in the values and distribution of the carbonate parameters in the near-bottom waters of the bay. The maximum values of the carbon dioxide partial pressure, the dissolved inorganic carbon, and the total alkalinity were associated with the areas of the minimum oxygen content. The microbial destruction of the dead phytoplankton greatly increased the partial pressure of carbon dioxide, which was over 2000 μatm in the hypoxia centers at a depth of about 20 m. At the same time, the carbon dioxide partial pressure in the surface waters of Amur Bay was considerably lower than that in the atmosphere. Hence, the bay’s aquatic area was a sink for the atmospheric CO2 despite its high content in the near-bottom waters. It was shown that the excess alkalinity associated with the hypoxia sites in the near-bottom layer of water was caused by the sulfate reduction proceeding in the upper layer of the sediment.  相似文献   

17.
On the basis of the experimental data accumulated in 1998–2005, we analyzed the space and time variations of the carbonate system of waters and the content of organic carbon in bottom sediments of the Sevastopol Bay. The intensity of gas exchange through the water-atmosphere interface was quantitatively estimated. It was shown that the partial pressure of carbon dioxide pCO2 in waters of the bay became much higher for the period of observations. The maximum changes were observed in summer. They were especially pronounced for the bottom layer of waters. For the entire period of observations, the invasion of carbon dioxide CO2 was predominant in the major part of the bay, and the content of organic carbon in the bottom sediments increased. The ability of waters in the bay to absorb CO2 is explained by the synthesis of organic substances, which becomes possible due to the presence of the equivalent load of nutrients. __________ Translated from Morskoi Gidrofizicheskii Zhurnal, No. 2, pp. 57–67, March–April, 2008.  相似文献   

18.
The oxygen (δ18O) and carbon (δ13C) isotope ratios of 10 species of living Bryozoa collected from the Otago Shelf, New Zealand were analysed to assess the extent to which isotopic equilibrium (relative to inorganic equilibrium isotope fractionation) is attained during the precipitation of skeletal calcium carbonate. The data reveal that whereas eight species of Bryozoa synthesise skeletal carbonate in apparent oxygen isotope equilibrium with respect to environmental conditions, two species (Celleporina grandis and Hippomonavella flexuosa) yield δ18Ocalcite values which indicate significant disequilibrium oxygen isotope fractionation during calcification. Sufficient data are available from one species (C. grandis) to demonstrate that disequilibrium is probably related to kinetic factors associated with diffusion‐controlled transport of HCO3‐ to the site of calcite precipitation. Carbon isotope signatures indicate significant departures from inorganic isotope equilibrium in all but one bryozoan species (Hippomenella vellicata). Although greater uncertainties are associated with estimates of the isotopic composition of total dissolved inorganic carbon (δ13CSDIC), the data suggest that two factors—kinetic fractionation and incorporation of respiratory CO2—are important in controlling carbon isotope disequilibrium. Where bryozoan species exhibit evidence for disequilibrium in both oxygen and carbon isotope systems (C. grandis, H. flexuosa), it is likely that kinetic factors are primarily responsible for observed departures from carbon isotope equilibrium. In contrast, the probable explanation for those species which display evidence for carbon isotope disequilibrium only, is that skeletal carbonate is precipitated from a DIC pool modified by the incorporation of respiratory CO2. Differences between the carbon isotope composition of skeletal elements from the same species and co‐existing species living in the same community suggests that significant variations may occur in the extent to which marine DIC and respiratory CO2 are utilised during calcification. Additional studies of carbon pathways associated with calcification are required to assess the relative effects of kinetic, metabolic, and environmental factors on the carbon isotopic composition of bryozoan skeletal carbonate.  相似文献   

19.
A correction formula is theoretically derived to evaluate the change in partial pressure of carbon dioxide in seawater upon heating. The constraints on the heating process are constant salinity, total alkalinity, and total carbon dioxide concentration. The result is
Full-size image (1K)
. This equation fits δPCO2/δt for open ocean seawater compositions to within approximately 9%. The almost constant 4.4%/°C effect is in agreement with that measured by Kanwisher (1960).  相似文献   

20.
The refined data obtained from the spectroscopic measurements of carbon dioxide in the column of the continental atmosphere over the Issyk Kul Monitoring Station during the period 1980–2006 and the results of their comparison with the data obtained from the measurements of carbon dioxide in air samples and with the mean zonal empirical model of the Climate Monitoring and Diagnostics Laboratory (CMDL) are given. Seasonal variations and a long-term trend of carbon dioxide concentration in the atmospheric thickness over a 25-year period of measurements are analyzed. The monthly mean concentration of CO2 is increased by ～40.5 ppm, and the linear-trend index is 1.62 ppm per year. The results of the aircraft measurements of CO2 concentration in air samples are, on the average, in agreement with the data obtained from the spectroscopic measurements of carbon dioxide concentration in the atmospheric column. The CO2 concentration in the surface air varies from day to day, and only its minimum values coincide with the CO2 concentration in the atmospheric thickness. The results of measurements of CO2 concentration in the atmospheric thickness and in the atmospheric surface layer over the KZD and KZM stations nearest to each other are, on the whole, in disagreement; moreover, the KZD and KZM data are inconsistent. The CO2 concentration in the atmospheric thickness is, on the average, 1–2% higher than that obtained with the CMDL model for 42.6° N latitude. The coefficient of correlation between the measurement results and model data is high (r= 0.95).  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号