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1.
东海海—气界面二氧化碳通量的季节变化与控制因素研究进展 总被引：1，自引：0，他引：1
通过对东海海—气界面二氧化碳(CO2)交换有关研究的总结,剖析了东海表层海水CO2分压(pCO2)的区域分布特征,探讨了海—气界面CO2通量(FCO2)的季节变化规律,诠释了影响海—气界面CO2转移的主要因素.结果表明,东海表层海水pCO2的区域分布具有明显的季节变化,可将其分为冬季、夏季、过渡季节(春季、秋季)3个时段.冬季西部近岸海域由于水体垂直交换强烈,造成表层水体pCO2较高,而中、东部陆架海域由于浮游生物的光合作用使得pCO2较低.夏季近岸河口海域由于陆源输入的影响导致pCO2较高,中、东部陆架海域受温跃层、长江冲淡水、浮游植物的综合作用pCO2较低.春季、秋季为过渡时段,表层海水pCO2分布变化剧烈,受控因素较为复杂.东海全年表现为大气CO2的净汇,其中冬、春、夏为碳汇,其海—气界面FCO2分别为(-6.68±6.93),(-4.94±0.80),(-3.67±1.09)mmol/(m2·d).秋季表现为碳源,通量约为(1.50±8.37)mmoL/(m2·d).东海全年平均通量约为-3.16 mmol/(m2·d),共可吸收CO2约为6.92×106 t C/a.不同季节海—气界面FCO2的年际变化凸显了人为因素的影响,近海富营养化加剧,三峡工程的运行都可能是造成东海冬季碳汇量减少、秋季碳源/汇格局转变的原因. 相似文献
2.
海表层二氧化碳分压之时间序列研究进展 总被引：1，自引：0，他引：1
简要总结了海表层二氧化碳分压(pCO2)时间序列的研究方法,重点综述了时间序列研究在确定pCO2控制过程、揭示pCO2年际差异、监测气候事件对pCO2的影响及估算海—气二氧化碳(CO2)通量等方面的研究进展.海表层pCO2时间序列的研究方法大致可以分为2类,一类是基于船舶调查,另一类是基于浮标的CO2自动测定.时间序列研究除了能够定性地记录和追踪一些特殊和偶然的物理和生物过程对pCO2的影响外,还能够定量地给出各种过程对pCO2变化的贡献,这对揭示海洋pCO2的控制机理有着重要意义.年际尺度的时间序列观测表明:人类活动已经造成了海表层pCO2的增加,厄尔尼诺事件和拉尼娜事件对海表层pCO2和海—气CO2通量有明显影响.另外,时间序列研究能够提高海—气CO2通量估算的准确性. 相似文献
3.
Huang Sijing Li Xiaoning Wu Wenhui Zhang Meng Hu Zuowei Liu Sibing Huang Keke Zhong Yijiang 《地球科学进展》2015,30(11):1185-1197
Carbon isotopic composition of marine carbonates is a record for various important geological events in the process of earth development and evolution. The carbonates of Carboniferous, Permian and Triassic, as the transition from Paleozoic to Mesozoic-Cenozoic have very high 13C value. Taking this as the main point, and combined with the oxygen, strontium isotopic composition in carbonates, distribution of carbonate basin area through geologic time, the correlation of carbon isotopic composition of marine carbonates to sea level change, organic carbon burial flux, exchange of CO2 content in atmosphere and ocean, and long cycle evolution of the earth ecosystems were approached. The results are shown as follows: ①The interval of 13C >3‰ during Phanerozoic was concentrated in Carboniferous, Permian and the beginning of Triassic, but the beginning of Triassic was characterized by higher frequency and larger fluctuations in 13C value during a short time, whereas the Carboniferous-Permian presented a continuously stable high 13C value, indicating a larger amount of organic carbon accumulation in this time interval. Relatively high 18O values during this time was also observed, showing a long time of glaciations and cold climate, which suggest a connection among rapid organic carbon burial, cold climate, as well as pCO2 and pO2 states of atmosphere. ②The over consumption of atmosphere CO2 by green plants during the time with high 13C of seawater forced CO2 being transferred from ocean to atmosphere for the balance, but the decrease in the seawater amount and water column pressure caused by the global cooling could weaken dissolution capacity of CO2 in seawater and carbon storage of marine carbonates, and also reduce the carbonate sedimentary rate and decrease the carbonate basin area globally from Devonian to Carboniferous and Permian. During the middle-late Permian carbonate was widely replaced by siliceous sediments even though in shallow carbonate platform, which resulted in the decrease of marine invertebrates, suggesting the Permian chert event should be global. ③The Phanerozoic 87Sr/86Sr trend of seawater showed a sharp fall in Permian and drop to a minimum at the end of the Permian, indicting input of strontium from the submarine hydrothermal systems (mantle flux). Such process should accompany with a supplement of CO2 from deep earth to atmosphere and ocean system, but the process associated with widespread volcanism and rises of earth’s surface temperature pricked up the mass extinction during the time of end Permian. ④Cold climate and increase of continental icecap volume, the amalgamation of northern Africa and Laurentia continentals were the main reasons responsible for the sea level drop, but the water consumption result from the significantly increased accumulation of organic carbon should also be one of the reasons for the sea level drop on the order of tens of meters. ⑤The mass extinction at the end Permian was an inevitable event in the process of earth system adjustment. It was difficult for marine invertebrates to survive because of the continuously rapid burial of organic carbon, and of the decrease of sea water amount and its dissolution ability to CO2. At last, at the end of Paleozoic, the supplement of CO2 to atmosphere and ocean by widely magma activities resulted in a high temperature of earth surface and intensified mass extinction. 相似文献
4.
在夏季分层期间对红枫湖南、北湖湖心的水样进行分层采集,同时测定了分层水样的温度、pH、HCO3-浓度、溶解氧(DO)、叶绿素a(Chl-a)及铵根离子(NH4+)、硝酸根离子(NO3-)、磷酸根离子(PO43-)的浓度,水体中CO2的分压(pCO2)由化学平衡及亨利定律求得。研究结果表明:光合作用、有机质降解及水体热分层是影响红枫湖夏季pCO2分布的主要因素。其中,温水层CO2欠饱和是光合作用吸收CO2引起的,温跃层中pCO2的急剧增加是光合产物降解产生CO2引起的。静水层沉积物附近pCO2最高并且还有持续增加的趋势,说明沉积物中有机质降解是静水层中CO2增加的主要原因,夏季湖底水温较高加快了沉积物中有机质的降解。分层现象使pCO2在水体中的分布差别明显,并且使静水层中CO2得到积累。此外,夏季红枫湖水体中pCO2的变化与NH4+、PO43-的变化密不可分,表现为温水层中光合作用消耗NH4+、PO43-,有机质降解过程伴随NH4+、PO43-的释放。 相似文献
5.
Marine carbon cycle of the South China Sea is an important part of global carbon cycle. Researches on the air-sea CO2 flux in the South China Sea will help us understand the global carbon cycle and improve the global carbon system parameter database. This paper concisely summarized the changes of partial pressure of CO2 (pCO2), air-sea CO2 fluxes (FCO2), and related environmental factors in four regions in domains in the South China Sea. The low-salinity area of the upper reaches of the Pearl River estuary in the northern of South China Sea shelf area acted as a strong source of atmospheric CO2, with high pCO2（405.3~810.6 Pa）all year round. The lower area of the Pearl River estuary (salinity > 33.7) acted as a weak sink of CO2 in winter, with relatively low pCO2 （35.2~37.0 Pa). The northern slope/basin in the South China Sea acted as a source of CO2 in warm seasons with a relatively high pCO2 (45.0 Pa), and acted as a sink of CO2 in cold seasons with a relatively low pCO2 (34.7 Pa). The west of the Luzon Strait acted as a sink of CO2 in spring, while it acted as a source of CO2 in other seasons, with relative high pCO2 (38.4~47.5 Pa) in winter. The central/southern basin in the South China Sea acted as sources of CO2, with relative high pCO2 (41.0 Pa) all the year. Generally, the estimation of annual sea-air CO2 fluxes showed that most domains in the South China Sea served as weak sources of atmospheric CO2. In the future, more researches should be focused on the time-series of sea surface pCO2 and the remote sensing of the sea-air CO2 fluxes. 相似文献
6.
根据2006年11月1~10日,秋季黄河平水期二氧化碳分压(pCO2)的现场实测数据及相关同步观测资料,对黄河表层水pCO2的分布及其影响因素进行了研究。结果表明:水体pCO2在80~166Pa,平均值110Pa,在世界主要河流中属中等偏下水平;空间分布存在较大的不均匀性,中游高于上游和下游。浮游植物的光合作用对pCO2有一定的影响但强度较弱,即使在叶绿素最高值3.58μg/L的包头站pCO2仍达到91Pa。黄河水体有机物含量较低且继承了陆源有机物难降解的特性,干流和库区EpCO2/AOU的比值为0.14和0.20,远低于生物好氧呼吸作用控制水体pCO2的理论下限0.62,因此,生物好氧呼吸作用对水体pCO2的贡献不大。悬浮物(TSS)含量为3.77~1308mg/L,溶解无机碳(DIC)含量为3.03~4.14mmol/L,普遍高于世界其它河流且最大值均出现在潼关站;同时水体pCO2与TSS、PIC、DIC含量具有极好的正相关性。因此黄河流域强烈的机械侵蚀和化学风化作用形成的碳酸盐体系是控制水体pCO2的主要因素。利用Wanninkhof提出的淡水水-气交换系数的通量模式估算,黄河水域水-气界面CO2交换速率约为0.229μmol/m2·s,秋季可向大气释放CO214.5亿moL,相当于8250km2草原或是112km2森林一年的固碳量。黄河CO2释放通量与渥太华河相近,但要远小于亚马逊河。 相似文献
7.
以2010年6月~2011年5月三峡澎溪河回水区CO2与CH4通量监测数据为基础,参考澎溪河高阳平湖水域全年4次的24 h昼夜连续跟踪观测结果,对每月各采样点的日通量值进行估算。提出了水下地形划分法和环境因素控制法,将各采样点日通量数据外延至整个回水区水域,并估算了澎溪河回水区水域CO2与CH4年总通量值。研究期间,澎溪河回水区全年各采样点CO2通量均值为(3.05±0.46)mmol/(m2·h);CH4为(0.050 1±0.009 6)mmol/(m2·h)。以水下地形法为基础,该水域全年CO2和CH4总通量分别为40 060.5 t和540.9 t;以环境因素控制法为基础,全年CO2与CH4总通量分别为39 073.0 t和467.2 t。以环境要素控制法为参考,该水域CO2全年平均释放强度为43.26 mmol/(m2·d),在全球水库数据序列中处于中等略偏高水平,CH4全年平均释放强度为1.42 mmol/(m2·d),在全球水库序列中处于中等水平。 相似文献
8.
Abuse of fossil energy resources results in the excessive discharge of greenhouse gases, especially CO2, enhancing the trend of global climate warming. Carbon sequestration is an important method to lower the increasing rate of CO2 concentration in the atmosphere. Marine carbon sequestration is a novel idea for reducing CO2 emission, and its reservoir mainly includes seawater and submarine sediment, which not only possess a great potential capacity of carbon sequestration, but also have high safety in relation to continental reservoirs. In this paper, we expounded the technique principle and mechanisms of marine carbon sequestration, potential capacity and time duration of marine carbon sequestration, main factors influencing marine carbon sequestration, CO2 injection technique, impacts on marine biota from over emission of CO2 and technique monitoring the leakage of CO2. Finally, a prospect of marine carbon sequestration was proposed, and its hot topics were accordingly pointed out. 相似文献
9.
S. R. Gí slason . Snorrason H. K. Kristmannsd ttir . E. Sveinbj rnsd ttir P. Torsander J.
lafsson S. Castet B. Dupr 《Chemical Geology》2002,190(1-4):181-205
The October 1996 eruption within the Vatnajökull Glacier, Iceland, provides a unique opportunity to study the net effect of volcanic eruptions on atmospheric and oceanic CO2. Volatile elements dissolved in the meltwater that enclosed the eruption site were eventually discharged into the ocean in a dramatic flood 35 days after the beginning of the eruption, enabling measurement of 50 dissolved element fluxes. The minimum concentration of exsolved CO2 in the 1×1012 kg of erupted magma was 516 mg/kg, S was 98 mg/kg, Cl was 14 mg/kg, and F was 2 mg/kg. The pH of the meltwater at the eruption site ranged from about 3 to 8. Volatile and dissolved element release to the meltwater in less than 35 days amounted to more than one million tonnes, equal to 0.1% of the mass of erupted magma. The total dissolved solid concentration in the floodwater was close to 500 mg/kg, pH ranged from 6.88 to 7.95, and suspended solid concentration ranged from 1% to 10%. According to H, O, C and S isotopes, most of the water was meteoric whereas the C and S were of magmatic origin. Both C and S went through isotopic fractionation due to precipitation at the eruption site, creating “short cuts” in their global cycles. The dissolved fluxes of C, Ca, Na, Si, S and Mg were greatest ranging from 1.4×1010 to 1.4×109 mol. The dissolved C flux equaled 0.6 million tonnes of CO2. The heavy metals Ni, Mn, Cu, Pb and Zn were relatively mobile during condensation and water–rock interactions at the eruption site. About half of the measured total carbon flood flux from the 1996 Vatnajökull eruption will be added to the long-term CO2 budget of the oceans and the atmosphere. The other half will eventually precipitate with the Ca and Mg released. Thus, for eruptions on the ocean floor, one can expect a net long-term C release to the ocean of less than half that of the exsolved gas. This is a considerably higher net C release than suggested for the oceanic crust by Staudigel et al. [Geochim. Cosmochim. Acta, 53 (1989) 3091]. In fact, they suggested a net loss of C. Therefore, magma degassed at the ocean floor contributes more C to the oceans and the atmosphere than magma degassed deep in the oceanic crust. The results of this study show that subglacial eruptions affecting the surface layer of the ocean where either Mn, Fe, Si or Cu are rate-determining for the growth of oceanic biomass have a potential for a transient net CO2 removal from the ocean and the atmosphere. For eruptions at high latitudes, timing is crucial for the effect of oceanic biota. Eruptions occurring in the wintertime when light is rate-determining for the growth of biota have much less potential for bringing about a transient net negative CO2 flux from the ocean atmosphere reservoir. 相似文献
10.
11.
黄渤海有机碳的分布特征及收支评估研究 总被引：4，自引：1，他引：3
陆架边缘海是陆海相互作用研究中最为关键的区域,也是全球重要的碳储库,在区域物质循环过程中发挥着重要的作用。基于2012年5月和11月对黄渤海海域的综合调查,对该海域水体和沉积物中有机碳的含量与分布进行了分析,并结合相关文献资料对黄渤海有机碳的收支进行了估算。主要结论为:黄渤海溶解有机碳和颗粒有机碳均呈近岸河口区域高、离岸低的分布趋势;有机碳的组成以溶解有机碳为主,颗粒有机碳由海洋自生的有机碳和陆地来源的有机碳组成;黄渤海沉积物有机碳高值区主要分布在河口和泥质区,其组成也是由海洋自生和陆源混合而成,其中渤海以陆源为主,而黄海以海源为主。黄渤海有机碳收支评估表明,有机碳的主要来源为初级生产力产生的有机物,其贡献为(6 760±971)×104t/a,占有机碳输入总量的(74±10)%,沉积物再悬浮的通量为(884±200)×104t/a,东海向黄海输入的通量为(679±107)×104t/a,河流及陆源输入的通量为(643±63)×104t/a,大气干湿沉降的通量为(141±39)×104t/a,其贡献分别占有机碳输入总量的(10±2.2)%,(7.5±1.2)%,(7.0±0.7)%和(1.5±0.4)%;黄渤海有机碳的主要支出为呼吸消耗,其贡献为(5 190±746)×104t/a,占有机碳输出总量的(57±8.2)%,黄海向东海输出的通量为(2 150±370)×104t/a,有机碳沉积通量为(1 030±225)×104t/a,有机碳降解通量为(737±191)×104t/a,其贡献分别占有机碳输出总量的(24±4.1)%,(11±2.5)%和(8.0±2.1)%。有机碳收支评估表明黄渤海有机碳以海洋自生来源为主,且具有潜在碳的"汇"的特性,水体中外源输入和海洋自生有机碳的(1.6±0.3)%埋藏于该海域内。 相似文献
12.
温度对青藏高原高寒灌丛CO2通量日变化的影响 总被引：1，自引：0，他引：1
应用涡度相关技术连续监测的CO2通量及温度数据(2003年1月1日至2004年12月31日),分析了青藏高原高寒灌丛净生态系统CO2交换(NEE)日变化与温度之间的关系.结果表明:1)在暖季夜间(21:00至次日06:00时)温度与NEE变化呈显著正相关关联,而白昼(07:00~20:00时)NEE变化与温度无显著关联;2)在冷季不论夜间还是白昼,NEE变化均与温度密切相关,温度是决定冷季高寒灌丛生态系统CO2交换的主要因素.在全球气候变暖背景下,青藏高原气候变化呈现出冬季增温率明显高于春、夏季特征,未来气候变暖导致的增温效应可能会加速青藏高原高寒灌丛生态系统CO2排放,使其作为碳汇的能力而减弱. 相似文献
13.
研究青藏高原多年冻土区高寒草甸土壤CO2通量有助于准确估算该区域的土壤CO2排放, 对认识高原土壤碳循环及其对全球气候变化的响应具有重要意义. 利用静态箱-气相色谱法和LI-8100土壤CO2通量自动测量系统对疏勒河上游多年冻土区高寒草甸土壤CO2通量进行了定期观测, 结合气象和土壤环境因子进行了分析. 结果表明: 整个观测期高寒草甸土壤表现为CO2的源, 土壤CO2通量的日变化范围为2.52～532.81 mg·m-2·h-1. 土壤CO2年排放总量为1 429.88 g·m-2, 年均通量为163.23 mg·m-2·h-1; 其中, CO2通量与空气温度和相对湿度、活动层表层2 cm、10 cm、20 cm、30 cm 土壤温度、含水量和盐分均显著相关. 2 cm土壤温度、空气温度和总辐射、空气温度、2 cm土壤盐分分别是影响活动层表层2 cm土壤完全融化期、冻结过程期、完全冻结期、融化过程期土壤CO2通量的最重要因子. 在完全融化期、冻结过程期和整个观测期, 拟合最佳的温度因子变化分别能够解释土壤CO2通量变化的72.0%、82.0%和38.0%, 对应的Q10值分别为1.93、6.62和2.09. 冻融期(含融化过程期和冻结过程期)和完全冻结期的土壤CO2排放量分别占年排放总量的15.35%和11.04%, 在年排放总量估算中不容忽视. 相似文献
14.
Do we have enough pieces of the jigsaw to integrate CO2 fluxes in the coastal ocean? 总被引：1，自引：0，他引：1
Alberto V. Borges 《Estuaries and Coasts》2005,28(1):3-27
Annually integrated air-water CO2 flux data in 44 coastal environments were compiled from literature. Data were gathered in 8 major ecosystems (inner estuaries,
outer estuaries, whole estuarine systems, mangroves, salt marshes, coral reefs, upwelling systems, and open continental shelves),
and up-scaled in the first attempt to integrate air-water CO2 fluxes over the coastal ocean (26×106 km2), taking into account its geographical and ecological diversity. Air-water CO2 fluxes were then up-scaled in global ocean (362×106 km2) using the present estimates for the coastal ocean and those from Takahashi et al. (2002) for the open ocean (336×106 km2). If estuaries and salt marshes are not taken into consideration in the up-scaling, the coastal ocean behaves as a sink for
atmospheric CO2(−1.17 mol C m−2 yr−1) and the uptake of atmospheric CO2 by the global ocean increases by 24% (−1.93 versus −1.56 Pg C yr−1). The inclusion of the coastal ocean increases the estimates of CO2 uptake by the global ocean by 57% for high latitude areas (−0.44 versus −0.28 Pg C yr−1) and by 15% for temperate latitude areas (−2.36 versus −2.06 Pg C yr−1) At subtropical and tropical latitudes, the contribution from the coastal ocean increases the CO2 emission to the atmosphere from the global oceam by 13% (0.87 versus 0.77 Pg C yr−1). If estuaries and salt marshes are taken into consideration in the upscaling, the coastal ocean behaves as a source for
atmospheric CO2 (0.38 mol C m−2 yr−1) and the uptake of atmospheric CO2 from the global ocean decreases by 12% (−1.44 versus −1.56 Pg C yr−1) At high and subtropical and tropical latitudes, the coastal ocean behaves as a source for atmospheric CO2 but at temperate latitudes, it still behaves as a moderate CO2 sink. A rigorous up-scaling of air-water CO2 fluxes in the coastal ocean is hampered by the poorly constrained estimate of the surface area of inner estuaries. The present
estimates clearly indicate the significance of this biogeochemically, highly active region of the biosphere in the global
CO2 cycle. 相似文献
15.
M. Tranter P. Huybrechts G. Munhoven M. J. Sharp G. H. Brown I. W. Jones A. J. Hodson R. Hodgkins J. L. Wadham 《Chemical Geology》2002,190(1-4):33-44
Chemical erosion in glacial environments is normally a consequence of chemical weathering reactions dominated by sulphide oxidation linked to carbonate dissolution and the carbonation of carbonates and silicates. Solute fluxes from small valley glaciers are usually a linear function of discharge. Representative glacial solute concentrations can be derived from the linear association of solute flux with discharge. These representative glacial concentrations of the major ions are 25% of those in global river water. A 3-D thermomechanically coupled model of the growth and decay of the Northern Hemisphere ice sheets was used to simulate glacial runoff at 100-year time steps during the last glacial cycle (130 ka to the present). The glacially derived fluxes of major cations, anions and Si over the glaciation were estimated from the product of the glacial runoff and the representative glacial concentration. A second estimate was obtained from the product of the glacial runoff and a realistic upper limit for glacial solute concentrations derived from theoretical considerations. The fluxes over the last glacial cycle are usually less than a few percent of current riverine solute fluxes to the oceans. The glacial fluxes were used to provide input to an oceanic carbon cycling model that also calculates changes in atmospheric CO2. The potential change in atmospheric CO2 concentrations over the last glacial cycle that arise from perturbations in glacial solute fluxes are insignificant, being <1 ppm. 相似文献
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17.
The measurement of metabolism using diel free-water oxygen techniques requires the estimation of atmospheric oxygen exchanges. We measured such exchange on nine different occasions in the freshwater, tidally-influenced Hudson River estuary using a floating dome technique. We also analyzed previously published data on the exchange of a variety of gases measured in lakes, estuaries, and open ocean waters using a wide variety of techniques. Data were expressed as a “transfer velocity” and normalized to an exchange of oxygen at 20°C. Considered together, these data indicate a significant predictive relationship when the natural log of transfer velocity is regressed with measured wind speed (r2 = 0.55; p = 0.0001). The influence of wind was particularly pronounced in estuaries and in lakes. Data from open-ocean waters showed much less influence of wind, probably because surface turbulence in these deeper waters can be temporally and spatially decoupled from wind. Our Hudson data agreed well with data collected in other systems. In general, data from estuaries—including the Hudson—indicated slightly higher transfer velocities at any given wind speed than do data from lakes (although this difference was less pronounced for our Hudson data than for other estuaries). The difference may result from some interaction of wind and tidal currents, or it may reflect a bias in the dome method of measurements; all of the estuarine data were collected using the dome approach, while the majority of the lake data were determined using an added tracer. If the dome method actually gives a biased, high estimate of oxygen flux, this is in contradiction to previous criticisms of this method that domes may underestimate fluxes by blocking wind at the water surface. We have used the regression of the natural log of transfer velocity versus wind speed developed here to estimate respiration in the Hudson estuary from diel changes in dissolved oxygen. To allow for possible biases in technique and for measurement error, we estimated 95% confidence limits around the regression. Estimates of respiration in the Hudson determined using the upper and lower 95% confidence limits are 30% higher and 12% lower than that determined when using the best-fit regression. An independently-constrained carbon budget for the tidally-influenced, freshwater Hudson River estuary indicates that respiration rates cannot be much higher than our mean estimate as calculated using the linear regression of the gas transfer and wind data to correct for air-water oxygen exchange. Gas transfer in natural systems is difficult to measure and is controlled by many interrelated physical factors. In the absence of extensive, system-specific field studies, the regression presented here should be useful in estimating atmospheric oxygen exchange in other estuarine or riverine ecosystems which are relatively deep and wide. 相似文献
18.
CO2在地下深部咸水含水层地质封存的多种封存机理中,束缚气封存的潜力很大,可占封存总量的30%左右。残余气饱和度是评价束缚气封存量的一个十分重要的参数。通过测定不同成分盐水驱CO2的残余CO2饱和度,对不同咸水含水层的束缚气封存潜力进行定性的评价,进一步为深部咸水含水层的CO2封存量的评估提供了参数依据。同时也对深部咸水含水层CO2地质封存的工程选址和目标含水层的选择具有一定的指导和借鉴意义。实验使用饱和CO2的蒸馏水、NaCl溶液、CaCl2溶液以及NaCl和CaCl2的混合溶液(质量比1∶1),溶液质量浓度都为10%,驱替饱和CO2的岩心,最后计算残余CO2饱和度。饱和CO2的溶液驱替CO2的过程可以分为两个阶段：活塞式驱替和携带式驱替。实验结果显示,4种液体驱替实验的残余CO2饱和度由小到大依次为：蒸馏水、混合溶液、NaCl溶液、CaCl2溶液。结果表明：在界面张力和流体粘性共同作用下,界面张力对岩心中CO2驱替效果的影响起主导作用;这3种类型盐水中,Cl-Ca型水束缚气封存潜力最大,其次是Cl-Na型水,Cl-Na·Ca型水最差。 相似文献
19.
New CO2 /3 He data from the East Sunda Arc (Indonesia) confirm earlier observations that arc volcanic gases have higher CO2 /3 He ratios than MOR environments.On average, > 80% of arc volcanic CO2 is recycled, exogene carbon. Addition of a few percent of carbonate-bearing sediments to the mantle wedge explains much of the carbon abundance andcarbon isotopic data of arc gases, but can not explain the He isotope observations. The CO2 /3 He in arc volcanoes is not strongly dependent on the composition of modem trough sediments (e.g. deep sea clays vs carbonate-rich sequences), and calcite veins in the hydrothermally altered subducted slab may provide a contribution to the recycled carbon flux of, arcs. The sum of globally deep-subducted sediment and slab carbon exceeds the estimated arc CO2 flux, and approximately 3.5 teramole of carbon may return annually to the mantle in convergent zones. The modem combined processes of MOR volcanism, slab alteration, and subduction volcanism do not produce a substantial carbon flux into the exosphere, and rate-changes in ocean floor spreading are unlikely to cause major changes in atmospheric CO2 as a result of changes in the volcanic CO2 fluxes. Intense pulses of flood basalt volcanism, however, may alter the CO2 contents of the atmosphere over the course of a millenium or so, and influence global climate. 相似文献
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Christopher W. Hunt Joseph E. Salisbury Douglas Vandemark Wade McGillis 《Estuaries and Coasts》2011,34(1):68-77
Four surveys of the adjacent Cocheco, Bellamy, and Oyster estuaries reveal spatial heterogeneity with respect both to river-born
carbon dioxide (CO2) fluxes and CO2 exchange with the atmosphere (−17 to 51 mmol m−2 day−1), a finding partially explained by CO2 inputs from contributing watersheds. Nonuniform nutrient and organic carbon loading from upstream rivers and within the estuaries
is considered as a mechanism resulting in the variability between estuaries. Conditions during the surveys included spring
river runoff and phytoplankton blooms, drought with baseline river flow, and a historic flood which led to a large CO2 release to the atmosphere. This study highlights the variability of CO2 transport and release found between proximate estuaries over a wide range of flow conditions. 相似文献