首页 | 官方网站   微博 | 高级检索  
相似文献
 共查询到10条相似文献,搜索用时 171 毫秒
1.
The China Seas include the South China Sea, East China Sea, Yellow Sea, and Bohai Sea. Located off the Northwestern Pacific margin, covering 4700000 km~2 from tropical to northern temperate zones, and including a variety of continental margins/basins and depths, the China Seas provide typical cases for carbon budget studies. The South China Sea being a deep basin and part of the Western Pacific Warm Pool is characterized by oceanic features; the East China Sea with a wide continental shelf, enormous terrestrial discharges and open margins to the West Pacific, is featured by strong cross-shelf materials transport; the Yellow Sea is featured by the confluence of cold and warm waters; and the Bohai Sea is a shallow semiclosed gulf with strong impacts of human activities. Three large rivers, the Yangtze River, Yellow River, and Pearl River, flow into the East China Sea, the Bohai Sea, and the South China Sea, respectively. The Kuroshio Current at the outer margin of the Chinese continental shelf is one of the two major western boundary currents of the world oceans and its strength and position directly affect the regional climate of China. These characteristics make the China Seas a typical case of marginal seas to study carbon storage and fluxes. This paper systematically analyzes the literature data on the carbon pools and fluxes of the Bohai Sea,Yellow Sea, East China Sea, and South China Sea, including different interfaces(land-sea, sea-air, sediment-water, and marginal sea-open ocean) and different ecosystems(mangroves, wetland, seagrass beds, macroalgae mariculture, coral reefs, euphotic zones, and water column). Among the four seas, the Bohai Sea and South China Sea are acting as CO_2 sources, releasing about0.22 and 13.86–33.60 Tg C yr~(-1) into the atmosphere, respectively, whereas the Yellow Sea and East China Sea are acting as carbon sinks, absorbing about 1.15 and 6.92–23.30 Tg C yr~(-1) of atmospheric CO_2, respectively. Overall, if only the CO_2 exchange at the sea-air interface is considered, the Chinese marginal seas appear to be a source of atmospheric CO_2, with a net release of 6.01–9.33 Tg C yr~(-1), mainly from the inputs of rivers and adjacent oceans. The riverine dissolved inorganic carbon (DIC) input into the Bohai Sea and Yellow Sea, East China Sea, and South China Sea are 5.04, 14.60, and 40.14 Tg C yr~(-1),respectively. The DIC input from adjacent oceans is as high as 144.81 Tg C yr~(-1), significantly exceeding the carbon released from the seas to the atmosphere. In terms of output, the depositional fluxes of organic carbon in the Bohai Sea, Yellow Sea, East China Sea, and South China Sea are 2.00, 3.60, 7.40, and 5.92 Tg C yr~(-1), respectively. The fluxes of organic carbon from the East China Sea and South China Sea to the adjacent oceans are 15.25–36.70 and 43.93 Tg C yr~(-1), respectively. The annual carbon storage of mangroves, wetlands, and seagrass in Chinese coastal waters is 0.36–1.75 Tg C yr~(-1), with a dissolved organic carbon(DOC) output from seagrass beds of up to 0.59 Tg C yr~(-1). Removable organic carbon flux by Chinese macroalgae mariculture account for 0.68 Tg C yr~(-1) and the associated POC depositional and DOC releasing fluxes are 0.14 and 0.82 Tg C yr~(-1), respectively. Thus, in total, the annual output of organic carbon, which is mainly DOC, in the China Seas is 81.72–104.56 Tg C yr~(-1). The DOC efflux from the East China Sea to the adjacent oceans is 15.00–35.00 Tg C yr~(-1). The DOC efflux from the South China Sea is 31.39 Tg C yr~(-1). Although the marginal China Seas seem to be a source of atmospheric CO_2 based on the CO_2 flux at the sea-air interface, the combined effects of the riverine input in the area, oceanic input, depositional export,and microbial carbon pump(DOC conversion and output) indicate that the China Seas represent an important carbon storage area.  相似文献   

2.
Studies worldwide have indicated that agricultural pollution is the main source of nitrogen and phosphorus (N and P) in surface waters. A systematic understanding of N and P sources and sinks in agricultural systems is important for selecting the appropriate remedial strategies to control nutrient losses and water pollution. Based on nationwide data and a long-term monitoring program in Southeast China, the nationwide spatial and temporal patterns of N and P losses and the relationships between such losses and N and P inputs and rainfall were analyzed. The results showed that the annual nutrient losses from agricultural systems in China strongly varied, and the N/P values ranged from 0.01 to 51.0, with a majority at approximately 0–20, and an arithmetic mean of 9.73; these values mostly overlap the suitable range of N/P (6–15) for red bloom algae.  相似文献   

3.
The Yellow River (YR) supplies a large amount of nutrients and fresh water to the northern Chinese marginal seas, and greatly influences the ecosystem and current patterns. The relocation of the YR outlet from the southern Yellow Sea (YS) to the Bohai Sea in 1855 was demonstrated using northern East China Sea (ECS) sediment characteristics. Both isotopic (δ13C, δ15N) signals and C/N ratios in the organic matter (OM) indicate that prior to 1750, the predominant source of OM to the sediments was terrestrial. The terrestrial influences continuously weakened until 1855, when the YR estuary moved; after 1855, the OM was characterized by oceanic sources. Major elements (Al, Ti, Fe, Mn) and trace elements (Ni, Cr, Cu, Pb) had a much closer association with Malan loess prior to 1855, as >90% of the YR sediment was loess-derived. These results reveal that the relocation of the YR induced significant changes in the current patterns of the northern China Seas in the last 250 years; however, more studies are needed to further examine these linkages.  相似文献   

4.
To simulate the dynamic process of total nitrogen (TN) in seas, numerical modelling combined with the adjoint method is implemented in this study. Because nonpoint source terms (ST) and initial values (IV) of TN are essential but difficult to determine, the adjoint method was applied to a numerical model, and the ST and IV terms of TN were inverted via routine monitoring data in the Bohai Sea. In twin experiments, the adjoint method was capable of inverting the prescribed spatio-temporally distributed ST and the spatial distributed IV. In practical experiments, the results demonstrated that the simulation precision with ST inversion was higher than that with IV inversion and was accurate with joint initial values and source term (IST) inversion. This result indicates that nonpoint source TN is essential for the simulation of TN concentration. Furthermore, the simulated results indicate that the pollution in three bays of the Bohai Sea is rather severe. The model in this study is not specific to the Bohai Sea and can be generalized to other areas, such as the Beibu Gulf. These findings may assist in the development of cost-effective controls for accidental or planned industrial pollutant releases into coastal waters.  相似文献   

5.
海平面变化是社会经济发展和科学研究的重要内容.利用1993年1月至2012年12月共20年的TOPEX/Poseidon、Jason-1和Jason-2卫星测高数据,研究中国海海平面的时空变化.首先通过三颗卫星伴飞阶段数据得到三颗卫星之间的逐点海面高系统偏差,进行逐点海面高改正,建立了20年的中国海海面高异常时间序列.分析了中国海海面高异常空间分布,给出了1月到12月月均平均海平面异常的空间变化规律.分析了中国海海面高异常的时变规律,分别给出了年、季度和月的海面上升速率.利用小波分析研究了中国海海面高异常周期变化规律,分别给出了渤海、黄海、东海和南海的海面高变化周期.讨论了ENSO对海面高异常的影响.  相似文献   

6.
Dissolved trace element concentrations (Ba, Fe, Mn, Si, Sr, and Zn) were investigated in the Haicheng River near to the Liaodong Bay in Northeast China during 2010. Dissolved Ba, Fe, Mn, and Sr showed significant spatial variation, whereas dissolved Fe, Mn, and Zn displayed seasonal variations. Conditions such as water temperature, pH, and dissolved oxygen were found to have an important impact on redox reactions involving dissolved Ba, Fe, and Zn. Dissolved Fe and Mn concentrations were regulated by adsorption or desorption of Fe/Mn oxyhydroxides and the effects of organic carbon complexation on dissolved Ba and Sr were found to be significant. The sources of dissolved trace elements were found to be mainly from domestic sewage, industrial waste, agricultural surface runoff, and natural origin, with estimated seasonal and annual river fluxes established as important inputs of dissolved trace elements from the Haicheng River into the Liaodong Bay or Bohai Sea.  相似文献   

7.
我国近海地震活动特征及其与地球物理场的关系   总被引:1,自引:1,他引:0       下载免费PDF全文
对我国近海海域有历史记载以来的地震的震级、震中参数进行了整理分析,并分析了各海域地震活动的时、空分布规律,根据历史地震资料,确定海域受历史地震影响的最大影响烈度,然后初步分析了地震活动与现代构造应力场、地球物理场的关系.研究发现:(1)近海海域历史地震资料的精度较低,中强地震存在明显的遗漏.(2)渤海、台湾海峡、南海北部地震活动性较强,黄海次之,东海最弱.(3)近海海域的震害主要来自海域地震和近岸陆地强震的影响,影响强弱依次为:渤海、黄海、东南沿海、东海.(4)现代构造应力场以水平向构造应力场作用下的走滑运动为主,最大主应力方向受印度板决和太平洋板块、菲律宾海板块的俯冲挤压方向影响.(5)海域地球物理场,特别是布格重力异常、地壳厚度分布与强震构造带的空间分布关系的相关性较好.本文的研究结果可为我国海域及滨海重要工程的抗震设防、海域地震危险性区划提供一定的基础.  相似文献   

8.
Jellyfish blooms in China: Dominant species, causes and consequences   总被引:11,自引:0,他引:11  
Three jellyfish species, Aurelia aurita, Cyanea nozakii and Nemopilema nomurai, form large blooms in Chinese seas. We report on the distribution and increasing incidence of jellyfish blooms and their consequences in Chinese coastal seas and analyze their relationship to anthropogenically derived changes to the environment in order to determine the possible causes. A. aurita, C. nozakii and N. nomurai form blooms in the temperate Chinese seas including the northern East China Sea, Yellow Sea and Bohai Sea. N. nomurai forms offshore blooms while the other two species bloom mainly in inshore areas. Eutrophication, overfishing, habitat modification for aquaculture and climate change are all possible contributory factors facilitating plausible mechanisms for the proliferation of jellyfish blooms. In the absence of improvement in coastal marine ecosystem health, jellyfish blooms could be sustained and may even spread from the locations in which they now occur.  相似文献   

9.
The availability and partition of nitrogen (N) and phosphorus (P) in inorganic and organic compartments, as well as their stoichiometric ratio, are influenced by both physical and biological forcing factors. On this basis, the temporal and spatial dynamics in N:P atomic ratios in different compartments may provide information on the functioning of marine ecosystems. Here we explore the relative importance of water temperature, river inputs, wind mixing, stratification, ingression of nutrient-depleted Eastern Adriatic Current and phytoplankton biomass on concentrations and ratios between nitrogen and phosphorus in a semi-enclosed bay (the Gulf of Trieste), using data from monitoring programs carried out during 8 years. Water samples are first classified in 6 water types based on N:P ratios in different components, and then relationships between water type space-time distribution and a set of forcing factors is sought. Results show that the gulf is characterised by relatively stable N:P ratios in all compartments (about 23-26), always exceeding the classical Redfield ratio. In the surface layer, however, nitrogen and phosphorus dynamics are decoupled because of river input and plankton productivity, and a significant spatial and temporal variability is observed in terms of stoichiometric balance, nutrient concentrations and partition among the different pools. Deviations from stable N:P ratios follow a seasonal evolution. In spring, continental inputs alter inorganic nutrient compartments (N:P up to 115); later on, during the seasonal succession of biological processes (e.g. late spring phytoplankton blooms, summer increase in microbial activities and autumn phytoplankton blooms), a change is also seen in the organic dissolved and particulate pools. Multivariate statistical analysis suggests that, among the considered forcing factors, the most relevant in modulating the N:P stoichiometry in the Gulf of Trieste are river inputs and ingression of the Eastern Adriatic Current (acting in opposite directions) along with phytoplankton dynamics. During the whole period, besides variations in N:P stoichiometry, in the Gulf of Trieste dissolved organic matter represents the largest pool of N and P, which can provide a source of nutrients for the planktonic community alternative to inorganic nutrient.  相似文献   

10.
中国海地球物理场与油气资源   总被引:4,自引:5,他引:4       下载免费PDF全文
中国海是祖国的神圣国土,它面积近300万平方千米,包括渤海、黄海、东海和南海四大海域.中国海关系到国家的主权和权益.而在维护主权和权益的斗争中,核心问题是海底矿产资源,特别是油气资源.地球物理方法是认识海底矿产资源的主要技术手段.本文概述了过去50年中国海地球物理场的数据采集与编图工作,经过地质、地球物理综合研究所取得的基本认识、油气勘探在四大海域中所取得的成就,及其前景展望.  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-23

京公网安备 11010802026262号