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Nutrient profiles in interstitial water and flux in water-sediment interface of the Zhujiang Estuary of China in summer
PanJianming, ZhouHuaiyang, LiuXiaoya, HuChuanyu, DengLixian, ZhangMei
2001(4): 523-533.
关键词: TheZhujiangEstuary, sediment, interstitialwater, nutrientsalts
The profiles of nutrient salts in the interstitial water of sediment were analyzed in the Zhujiang Estuary in the summer of 1999, and based on the profiles of content and characteristic of nutrients, the relationship between nutrients in the interstitial water and organic matter decomposition in sediment was discussed. The results showed that ammonium with high content was the main existence form of nutrients in the interstital water of sediment, and the organic matter decomposition was completed in anaerobic condition. The increase of ammonium content in the bottom water resulted from the decomposition of organic matter and release of metabolic production, and the ammonium bottom flux was an important resource for nutrients geochemistry in the Zhujiang Estuary.
Changjiang River sediment delivering into the sea in response to water storage of Sanxia Reservoir in 2003
CHUZhongxin, ZHAIShikui, CHENXiufa
2006(2): 71-79.
关键词: Changjiang(Yangtze)River, SanxiaReservoir, waterstorage, sediment
The Sanxia Reservoir on the Changjiang River stored water from 1 to 10 June and from 25 October to 5 November in 2003, elevating the water level to 135 and 139 m above mean sea level at the dam, respectively.A monthly dataset of water discharge, suspended sediment concentration (SSC) and sediment load of the Changjiang River from 1953 to 2003 measured at the Datong Hydrological Gauging Station of the downstreammost Changjiang River was mainly used to examine the Changjiang River sediment delivering into the sea in 2003 in response to the Sanxia Reservoir water storages in the same year.The results show that (1) compared with those in 2002, 2001, and the multi-yearly (1953~2000) average, both annual SSC and sediment load at Datong in 2003 were markedly reduced, and they were even smaller than the multi-yearly (1953~2000) minimum, although the annual runoff in 2003 did not change largely; and (2) compared with those in the corresponding months in 2002, 2001 and the multi-monthly average from 1953 to 2000, monthly SSC and sediment load at Datong both in June and November of 2003 were also markedly reduced, and those in June 2003 were even smaller than the multi-monthly minimum from 1953 to 2000.These may indicate that sediment sedimentation in the Sanxia Reservoir resulting from the Sanxia Reservoir water storage should be the main cause of the decreased annual and monthly SSC and sediment load of the Changjiang River into the sea in 2003.Besides, it seems that the Sanxia Reservoir water storage in the early June (flood season) of 2003 had more impacts on the decreased monthly SSC into the sea than that in the late October and early November (approximately non-flood season) of 2003.
Environmental impact factors and mercury speciation in the sediment along Fujian and eastern Guangdong coasts
ZHANGYuanbiao, HUOYunlong, LIUXiyao, KUANGWeiming, YUANDongxing, JIWeidong
2013, 32(2): 76-80. doi: 10.1007/s13131-013-0279-3
关键词: mercury, methylmercury, coastalarea, sediment, speciation
Concentrations of total mercury (THg) and methyl mercury (MeHg) were determined for 32 surface sediments collected along the coastal line of Fujian Province and eastern Guangdong Province. The spatial distributions of THg and MeHg and their environmental impact factors were investigated. The average concentrations of THg and MeHg in the sediments were 31.5 ng/g and 0.096 ng/g, respectively. Both sediment THg and MeHg concentrations showed relatively high value in the Minjiang Estuary and the coastal areas of Quanzhou and Putian. The concentrations overall decreased as the distance to the shoreline increased. The correlations among environmental impact factors and THg, MeHg were analyzed. The sediment THg concentration was highly correlated to the concentrations of organic matter, copper, total nitrogen (TN) and total phosphorus (TP), and significantly correlated to pH value of the bottom seawater and concentration of sediment sulfide. The sediment MeHg concentration was highly correlated to the concentrations of organic matter and copper, and significant correlated to the concentrations of sulfide, TN, TP and pH value of the bottom seawater.
LEADAT: a MATLAB-based program for lead-210 data analysis of sediment cores
LUXueqiang, MATSUMOTOEiji
2006(6): 128-137.
关键词: Lead-210method, sediment, dating, sedimentationrate, environmentalchange
The program described herein (LEADAT) serves to calculate sediment date and sedimentation rate using the 210Pb method for the studies of environmental processes and pollution history on a time scale of 100~150 a.The program written in MATLAB (Version7.0) permits the user to select the principal models of 210Pb method, I.e., the constant fluxes of sediment and lead-210 (CFSL) model, the constant flux of lead-210 (CFL) model, the constant initial concentration of lead-210 (CICL) model and the two-layer mixing (TLM) model.Although appropriate model selection is essentially based on understanding of the sedimentary processes, the pattern of the excess 210Pb profile is also helpful for model selection.The excess 210Pb profiles for two sediment cores collected from a brackish lake and an embayment respectively are used to demonstrate the application of the program.With a graphical user interface, the program can be easily executed.Not only ASCⅡ but also graphical output can be generated by means of the program.Meanwhile, the code can be modified easily for extension.
磨刀门拦门沙区域枯季波流共同作用近底切应力和泥沙运动研究
JIALiangwen, RENJie, NIEDan, CHENBenzhong, LVXiaoying
2014, 33(7): 107-115. doi: 10.1007/s13131-014-0510-x
关键词: 磨刀门, 波流共同作用, 底切应力, 泥沙
基于2012年2月磨刀门河口拦门沙区域的波、流、沙水文实测资料,应用Soulsby公式采用迭代方法计算了测点的底部切应力,分析了底部切应力的组成及对泥沙的起动作用。研究表明:磨刀门枯季拦门沙测点区域底部切应力主要由涌浪作用下的底部切应力组成,其次为风浪,而潮流作用形成的底部切应力贡献较小,仅为10%左右;底部悬沙含量与波流共同作用下的底部切应力呈强相关,而与潮流底切应力呈弱相关,含沙量峰值与涌浪波高和涌浪作用下的剪切应力有良好的对应关系。涌浪作用是枯季磨刀门拦门沙区域底部泥沙再悬浮的主要机制。含沙量峰值集中在高潮位附近,涨潮流的作用使波浪作用得到增强、底部含沙量峰值增大。测点附近泥沙临界切应力为0.20 -0.30 N/m2,仅是在潮流作用下,大部分时间底部泥沙将无法起动,但是在波流共同作用下,即使是粗颗粒泥沙也多可以起动。
2022, 41(1): 21-29. doi: 10.1007/s13131-021-1916-x  刊出日期:2022-01-10
The Kongsfjorden is highly sensitive region to climate variability, however, the study of gamma-ray radionuclides in related areas is relatively scarce. In this study, the grain size, total organic carbon (TOC), 13Corg isotopes, and specific activities of seven gamma nuclides were analysed in surface sediments of the Kongsfjorden in the Arctic during the summer of 2017. The specific activities of 210Pbex, 137Cs, 238U, 226Ra, 228Ra, 228Th, and 40K were 12–256 Bq/kg, 0–3.8 Bq/kg, 25–42 Bq/kg, 24–38 Bq/kg, 22–40 Bq/kg, 22–40 Bq/kg, and 354–738 Bq/kg, respectively, with average values of (121±94) Bq/kg, (2.0±1.2) Bq/kg, (34±6) Bq/kg, (32±4) Bq/kg, (32±6) Bq/kg, (33±6) Bq/kg, and (611±119) Bq/kg. This study observed a significant positive correlation (r=0.845, p<0.05) between TOC and 210Pbex, highlighting the strong influence of organic matter on the distribution of 210Pbex. The boundary scavenging of 210Pb from the open sea contributed 27.5%–46.2% to the total 210Pbex in the sediments of the outer Kongsfjorden. The grain size was an important factor affecting the activity distribution of several radionuclides (238U, 228Ra, 228Th, 226Ra, and 40K). The specific activity of 137Cs indicated the transport of terrestrial materials from the exposed area of the Kongsfjorden. The sediments in the Kongsfjorden were derived from various material contributions of glacial meltwater debris, glacial rivers, bare soil, atmospheric deposition, and marine sources. This study explains the source of the Kongsfjorden sediment and the distribution characteristics of radionuclides, and illustrateas the main factors affecting the distribution of radionuclides, which provides a reference for the behavior of polar radionuclides in future research.
Water, organic matter, nitrogen and phosphorus contents in sediment of a large-scale mariculture area in the Zhelin Bay of eastern Guangdong Province, China
DONGQiaoxiang, LINJunda, SHANGXu, LIJin, HUANGChangjiang
2008(2): 133-148.
关键词: ZhelinBay, sediment, nitrogen, phosphorus, watercontent, organicmatter
The Zhelin Bay is one of the most important bays for large-scale mariculture in Guangdong Province, China.Owing to the increasing human population and the expanding mariculture in the last two decades, the ecological environment has greatly changed with frequent harmful algal blooms.A monthly survey of water content, organic matter (TOM), and various forms of nitrogen and phosphorous in sediment from July 2002 to July 2003 in the bay was conducted.The results showed that the water content was correlated significantly with TOM and various forms of nitrogen and phosphorus and can be used as proxy for quick and rough estimate of these factors in the future surveys.TOM was also correlated significantly with various forms of nitrogen and phosphorus, indicating that it was one of the key factors affecting the concentrations and distributions of nitrogen and phosphorus in the investigated waters.Average total Kjeldhal nitrogen (TkN) content was (1 113.1±382.5)μg/g and average total phosphorus (TP) content was (567.2±223.3)μg/g, and both were much higher than those of similar estuaries in China and elsewhere.Average nitrogen and phosphorus tended to be higher inside than outside the bay, higher at aquaculture than non-aquaculture areas, and higher at fish-cage culture than oyster culture areas, suggesting that large-scale mariculture inside the bay played an important role in the eutrophication of the Zhelin Bay.Various forms of nitrogen and phosphorus concentrations were higher during the warm season (July-September), which was due to the increased decomposition and concentration of organic matter resulted from the fast growth and high mortality of the cultured species.Compared with July 2002, TkN and TP contents were much higher in July 2003, in consonance with the eutrophication of the Zhelin Bay.Because exchangeable phosphorus (Ex-P), iron-bounded phosphorus (Fe-P) and organic phosphorus (OP) combined accounted for 34.3% of the TP and authigenic phosphorus (Au-P) accounted for 49.2% of the TP, biological phosphorus (BP) that includes Ex-P, Fe-P, OP, and a portion of Au-P, thus accounted for 34.3% to 83.5% of the TP in the Zhelin Bay, which was within the percentage range, but with a high absolute value among the estuaries.Au-P was the most important species of phosphorus and accounted for 49.2% of the TP during the investigation.Since eutrophication in the water column can lead to reduction of pH in sediment and release of phosphorus in Au-P combined with authigenic spodiosite and calcium carbonate, high content of Au-P in the sediment maybe act as a time bomb that can trigger a vicious cycle of eutrophication and large-scale harmful algal bloom in the Zhelin Bay.
冲绳海槽北部氧化还原敏感元素的早期成岩过程
王小静, 李力, 刘季花, 吴永华, 高晶晶, 曹鹏, 张颖, 石学法
2019, 38(12): 14-25. doi: 10.1007/s13131-019-1512-5
关键词: 早期成岩过程, , , , 孔隙水, 沉积物, 冲绳海槽
本文利用冲绳海槽北部的5根沉积物短柱(~25 cm),对氧化还原敏感元素(Mo、U、V)在早期成岩过程中的地球化学行为进行了系统的研究,探讨了影响其分布的主控因素,并定量估算了其在沉积物-海水界面扩散通量和沉积物中的自生累积埋藏通量,为阐明西北太平洋边缘海地区氧化还原敏感元素的早期成岩过程提供了科学依据。结合孔隙水及沉积物中Fe、Mn、Mo、U和V的垂向分布结果发现,所有沉积物短柱的沉积环境介于氧化和次氧化之间,直到短柱底部均未达到缺氧环境。Mo的早期成岩受到Mn氧化物地球化学循环过程的影响,在沉积物中基本没有自生累积。U在沉积物短柱的含量随着深度的增加而增加,自生累积通量(MAR)约为长江和黄河输入量的23%左右。沉积物-海水扩散通量与沉积物自生累计通量对比发现,U为向下扩散进入沉积物,而V为向上扩散进入上覆水体,扩散通量的方向和大小与自生累积通量基本一致,说明扩散过程是控制U和V在沉积物中埋藏或者迁移的主要因素。
桑沟湾及附近海域表层沉积物碳氮同位素分析及有机质来源
夏斌, 崔毅, 陈碧鹃, 崔正国, 曲克明, 马菲菲
2014, 33(12): 48-57. doi: 10.1007/s13131-014-0574-7
关键词: , , 稳定同位素, 有机质, 来源, 沉积物, 桑沟湾
天然存在的碳氮稳定同位素对于研究海洋沉积物有机质的来源具有非常重要的作用.本文于2012年8月和11月对桑沟湾养殖区及附近海域表层沉积物进行采样,分析了沉积物粒径以及有机碳、总氮、碳、氮同位素的分布特征,探讨了沉积物有机质的来源,并在此基础上估算了不同来源的贡献.结果表明,8月有机碳和总氮的含量范围分别是0.17%~0.76%和0.04%~0.14%;11月有机碳和总氮的含量范围是0.23%~0.87%和 0.05%~0.14%.OC%与TN%呈极显著的正相关(R=0.98,P<0.0001),表明沉积物有机碳和总氮具有同源性.8月有机质的δ13C和δ15N变化范围分别是-23.06‰~-21.59‰和5.10‰~6.31‰.11月有机质的δ13C和δ15N变化范围分别是-22.87‰~-21.34‰和5.13‰~7.31‰.有机质来源分析表明,贝类生物沉积、海藻养殖以及土壤有机质是沉积物有机质主要的三种来源.运用三元混合模型计算得出,8月和11月沉积物有机质主要来源是贝类生物沉积物,平均贡献率分别为65.53%和43.00%.所以,贝类养殖对近海碳循环具有显著影响.
一种分层海底反向散射模型
于盛齐, 刘保华, 于凯本, 杨志国, 阚光明
2017, 36(7): 56-65. doi: 10.1007/s13131-017-1084-1
关键词: 海底反向散射模型, 分层海底, 沉积物, 基岩
为了更为准确地对海底反向散射强度进行预报,本文考虑了海底的分层结构,认为海底由有限厚度的沉积层和半无限空间的基岩构成。在计算海水、沉积层和基岩中声场的基础上,考虑了包括海水-沉积物界面粗糙散射、沉积层体积散射、沉积物-基岩界面粗糙散射和基岩体积散射在内的四种散射机制,建立了适用于低频(100 Hz-10 kH)条件下的分层海底反向散射模型。仿真结果表明:频率较低时(小于1 kHz),沉积物-基岩界面粗糙散射和基岩体积散射更为显著;而随着频率的增大,两者对海底反向散射强度的贡献逐渐减弱,反向散射强度最终趋近于高频(10-100 kHz)海底散射模型的预报结果;当基岩中的剪切波声速和衰减逐渐减小时,预报结果趋近于全流体模型,继而从另一个方面验证了本文提出的分层海底散射模型的有效性。
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