Biogeochemistry of dissolved carbon,major, and trace elements during spring flood periods on the Ob River     

Sergey N. Vorobyev  Oleg S. Pokrovsky  Larisa G. Kolesnichenko  Rinat M. Manasypov  Liudmila S. Shirokova  Jan Karlsson  Sergey N. Kirpotin 《水文研究》2019,33(11):1579-1594

Detailed knowledge of the flood period of Arctic rivers remains one of the few factors impeding rigorous prediction of the effect of climate change on carbon and related element fluxes from the land to the Arctic Ocean. In order to test the temporal and spatial variability of element concentration in the Ob River (western Siberia) water during flood period and to quantify the contribution of spring flood period to the annual element export, we sampled the main channel year round in 2014–2017 for dissolved C, major, and trace element concentrations. We revealed high stability (approximately ≤10% relative variation) of dissolved C, major, and trace element concentrations in the Ob River during spring flood period over a 1‐km section of the river channel and over 3 days continuous monitoring (3‐hr frequency). We identified two groups of elements with contrasting relationship to discharge: (a) DIC and soluble elements (Cl, SO₄, Li, B, Na, Mg, Ca, P, V, Cr, Mn, As, Rb, Sr, Mo, Ba, W, and U) negatively correlated (p < 0.05) with discharge and exhibited minimal concentrations during spring flood and autumn high flow and (b) DOC and particle‐reactive elements (Al, Fe, Ti, Y, Zr, Nb, Cs, REEs, Hf, Tl, Pb, and Th), some nutrients (K), and metalloids (Ge, Sb, and Te), positively correlated (p < 0.05) with discharge and showed the highest concentrations during spring flood. We attribute the decreased concentration of soluble elements with discharge to dilution by groundwater feeding and increased concentration of DOC and particle‐reactive metals with discharge to leaching from surface soil, plant litter, and suspended particles. Overall, the present study provides first‐order assessment of fluxes of major and trace elements in the middle course of the Ob River, reveals their high temporal and spatial stability, and characterizes the mechanism of river water chemical composition acquisition.  相似文献   

Inland saline lakes of Wadi El Natrun depression, Egypt     

Amany G. Taher 《International Journal of Salt Lake Research》1999,8(2):149-169

The morphology and geochemistry of saline lakes in the Wadi El Natrun depression were studied. All lakes had pH values of 8.5--9.5 and a salinity from 283 to 540 g/L. The main ionic components were sulphate, chloride, carbonate and sodium. Traces of magnesium were also present. The water of the lakes is of the Cl^– to SO ₄ ^2– -Cl^– type. Increased Cl^– in Wadi El Natrun brines can increase metal solubility due to the formation of soluble chloro-complexes of trace elements. The metal concentrations decrease in the order: Pb > Cu > Cd > Ni > Zn > Fe > Mn. The characteristics of Wadi El Natrun saline lakes are compared with those from other saline lakes.  相似文献   

Quaternary charophytes from Salina del Bebedero, Argentina: their relation with extant taxa and palaeolimnological significance     

Adriana García 《Journal of Paleolimnology》1999,21(3):307-323

Charophyte (Charales, green macroscopic algae) assemblages found in Quaternary shoreline sediments from Salina del Bebedero, Argentina, are described in detail, illustrated, and statistically analysed. Fossil gyrogonites, Late Pleistocene and Holocene in age, of Chara cf. hispida var. major (Hartman) Wood, Chara halina García, Chara hornemannii Wallmann, Chara bulbillifera (Donterberg) García, Lamprothamnium haesseliae Donterberg and Lamprothamnium succinctum (Braun ex Ascherson) Wood were identified. A comparison with extant charophyte species of similar ecological requirements allowed for an accurate systematical determination and provided useful data for complementary palaeoecological and palaeobiogeographical approaches. On this basis, a reconstruction of palaeo-salinities for the Salina del Bebedero lake, represented by eleven palaeo-beaches, is proposed. Also the associations of charophytes with the ostracods Cyprideis sp., Limnocythere sp., Pampacythere sp., Cypridopsis sp., Darwinula sp., Ilyocypris gibba (Randohr) Brady and Norman, and the foraminifers Ammonia sp., Elphidium gunteri Cole, Quinqueloculina sp., and one species of Discorbacea are analysed, since they are present in both the fossil and modern environments.  相似文献   

Development of a diatom-based specific conductivity model for the glacio-isostatic lakes of Truelove Lowland: implications for paleoconductivity and paleoenvironmental reconstructions in Devon Island lakes, N.W.T., Canada     

Sai L. Ng  Roger H. King 《Journal of Paleolimnology》1999,22(4):367-382

Diatoms are identified and enumerated from the surface sediments of 100 lakes of Truelove Lowland, Devon Island, N.W.T., Canada. These lakes range from large oligotrophic lakes, to small tundra ponds, to coastal marine lagoons which are diverse in terms of ionic concentration and composition. The relationship between diatoms and 15 limnological variables is examined using Canonical Correspondence Analysis (CCA). Specific conductivity is identified as the most important variable influencing the distribution of diatoms in the Truelove lakes. A Weighted Averaging (WA) calibration model is developed to predict diatom-inferred specific conductivity. The reliability of the model is tested by evaluating the correlation between observed and diatom-inferred values and determining the error of prediction by bootstrapping. The applicability of the predictive conductivity equation is demonstrated by reconstructing the paleoconductivity history of Fish Lake.  相似文献   

南极大陆沿海湖泊生态结构研究   总被引：2，自引：1，他引：1       下载免费PDF全文

王自磐  atrick Deprez 《极地研究》1999,11(2):11-22

南极大陆沿海地带是南极海、陆、冰的交集带,它同时受到来自海洋、大陆冰以及人类活动的影响,因而成为南极生态环境最脆弱的环节。存在于该地带的许多湖泊,因其各自的地理环境和发育过程,以及所受诸多外部因子如气候、降水等的不同影响,不同湖泊中水体的理化因子差异很大,由此造成湖泊中生物种类分布和生态结构的显著不同。本文报道了对南极大陆沿海维斯特福尔德丘陵和拉斯曼丘陵等地湖泊中以浮游生物为主体,各类生物的组成分布和群落结构进行考察研究的结果,并分析讨论了不同类型湖泊的生物多样性、生物营养结构及其与环境的关系,为深入研究全球气候变化对南极区域环境的影响,和制订南极生态环境保护决策提供科学依据。  相似文献   

THE 1998 FLOOD OF THE YANGTZE RIVER     

ZHOU Wenhao  CHEN Yuchong 《国际泥沙研究》1999,(4)

1INTRODUCTIONDuringthefloodseasonof1998,anothercatastrophicfloodoccurredinthemiddleandlowerYangtzeRiverfollowingthecatastrophicfloodin1954.Ascomparedwiththe54flood,the1998floodwascharacterizedbythefactsthatthedurationofthehighwaterstagewasmuchlonger,thefloodcontrolwasmuchmoredifficult,andthetotalmanpowerandmaterialresourcesexpelldedintilefloodfightingweremuchmoreenormous.TOsummarizetheexperienceandlessonsfromthefloodissignificanttotilehydraulicengineeringandfloodcontroloftheYangtzeRiver.…  相似文献   

浅水湖泊生态系统的多稳态理论及其应用   总被引：48，自引：11，他引：37  

李文朝 《湖泊科学》1997,9(2):97-104

在“八五”期间太湖研究工作的基础上,发展和充实了浅水湖泊多稳态理论,简要介绍了多稳态概念模型,并将这一理论和模型贯穿于太湖富营养化防治研究中;总结了太湖各湖区的状态演化过程,提出保护东太湖生态环境和治理五里湖的策略及技术路线,并付诸于实验;证明了利多稳态理论和多稳态模型指导湖泊富营养化防治的可行性。  相似文献   

人类活动对江汉湖群沼泽化的影响   总被引：3，自引：0，他引：3  

邹尚辉 《湖泊科学》1992,4(4):71-76

从破坏植被加速湖泊淤积速度、围湖造田使湖泊日渐萎缩、江湖隔绝促进水生高等植物生长、垸湖沼同体而互相转化等方面论述了人类活动加速了江汉湖群湖泊沼泽化的进程,并提出缓解湖泊沼泽化的措施;人类活动既具有加速湖泊沼泽化进程的作用亦具有延缓甚至逆转沼泽化进程的双向作用。  相似文献   

大气污染的湖泊响应及其代用标志   总被引：4，自引：0，他引：4  

王云飞  胡守云  尹宇  朱育新  潘红玺 《湖泊科学》2003,15(2):97-104

通过洱海和阳宗海大气污染的湖泊响应、代用标志提取和原因分析以及地表水酸化理论和自然酸性湖泊的对比研究,揭示湖水总矿化度和S04^2—的同步异常增大是湖泊早期受酸沉降危害的标志．保存于沉积记录中的磁化率、非磁滞剩磁和介形类、硅藻的数值和种群、密度等变化,可灵敏地揭示湖泊受大气污染的起点、过程和环境影响,可作为酸沉降较重湖区的代用标志．  相似文献   

太湖水体理化指标在夏季短时间尺度上的分层及其控制因素   总被引：5，自引：4，他引：1  

赵林林  朱梦圆  冯龙庆  刘笑菡  朱广伟  陈元芳  秦伯强 《湖泊科学》2011,23(4):649-656

通过连续9d(2010年7月24日至2010年8月1日)对太湖水体理化指标垂向分层的高频率观测,揭示太湖多指标垂向分层规律.观测表明:(1)太湖中各水质指标频繁出现分层现象,但不稳定;(2)分层的主要控制因素包含气温的日变化、蓝藻水华堆积与风浪扰动等;(3)气温和太阳辐射日变化影响水温分层,水温垂向变幅可达3.94℃,...  相似文献