Soil saturation index of salt marshes subjected to spring‐neap tides: a new variable for describing marsh soil aeration condition     

Pei Xin  Badin Gibbes  Ling Li  Zhiyao Song  David Lockington 《水文研究》2010,24(18):2564-2577

Organized spatial distribution of plants (plant zonation) in salt marshes has been linked to the soil aeration condition in the rhizosphere through simplistic tidal inundation parameters. Here, a soil saturation index (ratio of saturation period to tidal period at a soil depth) is introduced to describe the soil aeration condition. This new index captures the effects of not only the tidal inundation period and frequency but also the flow dynamics of groundwater in the marsh soil. One‐dimensional numerical models based on saturated flow with the Boussinesq approximations and a two‐dimensional variably saturated flow model were developed to explore the behaviour of this new soil aeration variable under the influence of spring‐neap tides. Simulations revealed two characteristic zones of soil aeration across the salt marsh: a relatively well aerated near‐creek zone and a poorly aerated interior zone. In the near‐creek zone, soils undergo periodic wetting and drying as the groundwater table fluctuates throughout the spring‐neap cycle. In the interior, the soil remains largely water saturated except for neap tide periods when limited drainage occurs. Although such a change of soil aeration condition has been observed in previous numerical simulations, the soil saturation index provides a clear delineation of the zones that are separated by an ‘inflexion point’ on the averaged index curve. The results show how the saturation index represents the effects of soil properties, tidal parameters and marsh platform elevation on marsh soil aeration. Simulations of these combined effects have not been possible with traditional tidal inundation parameters. The saturation index can be easily derived using relatively simple models based on five non‐dimensional variables. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Relevance of intracellular partitioning of metals in prey to differential metal bioaccumulation among populations of mummichogs (Fundulus heteroclitus)     

Daisuke Goto  William G. Wallace   《Marine environmental research》2009,68(5):257-267

Intracellular partitioning of trace metals is critical to metal tolerance in aquatic organisms and may also influence metal trophic transfer in ecosystems. In this study, we tested the relevance of metal (Cd, Cu, Pb, and Zn) intracellular partitioning in prey as an indicator of metal trophic availability to benthic forage fish, mummichogs (Fundulus heteroclitus), in chronically metal-polluted salt marshes in New York, USA. Two common prey of mummichogs in the study area, Palaemonetes pugio and Nereis acuminata, generally stored increasingly higher proportions of non-essential metals (particularly Pb) in insoluble (less trophically available) cellular components, as the whole body burdens increased. In contrast, intracellular partitioning of essential metals (Cu and Zn) in invertebrate prey varied relatively little among sites. Differential Cd and Pb intracellular partitioning patterns within P. pugio among sites were significantly associated with Cd and Pb whole body burdens in mummichogs, respectively (i.e., prey-driven bioreduction of metals), while bioaccumulation of Cu and Zn in mummichogs was similar among populations. The findings in this study suggest that metal intracellular partitioning within prey may be partially responsible for metal trophic availability to a predator in metal-polluted habitats, while there was also evidence that some predator-dependent processes may offset differential trophic availabilities from prey.  相似文献   

东风盐场卤水中可溶性糖的研究──Ⅰ、盐田卤水中可溶性糖的季节变化及其与海盐产量和质量之间的关系     

宫相忠  董树刚  吴以平  魏建功  高尚德  李永祺 《海洋湖沼通报》1997,(2)

对东风盐场9个站位卤水中由藻类植物产生的可溶性糖浓度的变化规律及其与海盐产量和质量之间的关系进行了研究。结果表明，各站位可溶性糖含量的变化范围为0．7－124．3mg／L，以6月份最高，2月份最低；卤水中可溶性糖在111mg／L－215mg／L范围内，结晶盐的产量随卤水中可溶性糖含量的增加而提高，但同时降低了NaCl的含量，并增加了可溶性杂质及水分的含量，从而降低了盐质。初始可溶性糖浓度为111mg／L、137mg／L、160mg／L、193mg／L和215mg／L的25．4°Be’的卤水，在日照下实验12天，其对应结晶盐的NaCl含量分别为91．66％、90．63％、90．48％、90．23％和88．46％，可溶性杂质的含量分别为3．05％、3．32％、3．33％和4．54％。  相似文献   

EFFECTS OF AGRICULTURE RECLAMATION ON THE HYDROLOGIC CHARACTERISTICS IN THE SANJIANG PLAIN, CHINA   总被引：1，自引：1，他引：0  

WANG Yi-yong  YANG Yong-xing 《中国地理科学(英文版)》2001,11(2):163-167

1 THE NATURAL ENVIRONMENTAL CHARACTERISTICS The Sanjiang Plain is located in the northeast of Heilongjiang Province, China. Russia borders this region in the north and east. Its total area is 1.088×107ha. The area of plain occupies 61.21％of the total land area and that of hill and mountain amounts to 38.79％of the total land area. It is not only one of the most important regions with large area of fresh water wetlands and with varieties of rare migratory waterfowls, but a…  相似文献   

浅钻技术在若尔盖地区泥炭调查中的应用          下载免费PDF全文

冉灵杰  祝强  苏兴涛  宋殿兰 《地质论评》2023,69(1):299-304

泥炭是一种具有多种用途的宝贵自然资源,泥炭中的有机碳储量是研究全球碳库变化及碳循环过程的重要参数。由于泥炭多分布于沼泽中,且泥炭松软含水量大的特性,对于泥炭深度的调查、获取用于测试泥炭原状样品的质量不高,导致泥炭碳储量评价仍存在不确定性和偏差。笔者等在典型泥炭形成地若尔盖沼泽湿地地区,开展了浅钻泥炭调查取样工作,通过在泥炭斑块边缘及中心两种不同沼泽湿地地层开展的试验,验证了轻便钻机在难进入的沼泽湿地的适应性,配套的振动冲击工艺可高质量的获得无扰动的泥炭样品,同时查明了泥炭层的厚度。通过试验初步探索了采用轻便钻机配套振动冲击钻进工艺进行泥炭调查取样的有效性。浅层取样钻探作为泥炭调查取样的一种直接有效的技术手段,可以有效地提高泥炭调查效率和精度,为准确评价泥炭储量数据提供可靠的钻探技术服务支撑。  相似文献   

沉积特征对低品位钾矿水溶开采的影响——以柴达木盆地马海盐湖北部矿段全新统为例     

王朝旭  赵艳军  赵宪福  王青春  何继辉  胡宇飞  龙鹏宇 《岩石矿物学杂志》2022,41(5):929-940

马海盐湖是柴达木盆地全新世形成的富低品位固体钾盐矿干盐湖,钾盐水溶开采潜力巨大。本文采用岩矿鉴定方法,对含盐系地层的沉积韵律岩性、钾盐矿物与矿层分布特征进行了研究,并分析了地层岩性的分布规律。结果表明,在马海盐湖北部矿区的主要沉积中心,沉积了一套以粘土-粉砂-石盐-粉砂石盐为主的沉积地层,同时在东南部形成了一个次级沉积中心;研究区钾盐矿物主要为杂卤石、光卤石、钾石盐等;沉积韵律分析结果显示,钾盐矿层多分布在Ⅳ₂韵律层顶部和Ⅳ₃-Ⅳ₄韵律层,产出形态在垂向上为层状、透镜状,平面上呈NE-SW向展布且连续性减弱;钾盐矿物和矿层分布与沉积演化关系密切,表明沉积特征对研究区钾盐矿水溶开采具有重要影响,为同类型低品位钾盐矿开采提供了一些参考。  相似文献   

库车坳陷克拉苏构造带协同变形机制及盆山耦合关系     

刘立炜  周慧  张承泽  闫炳旭  杨凤来  屈元基 《地质科学》2022,57(1):61-72

克拉苏构造带构造非常复杂,经过30余年的油气勘探开发,构造规律不清楚、构造圈闭不落实的问题仍然非常突出。本文通过大量三维地震资料的构造解释、建模及实钻资料验证,发现克拉苏构造带在剖面上呈分段分层变形、平面上呈雁列式展布特征。提出克拉苏构造带两种协同变形机制,较好地解释了在膏盐层调节作用下盐上、盐层、盐下3个构造层的差异变形现象。结合遥感影像及重力异常影像分析了盆山耦合关系,提出了南天山造山带的差异隆升推覆作用,南部温宿、新和、牙哈古隆起的阻挡作用和古近系膏盐层的调节作用是变形的3个主要影响因素,并据此较好地解释了克拉苏构造带构造圈闭平面展布格局。  相似文献   

Physical analog (centrifuge) model investigation of contrasting structural styles in the Salt Range and Potwar Plateau,northern Pakistan     

《Journal of Structural Geology》2015

We use scaled physical analog (centrifuge) modeling to investigate along- and across-strike structural variations in the Salt Range and Potwar Plateau of the Himalayan foreland fold-thrust belt of Pakistan. The models, composed of interlayered plasticine and silicone putty laminae, comprise four mechanical units representing the Neoproterozoic Salt Range Formation (basal detachment), Cambrian–Eocene carapace sequence, and Rawalpindi and Siwalik Groups (Neogene molasse), on a rigid base representing the Indian craton. Pre-cut ramps simulate basement faults with various structural geometries.A pre-existing north-dipping basement normal fault under the model foreland induces a frontal ramp and a prominent fault-bend-fold culmination, simulating the Salt Range. The ramp localizes displacement on a frontal thrust that occurs out-of-sequence with respect to other foreland folds and thrusts. With a frontal basement fault terminating to the east against a right-stepping, east-dipping lateral ramp, deformation propagates further south in the east; strata to the east of the lateral ramp are telescoped in ENE-trending detachment folds, fault-propagation folds and pop-up structures above a thick basal detachment (Salt Range Formation), in contrast to translated but less-deformed strata with E–W-trending Salt-Range structures to the west. The models are consistent with Salt Range–Potwar Plateau structural style contrasts being due to basement fault geometry and variation in detachment thickness.  相似文献   

Displacement transfer from fault-bend to fault-propagation fold geometry: An example from the Himalayan thrust front     

《Journal of Structural Geology》2015

The leading edge of the ENE-trending Himalayan thrust front in Pakistan exhibits along-strike changes in deformational style, ranging from fault-bend to fault-propagation folds. Although the structural geometry is very gently deformed throughout the Salt Range, it becomes progressively more complex to the east as the leading edge of the emergent Salt Range Thrust becomes blind. Surface geology, seismic reflection, petroleum well, and chronostratigraphic data are synthesized to produce a 3-D kinematic model that reconciles the contrasting structural geometries along this part of the Himalayan thrust front. We propose a model whereby displacement was transferred, across a newly-identified lateral ramp, from a fault-bend fold in the west to fault-propagation folds in the east and comparable shortening was synchronously accommodated by two fundamentally different mechanisms: translation vs. telescoping. However, substantially different shortening distribution patterns within these structurally contrasting segments require a tear fault, which later is reactivated as a thrust fault. The present geometry of this S-shaped displacement transfer zone is a combined result of the NW–SE compression of the lateral culmination wall and associated tear fault, and their subsequent modification due to mobilization of underlying ductile salt.  相似文献   

Estimating evapotranspiration for a temperate salt marsh,Newcastle, Australia     

C. E. Hughes  J. D. Kalma  P. Binning  G. R. Willgoose  M. Vertzonis 《水文研究》2001,15(6):957-975

Evapotranspiration was studied at a salt marsh site in the Hunter River estuary, NSW, Australia, during 1996–8. Estimates of actual evapotranspiration (E_a) were obtained for three sites using the eddy correlation method. These values were compared with results obtained with the Penman and Penman–Monteith equations, and with pan evaporation. The Penman–Monteith method was found to be most reliable in estimating daily and hourly evapotranspiration. Surface resistance values averaging 12 s m^?1 were derived from the eddy correlation estimates. Recent tidal flooding and rainfall were found to decrease surface resistance and increase E_a/E_p ratios. Estimates of evapotranspiration obtained using the Penman–Monteith method were shown to be sensitive to changes in surface resistance, canopy height and the method used to estimate net radiation from incoming solar radiation. These results underline the importance of accurately estimating such parameters based on site‐specific data rather than relying on empirical equations, which are derived primarily for crops and forests. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献