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1.
盐渍土是江苏沿海地区开发建设需关注的地质环境问题之一。本文系统采集5 m以浅的土样,开展易溶盐试验,研究了江苏沿海盐渍土分布规律、盐渍化程度及影响因素。研究结果表明:全区盐渍土平行于海岸线分布;以中、弱盐渍土为主,强盐渍土零星分布。受沉积环境、气候、水文地质条件、人类活动等共同影响,盐渍化程度空间差异明显。平面上,盐渍化程度呈北强南弱、向海岸线方向延伸有逐渐增强的趋势,强盐渍土分布于连云港黏性土区,岩性、地下水矿化度为主导影响因素。垂向上,表层普遍积盐,连云港地区分带不明显,大丰和南通地区自地表而下可划分为三带,表层土蒸发积盐、中层盐动态变化、下层土饱水盐稳定,地下水位、土体结构为主导影响因素。随着沿海大开发的快速推进,为防止次生盐渍化问题,需关注地面沉降导致的地面高程损失诱发海水入侵加重表层土盐渍化,工程建设中可设置隔离层截断高矿化度地下水的毛细作用。 相似文献
2.
北京市延庆区是首都生态涵养区,开展土壤重金属分布特征及来源解析研究对保障土地安全利用、防控生态环境风险具有重要意义。采集延庆区2 354件表层土样及44件深层土样,测试分析了重金属元素As、Cd、Cr、Hg、Ni、Pb、V、Zn及Sc等含量。采用空间分布分析、多元统计分析与受体模型相结合的方法,阐明了土壤重金属元素分布特征,解析了土壤重金属潜在来源,并计算了不同来源对土壤重金属的相对贡献率。结果表明,表层土壤中V、Cr、Ni、As元素主要来源于成土母质,Cd、Zn、Pb含量高值区集中分布于人口密集区域,人为活动对该3种元素影响较大,而Hg主要受大气干湿沉降的影响。深层土壤中Hg元素在居民区含量较高,而其余元素均未受到人为活动的影响。 相似文献
3.
【研究目的】球囊霉素作为丛枝菌根真菌（AMF）分泌的一种难降解土壤蛋白,广泛分布于陆地生态系统中,是长期碳贮的重要组成。当前鲜有研究涉及其在滨海湿地中的分布。基于此,本文对中国环渤海主要滨海湿地表层沉积物中球囊霉素相关土壤蛋白（GRSP）的空间分布进行表征,探讨不同湿地生境下GRSP分布及其对沉积物风化的指示意义。【研究方法】本文选取辽河三角洲、北大港和黄河三角洲湿地作为研究区,对166个表层样（0~5 cm）和4个柱状样（0~35 cm）的GRSP、粒度以及常量元素进行测定,并计算化学蚀变系数（CIA）。【研究结果】研究区GRSP在空间上的动态变化受植被类型影响显著,范围在0.06~11.31 mg/g,均值为（2.35±0.16） mg/g;沉积物以粉砂质砂和砂为主,CIA值分布范围为44.79~69.59,部分区域达到中等化学风化;CIA与GRSP呈显著相关（R=~0.49,p<0.01）,总体上CIA随GRSP的增加呈现先增加后减少的趋势。【结论】GRSP在滨海湿地沉积物中的分布受到生境差异性的影响,其与CIA的相关性表征AMF及其代谢产物在地质体风化过程中发挥了潜在的生态功能。创新点：揭示了球囊霉素相关土壤蛋白与地质过程的互馈作用;阐明了丛枝菌根真菌潜在的生态功能。 相似文献
4.
黄河三角洲滨海湿地健康条件评价 总被引：3，自引：0，他引：3
以黄河三角洲滨海湿地系统为研究对象,基于描述滨海湿地健康条件的4项功能,充分考虑滨海湿地生态地质环境系统的特征及其健康响应因素,建立了黄河三角洲滨海湿地健康条件评价的概念模型和指标体系。以统计监测和遥感数据为基础,采用RS和GIS技术,通过栅格化实现分区评价及其结果的优化整合,探讨了黄河三角洲滨海湿地健康的时空分布规律。结果显示：黄河三角洲滨海湿地现状健康条件处于健康的占14.2%,亚健康的占61.9%,一般病态的占23.9%;近期（2010－2015年）,河口三角洲湿地生境质量会逐步改善,向健康方向发展,而北部和南部部分滩涂区及神仙沟流路等局部地区在自然和人为因素的共同作用下,环境质量会有一定的降低;影响黄河三角洲滨海湿地健康条件的主要因素是全球气候变化背景下的区域水循环关键过程及其时空变化、湿地开发等人类负面干扰和黄河下游生态调度。应继续加大黄河下游生态调度的力度、积极实施生态修复工程,以促进黄河三角洲滨海湿地持续健康发展。 相似文献
5.
Benjamin J. Wilson Shelby Servais Sean P. Charles Stephen E. Davis Evelyn E. Gaiser John S. Kominoski Jennifer H. Richards Tiffany G. Troxler 《Estuaries and Coasts》2018,41(8):2147-2158
Coastal wetlands, among the most productive ecosystems, are important global reservoirs of carbon (C). Accelerated sea level rise (SLR) and saltwater intrusion in coastal wetlands increase salinity and inundation depth, causing uncertain effects on plant and soil processes that drive C storage. We exposed peat-soil monoliths with sawgrass (Cladium jamaicense) plants from a brackish marsh to continuous treatments of salinity (elevated (~?20 ppt) vs. ambient (~?10 ppt)) and inundation levels (submerged (water above soil surface) vs. exposed (water level 4 cm below soil surface)) for 18 months. We quantified changes in soil biogeochemistry, plant productivity, and whole-ecosystem C flux (gross ecosystem productivity, GEP; ecosystem respiration, ER). Elevated salinity had no effect on soil CO2 and CH4 efflux, but it reduced ER and GEP by 42 and 72%, respectively. Control monoliths exposed to ambient salinity had greater net ecosystem productivity (NEP), storing up to nine times more C than plants and soils exposed to elevated salinity. Submersion suppressed soil CO2 efflux but had no effect on NEP. Decreased plant productivity and soil organic C inputs with saltwater intrusion are likely mechanisms of net declines in soil C storage, which may affect the ability of coastal peat marshes to adapt to rising seas. 相似文献
6.
Spatial and seasonal variation of salt ions under the influence of halophytes,in a coastal flat in eastern China 总被引：1，自引：0，他引：1
Yanyou Wu Rongcheng Liu Yuguo Zhao Pingping Li Congqiang Liu 《Environmental Geology》2009,57(7):1501-1508
The high salinity of coastal saline field is a key factor limiting the reclamation. Halophytes have been utilized in the reclamation
of saline land. The study area is in Yancheng, China. An analysis of the concentrations of Rb, Cs, Sr, and Ba, the ratio of
Rb/Cs, and Sr/Ba in soils in autumn shows that the soil of this study area has great homogeneity. Artemisia halodendron, Gossypium hirsutum, and Sesbania cannabina were selected as the reclamation plants in the present study. In order to know the spatial-temporal distribution of soil
salinity, the influence of plant-specific vegetation, and the difference of desalination among these halophytes in coastal
flat, the authors analyze the soil-layers and seasonal variation in salt ions. Sodium chloride was accumulated in 0–5 cm topsoil
with no vegetation during the winter and spring. The effect of desalinization of halophytes is significant. Of the three plant
species, Sesbania cannabina has the greatest desalinization. The difference of ions composition of soils covered with various plant species is significant.
It can be concluded that halophytes have better amelioration of coastal soil salinity. Special attention should be paid to
the selection of plant species and measures to plant and cultivate crops in the reclamation of saline land. 相似文献
7.
Catchment scale spatial variability of soil salt content in agricultural oasis,Northwest China 总被引：4，自引：0，他引：4
Soil salinization is a serious environmental problem in the world, especially in arid and semi-arid regions. Therefore, estimating
spatial variability of soil salinity plays an important role in environmental sciences. Aiming at the problem of soil salinization
inside an oasis, a case study was carried out at the Sangong River catchment in Xinjiang province, northwest China. Methods
of classical statistics, geostatistics, remote sensing (RS) and geographic information system (GIS) were applied to estimate
the spatial variability of soil salt content in the topsoil (0–20 cm) and its relationship with landscape structure at catchment
scale. The objective of this study was to provide a scientific basis to understand the heterogeneous of spatial distribution
of soil salt content at a large scale. The results revealed that (1) elevation of landform was a key factor for soil salt
content’s spatial variability, and soil salt content had a strong spatial autocorrelation, which was mainly induced by structural
factors. (2) Mapping of soil salt content by Kriging and comparing it with landscape maps showed that area of soil salinization
in old oasis was smaller than that in new oasis, and degree of soil salinization in old oasis was also lower than that in
the new one. Among all landscapes, cropland was mostly affected by salinity, with 38.8% of the cropland in new oasis moderately
affected by soil salinity, and 8.54% in old oasis. 相似文献
8.
柴达木盆地盐湖众多,表土盐渍化和盐漠化极为发育,含盐表土经风吹蚀后产生的大量盐尘将危害盆地生态环境和人类健康。笔者在柴达木盆地中东部系统采集129个不同类型的表土样品,对其中盐类矿物成分及分布特征进行了分析。分析结果表明,表土中的主要盐类矿物是石盐、石膏以及少量的无水芒硝;盆地中东部含盐量高值区集中分布在尕斯库勒湖以东的一里坪盐湖、西台吉乃尔盐湖和东台吉乃尔盐湖周边以及中部格尔木—诺木洪一带绿洲前缘的区域;盆地不同表土的含盐量从高到低依次为干盐滩(盐壳)、雅丹、盐化草原、戈壁滩和沙漠。研究结果显示,雅丹和干盐滩很可能是盐尘暴的主要物源区,其他类型表土贡献较小;表土含盐特征及其分布规律可能受区域构造、盐湖演化、气候与水文等多种因素的影响。本文成果可以为柴达木盆地盐尘暴的形成机制和灾害防治等提供重要科学依据。 相似文献
9.
Assessment of temporal and spatial variability of soil salinity in a coastal saline field 总被引：1，自引：0，他引：1
Many coastal tideland areas in southern Hangzhou Gulf in Zhejiang Province of China have been successively enclosed and reclaimed for agricultural land uses under a series of reclamation projects over the past 30 years. The variability of soil salinity was considerably great and an understanding of the temporal and spatial components of soil salinity variability is essential before decisions can be made about the feasibility of site-specific management. In this paper, a 5.35-ha field reclaimed in 1996 was selected as the study site and 112 bulk electrical conductivity (ECb) measurements were performed in situ by a hand held device in the topsoil (0–20 cm) at regular 20-m intervals across the field over a two-year period. Conventional statistics and geostatistical techinques were used to assess the spatial variability and temporal stability of soil-salinity distribution. The results indicated high coefficients of variation in topsoil salinity over the three samplings. Simple mean ECb comparison revealed that soil salinity increased from winter to spring. Kriged contour maps showed the spatial trend of salinity distribution and revealed the consistently high and low salinity areas of the field. In percentage terms, the proportions of the moderately saline class, strongly saline class, and extremely saline class were 37, 39, and 24%, respectively. Temporal stability map indicated that more than 60% of the study field was determined as the stable class. Based on the spatial and temporal characteristics, a similarity assessment map was created, which presented 5 homogenous sub-zones, each with different characteristics that can have an impact on the way the field is managed. It was concluded that saline soil land might be managed in a site-specific way based on the clearly defined management sub-regions within the field. 相似文献
10.
R. Eugene Turner 《Estuaries and Coasts》2011,34(5):1084-1093
Although the broadly observed increase in nutrient loading rates to coastal waters in the last 100 years may increase aboveground
biomass, it also tends to increase soil metabolism and lower root and rhizome biomass—responses that can compromise soil strength.
Fourteen different multiyear field combinations of nutrient amendments to salt marshes were made to determine the relationship
between soil strength and various nitrogen, phosphorus, and nitrogen+phosphorus loadings. There was a proportional decline
in soil strength that reached 35% in the 60- to 100-cm soil layer at the highest loadings and did not level off. These loading
rates are equivalent to those in the flow path of the Caernarvon river diversion, a major wetland restoration project near
New Orleans; 12% of the wetlands in the flow path were converted to open water in 2005. The increased nutrient loading from
the Mississippi River watershed this century has also driven the formation of the low oxygen zone (the “Dead Zone”) that forms
off the Louisiana–Texas shelf each summer. These results suggest that improving water quality in the watershed will aid the
restoration of both offshore waters and coastal wetland ecosystems. 相似文献
11.
黄河三角洲滨海湿地健康条件评价概念模型 总被引：3，自引：0，他引：3
滨海湿地健康与生物学特征主要取决于区域上的水文与盐度体制以及景观尺度上的土地利用现状。然而,由于滨海湿地条件评价的指标和标准并不十分清楚,因此,对滨海湿地系统条件进行评价,目前仍是环境科学的难点。中国地质调查局（CGS）青岛海洋地质研究所与美国地质调查局湿地研究中心合作先后为美国密西西比河下游生态环境及中国黄河三角洲（YRD）滨海湿地评价建立了概念模型。本文将陈述YRD湿地评价的概念模型。此模型的建立在于确定滨海湿地当前的条件和随时间改善或退化的过程,以及确定优先管理的区域。CGS项目之所以选取YRD作为滨海湿地的研究对象主要是因为它具有重要的生态意义。由于上游来水减少或黄河断流,该区湿地生境十分脆弱。本文提出此概念模型可为今后湿地条件评价指标确定、调查研究活动和数据采集提供指导。通过该模型的构建,使环境变化可用具体指标来度量,从而服务于滨海湿地生态系统的保护与管理活动。 相似文献
12.
Coastal Wetlands of China: Changes from the 1970s to 2007 Based on a New Wetland Classification System 总被引：1，自引：0，他引：1
A new classification of coastal wetlands along the coast of China has been generated that is compatible with the Ramsar Convention of 1971. The coastal wetlands have been divided into two broad categories with overall nine subcategories. On this basis, a series of coastal wetland maps, together covering the coast of mainland China, have been produced based on topographic maps acquired in the 1970s and satellite images acquired in 2007. These document substantial wetland losses over this period. In the 1970s, the total coastal wetland area in China was 5.76?×?104?km2, whereas in 2007, it was 5.36?×?104?km2, indicating a loss of 7 %. Over this approximately 40-year period, the area of natural coastal wetlands decreased from 5.74?×?104 to 5.09?×?104?km2, while that of artificial coastal wetlands increased from 240 to 2,740 km2. Due to shoreline and sea-level changes, newly formed coastal wetlands amounted to 2,460 km2, while coastal wetland loss amounted to 6,310 km2 in the period from the 1970s to 2007. When excluding shallow coastal waters (depths between 0 and ?5 m), nearly 16 % of Chinese coastal wetlands have been lost between the 1970s and 2007. 相似文献
13.
为了探究江苏东台条子泥围垦区的水盐分布规律,揭示圆环状植被分布与土壤水盐条件的关系,于2019年9月对围垦区内用作湿地恢复的区域进行测量和采样。在植被环附近测量了二维、三维大地电阻率,采集降水、地表水、土壤、地下水等样品,测试样品的水盐指标和D、18O同位素组成。结果表明:植被圆环下方3 m深度内均存在对应的高电阻率/低盐度区域,且随着植被类型由中心向外环变化,对应的土壤水盐度也逐渐增大;土壤水盐度是不同植被呈现圆环状分布的重要影响因素,其变化受降水入渗和土壤蒸发引起的盐分集结共同作用;土壤盐度直接影响了不同植被种群的分布格局,而植被对入渗和蒸发过程的影响也反作用于土壤盐度分布。 相似文献
14.
生态地球化学评价中建立土壤元素地球化学背景方法研究:以太原盆地潮土中Hg、Cd、Pb、As为例 总被引：2，自引：0，他引：2
深层土壤与表层土壤中元素质量分数的差异被一些学者归因于表层土壤受人为污染所致。文中通过解析山西太原盆地深、表层潮土中Hg、Cd、Pb、As的地球化学分布特征,并通过对比研究区与基本保持清洁状态的源区土壤中相应元素质量分数变化特征,论述了成壤过程中元素的自然分异作用是造成深、表层潮土中Hg、Cd、Pb、As质量分数显著差异的主要原因,以及人为污染仅在局部地区造成Hg、Cd、Pb、As在表层潮土中富集的观点。通过求解太原盆地表层潮土中Hg、Cd、Pb、As地球化学背景值的实例,详细介绍了以深层土壤元素的地球化学背景为参照系,运用相关分析和累积频率分析求解表层土壤元素地球化学背景值的方法。 相似文献
15.
黄河三角洲内陆到潮滩土壤中碳、氮元素的梯度分布规律 总被引：1，自引：0，他引：1
黄河三角洲是我国典型的通过黄河冲积泥沙填海造陆形成的近代沉积区。区域受到黄河冲积、沉积等自然过程和农业耕种熟化等人类活动的双重影响。本研究通过在黄河三角洲地区内陆到河口海湾不同距离采集典型土壤类型剖面发生层样品,探讨土壤有机碳、总氮等生源要素的空间分布规律,为阐明我国典型海岸带地区陆源碳、氮的输送及循环特征提供基础依据。研究结果表明,黄河三角洲内陆与河口地区呈现出完全不同的土壤碳、氮分布规律。表层土壤碳、氮含量在黄河沿岸及三角洲南部均表现出由陆向海逐级递减的空间分布特征,而在黄河刁口流路和清水沟流路沿行水方向有梯度升高的趋势。内陆地区土壤碳、氮与盐分呈一定的负相关关系,表明土壤碳、氮主要受到耕作熟化过程的影响;而在河口地区两者呈显著的正相关关系（p〈0.01）,表明靠近海湾地区土壤碳、氮积累可能受到细颗粒泥沙沉积和滩涂湿地厌氧等环境影响。表层土壤碳、氮比变幅在3.6~8.6之间,说明该地区土壤有机质分解较快,不利于有机碳的积累。土壤剖面中,一些特殊发生层如红色夹黏层、黑色泥炭层对土壤碳、氮的富集具有明显的作用,其中红色夹黏层的土壤碳、氮含量接近耕层土壤。总之,黄河三角洲土壤在耕作垦殖、泥沙沉积等综合作用下形成的空间分布格局以及剖面特征发生层是影响碳、氮封存、释放和增汇等循环过程的关键驱动因素。 相似文献
16.
天津滨海新区被提到国家总体发展战略后,随着经济持续发展、城市化进程不断加速及产业转移,进行了大规模围海造陆,在拓展土地空间的同时,也造成了相当多的环境问题。利用滨海新区由陆到海的3条水文地质剖面获取的地下水动态变化监测数据和土壤含盐量测试结果,开展了围海造陆对沿海低地浅层地下水环境的影响研究。结果显示:1受围海造陆影响,对应的沿海低地浅层水位已经出现由陆到海逐渐增高的现象,造成地下水位反向倾斜,阻碍了地下水径流和排泄;2由陆到海浅表土壤全盐量出现逐渐增高的特征,在浅层地下水反向径流作用下,东部区域大量的盐分将被携带至沿海低地,使沿海低地盐渍化程度加重,严重影响到湿地保护和生态建设;3围海造陆对海岸带生态环境的影响是一个长期缓慢的过程,应持续监测近岸海域和陆域沿海低地生态环境的变化情况,以便提出合理的修复建议。 相似文献
17.
在福建省沿海经济带生态地球化学调查的基础上,应用富集因子法对福建省沿海地区表层土壤中铅的来源进行了分析,并对其自然来源和人为来源的分布特征及影响因素做了初步探讨。结果表明,福建沿海地区约98.2%的土地面积表层土壤中铅属于自然来源,其余地区含有人为来源铅,且集中分布于个别市县城区;铅自然来源区呈现广域性分布特征,人为来源区则呈现零星的斑点状分布特点;铅自然来源区和人为来源区的空间分布特征在很大程度上受到土壤类型、森林植被分布以及人为活动等因素的影响。 相似文献
18.
Changes of freshwater-lens thickness in basaltic island aquifers overlain by thick coastal sediments 总被引：1，自引：1，他引：0
Freshwater-lens thickness and long-term changes in freshwater volume in coastal aquifers are commonly assessed through repeated measurement of salinity profiles from monitor wells that penetrate into underlying salt water. In Hawaii, the thickest measured freshwater lens is currently 262 m in dike-free, volcanic-rock aquifers that are overlain by thick coastal sediments. The midpoint depth (depth where salinity is 50% salt water) between freshwater and salt water can serve as an indicator for freshwater thickness. Most measured midpoints have risen over the past 40 years, indicating a shrinking lens. The mean rate of rise of the midpoint from 1999–2009 varied locally, with faster rates in highly developed areas (1.0 m/year) and slower rates in less developed areas (0.5 m/year). The thinning of the freshwater lenses is the result of long-term groundwater withdrawal and reduced recharge. Freshwater/salt-water interface locations predicted from measured water levels and the Ghyben-Herzberg principle may be deeper than measured midpoints during some periods and shallower during other periods, although depths may differ up to 100 m in some cases. Moreover, changes in the midpoint are slower than changes in water level. Thus, water levels may not be a reliable indicator of the amount of freshwater in a coastal aquifer. 相似文献
19.
The drought and salt tolerance of two pioneer species, Populus euphratica and Tamarix ramosissima, were studied by monitoring the stem and leaf water potentials under various soil moisture and salinity at depths of 0–180 cm. The plants are naturally distributed in arid environment in the lower reaches of the Tarim River in Xinjiang, China. The results showed that P. euphratica can withhold water by prolonging dewatering and adapt to the dry desert weather by reducing water consumption. The lowest soil moisture that would unfavorably influence its growth was found to be 7% soil moisture. T. ramosissima was found to have low water potential and high transpiration efficiency. It is capable of absorbing water from the soil by keeping a low water potential, so there is no critical limit of soil moisture for T. ramosissima. In terms of salt resistance, P. euphratica was found to secrete salt from its body by discharging salty water through portals in its trunks and leaves. A soil salinity of 20% was the minimum concentration at which the salt secretion mechanism of P. euphratica was activated. T. ramosissima secreted salt by storing the accumulated salt in the vacuoles of its salt secretion glands for separation. Thus, it has no minimum soil salinity limit. T. ramosissima was found to have better resistance to drought and salt stress than P. euphratica. 相似文献
20.
Qicheng Zhong Kaiyun Wang Qifang Lai Chao Zhang Liang Zheng Jiangtao Wang 《Estuaries and Coasts》2016,39(2):344-362
Large areas of natural coastal wetlands have suffered severely from human-driven damages or conversions (e.g., land reclamations), but coastal carbon flux responses in reclaimed wetlands are largely unknown. The lack of knowledge of the environmental control mechanisms of carbon fluxes also limits the carbon budget management of reclaimed wetlands. The net ecosystem exchange (NEE) in a coastal wetland at Dongtan of Chongming Island in the Yangtze estuary was monitored throughout 2012 using the eddy covariance technique more than 14 years after this wetland was reclaimed using dykes to stop tidal flooding. The driving biophysical variables of NEE were also examined. The results showed that NEE displayed marked diurnal and seasonal variations. The monthly mean NEE showed that this ecosystem functioned as a CO2 sink during 9 months of the year, with a maximum value in September (?101.2 g C m?2) and a minimum value in November (?8.2 g C m?2). The annual CO2 balance of the reclaimed coastal wetland was ?558.4 g C m?2 year?1. The ratio of ecosystem respiration (ER) to gross primary production (GPP) was 0.57, which suggests that 57 % of the organic carbon assimilated by wetland plants was consumed by plant respiration and soil heterotrophic respiration. Stepwise multiple linear regressions suggested that temperature and photosynthetically active radiation (PAR) were the two dominant micrometeorological variables driving seasonal variations in NEE, while soil moisture (M s) and soil salinity (PSs) played minor roles. For the entire year, PAR and daytime NEE were significantly correlated, as well as temperature and nighttime NEE. These nonlinear relationships varied seasonally: the maximum ecosystem photosynthetic rate (A max), apparent quantum yield (?), and Q 10 reached their peak values during summer (17.09 μmol CO2?m?2 s?1), autumn (0.13 μmol CO2?μmol?1 photon), and spring (2.16), respectively. Exceptionally high M s or PSs values indirectly restricted ecosystem CO2 fixation capacity by reducing the PAR sensitivity of the NEE. The leaf area index (LAI) and live aboveground biomass (AGBL) were significantly correlated with NEE during the growing season. Although the annual net CO2 fixation rate of the coastal reclaimed wetland was distinctly lower than the unreclaimed coastal wetland in the same region, it was quite high relative to many inland freshwater wetlands and estuarine/coastal wetlands located at latitudes higher than this site. Thus, it is concluded that although the net CO2 fixation capacity of the coastal wetland was reduced by land reclamation, it can still perform as an important CO2 sink. 相似文献