Water Flows Toward Power: Socioecological Degradation of Lake Urmia,Iran

Water is an invaluable resource, and equitable access to it is a fundamental human right. Disenfranchised groups often lose access to water resources because their interests are not well represented by decision makers. Excluding these groups from resource management policy often results in myopic decisions that contribute to further ecosystem damage. We describe the ecological degradation of Lake Urmia in Iran, which has recently experienced increased salinity and declining water quantity. The lake is a UNESCO Biosphere Reserve and Ramsar site, and supports unique biodiversity in the region. The lake's decline is driven by the destruction of Zagros forests and the government's water policies, which diverted water to more politically connected agricultural land users, increasing social inequity and prompting more deforestation. The most straightforward restoration solution is to discontinue the diversions and allow critical inflows to recharge Lake Urmia, preserving the lake and wetlands for migratory birds, tourists, and local communities.     

哈拉湖岩芯XRF扫描元素统计分析及其环境意义

青藏高原东北缘高山湖泊哈拉湖是位于季风与西风影响的交汇带的封闭深水湖泊,是区域环境和气候变化的良好记录载体。目前对该湖的研究还较少,缺乏对沉积物中元素环境意义的系统认识。通过高分辨率XRF岩芯扫描,用相关、聚类和因子分析的方法对哈拉湖沉积岩芯地球化学元素进行分析。结果显示Ti、K、Si、Al、Fe、Mn等元素变化一致,相关性高,归为同一类,即径流输入的陆源碎屑组分,反映了流域水文状况如径流量的变化。Sr、Zr元素相关性高,为赋存在粗颗粒沉积物中的元素,根据哈拉湖实际,应为冬季湖泊冰面风力搬运,反映了湖区冬季风力强度的变化。Ca元素既与径流输入元素总体变化一致,也与Sr、Zr元素显著相关,且在第一和第二主成分(径流和风力)上的载荷相当,表明哈拉湖沉积物中的碳酸盐既有粗颗粒的外源碎屑,也有湖泊自生的组分,这在利用碳酸盐进行地球化学研究时应重视,注意去除外源碎屑碳酸盐的影响。可溶元素S和Cl可能反映了入湖水量与蒸发对比情况,与湖泊盐度有关。     

柴达木盆地西部大浪滩梁中矿区软钾镁矾沉积的矿物组合特征

柴达木盆地西部大浪滩梁中矿区是一个以液体钾矿为主、固液并存的大型钾镁盐矿田。通过对梁中矿区大浪滩凹地钾镁盐矿点实地考察,以兴元钾肥厂开挖的固体钾盐(软钾镁矾、钾石盐和杂卤石等矿物)剖面为研究载体,采集73件固体盐样。通过XRD矿物组成分析,发现梁中凹地盐类呈石盐+泻利盐—石盐+泻利盐+软钾镁矾—石盐+泻利盐+钾石盐—石盐+钾石盐+光卤石—石盐+水氯镁石矿物组合变化。其中,在Ⅱ阶段(5.3².6 m)沉积了层状的固体钾盐矿物(包含软钾镁矾、钾石盐和光卤石)。地层中沉积的软钾镁矾,结晶良好。通过对比分析认为,软钾镁矾的形成条件:1)外来水体的混入,溶滤了地表盐滩中可溶性钾;2)(全新世)相对较高的温度条件,芒硝等矿物的溶解,会使湖表卤水中硫酸盐含量明显增加,卤水组成点易落在25℃介稳相图的白钠镁矾相区,有利于软钾镁矾结晶析出;3)干旱的气候条件。     

Effect of Groundwater Level Fluctuation on Phragmites australis Evapotranspiration in the Baiyangdian Lake

Abstract:Hydrological regimes influence ecological patterns and processes as well as alter rates of wetland evapotranspiration.This study aimed to investigate the impact of groundwater fluctuation on evapotranspiration of Phragmites australis.Supported by field data obtained from the Baiyangdian Lake in northern China,the variations in groundwater levels were explored,and the changes in soil water and evapotranspiration of reed were analyzed to investigate different groundwater level scenarios using HYDRUS-1D model.The results showed that soil water content,recharged by groundwater,remained stable in the lower soil layer but varied strongly in the upper layer of the soil profile;in comparison to evaporation,Phragmites australis transpiration contributed significantly more to the overall evapotranspiration rate;the high levels of evapotranspiration could be maintained when groundwater levels vary between 1.0 m and 1.8 m,while it was reduced with an increase in groundwater levels as a result of water stress conditions.The results also indicated that the evapotranspiration of Phragmites australis could maintain higher evapotranspiration rates under natural water levels.The evapotranspiration,in other words,might be the main water consumer,but it nevertheless has little effect on water levels during water shortages.The evapotranspiration of Phragmites australis responded to the changes in groundwater levels could help researchers understand water requirements of the wetlands and establish suitable water levels for the wetlands.     

夏季贝加尔湖南侧环流异常的前兆信号

利用1978—2012年NCEP/NCAR逐月再分析资料,对夏季贝加尔湖南侧环流异常的前兆信号进行分析。结果表明:前期冬季印度尼西亚到西太平洋地区对流与夏季贝加尔湖南侧反气旋式环流异常存在一致的变化,为预测夏季贝加尔湖南侧环流异常的前兆信号之一。即当前期冬季印度尼西亚到西太平洋地区对流活动偏强时,夏季对流区北抬至青藏高原西侧,进而有利于贝加尔湖南侧反气旋式环流异常的发生和维持。但是,进一步研究表明,夏季西印度洋对流活动异常将干扰青藏高原及其西侧的对流上升运动对贝加尔湖环流的影响。当夏季西印度洋对流偏强时,前期冬季印度尼西亚到西太平洋对流和夏季青藏高原西侧对流变化表现出不一致。偏强的西印度洋对流将干扰青藏高原及其西侧的对流上升运动对贝加尔湖环流的影响,进而不利于贝加尔湖南侧反气旋式环流异常的形成。当夏季西印度洋对流异常弱时,前期冬季印度尼西亚到西太平洋地区的对流可能引起夏季贝加尔湖南侧环流异常,两者呈现一致的变化;但当夏季西印度洋对流强盛时,将可能改变上述两者的变化关系。     

Lacustrine basin unconventional resource plays: Key differences

There has been a revival in hydrocarbon source rock characterization and development associated with growing interest in unconventional resources, where these fine-grained organic-rich rocks act as both source and reservoir. To-date, the exploration focus on shale reservoirs has been largely on marine systems. Lacustrine source rocks for conventional resources are geographically important, dominating regions such as China, Indonesia, and Brazil's resource-base. However, they have been generally untested for unconventional resources.There are a number of key differences in the nature of these hydrocarbon systems that should be considered when assessing whether lacustrine systems may represent future unconventional opportunities in areas where the conventional resource-base is dominated by lacustrine-sourced oil. Among the key differences between these depositional systems is the greater sensitivity to high frequency climatic variability within lacustrine systems. Lacustrine systems are highly sensitive to changes in the balance between precipitation and evaporation, which may lead to rapid changes in lake level, potentially exceeding 600 m. These changes in depositional conditions are geologically rapid and may occur over periods of thousands of years. Such changes can reduce the areal extent of potentially thick source rock intervals to only those portions of a basin where a permanent deep lake was present. Thus the core unconventional target area may be geographically limited compared with their marine counterpart. Although potentially areally limited, a review of many lacustrine source rocks suggests that their thicknesses are often significantly greater than marine source rocks. An examination of the more distal portions of lacustrine systems, where better source rock potential is present reveals that there is generally limited connectivity between source and conventional reservoir. In these settings, such as the Wind River basin (Waltman Shale), the hydrocarbons remain trapped within the shales, potentially leading to over-pressured hydrocarbon charged systems. Such conditions suggest that although areally limited, viable unconventional targets may exist, if suitable reservoir conditions are present. Finally, the character of the oils produced is different in these settings, with lacustrine oils being waxy and displaying different hydrocarbon generation and cracking kinetics. High wax oils display distinct flow characteristics, being more viscous, and may offer different production challenges than their non-waxy marine equivalents. Additionally, differences in their cracking kinetics may indicate that the timing of gas generation for shale gas plays may differ significantly from marine systems.     

荣成天鹅湖越冬大天鹅粪便的重金属水平

为对大天鹅(Cygnus cygnus)保护及湖区管理提供基础数据,作者于2011年11月~2012年3月研究了山东荣成天鹅湖越冬大天鹅食物来源及其粪便的重金属水平。结果表明:所选择的食物来源中,Zn、As和Cr在硬毛藻(Chaetomorpha linum)中含量最高,Cd在大叶藻(Zostera marina L.)叶片中含量最高,Pb在大叶藻根茎中含量最高,Cu在石莼(Ulva pertusa)中含量最高,Hg在小麦(Triticum aestivum)中含量最高;水生植物来源的粪便中Cd含量极显著高于陆地植物来源的粪便,陆地植物来源的粪便中Cr,Pb和Hg含量显著高于水生植物来源的粪便;摄食小麦苗可能造成大天鹅对Cd和Hg的积累。     

2000—2019年鄱阳湖生态经济区水源涵养时空变化

水源涵养是生态保护的一个重要方面,对鄱阳湖生态经济区生态保护具有重要意义。本文基于InVEST模型,对鄱阳湖生态经济区2000—2019年产水和水源涵养时空变化进行了分析,并运用空间自相关探究了高程、坡度与水源涵养功能的空间关系。结果表明:①鄱阳湖生态经济区多年平均产水深度为971.04 mm,多年平均水源涵养深度为299.298 mm;②2000—2019年水源涵养深度先上升后下降,变化幅度较大,整体呈上升趋势;③水源涵养功能呈地域分布,重要区和极为重要区主要分布在东部和西北部林地,一般重要区分布在鄱阳湖平原;④水源涵养与高程和坡度呈正相关,高值多出现在高海拔和坡度较大的地区。     

新疆赛里木湖的湖滩岩特征、时代及其对 MIS3阶段湖面变化的指示意义

在对西天山赛里木湖盆地进行第四纪地质调查与5万填图基础上,发现沿该湖泊的不同湖岸阶地上都不同程度地发育了可指示湖面变化的湖滩岩。水准测量结果表明,典型的湖滩岩最常见于高出现今湖面7.1~9.4 m和33.4~39.4 m的低、高两级湖积台地上。对湖滩岩样品进行岩石学和矿物学研究进一步揭示,湖滩岩主要由内碎屑、藻团块、陆源碎屑、胶结物和填隙物等构成,胶结物主要为亮晶方解石,夹少量文石,表明赛里木湖周边的湖滩岩为典型的方解石胶结砂屑砾屑岩。湖滩岩样品的U系年代测试结果表明,低、高两级台地上的湖滩岩主要形成于距今24.8±1.5 ka至27.6±1.5 ka和55.4±3.8 ka的晚更新世晚期,大致对应末次冰期间冰阶MIS3阶段早期和末期的相对暖湿气候阶段。湖滩岩及其测年结果指示,赛里木湖最近一期最高湖面出现在距今55.4 ka左右末次间冰阶早期,其后由于气候的干旱化,湖面整体处于逐步下降过程,在相对暖湿期间经历了多次湖面相对稳定期并形成湖滩岩。     

内蒙古布日敦湖湖泊沉积物粒度的风沙活动指示意义

本文通过研究位于东亚季风过渡带的布日敦湖湖泊沉积物粒度组成和碳、氧同位素特征,结合210Pb/137Cs年代数据,建立布日敦湖近50年的粒度变化序列。通过与中国北方100个气象站数据的年平均沙尘暴日数进行对比,建立研究区可靠的风沙活动指标。研究发现,布日敦湖湖泊沉积物粒度特征对研究区风沙活动具有指示意义。其中,细颗粒(4~16μm)含量变化与翁牛特旗沙尘暴日数变化趋势较吻合,可以指示区域风沙活动;而粗颗粒组分(64μm)含量变化趋势与沙尘暴日数变化差异较大,推测可能受到大规模人类活动导致的湖区附近土地沙化影响,所以不能指示风沙活动。研究区生态环境脆弱,大规模人类活动会导致生态环境恶化和土地沙化,为现代北方沙尘活动提供沙源,并为未来的沙尘活动恶化埋下隐患,因而研究区不适宜进行大规模人类活动。本文的研究成果对保护研究区生态环境和区域防风固沙具有重要意义。