平衡地质剖面技术发展现状与实际应用——以苏北盆地溱潼凹陷为例

平衡剖面技术广泛应用于构造解释合理性检验和构造演化史分析。平衡剖面发展历史与现状表明,二维平衡剖面技术理论与应用已趋于成熟,真三维平衡恢复算法的精确实现和实际应用是今后的主要发展方向。在详细总结二维平衡剖面技术原理和制作过程后,以苏北盆地溱潼凹陷为例,紧密结合区域地质与地球物理资料、选择合理的剖面走向、采用变速时深转换,多次修改地震构造解释方案并最终制作平衡剖面。结果表明,合理运用平衡剖面技术可检验地震构造解释的合理性并分析构造演化历史,指导油气资源勘探。     

Assessing fish quality status in transitional waters,within the European Water Framework Directive: Setting boundary classes and responding to anthropogenic pressures

Validation of the AZTI's Fish Index (AFI), proposed for the Basque Country (northern Spain), in assessing fish quality within the Water Framework Directive (WFD), is undertaken. The response to anthropogenic pressure is investigated, in setting the boundaries between the different quality status classes. Hence, 12 estuaries were sampled, at different frequencies, between 1989 and 2007, by means of a beam trawl. Significant (p < 0.0001) correlations were found between the AFI and oxygen saturation and ammonia. Oxygen quality standards are used to set boundaries between quality classes. Then, the AFIs obtained are compared with different anthropogenic pressures, including urban and industrial discharges, engineering works and dredging. The effects of the removal of some of these pressures are also studied. The total number of pressures within an estuary shows significant (p < 0.009) negative correlation with AFI, explaining between 51 and 62% of the variability in fish quality. The impact of pressures upon fish and demersal assemblages is detected as required by the WFD. Nonetheless, further investigation and intercalibration of the methods used, are necessary.     

围填海对海洋水动力与生态环境的影响

近10年来,中国海岸带围填海活动呈现出规模大、速度快的发展态势。围填海能带来显著的经济效益,但对海洋环境与生态的负面影响也不可忽视。针对围填海对海洋环境和生态的影响及作用机制,分别从水动力和生态系统两个方面进行了概述。围填海改变了海洋的自然几何属性(原始岸线、地形地貌、海湾面积),引起水动力环境的变化(潮汐系统和海湾水交换能力),进而影响了海湾的环境容量;围填海破坏了生物栖息地、导致生物多样性的丧失,影响到生态系统结构与功能的稳定性;水动力与生物多样性的变化可显著影响到生物地球化学过程,加速富营养化进程,恶化水质,增加生态灾害风险。目前,围填海后的生态修复策略主要有增加生物量、建设自然保护区、退陆还海3种方式;而生态补偿策略则多基于“生态系统服务功能与生境面积的大小为线性关系”,通过对其经济价值的量化后进行生态补偿与实施相关政策。国际上,生态系统服务功能的量化参数逐步纳入实际管理,并在线性关系研究的基础上,逐步纳入一些非线性的理念,使生态补偿机制更为合理化;而我国对于围填海生态效应的定量化研究及科学理论在管理政策中的实际应用仍亟待提高。整体而言,全面、准确地评估围填海对海洋环境与生态的影响离不开自然科学与社会科学的交叉与融合。     

腾格里沙漠西北缘湖泊沉积记录的全新世中期气候环境

通过腾格里沙漠西北缘青土湖沉积物粒度、有机碳、碳酸盐、碳氮比和有机质稳定同位素等多项沉积学气候代用指标及精确定年的综合分析,建立了该区域全新世中期9.0~3.0 cal.kaBP的古气候演化序列。结果表明,9~7.8 cal.kaBP期间,区域的水分条件和温度逐渐上升,植被状况好转,此阶段属于全新世早期向全新世暖湿期转变的过程;而在7.8~7.5 cal.kaBP期间出现了显著的百年尺度的干旱事件,沉积物主要以砂质沉积为主,此时湖泊生产力显著下降;全新世期间最为暖湿的气候适宜期出现在7.5~5.0 cal.kaBP;5.0 cal.kaBP以来,该区域出现了较为明显的干旱化趋势。     

Hydrological effects of water management measures in the Dovinė River basin,Lithuania

Abstract

Lake ?uvintas, located in southern Lithuania in the Dovin? River basin, is one of the largest lakes and oldest nature reserves in the country. However, changes in the hydrology of the Dovin? River basin, caused by large-scale land reclamation and water management works carried out in the 20th century, have resulted in a significant decrease in the biodiversity of the lake and surrounding wetlands. In order to halt the ongoing deterioration of the lake and wetlands, solutions have to be found at the basin level. Using the SIMGRO model, various measures were therefore analysed to evaluate their impact on the water management in the Dovin? River basin. The results show that it is impossible to fully restore the water dynamics and flow pattern in the Dovin? River to their original state. However, a good measure for improving the hydrological conditions is to block drainage ditches and remove bushes and trees from the wetlands.     

内蒙古察干淖尔盐湖29-8ka时段的湖面波动

以内蒙古锡林郭勒盟苏尼特右旗的察干淖尔盐湖为研究对象,利用OSL(Optically Stimulated Luminescence)测年技术和DEM(Digital Elevation Model)数字高程模型,重建湖面波动历史,探讨湖泊形成与环境变化过程.通过对察干淖尔盐湖周边大量的野外考察,发现湖泊周围存在海拔高程为1020、978和973 m的三级古湖岸阶地,其OSL测年结果分别为29.2±1.3、18.4±0.8及8.2 8.0 ka.通过湖岸阶地高程恢复的上述3个时期的古湖面积分别为3600、500和400 km~2.与现今的干旱盐湖景观迥然不同.     

Public participation in monitoring programmes as a tool for lakeshore monitoring: the example of Lake Pyhäjärvi, Karelia, Eastern Finland

Lake Pyhäjärvi, on the border between Finland and Russia in Karelia, is a very valuable clear-water lake of the Lobelia type. It belongs to the European Union's Natura 2000 programme in Finland, and has been included in regional and national monitoring programmes since the 1960s. The main monitoring station is situated near the outlet of the lake. Deterioration of its water quality was suspected already in the 1980s because of decreasing Secchi depths (transparency) and increasing chlorophyll a.The occurrence of algal blooms on the lakeshores is monitored weekly during each summer at one site on Lake Pyhäjärvi (site 1). This is a part of nationwide intensive algae monitoring programme organised by the environmental authorities together with voluntary observers at some 270 lake sites in Finland since 1998. Since 1997, Secchi depth observations have been carried out by volunteers biweekly or monthly at 17 sites on the lake. In the vicinity of one of these transparency observation sites (station 100), intensive monitoring of algae has been carried out. At this lakeshore monitoring site 69 algal observations were made, ten of which recorded algal blooms during the study period 1998–2002. The observed algal blooms were caused by algae of the Anabaena species, mainly by Anabaena lemmermannii. At Lake Pyhäjärvi the number of algal bloom observations received from the public have decreased from the 1990s to the 2000s. The range of Secchi disc transparency was 5.0–8.4 m with a mean value of 6.2 m at station 100 and 4.3–7.7 m (mean 6.1 m) at the main monitoring station 2 during the open water periods in 1998–2002. During this study period, the maximum values at site 100 seem to have increased slightly, which might indicate some improvement in the water quality due to decreased point source loading.We conclude that the intensive algal monitoring results of 5 years at the lakeshore site and the transparency results — both compiled by trained volunteers — reflect an improvement in the state of Lake Pyhäjärvi in Karelia. This conclusion is in accordance with the long-term water quality and short-core studies of sedimentary diatoms in Lake Pyhäjärvi. We suggest that the intensive algal observations and transparency measurements are both suitable methods for the monitoring of lakeshores and lakes, and that both are suitable for voluntary monitoring. We found public participation a good tool for monitoring lakes and lakeshores.     

富营养化高原浅水湖泊持续多年生态修复工程效果分析——以滇池大泊口为例

大泊口位于滇池草海南部,水域面积0.52 km²,平均水深约2 m,作为滇池草海重富营养化水域生态修复示范区,大泊口分别于2015和2019年开展了两期生态修复工程,经过近年来的系统治理,大泊口水生态治理效果初步显现。为分析探究成功修复湖区水质改善、生态系统企稳向好的原因,本研究选择2015年2月—2021年12月共7年的连续监测数据,根据工程开展情况以及水生态状况将大泊口水域划分为4个部分(A1～A4水域),首先分析4个区域内主要的水质指标(悬浮物(SS)、化学需氧量(COD_Cr)、总磷(TP)、总氮(TN)和叶绿素a(Chl.a))的变化趋势和相关性,其次探究不同类型生态工程的修复效果,最后与草海和外海水域进行对比,分析大泊口的治理效果。结果表明,治理后大泊口A1～A4水域的COD_Cr、TP和Chl.a稳定下降,COD_Cr分别降低18.65、27.96、25.26、40.92 mg/L,TP分别降低0.11、0.10、0.11、0.14mg/L,Chl.a分别降低0.037、0.068、0.06...     

改性粘土辅助沉水植物修复技术维持清水稳态的原位研究

在富营养湖泊治理实践中,修复沉水植被被认为是改善水质的长效措施,而壳聚糖改性粘土是短期快速改善水质的有效手段.本研究利用改性粘土辅助沉水植被修复,旨在探索改善水质的长效方案.2011年5-11月在太湖梅梁湾开展了四组不同处理(对照、水草、水草+粘土、粘土)围隔实验,在水草(盖度13.0%)和水草+粘土(盖度52.3%)围隔中不同程度重建了苦草群落.实验期内每3 d一次的水质监测表明,粘土处理可显著改善水质,水体总氮(TN)、总磷(TP)、正磷酸盐(PO34--P)和叶绿素a(Chl.a)含量分别比对照下降了20.7%、74.6%、31.0%和80.4%,透明度(SD)升高了90.4%;粘土辅助植被修复改善水质效果最长稳,水体TN、TP、PO34--P和Chl.a含量分别比对照下降了36.2%、64.0%、28.6%和71.1%,SD升高了76.4%;低盖度苦草群落单独处理对水质改善效果不显著.在三种处理中,粘土辅助植被修复改善底质效果最好,使间隙水的TN、TP、PO34--P、NH4+-N分别比实验前下降了15.6%、61.7%、55.8%和82.8%.本研究表明改性粘土辅助沉水植被修复可作为重富营养水体中水质改善的整合技术,但其长期生态效应仍需谨慎评估.     

鄱阳湖湿地生态功能重要性分区

在分析鄱阳湖湿地自然环境特征和湿地生态系统服务功能特征基础上,利用GIs技术,对鄱阳湖湿地范围进行界定,湿地面积为3886km2.基于湿地生态环境保护和社会经济发展总体要求,按照生态功能区划原理,对湿地进行生态功能重要性分区研究.根据湿地生态功能重要性评价结果将湿地分为极重要区、高度重要区、重要区、一般重要区四个区域,...