太湖东部湖湾水生植物生长区底泥氮磷污染特征

为了解太湖东部湖湾(贡湖湾、光福湾、渔洋湾)表层底泥中氮、磷的污染特征及其与水生植物生长的关系,采集了各湖湾滨岸带水生植物生长区的表层底泥,探讨了水生植物的生长与分布对表层底泥中总氮(TN)、总磷(TP)及总有机碳(TOC)等含量的影响,并对表层底泥进行营养评价.结果表明,水生植物生长密集区底泥中TN、TP、TOC的含量均显著低于水生植物零星生长区,说明水生植物的生长对太湖东部湖湾表层底泥中营养盐与有机碳含量具有较为明显的影响;相关性分析显示,表层底泥中TOC与TN含量呈显著相关性(R2=0.832 8),而与TP的相关性则较弱(R2=0.166 5),反映了TOC在湖泊底泥中的沉积可能成为湖泊氮的重要来源,而对磷的影响较小.利用有机指数与有机氮指数两种方法分别对东部各湖湾底泥进行污染评价,贡湖湾、光福湾、渔洋湾底泥有机指数平均值分别为0.142 7、0.228 6与0.208 6,均属较清洁与尚清洁水平,而各湖湾有机氮指数平均值均为Ⅲ与Ⅳ级,说明底泥已遭受了一定程度的氮污染.因此,对水生植物零星生长区表层底泥中氮含量的控制与削减有利于湖泊富营养化的预防与治理.     

松辽盆地东部湖湾环境的识别及意义

通过对宾县鸟河乡鸟河剖面和红石山剖面的沉积学分析,结合古生物、地球化学和古地理位置等资料,初步恢复了当时的古环境特征。鸟河剖面以灰绿色泥岩为主,夹有黄铁矿和白云岩结核层,属于湖湾环境沉积;红石山剖面下部以绿色泥岩为主,中上部变为以红色泥岩为主的沉积,早期属滨浅湖环境,之后水体变浅逐步转为泥坪相沉积。当物源不充足时,沉积物以泥岩为主,发育水平层理,化石种类少但成层性好,泥岩中常夹有白云岩和黄铁矿层。湖湾从湖盆断裂坳陷开始,经水体加深接受沉积,水流波浪侵蚀破坏湖底及湖岸阻隔,后水体逐步变浅,最终转化为泥沼。     

沉水植物黑藻对沉积物磷吸附动力学的影响

在室内模拟条件下,通过吸附动力学实验,研究了沉水植物黑藻对沉积物吸附磷动力学模型拟合和吸附速度的影响,并从有机质和铁铝氧化物含量的角度,讨论了沉水植物黑藻对沉积物吸附磷动力学的影响机理。初步得出如下结论:(1)一级反应动力学模型虽然从模型拟合的角度达到了极显著水平,但不能真实地反映沉水植物对沉积物吸附磷动力学过程的影响。其余三个模型均能很好地反映,其中抛物线扩散模型的拟合效果最好,修正的Elovich模型和双常数速率模型的拟合效果较好。种植沉水植物与否并不影响这一趋势;(2)沉水植物黑藻提高了沉积物吸附磷的强度和速度,特别是提高了0～0.5h内的吸附速度,沉水植物影响有机质和铁铝氧化物含量是增强沉积物吸附磷强度和速度的重要机理。     

草地植被盖度的多尺度遥感与实地测量方法综述

植被盖度作为一个重要的生态学参数被用在许多气候模型和生态模型中。地表实测和遥感测量是获取植被盖度的两种基本途径。以草地植被盖度的测量为研究对象,综合讨论了目前地表实测和遥感测量常用的方法,分析了它们的优缺点,并对如何提高草地植被盖度的测量精度做出展望。数码相机、高光谱遥感以及多尺度遥感数据的综合使用可能是未来草地植被盖度测量发展的趋势。     

北澜沧江紫曲流域卡贡群的层序及时代

根据1∶20万区域地质调查新资料描述了北澜沧江紫曲流域卡贡群的代表性剖面。采用剖面对比及地质填图追索法确定的卡贡群层序自下而上为哎保那组、日阿泽弄组、玛均弄组和钟弄组。卡贡群生物群与毗邻昌都、华南地区相似，同属欧亚-北美生物大区，其主体形成时代为早石炭世。     

青藏高原多年冻土区植被盖度变化对活动层水热过程的影响

不同植被盖度变化下活动层水热过程是多年冻土区水能循环中一个重要的不确定因素.为了研究植被盖度变化对活动层水热过程的影响,在青藏高原多年冻土区,选择坡向、坡型和坡度趋于一致植被覆盖度分别为92%、65%、30%的坡面建立天然径流观测场,觎测多年冻土活动层中的地温和水分状况.结果表明:活动层开始冻结和消融时间随着植被盖度的减少不断提前,且冻结持续时间缩短;随着植被盖度减小,活动层地温水分变化速率增大,植被起到抑制土壤地温水分变化速率的作用;植被盖度对夏季融化过程和秋季冻结过程活动层地温和水分的影响明显大于冬季降温和春季升温过程,对融化过程的影响较冻结过程更明显.     

山区流域高盖度斜坡对极端降雨事件的地下水响应

受到日益加剧的全球变暖趋势的强力驱动,极端降雨及与之相伴的山区流域植被发育斜坡的群发性失稳事件在包括中国在内的多山国家的发生频率越来越高,因此对这一问题的深入研究具有重大的现实意义.到目前为止,降雨-滑坡领域的现有研究成果主要集中在并无成因联系的降雨事件与滑坡事件之间的相互关系及斜坡岩土体水岩相互作用方面,而降雨→滑坡...     

干旱区植被盖度增加对降水入渗补给地下水的影响——试验研究与数值模拟

随着西北旱区生态恢复工程的实施,该区生态环境持续改善,植被盖度不断增加。但植被冠层截留与蒸腾耗水加剧了包气带水分的亏空程度,减小了降雨对地下水的补给。采用原位试验方法,分析了植被覆盖区和裸土区不同深度土壤水势的变化规律。结果表明,受蒸发和蒸腾的共同作用,植被覆盖区平均土壤水势（-74kPa）远低于裸土区（-16kPa）,且变化剧烈,土壤水以向上运动为主。而裸土区土壤水势高,变化小,40cm以下土壤水向下运移,因此可以持续补给地下水。采用Hydrus-1D软件进行了长序列土壤水数值模拟,定量分析了植被盖度增加与地下水补给的关系。数值模拟结果表明,在裸土条件下,降雨对地下水的补给量介于82~333mm/a之间,平均值为197mm/a,平均降水入渗补给系数为0.53。而在植被覆盖的情况下,地下水的补给量几乎为0。最后,从植被蒸腾耗水和冠层降水截留2个方面讨论了旱区植被盖度增加对降雨入渗补给地下水的影响,提出了旱区水与生态和谐发展的建议。     

锡林郭勒典型草原植被高度和盖度对风吹雪的影响

采用野外调查与风雪流实测的方法对内蒙古锡林郭勒大针茅典型草场风雪流与植被高度、盖度的关系进行了研究.结果表明:随着草场退化程度的减轻和草场植被高度、盖度的增大,下垫面粗糙度、积雪厚度和积雪量呈增大趋势,而近地表风速、移雪强度与上层含雪量则呈下降趋势.移雪强度与距地表高度,积雪深度与植被高度,积雪深度与盖度间均符合指数函数关系.中度、轻度退化草场和封育草场的积雪深度分别是重度退化草场的1.7、3.1和5.2倍.随着退化程度的增加,风吹雪灾害形成的可能性增大.加强草原保护与建设,对减轻风吹雪危害和积蓄积雪资源具有重要作用.     

沉水植物黑藻对上覆水中各形态磷浓度的影响

室内模拟研究了沉水植物黑藻对上覆水中不同形态磷浓度的影响及其季节性变化,并从沉水植物生长、间隙水和碱性磷酸酶活性(APA)三方面进行了讨论,进一步揭示磷在浅水湖泊水-沉积物界面的交换机理。结果表明,在本研究条件下,上覆水中各形态磷以溶解性总磷(DTP)为主,其他形态磷浓度变异较大,黑藻降低了上覆水中总磷(TP)、溶解性活性磷(SRP)和DTP浓度,也降低了DTP和SRP占总磷的比例,从而使颗粒态总磷(PP)和溶解性有机磷(DOP)占总磷比例升高。黑藻主要通过吸收上覆水中的磷和抑止沉积物、上覆水中APA使上覆水中各形态磷浓度保持较低水平,其中对SRP和DTP浓度的影响更明显。上覆水中各形态磷浓度呈现明显的季节性变化。在7～8月,TP、SRP和DTP浓度呈下降趋势,并在8月达到最低值;9～10月间有所升高,但仍然维持在较低水平,不同采样时间存在波动。     

Antibiotics pollution in Gonghu Bay in the period of water diversion from Yangtze River to Taihu Lake

As a famous project in China, the water diversion from Yangtze River to Taihu Lake Project has impacts on the water quality of Taihu Lake, especially Gonghu Bay, which is the entrance of the diversion water and the drinking water source for Wuxi and Suzhou. To investigate contamination of the antibiotics in Gonghu Bay in the period of water diversion, 16 antibiotics in 14 water samples collected from Wangyu River and Gonghu Bay in China were analyzed by liquid chromatography–tandem mass spectrometry. The results indicated that the concentration of total antibiotics in Wangyu River and Gonghu Bay ranged from 1320 to 17,209 ng/L (mean: 3920?±?3841 ng/L). The average level of different antibiotics was tetracyclines (range 1082–15,310 ng/L, mean 3161?±?3479 ng/L)?>?quinolones (range 225–1325 ng/L, mean 463?±?276 ng/L)?>?sulfonamides (range n.d.–888 ng/L, mean 402?±?248 ng/L)?>?macrolides (range 12–17 ng/L, mean 14?±?2 ng/L), and levels of the detected antibiotics in Gonghu Bay were higher than that in Wangyu River, indicating that the antibiotics pollution in Gonghu Bay were much severer than Wangyu River. Ecological risk evaluation showed that in the Wangyu and Gonghu water, trimethoprim (TMP), sulfacetamide (SAAM), sulfamethoxypyridazine (SMP), and sulfamerazine (SMRZ) presented low ecological risk levels, chlortetracycline (CTC), tetracycline (TC), roxithromycin (ROM), and sulfamethoxazole (SMX) had medium level of risk, and oxytetracycline (OTC), norfloxacin (NOR), ofloxacin (OFL), ciprofloxacin (CIP), and enrofloxacin (ENR) had high level of ecological risk. The total hazard quotient of antibiotic mixtures for each sample site indicated high risk of antibiotics in Wangyu River and Gonghu Bay. In summary, the water diversion could mitigate antibiotic pollution in Gonghu Bay to a certain degree. However, the risk of antibiotics in the Wangyu River and Gonghu Bay is still high.     

Response of sediment characteristics to trophic state change at submerged macrophyte zones in a large shallow Lake Wuliangsuhai, China

Sediment samples at different depths were collected from a large shallow lake named Wuliangsuhai in China, in order to determine the response of sediment characteristics to trophic state change. The lake changed from natural state to eutrophication in the late 1970s, creating a Transitional Sediment Layer （TSL） that can be visually used to separate sediments derived from multi-biology and macrophytes. Sediment characteristics were enumerated as a means of corroborating extant eutrophication data from sediment record. Inferences about the timing and trajectory of eutrophication were made using sediment characteristics-based reconstruction. Water content, electrical conductivity, pH, organic matter, nutrient （total nitrogen and total phosphorus） and metals （As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Zn and V） were measured in about 20 different layers of 63-71 cm deep columns of the sediment.     

Coenotypes in Submerged Paleoforests in the Qianhu Bay, Fujian Province

The paleoforest remains studied are distributed within a range of 18000 m^2 in the intertidal zone of the Qianhu Bay, Fujian Province. Eighty-nine ancient tree stumps can be clearly recognized in the paleoforest remains. Microscopic studies of 10 relatively low-carbonized stump samples definitely showed four species： Glyptostrobus pensUi （Staunt） Kouch, Schima superba Gardn., Cinnamomum Schaeffer, and Litsea Lam. The 14^C dating of some samples yielded the ages of 42560±350 to 〉43000 a B. P., corresponding to the late Late Pleistocene.     

Seasonal variations of adsorption/desorption equilibrium concentrations of P at water-sediment interface in the Meiliang Bay, Taihu Lake, China

Seasonal variations of adsorption/desorption equilibrium were investigated by collecting overlying water and seasonal sediment from the Meiliang Bay, Taihu Lake, China. At the same time, seasonal variations of TP and P fractions＇ concentrations in the initial and end of adsorption experiment were also carried out. In addition, the effects of temperature on the P translocation process were also conducted and discussed. The following conclusions were obtained： The sequence of adsorption/desorption equilibrium concentrations of P at water-sediment interface was spring〈winter〈autumn. In sediment the concentrations of TP decline. Concentration P decreased with temperature.     

水位变化对鄱阳湖苦草潜在生境面积的影响

苦草是鄱阳湖越冬水鸟的重要食物资源,为量化水位变化对鄱阳湖苦草生境的影响,基于环境流体动力学模型(EFDC)和生境适宜度曲线,构建了鄱阳湖苦草生境数值模拟模型;对三峡水库175 m试验性蓄水后鄱阳湖苦草潜在生境面积变化进行了连续模拟,建立了苦草潜在适宜生境和水深≤4 m水域面积变化与星子站水位的定量响应函数;并据此分析了三峡水库运用及拟建鄱阳湖水利枢纽对苦草潜在生境面积的影响。星子站水位15 m左右时苦草潜在生境面积最大,潜在适宜生境和水深≤4 m水域面积分别为1 703 km^2和2 336 km^2。三峡水库运用可有效保障鄱阳湖苦草潜在生境面积,但其扰动幅度也明显减小,潜在适宜生境和水深≤4 m水域面积序列标准差在三峡运用后减幅分别达到27%和47%。拟建鄱阳湖水利枢纽调控水位在其下闸蓄水期和长江上游水库蓄水调节期内宜分别控制在16 m以下和13.5 m以上,可保障潜在适宜生境及水深≤4 m水域面积与最大值相比减幅分别控制在20%和10%以内。成果明晰了水位变化对鄱阳湖苦草潜在生境面积的定量影响规律,为江湖新水沙条件下鄱阳湖生态系统保育提供了量化依据。     

Vertical variation of phosphorus forms in surface sediments from Wuli Bay, Taihu Lake, China

1IntroductionPhosphorus,an essential nutrient for the primaryproductivity in freshwater systems,is an important fac-tor controlling lacustrine eutrophication.Although ex-ternal input of phosphorus has been assumed as the vi-tal responsibility for the eutrophication of lakes(ZhuJun et al.,2005),the remobilization of phosphorus insediments has a distinct influence on it as well(Bostr m et al.,1982).The concentrations of totalphosphorus(Ptotal)in the sediments are often related tothe trophic st…     

Measurement of the total nitrogen in lake sediments： Comparison and its environmental significance

Nitrogen cycle is an important bio-geochemical process in the environment. Measurement of the total nitrogen （TN） is a routine experiment in agriculture, biology and environmental sciences. The Kjeldahl method （KM） and elemental analyzer method （EA） are both commonly used to determine TN. Total nitrogen by EA is the sum of nitrate （NO3）, nitrite （NO2）, organic nitrogen and ammonia. Total nitrogen by KM （TKN） is made up of both organic nitrogen and ammonia. A comparative study focused on the two methods is conducted by analysis of TN in 97 samples from the sediment sequence of Gouchi, a salt lake in North China. KM presents a higher degree of accuracy than EA with a standard deviation of 0.007 vs. 0.024. With the presence of nitrate and/or nitrite nitrogen, however, measurement by KM is considerably lower than that by EA. Therefore, for samples from lake sediment sequences or soils in North China, KM is inapplicable to determining TN because of usually high contents of nitrous salt. Despite the inconsistency, use of both methods to the same samples makes sense in reconstructions of climatic and environmental changes from lake sediments. In Lake Gouchi, the contents of nitrate and nitrite nitrogen vary from 1.40% in the lower part of the sequence to 14.77% in the uppermost part, suggesting a gradual evolution process from a fresh water lake to the present-day salt lake.     

水位变化对鄱阳湖苦草潜在生境面积的影响

苦草是鄱阳湖越冬水鸟的重要食物资源，为量化水位变化对鄱阳湖苦草生境的影响，基于环境流体动力学模型（EFDC）和生境适宜度曲线，构建了鄱阳湖苦草生境数值模拟模型；对三峡水库175 m试验性蓄水后鄱阳湖苦草潜在生境面积变化进行了连续模拟，建立了苦草潜在适宜生境和水深≤4 m水域面积变化与星子站水位的定量响应函数；并据此分析了三峡水库运用及拟建鄱阳湖水利枢纽对苦草潜在生境面积的影响。星子站水位15 m左右时苦草潜在生境面积最大，潜在适宜生境和水深≤4 m水域面积分别为1 703 km²和2 336 km²。三峡水库运用可有效保障鄱阳湖苦草潜在生境面积，但其扰动幅度也明显减小，潜在适宜生境和水深≤4 m水域面积序列标准差在三峡运用后减幅分别达到27%和47%。拟建鄱阳湖水利枢纽调控水位在其下闸蓄水期和长江上游水库蓄水调节期内宜分别控制在16 m以下和13.5 m以上，可保障潜在适宜生境及水深≤4 m水域面积与最大值相比减幅分别控制在20%和10%以内。成果明晰了水位变化对鄱阳湖苦草潜在生境面积的定量影响规律，为江湖新水沙条件下鄱阳湖生态系统保育提供了量化依据。     

Investigation and numerical simulation of summer sedimentation in Jiaozhou Bay,China

In recent years, development activities have had a significant impact on the environment of the Jiaozhou Bay, China. To ensure the sustainable economic and social development of the Jiaozhou Bay area, it is necessary to strengthen corresponding control measures. The important prerequisite is to properly understand the environmental conditions laws of natural change, especially the dynamic processes of sediment and the characteristics of landform evolution. Based on the data of continuous observation at 6 stations in Jiaozhou Bay for 25 hours, the Hydrodynamic Eutrophication Model (HEM-3D) was used to simulate the sediment erosion and deposition. The results show that the maximum suspended sediment concentration in the sea area of Jiaozhou Bay is about 40 mg/L, which appears in the northwestern area of the bay top and the Cangkou watercourse area, and the low concentration is located in the area of the central Jiaozhou Bay towards the bay mouth. The suspended sediment is 6–10 mg/L. Affected by a decrease in seawater material, the direction of the prevailing current in the Jiaozhou Bay area is different from that of the sediment transport. The velocity of the flood current is higher than that of the ebb current. However, during flood tide, the flux of resuspended seafloor sediment outside and at the mouth of the bay is limited and cannot contribute significantly to the suspended sediment in the bay. During ebb tide, the resuspended sediment at the shallow-water bay head and the east and west sides spreads toward the bay mouth with the ebb current, although it extends beyond the bay through the bay mouth. The research results can provide scientific support for the Jiaozhou Bay project construction and environmental protection.     

A Comprehensive Investigation of an Offshore Active Fault in the Western Sagami Bay, Central Japan

Offshore active faults, especially those in the deep sea, are very difficult to study because of the water and sedimentary cover. To characterize the nature and geometry of offshore active faults, a combination of methods must be employed. Generally, seismic profiling is used to map these faults, but often only fault-related folds rather than fracture planes are imaged. Multi-beam swath bathymetry provides information on the structure and growth history of a fault because movements of an active fault are reflected in the bottom morphology. Submersible and deep-tow surveys allow direct observations of deformations on the seafloor (including fracture zones and microstructures). In the deep sea, linearly aligned cold seep communities provide indirect evidence for active faults and the spatial migration of their activities.The Western Sagami Bay fault (WSBF) in the western Sagami Bay off central Japan is an active fault that has been studied in detail using the above methods. The bottom morphology, fracture