风浪作用下入湖河口内源释放特征

采用Y型沉积物再悬浮发生装置模拟3种风速条件下典型入湖河流河口沉积物再悬浮和沉降过程.结果表明,随着风速的增大,水柱中悬浮物总量增加;3种风速条件下氨氮(NH₄+-N)增量均为负;小风和中风过程,正磷酸盐(PO₄3--P)总量呈减小趋势,大风过程,正磷酸盐总量出现了明显上升,相对于初始值增加了46%,在5.1~8.7m/s的某一模拟风速条件下PO₄3--P的释放和吸附达到动态平衡,其表观值与初始值相等.总氮(TN)和总磷(TP)总量随着风速的增加而增大,TN最大增量是初始总量的2倍,而TP则是17倍;风浪过后TN、TP总量基本恢复到初始值.典型风速过程中,营养盐垂向分布无明显规律.     

埃及Burullus潟湖沉积生源要素变化:百年来人类活动影响

Burullus是尼罗河河口高封闭性潟湖,其生源要素主要来源于尼罗河,是研究Aswan大坝建成以来流域变化如何影响河口湖泊环境的最佳区域。研究通过对Burullus潟湖B1岩芯的210Pb测年、粒度、以及TOC、TN、TP、BSi生源要素的测试分析,结合历史资料,试图揭示Aswan建坝前后河口湖泊营养盐的差异变化,以及这些变化对生态环境的影响。结果表明:1）沉积物中TOC、TN和TP含量自下而上总体增加,表明尽管Aswan大坝导致营养盐通量急剧减少,但由于下游人类排放N、P通量大大增加,导致下游湖泊N、P浓度并没减少;且沉积TN/TP均小于16,表明湖泊仍为P限制。2）但BSi和BSi/ TOC自下而上总体呈减少趋势,表明Aswan大坝引起的水沙减少导致湖泊中硅藻的生物量及其总初级生产力占比都在减少,潟湖水体生态环境将趋于恶化。     

南印度洋海区营养盐的分布特征

探讨了南印度洋海区总有机磷(TOP)、总有机氮(TON)以及溶解无机营养盐的分布规律。分析结果表明：研究海区内溶解无机营养盐受水体中生物活动和物理过程的综合影响,表层水体由于生物活动的消耗,其磷酸盐等无机营养元素的含量一般是采样水深范围内最低的;中深层水体由于生物活动的降低以及有机质矿化作用的影响,无机营养元素的变化范围较小。表层水体中TOP和TON含量占TP和TN的主要部分,说明表层水体中的氮和磷主要以有机态形式存在,且沿着37.8°S从西向东,TOP和TON的含量以及TOP/TP和TON/TN的比值呈降低的趋势。研究海区叶绿素a的分析结果表明,初级生产力的变化可能是控制研究海区TON和TOP空间分布的主要因素。不同形态氮、磷营养元素的相关分析表明,有机营养盐和无机营养盐之间互为补充,且表层水体中有机氮和磷是水体初级生产所需营养盐的重要来源,总氮、总磷的关系表明研究区初级生产力并不受氮、磷的限制。     

洪湖流域自然农耕条件下营养盐沉积输移演化模拟研究

选择洪湖流域为研究区域,应用分布式流域模型SWAT,从长期演化的角度出发,对流域营养盐输移演化进行模拟。模拟的边界条件设置为自然农耕背景,探讨百年尺度洪湖流域营养盐输移演变规律。对TN、TP的模拟分汛期与非汛期两个时间段,分别进行200年的模拟运算。模拟结果显示模型可以很好的体现流域营养盐沉积输移演变的基本特征。TN、TP浓度变化有明显的季节特征,随时间变化特征与沉积记录相一致。模拟结果的时间序列分析,TN、TP显示出不同的变化趋势。流域模型为百年时间尺度上流域营养盐沉积输移演化的自然趋势研究,提供了很好评价依据。     

衡水湖浮游植物群落特征及其演替规律初分析

通过2011-2013年对衡水湖浮游藻类进行逐月采样调查、分析其群落结构特征,共鉴定浮游藻类51属,主要由绿藻（占49%）、硅藻（20%）和蓝藻（16%）等组成。分析衡水湖浮游藻类的群落和演替规律,讨论影响其生物量的原因。结果表明：绿藻从春末开始出现,夏季大量繁殖;蓝藻从8月开始优势明显,一直延续到冬初。这可能受汛期降水产流造成衡水湖周边营养盐的注入和捕鱼期过量捕捞的影响。     

滇池湖滨带叶绿素a与营养盐空间分布特征

为探讨滇池湖滨带叶绿素a与营养盐空间分布特征及其对滇池水体富营养化的影响,在滇池湖滨带设置21个采样点进行水质调查,采集滇池水样,分析测定总氮(TN)、总磷(TP)、化学需氧量(CODCr)、叶绿素a(Chla)和悬浮固体(SS)。结果表明:滇池湖滨带水体TN、TP、CODCr、Chla、SS浓度均值的空间分布存在差异,叶绿素a空间分布呈现北高南低,西高东低的趋势。滇池湖滨带的北部和东部水体Chla与TN极显著相关,TN具有强变异性。南部和西部TN与CODCr、TP显著相关,南部Chla与营养盐空间变异性较小,污染风险相对较小。按照"一区一策"的原则,滇池北部和东部湖滨带富营养化以控制TN的水平为主,南部、西部的富营养化防控则需要控制整体营养盐元素浓度。     

洪湖流域传统农业条件下营养盐输移模拟研究*

文章选择位于长江中游的洪湖流域作为研究对象,应用流域分布式水文模型SWAT,探讨传统农业条件下流域营养盐输移的规律。模拟时段选择为建国初期的1951~1960年,模拟的边界条件设置为自然地形、土壤、传统农业生产和土地利用方式,其中土壤资料包括营养盐(N和P)、有机质含量、粒径等理化参数等。根据流域汇水范围的变化,模拟分汛期与非汛期两个时间段进行。通过对模型参数率定和调试,水文模拟结果与实测值有较好的吻合程度,由此进行营养盐输出模拟。模拟结果显示,传统农业条件下流域营养盐输出,TN和TP浓度变化有明显的季节特征,体现了耕作制度对营养盐浓度的影响; 同时,该时段营养盐浓度相比较自然条件下有了很大的改变,体现了人类活动对流域营养盐输移的影响,主要是土地利用类型变化和湖泊水域面积的缩小。     

云南岩溶断陷盆地植被演替土壤碳氮磷化学计量学特征

岩溶断陷盆地生态环境脆弱,石漠化严重,植被恢复是该地区生态重建、水土保持的有效措施。文章采用空间换时间的方法,以云南省泸西县岩溶断陷盆地5种不同演替阶段（玉米地、人工林、草地、灌木林、原始林）不同土层（0～10、10～20 cm）的土壤为研究对象,对比分析不同植被类型和不同深度条件下土壤C（碳）、N（氮）、P（磷）含量及化学计量比差异,旨在探明研究区土壤养分垂向分布及化学计量学特征,为该地区植被恢复管理及土地合理利用提供科学依据。结果表明：不同演替阶段、不同土壤深度土壤养分含量存在较大差异;随着演替年限的增长,土壤SOC（土壤有机碳）、TN（总氮）含量总体呈增长趋势且主要表现在0～10 cm深度土层上,而TP（总磷）含量存在波动,未表现出明显变化规律;各演替阶段0～10 cm土层的SOC、TN含量数值上均要高于10～20 cm土层,除原始林地以外,其余演替阶段不同土层间TP含量没有显著差异;在0～10 cm土层上,C/N、C/P、N/P均与土壤SOC含量呈显著正相关,C/P、N/P与土壤TN含量呈显著正相关,土壤TP含量与C/N、C/P和N/P无显著相关性;植被类型和土壤深度显著影响研...     

黄龙风景区藻席嗜冷硅藻群落结构变化及其驱动因子分析

硅藻群落对环境变化十分敏感,是自然河流水质变化的指示生物。为了解黄龙风景区藻席及藻席嗜冷硅藻群落结构与环境变量的关系,对景区内8个典型景点进行水样和藻席的采集并分析。结果表明,黄龙风景区藻席是以钙华作为基底,丝状藻作为骨架,栖息着大量硅藻的高寒岩溶微生态系统,共鉴定出25属72种硅藻,其中优势种13种,以桥弯藻属（Cymbella）为主。通过冗余分析发现,水温（F=2.8,P=0.02）和溶解硅（F=2.3,P=0.04）是影响黄龙风景区藻席嗜冷硅藻群落结构特征的主要驱动因子,TN是潜在驱动因子。硅藻可以为高寒岩溶区地表水监测提供重要的补充信息,建立完整的硅藻物种数据库,有利于区域水质监测。     

贵阳天河潭旱洞硅藻生物多样性与环境初步研究

为了研究喀斯特洞穴硅藻的分布和生物多样性,丰富和积累硅藻研究的基础理论数据,2008年12月对贵阳天河潭旱洞进行了野外考察。经实验室鉴定共发现硅藻7属27种（含变种）,其中包括优势种7种。硅藻商为0,属和种的平均优势度分别为0.113和0.023,香浓维纳多样性指数值分别为2.60和4.43,均匀度均近似等于0.93,硅藻细胞平均密度为1609.36个/cm2。相对地表河流、湖泊(水库)、海洋等环境的硅藻生物多样性来说,天河潭旱洞硅藻生物多样性较高,但硅藻个体较小。硅藻与喀斯特洞穴环境具有很好的相关性,将硅藻作为喀斯特洞穴环境评价与监测的指示生物,具有重要的科学研究价值和理论现实意义。      

太湖大浦湖区近百年来湖泊记录的环境信息

通过对太湖TJ-2钻孔的137Cs、粒度、总有机碳(TOC)、总氮(TN)、总磷(TP)及化学元素等多指标综合分析,探讨了太湖大浦湖区近百年来的环境演变特征。研究结果表明,20世纪50年代以前,沉积物中大部分金属元素如Al、Mn、Cu、Cr、Ni、Zn与粘土含量具很好的相关性,相关系数在0.74～0.82之间。此阶段湖泊生产力不高,水环境较好,沉积物以较低的营养元素含量为特征。50—90年代,是太湖向现代湖泊环境转化的显著时期,湖区生产力大幅提高,人为活动对湖泊系统严重干扰,湖区迅速达到富营养化。在沉积物中表现为Fe/Mn值下降,有机碳、总氮、总磷与重金属元素急剧上升,且重金属元素变化明显不同于沉积物粒度及Al元素变化曲线。90年代以后,湖区一直持续着富营养化状态,富营养趋势渐缓,沉积物中粘土含量上升、营养元素稍降及重金属指标变化不明显的趋势很好地体现了这一特征。TJ-2钻孔显示的环境信息与湖泊实际环境监测结果基本一致。     

Distribution of Diatoms Along Environmental Gradients in the Charlotte Harbor,Florida (USA), Estuary and Its Watershed: Implications for Bioassessment of Salinity and Nutrient Concentrations

The relative abundance of diatom species in different habitats can be used as a tool to infer prior environmental conditions and evaluate management decisions that influence habitat quality. Diatom distribution patterns were examined to characterize relationships between assemblage composition and environmental gradients in a subtropical estuarine watershed. We identified environmental correlates of diatom distribution patterns across the Charlotte Harbor, Florida, watershed; evaluated differences among three major river drainages; and determined how accurately local environmental conditions can be predicted using inference models based on diatom assemblages. Sampling locations ranged from freshwater to marine (0.1–37.2 ppt salinity) and spanned broad nutrient concentration gradients. Salinity was the predominant driver of difference among diatom assemblages across the watershed, but other environmental variables had stronger correlations with assemblages within the subregions of the three rivers and harbor. Eighteen indicator taxa were significantly affiliated with subregions. Relationships between diatom taxon distributions and salinity, distance from the harbor, total phosphorus (TP), and total nitrogen (TN) were evaluated to determine the utility of diatom assemblages to predict environmental values using a weighted averaging-regression approach. Diatom-based inferences of these variables were strong (salinity R ²?=?0.96; distance R ²?=?0.93; TN R ²?=?0.83; TP R ²?=?0.83). Diatom assemblages provide reliable estimates of environmental parameters on different spatial scales across the watershed. Because many coastal diatom taxa are ubiquitous, the diatom training sets provided here should enable diatom-based environmental reconstructions in subtropical estuaries that are being rapidly altered by land and water use changes and sea level rise.     

太湖流域营养盐产量演变和趋势的数值模拟研究

认识流域湖泊水体富营养化的演变和趋势是湖泊污染控制和治理中的重要研究课题。本文将在分析和论证太湖流域营养盐自然本底、人类活动作用急剧增加的近50年来太湖流域营养盐的变化情况、以及全球气候变化和流域经济发展未来30年太湖流域营养盐变化趋势等三方面的基础上,对太湖流域营养盐产量变化做出评估和预测。研究表明,在未来气候变化概率分析和区域经济发展规划基础上,太湖流域未来30年营养盐流域产量将比现代（2000s）增加25%～33%,这将增大太湖水体污染的压力。     

Historical eutrophication in Lake Taihu: evidence from biogenic silica and total phosphorus accumulation in sediments from northern part of Lake Taihu

Sediment and water from the Meiliang Bay of Lake Taihu were analyzed to examine the historical relation between the accumulation of biogenic silica (BSi) and total phosphorus (TP). The results indicate that BSi accumulation in the northern part of Lake Taihu had been controlled by diatom production and phosphorus loading since the 1950s. BSi accumulation increased with the growing agricultural activity since the 1950s, up to a maximum level in the 1960s. After that, BSi accumulation decreased due to the diatom dissolution till the 1980s, and then the diatom biomass decreased with BSi accumulation increased. Lake Taihu came into an accelerated eutrophication periods since the 1990s, while BSi accumulation began to increase but the proportion of diatom decreased. Although the onset of silica depletion cannot be confirmed in the present work, it is clear that BSi accumulation was restrained by the input of TP.     

A statistical approach for determining the environment impact of surface sediments from the Dongting Lake area,central China

The Dongting Lake, the second biggest freshwater lake in China, consists of three wetlands of national importance, namely the East Dongting Lake, the South Dongting Lake, and the West Dongting Lake. Surface sedi-ments were sampled from 57 locations across the lake. Nutrient concentrations [total organic carbon (TOC), total N (TN) and total P (TP)] and 16 element concentrations (Al, As, B, Ca, Cd, Cr, Cu, K, Fe, Hg, Mn, Ni, Pb, Si, Ti and Zn) in the sediments were measured to investigate the impact of industrialization along the lake's coastline and sev-eral tributaries on the profiles of nutrients and heavy metals in the lake's surface sediments. R-mode cluster analysis (CA) was used to integrate geochemical data. The result showed that euthophication of the Dongting Lake resulted mainly from TN and TOC. The main polluting trace metals are Hg, As, Cd, Zn, Pb and Mn, which are largely ad-sorbed on clay minerals or Fe/Mn oxides, or deposited as carbonates. Principal component analysis (PCA) revealed the source of micropollutants. The worst affected district by heavy metals is the East Dongting Lake, the pollution sources may originate mainly from the Xiangjiang drainage area. The results demonstrated that multivariate methods are the potentially great tools for the interpretation of the environmental data on lake sediments.     

石臼湖近代环境演化历史

以2007年在石臼湖采集的浅岩芯钻孔(SJH07-C1)研究近代石臼湖湖泊环境演化历史以及人类活动的影响。运用核素²¹⁰Pb和 ¹³⁷Cs进行定年,²¹⁰Pb 的CRS模式定年结果与¹³⁷Cs方法获得的年代具有较好的可比性。同时分析了岩芯沉积物的理化指标,包括烧失量、总磷、金属元素和磁化率。分析表明：  1955年以前地球化学指标表明石臼湖湖泊沉积物中人类活动信息较弱,但总磷和有机质（烧失量）开始出现增加,湖泊营养水平开始升高。1955～1969年,湖泊沉积物磁化率较高,重金属（包括铜、铅、锌和汞）含量快速增加,可能与该期开始大量使用化肥、农药有关,导致入湖污染物增加。1969～1997年期间,1969～1979年时段湖泊沉积物磁化率最高,重金属含量比较稳定,在石臼湖进行了大规模的围垦;   1979～1997年,湖泊沉积物磁化率较高但呈减少趋势,重金属含量再次快速增加,总磷增加较快,说明该阶段入湖污染物增加,湖泊营养水平也在增加。1997～2007年,磁化率较低,重金属含量保持在高水平,总磷快速增加,显示该阶段湖泊营养水平较高,但入湖物质通量在减少。     

Diurnal laminations in the varved sediment of Lake Lovojärvi, south Finland

A man-induced extensive silty layer in the sediment of Lake Lovojärvi, dating back to the year 1960, contained 18 laminations due to rhythmical variations in the size classes of the mineral particles. A good agreement was found between the thicknesses of the successive laminae, and one period in a sequence of arbitrary 'wind sums' calculated from the meteorological statistics of the spring 1960 for periods of winds exceeding 3 m/s. Most of these wind pulses were diurnal; the longest one lasted for five days. The deposition of the layer in early spring was further confirmed through diatom analysis, which revealed within the laminated sequence a diatom succession typical of Lake Lovojärvi immediately after the melting of ice in spring     

雄安新区白洋淀表层沉积物重金属地球化学特征及生态风险评价

【研究目的】白洋淀为雄安新区核心生态功能区,为支撑白洋淀湿地生态修复与保护,系统开展了全淀区表层沉积物环境质量调查。【研究方法】在白洋淀湿地采集表层沉积物样品484组,查明了白洋淀表层沉积物重金属地球化学特征,并采用地累积指数法、潜在生态风险指数法等多种方法开展了重金属生态风险评价。【研究结果】白洋淀表层沉积物重金属含量普遍偏高于河北省表层土壤重金属含量背景值,府河入淀口及白沟引河入淀口为重金属元素主要富集区,入淀河流输入为白洋淀重金属主要来源;环境地球化学综合评价结果为清洁无污染等级分布面积144.54 km²,占表层沉积物分布总面积的96.68%;各重金属污染程度由重到轻排序为Cd＞Cu＞Hg＞Pb＞Zn＞Ni＞Cr＞As,Cd元素污染程度等级以中度和偏中度为主,Cu元素以轻度和清洁为主,其他元素以清洁无污染为主;重金属潜在生态风险以轻度和中度为主,河流入淀口所在淀区重金属潜在生态风险高于其他淀区,潜在生态风险由高到低排序为南刘庄＞烧车淀＞小白洋淀＞王家寨＞藻苲淀＞捞王淀＞池鱼淀＞泛鱼淀。【结论】白洋淀表层沉积物环境质量总体较好,南刘庄等局部淀区存在重金属污染潜在生态风险,以Cd元素污染最为突出。创新点：采用地累积指数法、潜在生态风险指数法等多种方法,系统评价白洋淀湿地表层沉积物重金属污染程度和生态风险;重金属地球化学特征分析与主成分分析法相结合,揭示表层沉积物重金属污染主要来源为河流输入。     

Comprehensive evaluation of the potential risk from cyanobacteria blooms in Poyang Lake based on nutrient zoning

The potential risk from cyanobacteria blooms is the basis for predicting, preventing, and managing eutrophication. Poyang Lake lies on the southern bank of the middle and lower reaches of the Yangtze River. This lake is a large shallow lake connected to the Yangtze River and is affected by monsoon. The comprehensive evaluation index system, evaluation model, and method of the potential risk from cyanobacteria blooms were constructed based on the nutrient zoning in Poyang Lake, and the potential risk from cyanobacteria blooms was evaluated in 2013. (1) The evaluation index system comprises physical, chemical, and biological indicators. The physical indicators consist of blocking degree, lake region location, transparency (Secchi disk depth, SD), and temperature; the chemical indicators consist of total nitrogen (TN) and total phosphorus (TP); and the biological indicators consist of chlorophyll a (Chla) and phytoplankton biomass. Among the indicators, blocking degree and lake region location along with the prevailing wind direction were selected to represent the indicators affected by water retention time and wind direction. (2) We established a comprehensive evaluation method for assessing the potential risk from cyanobacteria blooms by adopting both analytic hierarchy process weighting and a comprehensive evaluation method. (3) Results show that the high-risk periods for cyanobacteria blooms were August, July, and December, and the high-risk regions were in the Northeastern Lake Region, Western Lake Region and Northern Lake Region. The Northeastern Lake Region is particularly in high risk in August and July. These cyanobacteria blooms presented heavy risk or close to heavy risk. Based on the risk evaluation indicators, outbreaks of cyanobacteria blooms are limited by temperature and location. Chla and phytoplankton biomass were the key indices affecting the level of potential risk from cyanobacteria blooms during the high-water-level period (July and August). In contrast, TN and TP are the key indices affecting the level of harm during the low-water-level period. Within a year, Chla, phytoplankton biomass, and TP are key indicators for the prediction of cyanobacteria blooms in Poyang Lake.