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1.
太湖浮游植物和各形态无机氮的时空分布特征 总被引：6，自引：1，他引：5
为研究太湖浮游植物和各形态无机氮的时空分布特征及其相互关系,于2010年3月至2011年2月在太湖全湖范围内选取9个采样点进行每月采样分析,结果表明:太湖无机氮主要以硝态氮和铵氮形式存在,前者占76%,后者占22%;太湖北部靠近西北沿岸的湖区以及竺山湾的铵氮和亚硝态氮浓度通常要明显高于其他点位.太湖各采样点TIN(总溶解性无机氮)的季节变化趋势很相似,都表现为春季最高,夏秋季降低,冬季又有所升高;夏季北部湖区TIN降幅明显大于南部,使得前者TIN/TSP(总溶解性磷)远小于后者.春季太湖南部的微囊藻复苏量大于北部,但夏秋季微囊藻的暴发主要发生在太湖北部,此时微囊藻大暴发的点位(如梅梁湾)通常都伴随着很低的硝态氮浓度和TIN/TSP,使得这些点位比其他地方更容易发生N限制;Chl.a/浮游植物的比值与浮游植物总数呈极显著负相关,而与TIN/TSP的比值呈极显著正相关,这说明当藻类大量暴发而TIN/TSP下降时,浮游植物单个细胞内的平均Chl.a含量会有所下降,这种现象的原因有待进一步研究;绿藻、硅藻、裸藻和隐藻在时空分布上有一定相似性,而这四种藻与微囊藻则有较大差异. 相似文献
2.
风浪扰动下湖滨带悬浮物和营养盐响应特征 总被引：1，自引：0，他引：1
为研究风浪扰动下沉积物起悬过程中悬浮物浓度的分布特征和水体营养盐时空分布状况,以太湖西北湖滨带为例,选择代表4种不同生境的6个点位进行了连续12 d的野外观测.利用高精度分层同步采样装置,采用重量法计算悬浮量,并对悬浮过程中总磷(TP)、总氮(TN)、铵态氮(NH_4~+-N)和硝态氮(NO_3~--N)浓度进行分析.结果表明:风速是引起太湖西北湖滨带水体悬浮物增加的主要因素,沉积物悬浮的临界风速为3.6 m/s.各点位悬浮物浓度的均值差异明显,表现为:无植被区植被区河口区湖心区.太湖西北湖滨带水体氮、磷浓度日变化幅度较大,TN浓度为1.82~4.96 mg/L,TP浓度为0.10~1.47 mg/L.NH_4~+-N和NO_3~--N浓度分别在0.09~2.83和1.05~3.69 mg/L之间波动.近岸无植被区水柱的总悬浮量与风速的相关性最好,相关系数达到0.722;而远岸湖心区与风速的相关系数仅为0.039.悬浮物浓度除了受风情(风向和风速)的影响外,同样受水深、地形特征和水生植被的影响. 相似文献
3.
藻类生长与营养盐浓度存在藻类几何级数增长的营养盐浓度变化的下限阈值和藻类生长不受氮磷浓度增加影响的上限阈值,但由于蓝藻水华的形成受多种因素的综合影响,不同湖泊、不同区域及不同时段的氮磷浓度对蓝藻水华的影响差别较大,使得蓝藻生长的氮磷控制阈值难以确定.针对控制蓝藻水华暴发的氮磷阈值的研究虽然有所开展,但多集中在实验室研究阶段或对经验值的判断,虽然也有基于野外实测数据的研究,但也限制于某一特定区域,而基于野外长序列实测数据并且覆盖整个湖泊的氮磷阈值研究则是空白.太湖作为具有较高营养背景的富营养化浅水湖泊,蓝藻水华的发生受氮磷影响较大.对太湖总磷(TP)、总氮(TN)和叶绿素a(Chl.a)浓度的时空变化分析发现,太湖西北湖区的TP、TN与Chl.a浓度明显较高,并且TP、TN与Chl.a均呈显著性正相关.为探究太湖蓝藻水华暴发的TP和TN控制阈值,以轻富营养化等级下的Chl.a分级标准(10,26］作为表征水华暴发的条件,采用郑丙辉等的频率分布法,确定了太湖蓝藻水华暴发的TP和TN控制阈值分别为0.05~0.06和1.71~1.72 mg/L;通过空间验证,太湖藻型区TP和TN浓度远高于同级营养水平下全湖区TP和TN控制阈值,表明藻型区高氮磷水平为蓝藻水华发生提供充足营养盐条件,即使氮磷全湖平均浓度控制在蓝藻水华暴发的氮磷阈值水平之下,但在气象水文等因素适宜条件下,藻型区水华发生风险仍然较高;并且在高氮磷背景下,即便在水华发生风险低的季节,水华发生风险仍然较大.近十几年来,虽然太湖经历了大规模的高强度治理,但由于环太湖流域的湖西区入湖负荷占比大,导致太湖藻型区氮磷浓度仍处于高位运行状态,为蓝藻水华的暴发提供了充足的营养盐基础,因此,湖西区的控源减排仍然是太湖富营养化及蓝藻水华防控的重点. 相似文献
4.
太湖蓝藻水华暴发机制与控制对策 总被引：2，自引：0，他引：2
湖泊蓝藻水华暴发由于引发水生态系统的灾害和饮用水安全风险而成为国内外研究的热点之一.太湖蓝藻水华暴发原因多样，其中蓝藻自身的特性是水华暴发的内因，太湖的地理、水文和气象特征为蓝藻水华暴发提供了合适的温度和水动力条件，是蓝藻水华暴发的外因，湖泊草-藻型生态系统的转变以及氮、磷营养盐的高负荷输入更利于蓝藻生长，湖泊氮、磷营养盐四重循环是蓝藻水华不断暴发的维持机制，蓝藻水华暴发与氮、磷营养盐浓度之间存在交互作用关系.太湖蓝藻水华的控制应以陆源控源截污为基础，增加湖泊营养盐输出为重点，实现疏堵有机结合，其中恢复水生植被，重建草-藻结合型水生态系统是太湖湖泊生态修复的关键所在. 相似文献
5.
太湖浮游植物中重金属含量的季节变化特征及湖区差异 总被引：4，自引：2，他引：2
近年来随着社会经济的发展,排入太湖的污水中重金属含量不断增加,为研究太湖浮游植物中重金属的污染状况,分别于2009年春季(4月)、夏季(7月)和冬季(12月)对太湖不同湖区展开调查,通过HCA聚类分析和Pearson相关分析探讨不同湖区浮游植物中重金属含量的季节变化,并与优势藻种进行CCA分析,对浮游植物重金属与各藻种关系进行初步探讨.结果表明:太湖浮游植物中重金属的含量大小为:ZnMnPbCuNiCrAsCdHg,其中Zn、Cu、Mn、Pb、Ni的季节变化明显,Zn和Cu、Pb、Ni、Cr之间的相关系数很高且具有同源性.通过对比不同湖区,发现北部梅梁湾的浮游植物重金属含量较高,东太湖和湖心区含量均低于沿岸湖区.CCA分析表明春季重金属与优势藻种呈正相关,而夏季和冬季二者呈负相关.三季中重金属与蓝藻和绿藻的相关性最高,与隐藻的相关性最低.蓝藻中,重金属与铜绿微囊藻的相关性高于水华微囊藻. 相似文献
6.
长江中下游地区浅水湖泊群中无机氮和TN/TP变化的模式及生物调控机制 总被引：2，自引：2，他引：2
对长江中下游地区33个浅水性湖泊的氨态氮(NH3-N)、硝态氮(NO3-N)、亚硝氮(NO2-N)和氮磷比(TN/TP)在生长季节和非生长季节的变化进行了研究.各营养盐浓度之间均呈显著正相关,整体上生长季节的相关性较好.当TP>0.1 mg l-1时, 随TP浓度的升高,非生长季节氨态氮浓度增加较快, 硝态氮在生长季节呈增长趋势而在非生长季节有下降的趋势,这主要因为非生长季节超富营养湖泊中的溶氧和温度较生长季节低, 而硝化作用对溶氧和温度较敏感所致.当TP为0.035 mg·l-1~0.1 mg·l-1时,生长季节总氮和各种无机氮均低于非生长季节,浮游植物可能是关键的调控因子;当TP<
0.035mg·1-1时,各无机氮的浓度较低,且生长季节和非生长季节浮游植物与氨氮、亚硝氮呈著正相关,说明在低营养状态下氨氮和亚亚硝氮可能成为浮游植物的限制因子.此外,TN/TP比随TP浓度呈降低的趋势,生长季节总氮及各种无机氮的浓度明显低于非生长季节,说明氮(尤其是氨氮和硝太氮)在生长季节的降低是TN/TP低于非生长季节的现象在富营养、超富营养状态十分明显.由浮游植物和细菌的作用所导致氮的减少及沉积物磷的释放是生长季节TN/TP降低的重要原因,即生长季节氮磷比的降低是湖泊生态系统生命过程综合作用的结果. 相似文献
7.
三峡小江回水区段2007年春季水华与营养盐特征 总被引：19，自引：5，他引：14
2007年5月中下旬,三峡水库小江回水区发生水华,主要分布在高阳平湖、黄石代李子和双江大桥三处,对水华期间浮游植物群落特点和水环境特征的分析发现蓝藻占主导,约为浮游植物生物量的81.43%,优势藻种为水华鱼腥藻(Anabaena flos-aquae),结合水华期间总氮含量较非水华期间明显偏高且有机氮为氮素主要成份和许多蓝藻门藻种均带有异形胞的分析结果,认为此次水华是同氮型蓝藻水华,水华暴发前初春的强降雨过程导致小江回水区TP水平的普遍增加促使了TN/TP发生显著的变化,4月份较低的TN/TP水平诱使同氮型蓝藻在小江回水区迅速生长,并在5月份形成水华,水华期间生物量的增加造成水中磷酸盐浓度的降低,使得小江回水区表现出显著的磷限制特征,调查认为:高阳平湖段可能是小江回水区蓝藻水华的发源地,蓝藻生物体随流漂移至下游黄石代李子处并逐渐聚集,形成自岸边缓流带向河道中心逐渐延伸的肉眼可见的蓝藻生物聚集体,从而使得黄石代李子处具有最高的生物量和叶绿素值,而双江大桥处,则主要是由于河道过水断面的放大导致流速的降低,同时沿岸云阳县县城的排污使得这一河段的营养负荷相对提高,从而为上游随流漂移下来的蓝藻提供了较佳的生长环境. 相似文献
8.
2005-2017年北部太湖水体叶绿素a和营养盐变化及影响因素 总被引：7，自引：0，他引：7
利用国家生态观测网络太湖湖泊生态系统研究站对北部太湖14个监测点2005-2017年的营养盐和叶绿素a浓度逐月监测数据，分析了北部太湖2005年以来水体营养盐和叶绿素a变化特征，探讨了叶绿素变化的影响因素.结果表明，2015年以来，北部太湖水体叶绿素a浓度呈现显著增高特征，特别是5-7月的蓝藻水华灾害关键期，水体叶绿素a浓度增幅更加明显；营养盐方面，氮、磷对治理的响应完全不同：水体总氮、溶解性总氮、氨氮的降幅很明显，甚至在春末夏初的蓝藻生长旺盛期出现了供给不足的征兆；但水体总磷降幅却不明显，加之蓝藻水华的磷"泵吸作用"，近3 a来水体总磷浓度反而有升高趋势，溶解性总磷浓度也无明显下降趋势.不同湖区的营养盐变化也不相同：西北湖区溶解性总氮、溶解性总磷浓度显著高于梅梁湾、贡湖湾和湖心区，而且后3个湖区的水质呈现均一化趋势.统计分析表明，北部太湖水体叶绿素a浓度与颗粒氮、颗粒磷、总磷、高锰酸盐指数均呈显著正相关，与溶解态氮呈负相关；5-7月水华关键期北部太湖水体叶绿素a浓度与上半年（1-6月）逐日水温积温、总降雨量、年平均水位均呈显著正相关关系.从研究结果可以看出，近年来北部太湖水体叶绿素a浓度的波动很大程度上受水文气象因子的影响；2007年以来太湖流域一系列生态修复工程的实施，虽然明显降低了湖泊氮浓度，但由于流域和湖体的氮磷本底较高，磷的缓冲能力大，致使水体营养盐水平仍未降到能显著抑制蓝藻生长的水平，年际之间的水文气象条件差异成为蓝藻水华暴发强度差异的主控因素.为此，仍需加大对太湖流域氮、磷负荷的削减，使湖体氮、磷浓度降低到能显著影响蓝藻生长的水平，才能摆脱水文气象条件对蓝藻水华情势的决定作用. 相似文献
9.
太湖北部隐藻生物量时空动态 总被引：11，自引：1，他引：10
利用2005-2009年每月一次的监测资料,对太湖竺山湾、梅梁湾和贡湖湾理化因子和浮游植物,特别是隐藻生物量周年季节变化进行比较研究,探讨环境因子以及蓝藻变化对隐藻生物量的影响.结果显示,竺山湾内隐藻平均生物量(1.89 mg/L)高于梅梁湾(0.87 mg/L)、贡湖湾(0.43 mg/L).2008-2009年隐藻平均生物量(2.12 mg/L)高于2005-2007年平均生物量(0.28 mg/L).通过与环境冈子的时空差异比较分析,竺山湾内高营养盐浓度、高有机质浓度和高悬浮质浓度使得隐藻更具有竞争优势,而贡湖湾内浮游动物的摄食作用可能限制了隐藻生物量.同时,太湖隐藻与蓝藻的竞争演替趋势明显,春夏季高温和蓝藻的过度繁盛可能对隐藻的生长产生抑制作用. 相似文献
10.
为研究崇明岛河网浮游植物和无机、有机氮的时空分布特征及其相互关系,于2014年1、4、7和10月在崇明岛河网内选取界河、堡镇港、八滧港3条河道9个采样点采集浮游植物和表层水样,并选取崇西水闸作为对照点进行研究.结果表明:河网内浮游植物以绿藻和硅藻为主,其中水闸和堡镇港夏季裸藻生物量所占比例超过50%.八滧港总溶解性氮(TDN)的主要组分是溶解性无机氮,而水闸、界河和堡镇港溶解性有机氮(DON)在TDN中的比例在夏、秋季低于冬、春季,农田土壤释放可能是DON的重要来源.水温、溶解氧和化学需氧量是影响铵态氮浓度变化的重要环境因素.此外,通过冗余分析发现,铵态氮影响绿藻和裸藻分布,尿素影响甲藻分布. 相似文献
11.
This study analysed the importance of precipitation events from May 2003 to April 2004 on surface water chemistry and solute export from a 696 ha glaciated forested watershed in western New York State, USA. The specific objectives of the study were to determine: (a) the temporal patterns of solutes within individual storm events; (b) the impact of precipitation events on seasonal and annual export budgets; and (c) how solute concentrations and loads varied for precipitation events among seasons as functions of storm intensity and antecedent moisture conditions. Analysis of solute trajectories showed that NH4+, total Al and dissolved organic nitrogen (DON) peaked on the hydrograph rising limb, whereas dissolved organic carbon (DOC) concentrations peaked following the discharge peak. Sulphate and base‐cations displayed a dilution pattern with a minimum around peak discharge. End‐member mixing analysis showed that throughfall contributions were highest on the rising limb, whereas valley‐bottom riparian waters peaked following the discharge peak. The trajectories of NO3? concentrations varied with season, indicating the influence of biotic processes on the generation, and hence flux, of this solute. Storm events had the greatest impact on the annual budgets for NH4+, K+, total dissolved Al, DON and DOC. Storm events during summer had the greatest impact on seasonal solute budgets. Summer events had the highest hourly discharges and high concentrations of solutes. However, NO3? and DOC exports during a spring snowmelt event were considerably more than those observed for large events during other periods of the year. Comparisons among storms showed that season, precipitation amount, and antecedent moisture conditions affected solute concentrations and loads. Concentrations of solutes were elevated for storms that occurred after dry antecedent conditions. Seven of the largest storms accounted for only 15% of the annual discharge, but were responsible for 34%, 19%, 64%, 13%, 39% and 24% of the annual exports of NH4+, K+, Al, NO3?, DON and DOC respectively. These results suggest that the intense and infrequent storms predicted for future climate‐change scenarios will likely increase the exports of solutes like DOC, DON, NH4+, Al and K+ from watersheds. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
12.
This paper examines the impact of contrasting antecedent soil moisture conditions on the hydrochemical response, here the changes in dissolved nitrogen (NO3?, NH4+ and dissolved organic nitrogen (DON)) and dissolved organic carbon (DOC) concentrations, of a first‐order stream during hydrological events. The study was performed in the Hermine, a 5 ha forested watershed of the Canadian Shield. It focused on a series of eight precipitation events (spring, summer and fall) sampled every 2 or 3 h and showing contrasted antecedent moisture conditions. The partition of the eight events between two groups (dry or wet) of antecedent moisture conditions was conducted using a principal component analysis (PCA). The partition was controlled (first axis explained 86% of the variability) by the antecedent streamflow, the streamflow to precipitation ratio Q/P and by the antecedent groundwater depth. The mean H+, NO3?, NH4+, total dissolved nitrogen and DOC concentrations and electrical conductivity values in the stream were significantly higher following dry antecedent conditions than after wetter conditions had prevailed in the Hermine, although the temporal variability was high (17 to 138%). At the event scale, a significantly higher proportion of the changes in DON, NO3?, and DOC concentrations in the stream was explained by temporal variations in discharge compared with the seasonal and annual scales. Two of the key hydrochemical features of the dry events were the synchronous changes in DOC and flow and the frequent negative relationships between discharge and NO3?. The DON concentrations were much less responsive than DOC to changes in discharge, whereas NH was not in phase with streamflow. During wet events, the synchronicity between streamflow and DON or NO3? was higher than during dry events and discharge and NO3? were generally positively linked. Based on these observations, the hydrological behaviour of the Hermine is conceptually compatible with a two‐component model of shallow (DON and DOC rich; variable NO3?) and deep (DON and DOC poor; variable NO3?) subsurface flow. The high NO3? and DOC levels measured at the early stages of dry events reflected the contribution from NO3?‐rich groundwaters. The contribution of rapid surface flow on water‐repellent soil materials located close to the stream channel is hypothesized to explain the DOC levels. An understanding of the complex interactions between antecedent soil moisture conditions, the presence of soil nutrients available for leaching and the dynamics of soil water flow paths during storms is essential to explain the fluxes of dissolved nitrogen and carbon in streams of forested watersheds. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
13.
A model on a physico-biological engineering experiment for purifying water in Wulihu Bay of Lake Taihu by using Trapa natans var. bispinosa was constructed. The state variables in water in the physico-biological engineering were ammonium nitrogen (NH4+-N); nitrate nitrogen (NO3--N); nitrite nitrogen (NO2--N); phosphate phosphorus (PO43--P); dissolved oxygen (DO); nitrogen (N) and phosphorus (P) in detritus; biomass density, N and P in phytoplankton and in Trapa natans var. bispinosa, N and P in the substance adsorbed by the membrane of the engineering and the rootstocks of Trapa natans var. bispinosa. The state variables in bottom mud layer were PO43--P in the core water,exchangeable P and N. The external forcing functions were solar radiation, water temperature, NH4+-N; NO3--N; NO2--N; PO43--P; N and P in detritus; DO; phytoplankton concentrations in inflow water and the retention time of the water in physico-biological engineering channel. The main physical, chemical and biological processes considered in the model were:growth of Trapa natans var. bispinosa and phytoplankton; oxidation of NH4+-N and NO2--N, of detritus break down; N and P sorption by the enclosure cloth of the experimental engineering and by the rootstocks of Trapa natans var. bispinosa in water; reaeration of water; uptake of P, NH4+-N, NO3--N by phytoplankton and Trapa natans var. bispinosa:mortality of the phytoplankton and Trapa natans var. bispinosa:settling of detritus; and nutrient release from sediment. Comparison of calculated results and observed results showed that the model was constructed reasonably for the experiment. The mechanism of purifying lake water in the experiment engineering was discussed by the use of the model. 相似文献
14.
Michael R. McHale Christopher P. Cirmo Myron J. Mitchell Jeffrey J. McDonnell 《水文研究》2004,18(10):1853-1870
Wetlands often form the transition zone between upland soils and watershed streams, however, stream–wetland interactions and hydrobiogeochemical processes are poorly understood. We measured changes in stream nitrogen (N) through one riparian wetland and one beaver meadow in the Archer Creek watershed in the Adirondack Mountains of New York State, USA from 1 March to 31 July 1996. In the riparian wetland we also measured changes in groundwater N. Groundwater N changed significantly from tension lysimeters at the edge of the peatland to piezometer nests within the peatland. Mean N concentrations at the peatland perimeter were 1·5, 0·5 and 18·6 µmol L?1 for NH4+, NO3? and DON (dissolved organic nitrogen), respectively, whereas peatland groundwater N concentration was 56·9, 1·5 and 31·6 µmol L?1 for NH4+, NO3? and DON, respectively. The mean concentrations of stream water N species at the inlet to the wetlands were 1·5, 10·1 and 16·9 µmol L?1 for NH4+, NO3? and DON, respectively and 1·6, 28·1 and 8·4 µmol L?1 at the wetland outlet. Although groundwater total dissolved N (TDN) concentrations changed more than stream water TDN through the wetlands, hydrological cross‐sections for the peatland showed that wetland groundwater contributed minimally to stream flow during the study period. Therefore, surface water N chemistry was affected more by in‐stream N transformations than by groundwater N transformations because the in‐stream changes, although small, affected a much greater volume of water. Stream water N input–output budgets indicated that the riparian peatland retained 0·16 mol N ha?1 day?1 of total dissolved N and the beaver meadow retained 0·26 mol N ha?1 day?1 during the study period. Nitrate dominated surface water TDN flux from the wetlands during the spring whereas DON dominated during the summer. This study demonstrates that although groundwater N changed significantly in the riparian peatland, those changes were not reflected in the stream. Consequently, although in‐stream changes of N concentrations were less marked than those in groundwater, they had a greater effect on stream water chemistry—because wetland groundwater contributed minimally to stream flow. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
15.
太湖草源性"湖泛"水域沉积物营养盐释放估算 总被引：22，自引：12，他引：10
于太湖草源性"湖泛"暴发期,采集柱状沉积物并应用peeper被动采样装置获得"湖泛"区原位沉积物间隙水.泥水样品分析表明:"湖泛"发生水域表层(0~7 cm)沉积物的含水率、孔隙度和有机质含量均明显高于对照区,其中有机质含量更是对照区样品的4倍左右,沉水植物残体促使表层沉积物物化性质改变的作用明显;"湖泛"发生水域表层沉积物间隙水中铵态氮(NH+4-N)、溶解性反应磷(SRP)及Fe2+含量远高于未发生区,植物残体降解对沉积物厌氧环境的营造显著.运用分子扩散模型对沉积物释放通量估算:"湖泛"发生区沉积物NH+4-N、SRP和Fe2+的释放速率分别是对照区的49.8、15.3和123.1倍.研究认为,草源性"湖泛"水体氮、磷等营养物含量升高的主要原因是沉积物的释放,而"湖泛"所营造的厌氧环境是氮、磷释放急剧增加的主要驱动因素. 相似文献
16.
Aída Martínez-López Diana Cecilia Escobedo-Urías Ana Elsi Ulloa-Pérez Raul Aguirre 《Continental Shelf Research》2008
To investigate the relative importance of mesoscale physical events, such as upwellings and physical and chemical variables during an algae bloom of Prorocentrum minimum, 25 sampling sites were established offshore of the Navachiste Lagoon Complex on the east side of the Gulf of California. Samples were analyzed for phytoplankton concentration, water chemistry, and temperature during November 1999, January, March, April, May, and August 2000. Satellite imagery of sea surface temperature (SST) for April 2000 was processed to obtain a synoptic view of the area during the extraordinary bloom of P. minimum in the open waters of the Gulf of California. The bloom was associated with change of oceanographic conditions from moderate winds to calm period, temperature increase and high nitrate (NO3−-N) and ammonia (NH4+-N) content in the offshore waters. Depletion of these nutrients during the bloom suggests that this species uses both types of nitrogen substrates. Cysts in the northernmost sampling stations in January and March indicate that upwelling water, rich in nitrates, also carried a seed stock population of P. minimum. SST patterns in the satellite imagery suggest wind-forcing as the responsible mechanisms triggering the algal bloom offshore of the Navachiste Lagoon Complex. 相似文献
17.
湖光岩玛珥湖水体中营养盐的时空分布特征及其影响因素 总被引：1，自引：0，他引：1
湖光岩玛珥湖是世界上最大的玛珥湖，它几乎是封闭的，受外界的干扰小.目前有关玛珥湖的研究主要集中在古气候及生态环境研究方面，而有关玛珥湖营养盐在一年中的生物地球化学循环的研究较少，因此研究湖光岩玛珥湖营养盐的生物地球化学过程具有重要意义.于2015年10月-2016年9月对湖光岩玛珥湖全水柱的营养盐及其他相关参数进行逐月调查，分析营养盐的结构特征、垂直分布特征和时间变化情况，并讨论营养盐时空变化的影响因素.结果表明，湖光岩玛珥湖水中的无机氮（DIN）以铵态氮（NH4+-N）为主（>60%），其次是硝态氧（NO3--N），亚硝态氮（NO2--N）所占比利最低.湖光岩玛珥湖水中的硅酸盐（SiO32--Si）浓度较高，水体浮游植物生长受磷限制.冬季风期间，水体垂直混合较均匀，导致营养盐的垂直分布比较均匀；夏季风期间，水体层化，营养盐浓度在浅层水体较低，在深层水体较高.湖光岩玛珥湖表层水中的NO3--N、NH4+-N和SiO32--Si具有明显的时间变化规律：NO3--N浓度从10月-次年3月升高，从3-9月降低；NH4+-N浓度从10月-次年5月降低；SiO32--Si浓度从11月-次年5月降低，从5-9月持续升高.营养盐浓度的时间变化受有机质的矿化分解、水体的季节性混合、浮游植物的吸收、降雨的输入等多种因素的综合影响. 相似文献
18.
本研究在太湖梅梁湾采集沉积柱,采用一种自制的毫米级柱状沉积物自动垂向分层切割装置对表层50 mm沉积物进行垂向切割(间隔2 mm),结合高通量测序技术分析沉积物中细菌群落的毫米级垂向分布;同时采用毫米级高分辨透析技术和薄膜扩散梯度技术(DGT)分析溶解态和DGT可获取态铵态氮(NH4+-N)、硝态氮(NO3--N)、Fe、P的垂向分布特征。结果显示,沉积物中细菌群落与溶解态和DGT可获取态氮铁磷浓度在垂向上呈现显著的异质性。细菌硝酸盐还原主要发生在-16～0 mm沉积物深度,这可能导致了溶解态和DGT可获取态NO3--N含量在该沉积物深度的明显减少。细菌铁还原主要分布在-32～-18 mm沉积物深度,细菌硫酸盐还原主要分布在-50～-34 mm的沉积物深度;细菌硫酸盐还原是导致沉积物溶解态和DGT可获取态铁磷浓度从-32 mm随沉积物的深度增加而显著增加的主要原因。本研究加深了对富营养化湖泊沉积物中细菌影响氮磷在垂向上迁移转化的认识。 相似文献
19.
研究丹江口水库在完成高水位蓄水期间浮游植物群落的时空动态特征可为丹江口水库的水质保护与生态系统结构优化及健康管理提供一定科学依据。本研究基于2018—2020年的水库浮游植物监测数据,结合同期水库水体的理化参数,分析了丹江口水库浮游植物在不同年度、季度及空间的变化特征,以及影响浮游植物群落结构变化的主要环境因子。结果显示该区域共检测出浮游植物7个门类,其中蓝藻门、硅藻门、绿藻门、隐藻门为优势类群。2018—2020年浮游植物年均密度分别为1.96×106、2.55×106和5.07×106 cells/L,呈现出逐年增高趋势。浮游植物季度密度表现为秋季>夏季>春季>冬季,在夏秋季节蓝藻门和绿藻门占优势,春冬季节硅藻门和隐藻门占优势,同时硅藻门在四季中均占据生长优势。空间上库区浮游植物密度明显高于支流,且汉江库区浮游植物密度高于丹江库区,其中蓝藻门和绿藻门主要在库区大量出现,而支流则以硅藻门和隐藻门为主。RDA分析显示,影响丹江口水库浮游植物的主要环境因子是水温,其次为化学需氧量、氨氮和总磷。在不同季节和... 相似文献
20.
We studied the relationships between streamwater chemistry and the topography of subcatchments in the Dorokawa watershed in Hokkaido Island, northern Japan, to examine the use of topography as a predictor of streamwater chemistry in a watershed with relatively moderate terrain compared with other regions of Japan. Topographic characteristics of the Dorokawa watershed and its subcatchments were expressed as topographic index (TI) values, which ranged from 4·5 to 20·4 for individual grid cells (50 × 50 m2), but averaged from 6·4 to 7·4 for the 20 subcatchments. Streamwater samples for chemical analyses were collected four times between June and October 2002 from 20 locations in the watershed. The pH of water that passed through the watershed increased from ～5·0 to 7·0, with major increases in Na+ and Ca2+ and marked decreases in NO3? and SO . Distinctive spatial patterns were observed for dissolved organic carbon (DOC), dissolved organic nitrogen (DON), and NO3? concentrations of streamwater across the watershed. Statistical analyses indicated significant linear relationships between the average TI values of subcatchments and DOC, DON, and NO3? concentrations. Furthermore, the proportion of DOC in streamwaters in the wet season increased with TI values relative to other nitrogen species, whereas NO3? concentrations decreased with TI. The gradients of soil wetness and the presence of wetlands explained many of the observed spatial and temporal patterns of DOC, DON, and NO3? concentrations in the surface waters of the Dorokawa watershed. Our results suggest that the TI is especially useful for predicting the spatial distribution of DOC, DON and NO3? in the surface waters of Hokkaido, where topographical relief is moderate and wetlands more common than in other regions of Japan. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献