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富营养化和风浪是影响大型浅水湖泊浮游植物群落的重要因素,本文于2003年10月至2004年9月对太湖梅梁湾和五里湖理化环境因子(水温、透明度值、悬浮质浓度和氮、磷营养盐浓度)和浮游植物群落进行了逐月监测,通过对两个湖区理化因子和浮游植物群落结构在周年内季节变化的比较研究,探讨富营养化程度以及风浪对浮游植物群落结构的影响,结果为:(1)梅梁湾由于受风浪影响悬浮物含量较高,五里湖则富营养化水平更高.(2)周年内五里湖浮游植物平均生物量(6.85 mg/L)高于梅梁湾的平均生物量(4.99 mg/L),两个湖区都呈现夏秋高峰、冬季低谷的变化特征.梅梁湾浮游植物群落季节演替的模式基本为:冬季硅藻(小环藻属Cyclotella spp.)和隐藻(隐藻属Cryptomonas spp.)-春季绿藻(细丝藻属Planctonema sp.)-夏季绿藻(绿球藻目Chlorococcales种类)和蓝藻(微囊藻属Microcystis spp.和浮游蓝丝藻属Planktothrix spp.)-初秋蓝藻(微囊藻属)和硅藻(浮游直链硅藻Aulacoseira spp.)-秋季隐藻(隐藻属).五里湖的季节演替模式没有梅梁湾明显,全年隐藻(隐藻属)都占优势,在此基础上,秋冬季硅藻(小环藻属和浮游直链硅藻属)占优势,裸藻(裸藻属Euglena spp.)在冬春季占优势,绿藻(绿球藻目种类和团藻目衣藻属Chlamydomonas spp.)在整个春季和初夏的优势地位在夏季被蓝藻(微囊藻属和浮游蓝丝藻属)所取代.群落构成的差异是浮游植物对两个湖区不同风浪条件和富营养化水平的响应结果.(3)通过与PEG(Plankton Ecology Group)模式的比较,梅梁湾和五里湖浮游植物群落的季节演替主要受水温、光照、营养盐(氮、磷)浓度和浮游动物牧食等因子的影响,因此,大型富营养化浅水湖泊浮游植物群落演替规律需要进一步的研究. 相似文献
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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
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太湖梅梁湾冬季湖流特征 总被引：1，自引：1，他引：1
2003年元月在盛行西北偏北风的情况下,对位于太湖北部的梅梁湾进行了面上湖流调查,发现梅梁湾湾口的湖流较为稳定,以向南流为主,且流速相对较大,最大达8cm/s,梅梁湾西岸有稳定的向北流,而从五里湖口至拖山附近的梅梁湾东线湖水由北向南流动,且在中部附近分为两支,一支向西,再流向北以补偿西岸的向北流,另一支扩散至整个梅梁湾南部,向南流经湾口进入太湖.在梅梁湾东北部,发现有弱辐合中心,该范围内Chl.a和TP、TN的含量明显高于周围水域.从所有点的垂直运动判断,梅梁湾水流以弱上升运动为主,大小为2cm/s以下.从水量平衡分析,以梅梁湾流入太湖为主要特征,水量补给主要来自于北部的五里湖和直湖港及武进港. 相似文献
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太湖梅梁湾水动力及相关过程的研究 总被引：56，自引：13，他引：43
太湖是位于长江下游的一个大型水湖泊,水动力过程和要素对浅水湖泊的环境演化有着复杂和深远的影响,本文基于１９９８年开展的有关太湖梅梁湾的水动力过程的野外调查结果,总结了梅梁湾在夏季盛行风向条件下湖流特征,发现了梅梁湾在夏季偏南风条件下,表层湖流以顺时针环流为主要特征,但在湾内靠近梁溪河口地区,流场受地形影响而有所不同,反映在叶绿素浓度和总磷、总氮浓度分布上,因受湖流影响较大而富集在梁溪河口周转,即偏 相似文献
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原生动物纤毛虫对太湖梅梁湾水质富营养化的响应 总被引：12，自引：0，他引：12
１９９３年４月－１９９４年１月研究了太湖梅梁湾湖区纤毛虫的群落分布,共检出７目１９属,根据ＴＳＩ指标,该湖区可分为富营养型和中营养型水域,在富营养型水域中分布着特有的纤毛虫种类。 相似文献
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太湖不同生态类型湖区浮游甲壳动物群落结构季节变化比较 总被引：1，自引：0，他引：1
水体富营养化会对整个水生态系统产生重要影响.为了解太湖富营养化对浮游甲壳动物群落结构的影响,于2012年3月至2013年2月对太湖3个典型湖区——藻型湖区(梅梁湾)、草型湖区(胥口湾)和强扰动湖区(湖心区)开展浮游甲壳动物群落结构季节变化比较研究.3个湖区中,湖心区营养水平最高,胥口湾最低.梅梁湾浮游甲壳动物密度和生物量最高,其次是湖心区,胥口湾最低.梅梁湾、湖心区和胥口湾的浮游甲壳动物年平均密度分别为199、150和91 ind./L,年平均生物量分别为1.950、1.557和0.743 mg/L.在整个研究期间,梅梁湾、胥口湾和湖心区的浮游甲壳动物种类数分别为13、11和11;3个湖区的浮游甲壳动物优势种均为中华窄腹剑水蚤和简弧象鼻溞,其中中华窄腹剑水蚤在梅梁湾、胥口湾和湖心区的年平均密度分别为57、25和36 ind./L,简弧象鼻溞在3个湖区的年平均密度分别为40、22和32 ind./L.胥口湾浮游甲壳动物生物多样性指数显著低于梅梁湾和湖心区.相关分析表明,浮游甲壳动物密度与叶绿素a浓度呈极显著正相关.研究表明,同一湖泊不同生态类型湖区浮游甲壳动物会对水体富营养化产生不同的生态响应. 相似文献
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对太湖北岸贡湖和梅梁湾湖滨带(水-陆交错区)观测场中的主要水生植物群落的种类组成、生物量进行了测定,定量分析了其生长型和群落特征的季节变化,比较分析了上述两个湖滨带观测场的水质变化情况,并且在此基础上进一步探讨了影响湖滨带沉水植物生长的关键因素.结果表明:(1)贡湖观测场的荇菜(Nymphoides peltatum) 马来眼子菜(Potamogeton malaianus)群落由3种浮叶植物和3种沉水植物构成,共5种水生植物生长型.而梅梁湾观测场的菹草群落为单优群落,只有一种沉水植物菹草(Potamogeton crispus),其生长型为大眼子菜型.以上两个湖滨带观测场水生植物群落特征与人为活动的干扰(如水质污染、人工堤岸建设等)密切相关;(2)以上两湖湾的主要污染指标为氮、磷营养物,均已达到富营养水平,但贡湖观测场的水质(除透明度外)明显好于梅梁湾观测场;(3)透明度、水深和风浪可能是影响贡湖和梅梁湾湖滨带沉水植物种群数量、分布和格局的重要因素. 相似文献
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Variability in water-exchange time between Tokyo Bay and the Pacific Ocean during winter is investigated based on the results of intensive field observation from November 2000 to March 2001. Water-exchange time between Tokyo Bay and the Pacific Ocean during winter mainly depends on the strength of northerly monsoon, being about 16 days under the weak monsoon and about 12 days under the strong monsoon. Moreover, it becomes longer by about 1 day in spring tide and shorter in neap tide due to the coupling effect of estuarine circulation and vertical mixing. Water-exchange time also varies depending on the open-ocean condition. When the warm water mass approaches from the Pacific Ocean to the mouth of Tokyo Bay through the eastern channel of Sagami Bay, which connects Tokyo Bay and the Pacific Ocean, water-exchange time becomes longer by about 2 days because the warm water mass is blocked in the surface layer at the bay mouth. On the other hand, when the warm water mass approaches to the mouth of Tokyo Bay through the western channel of Sagami Bay, water-exchange time becomes shorter by about 1 day because the warm water mass intrudes into the middle or lower layers of Tokyo Bay. Such different behavior of warm water mass at the mouth of Tokyo Bay is due to the difference in density of approaching warm water masses, that is, the density of the warm water mass through the eastern channel is smaller than that of the warm water mass through the western channel of Sagami Bay.Responsible Editors: Yens Kappenberg 相似文献
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Collignon A Hecq JH Glagani F Voisin P Collard F Goffart A 《Marine pollution bulletin》2012,64(4):861-864
Neustonic microplastic and zooplankton abundance was determined in the North Western Mediterranean Sea during a summer cruise between July 9th and August 6th 2010, with a break between July 22 th and 25th due to a strong wind event. Ninety percent of the 40 stations contained microplastic particles (size 0.3-5mm) of various compositions: e.g., filaments, polystyrene, thin plastic films. An average concentration of 0.116 particles/m(2) was observed. The highest abundances (>0.36 particles/m(2)) were observed in shelf stations. The neustonic plastic particles concentrations were 5 times higher before than after the strong wind event which increased the mixing and the vertical repartition of plastic particles in the upper layers of the water column. The values rise in the same order of magnitude than in the North Pacific Gyre. The average ratio between microplastics and mesozooplankton weights was 0.5 for the whole survey and might induce a potential confusion for zooplankton feeders. 相似文献
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The fate of inflows into lakes has been extensively studied during summer stratification but has seen relatively little focus
during the weak winter stratification, with or without ice-cover. Field observations are presented of groundwater inflow into
a shallow bay of a subarctic lake. Atmospheric forcing of the bay during the study period was extremely variable and coincided
with spring ice-cover break-up. Two dominant wind regimes were identified; (1) weak wind-forcing (wind speed <5 m s−1 or land-fast ice-cover), and (2) strong wind-forcing (wind speed >5 m s−1 and open water). At a relatively constant temperature of ~3.3°C, the groundwater inflow was closer to the temperature of
maximum density than the water in the main body of the lake, which during the observed winter stratification is ~1.2°C. During
weak wind-forcing, the stratification within Silfra Bay approximated two-layers as this denser groundwater formed a negatively
buoyant underflow. A calculated underflow entrainment rate of 2.8 × 10−3 agrees well with other underflow studies. During strong wind-forcing, the water column out to the mouth of the bay became
weakly stratified as the underflow was entrained vertically by wind-stirring. Observed periods of mixing can be predicted
to occur when turbulent kinetic energy (TKE) production by wind stirring integrated over the underflow hydraulic residence
time in the bay exceeds the potential energy associated with the stratification. A decrease of ice cover, as observed in the
studied subarctic lake over the last decade, will result in the underflow being more frequently exposed to the strong wind-forcing
regime during winter, thereby altering the winter distribution of groundwater inflow within the lake. 相似文献
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淮河干流浮游动物群落结构特征 总被引：10，自引：2，他引：8
2011年3、6、9和12月对淮河干流11个采样点的浮游动物群落结构进行调查研究,共检出浮游动物79属206种,其中原生动物27属69种,占浮游动物总物种数的33.5%;轮虫35属104种,占50.5%;枝角类12属27种,占13.1%;桡足类5属6种,占2.9%.总体上看,从上游至下游,浮游动物物种数呈现逐渐减少的趋势.浮游动物的丰度和生物量分别为3527447 ind./L和2452 mg/L,轮虫和原生动物丰度是淮河干流浮游动物丰度的主体,轮虫生物量是淮河干流浮游动物生物量的主体,浮游动物及各类群丰度和生物量均表现为从上游到中游逐渐增高的趋势,而从中游到下游呈现逐渐降低的趋势.上游浮游动物多样性指数和均匀度指数高于中、下游.结果表明:淮河干流上游水质为轻污染,中、下游水质为中污染或重污染.浮游动物群落结构和环境因子的冗余分析表明,水温、溶解氧和流速是与淮河干流浮游动物群落结构相关性较强的环境因子. 相似文献
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《Limnologica》2021
Ecological restoration of eutrophic lakes using aquatic macrophytes is an important and practical technology. Here, we investigated the response of phytoplankton and zooplankton to a large-scale 2015-built aquatic macrophyte enclosure (AME, 200,000 m2) screened of by a PVC net in Baima Lake, a eutrophic lake, from spring to autumn of 2019. AME significantly improved water quality by increasing water transparency, and reducing total nitrogen, total phosphorus, and chlorophyll-a content during the growing season. AME significantly decreased phytoplankton abundance and biomass and marginally increased zooplankton abundance and biomass. Phytoplankton and zooplankton communities were closely related to environmental factors, such as water temperature, conductivity, total phosphorus, chemical oxygen demand, and chlorophyll-a inside and outside the AME. The zooplankton:phytoplankton biomass ratio inside was slightly higher than outside the AME. Zooplankton and phytoplankton biomass were significantly positively correlated inside and outside the AME, as were chlorophyll-a and total phosphorus. We found phosphorus to be a key factor limiting primary productivity in Baima Lake, and that bottom-up effects were the main driver to control phytoplankton in the AME. Using aquatic macrophytes to reduce nutrient loads is an effective way to manage eutrophication in Baima Lake. 相似文献
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城市河-湖连通使不同水文特征的水体连通构成多样化水环境,环境异质性为提高浮游动物多样性提供了多样性生境条件.为了解湖南常德柳叶湖及其邻近水体轮虫群落结构变化对不同水体连通性和异质性的响应,于2018年对柳叶湖、穿紫河和沅江常德市区河段共15个站点进行了每季度1次的轮虫群落结构和环境特征调查分析.调查期间,不同水体的营养水平呈现:穿紫河柳叶湖沅江,穿紫河和柳叶湖呈富营养化状态,沅江呈中营养状态.本研究共检出轮虫88种(包括亚种8种和变种1种),其中,长肢多肢轮虫(Polyarthra dolichoptera)为水系第一优势种.轮虫最高丰度为2535ind./L,全年平均丰度空间分布呈现:柳叶湖穿紫河沅江;季节分布呈现:6月 9月 3月 12月.轮虫群落对水体连通性的响应表现为:柳叶湖、穿紫河和沅江3个水体轮虫种类组成具有一定的相似性且第一优势种相同.对异质性的响应表现为:不同水体轮虫群落年平均丰度和多样性指数存在空间差异.典范对应分析表明水温是影响轮虫群落结构变化的主要环境因子. 相似文献
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Wen Zhao Yuanyi Zhao Qiaohan Wang Mianping Zheng Peng Zhang Zhihui He 《洁净——土壤、空气、水》2010,38(10):960-968
The seasonal variations in biomass, abundance, and species composition of plankton in relation to hydrography were studied in saline lake Namuka Co, northern Tibet, China. The sampling was carried out at approximately monthly intervals from June 2001 to July 2002. The salinity ranged from 5.5 to 26 g/L. The mean annual air and water temperature showed a clear seasonal pattern, which was approximately 4.4 and 7.4°C, respectively, with the lowest water temperature in winter (from December to March, −1°C) and the highest in June and July (18°C). The results showed that 36 taxa of phytoplankton and 16 taxa of zooplankton were identified. Both the biomass and abundance of total phytoplankton were lower in the winter and peaked once or twice during the summer and spring in the early August (8.23 mg/L and 158.2 × 106 ind./L). The seasonal variation in total zooplankton biomass and abundance was characterized by lower values in both winter and early spring, and one maximum (90.5 mg/L and 935 ind. L−1) occurred in the late summer. Major phytoplankton species were Gloeothece linearis, Oscillatoria tenuis, Gloeocapsa punctata, Ctenocladus circinnatus, Ulothrix sp., and Spirogyra sp. And major zooplankton species included Vorticella campanula, Brachionus plicatilis, Daphniopsis tibetana, Cletocamptus dertersi, Arctodiaptomus stewartianus. The production of D. tibetana was 420.3 g m3 a−1. The total number of plankton species has a significant negative correlation with the salinity. 相似文献
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Kelly J. Benoit-Bird Mark A. Moline Chad M. Waluk Ian C. Robbins 《Continental Shelf Research》2010,30(1):17-28
This study combined measurements from multiple platforms with acoustic instruments on moorings and on a ship and optics on a profiler and an autonomous underwater vehicle (AUV) to examine the relationships between fluorescent, bioluminescent, and acoustically scattering layers in Monterey Bay during nighttime hours in July and August of 2006 and May of 2008. We identified thin bioluminescent layers that were strongly correlated with acoustic scattering at the same depth but were part of vertically broad acoustic features, suggesting layers of unique composition inside larger biomass features. These compositional thin layers nested inside larger biomass features may be a common ecosystem component and are likely to have significant ecological impacts but are extremely difficult to identify as most approaches capable of the vertical scales of measurement necessary for the identification of sub-meter scale patterns assess bulk properties rather than specific layer composition. Measurements of multiple types of thin layers showed that the depth offset between thin phytoplankton and zooplankton layers was highly variable with some layers found at the same depth but others found up to 16 m apart. The vertical offset between phytoplankton and zooplankton thin layers was strongly predicted by the fraction of the water column fluorescence contained within a thin phytoplankton layer. Thin zooplankton layers were only vertically associated with thin phytoplankton layers when the phytoplankton in a layer accounted for more than about 18–20% of the water column chlorophyll. Trophic interactions were likely occurring between phytoplankton and zooplankton thin layers but phytoplankton thin layers were exploited by zooplankton only when they represented a large fraction of the available phytoplankton, suggesting zooplankton have some knowledge of the available food over the entire water column. The horizontal extent of phytoplankton layers, discussed in the second paper in this series, is likely an important factor contributing to this selective exploitation by zooplankton. The pattern of vertical offset between phytoplankton and zooplankton layers was consistent between studies in different years and using different combinations of platforms, indicating the importance of the relationship between zooplankton layers and the fraction of phytoplankton within a layer at night within Monterey Bay. These results highlight the value of integrating measurements of various types of organisms to understand thin layers processes and the importance of assessing ecological interactions in plankton thin layers within the context of the properties of the entire water column, like the animals themselves do. 相似文献
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Acoustic Doppler current profiles and current meter data are combined with wind observations to describe the transport of water leaving Florida Bay and moving onto the inner shelf on the Atlantic side of the Florida Keys. A 275-day study in the Long Key Channel reveals strong tidal exchanges, but the average ebb tide volume leaving Florida Bay is 19% greater than the average flood tide volume entering the bay. The long-term net outflow averages 472 m3 s−1. Two studies in shelf waters describe the response to wind forcing during spring and summer months in 2004 and during fall and winter months in 2004–2005. During the spring–summer study, southeasterly winds have a distinct shoreward component, and a two-layer pattern appears. Surface layers move shoreward while near-bottom layers move seaward. During the winter study, the resultant wind direction is parallel to the Keys and to the local isobaths. The entire water column moves in a nearly downwind direction, and across-shelf transport is relatively small. During the summer wet season, Florida Bay water should be warmer, fresher, and thus less dense than Atlantic shelf waters. Ebbing bay water should move onto the shelf as a buoyant plume and be held close to the Keys by southeasterly winds. During the winter dry season, colder and saltier Florida Bay water should leave the tidal channels with relatively high density and be concentrated in the near-bottom layers. But little across-shelf flow occurs with northeasterly winds. The study suggests that seasonally changing wind forcing and hydrographic conditions serve to insulate the reef tract from the impact of low-quality bay water. 相似文献
20.
Wind effects on the lateral structure of density-driven circulation in Chesapeake Bay 总被引：3，自引：0，他引：3
The response of the density-driven circulation in the Chesapeake Bay to wind forcing was studied with numerical experiments. A model of the bay with realistic bathymetry was first applied to produce the density-driven flow under average river discharge and tidal forcing. Subsequently, four spatially uniform wind fields (northeasterly, northwesterly, southwesterly, and southeasterly) were imposed to examine the resulting cross-estuary structure of salinity and flow fields. In general, northeasterly and northwesterly winds intensified the density-driven circulation in the upper and middle reaches of the bay, whereas southeasterly and southwesterly winds weakened it. The response was different in the lower bay, where downwind flow from the upper and middle reaches of the bay competed with onshore/offshore coastal flows. Wind remote effects were dominant, over local effects, on volume transports through the bay entrance. However, local effects were more influential in establishing the sea-level slopes that drove subtidal flows and salinity fields in most of the bay. The effect of vertical stratification on wind-induced flows was also investigated by switching it off. The absence of stratification allowed development of Ekman layers that reached depths of the same order as the water depth. Consequently, bathymetric effects became influential on the homogeneous flow structure causing the wind-induced flow inside the bay to show a marked transverse structure: downwind over the shallow areas and upwind in the channels. In the presence of stratification, Ekman layers became shallower and the wind-induced currents showed weaker transverse structure than those that developed in the absence of stratification. In essence, the wind-driven flows were horizontally sheared under weak stratification and vertically sheared under stratified conditions. 相似文献