小水库季节性水面育种技术

鱼种,是渔业生产的基础,而大规格多品种优质鱼种是夺取渔业丰产高效的关键。近几年随着养鱼业的大发展,群众买种难特别买大鱼种难的问题越来越突出。为试求缓解这一矛盾,山东省宁阳县水产站于1983—1984年,会同泰安市水产研究所,利用石集、二号两座小型水库,季节性水面480亩,投放乌仔、寸片鱼种进行大鱼种培育试验,获得显著的效果,共培育生产13—16.5厘米优质鱼种62.23万尾,解决了近万亩水库放养的需要,总产值3.7万元,盈利2.8万元。他们的主要措施是:

季节性水浸路基形变协调设计分析研究

基于轻交通公路3级规范标准,针对季节性水浸路基形变协调设计,提出构造组合初步设计、构造优化组合调整以及方案比较选择的设计思路。

西北黄土高原旱地全膜双垄沟播种植对玉米季节性耗水和产量的调节机制

【目的】从玉米季节性耗水调节产量和水分利用效率的角度,揭示旱地全膜双垄沟播的增产机制。【方法】通过测定土壤温度、含水量、玉米地上干物质和产量及其构成因子,以及计算土壤温度梯度等,探讨旱地全膜双垄沟播对玉米季节性耗水和产量的调节机制。【结果】全膜双垄沟播(PMF)和全沙覆盖平作(SM)对玉米生长期的水分环境有显著的调节作用。与裸地平作(CK)相比,PMF和SM能提高地温最低点玉米全生育期土壤温度梯度和地温最高点玉米拔节前土壤温度梯度,在显著高于CK和地温最高、最低点反方向温度梯度驱动下实现了对土壤水分的调节,使玉米在需水较少阶段保蓄更多的水分以供需水盛期利用;各处理玉米耗水高峰出现的时期与当年降雨分布密切相关,PMF和SM可以促进玉米拔节后耗水,其中灌浆期增加最为显著,该时期PMF和SM的耗水量分别较CK增加237.7%和83.1%,差异显著(P<0.05);其次是拔节-抽雄期,分别较CK增加31.8%和27.4%,差异显著(P<0.05);玉米收获指数分别提高132.5%和116.1%。【结论】PMF能够增大土壤温度梯度,减少前期地表蒸发为主的水分耗散,保蓄更多水分供后期使用;在后期雨季能够充分利用降水,促进籽粒形成和灌浆,表现较高的穗粒数和百粒重,显著提高产量和水分利用效率。

西安地区地下热水季节性活动与区域地震活动的关系研究

根据西影井热水水位的观测资料,分析了西安地区地下热水活动的季节性特征及其与区域地震活动的相关性。结果表明西安地区地下热水活动与区域地震活动明显相关,其相关性基本不受季节性用水的影响,反映出它们受同一构造力源的控制,同时,西安地区地下热水活动与西安及邻区的地震活动最为密切。

季节性淹水对长江滩地69杨木材材性及其变异的影响

以安徽新洲滩地上生长的６９杨为材料，研究季节性淹水对６９杨木材材性及其变异的影响，结果表明，与未淹水相比，长江滩地季节性淹水对６９杨纤维形态特征影响不大，０．０５水平下方差分析检验不显著；对木材微纤丝角，木材密度，木材干缩率和力学性质影响较大，０．０５水平下方差分析检验显著，其中，微纤丝角、基本密度、抗弯弹性模量、抗弯强度和气干体积缩率分别增加了１５．６％、５．９％、１５．７％、１７．２％和２８．５％；而主要解剖特征的径向变异模式基本不受影响。

季节性涌水隧道施工技术探讨

根据施家梁隧道中溶洞的特征和溶洞段二次衬砌施作后暴雨期间溶洞内的涌水情况,采用洞内排水的方法对隧道涌水进行了处理,取得了良好的效果,为同类工程的设计施工积累了经验。

沉砂横洞处治岩溶隧道拱墙外侧季节性涌水溶洞施工技术

为有效解决隧道施工中穿越涌水溶洞的问题,文章提出采用沉砂横洞的处治方案,并介绍了其技术原理和施工要点。结果表明,处治后隧道排水迅速,对围岩扰动小,能够很大程度地提高隧道的结构耐久性,施工安全和施工质量得到了保证。

庐山不同海拔植物季节水分利用策略

为探讨在气候变化下不同海拔植物对水分的响应及植物适应性变化,选择庐山不同海拔自然演替中典型树种山鸡椒(Litsea cubeba)、蜡瓣花(Corylopsis sinensis)、山茶(Camellia japonica)和老鼠矢(Symplocos stellaris)为研究对象,采用氢氧同位素技术,基于Iso-source模型量化水源贡献比例。结果表明:(1)土壤水、植物水的δD值呈现不同的季节特征,表现为旱季δD值比雨季更加贫化;土壤水、植物水δD值的海拔效应不明显,土壤水δD值总体呈现出表层富集而深层贫化。(2)随着海拔升高,植物主要水分来源存在差异。在雨季,山鸡椒对表层(0—10 cm)土壤水分的比例呈现逐渐增加趋势,山茶对下层(30—50 cm)土壤水的比例逐渐增大,在旱季,蜡瓣花对表层土壤水的吸收比例逐渐降低。(3)植物的主要水分来源存在季节性差异,且不同海拔的同种植物表现不一。海拔1287 m区,雨季表层(0—10 cm)土壤水分对蜡瓣花的贡献率为68.50%,旱季仅占9.00%,而对山茶的贡献率从3.10%变为76.50%;海拔1078 m区,随雨旱交替,山鸡椒从均匀(0—50 cm)吸收土壤水变为优先利用表层(82.20%)给土壤水,蜡瓣花从主要吸收利用上层(0—20 cm,74.40%)土层变为均匀用水,山茶主要从深层转为上层(66.18%),老鼠矢从下层转向表层(86.40%);海拔884 m区,在雨季,山鸡椒、山茶、老鼠矢主要水分来源分别是10—40 cm(88.20%),40—50 cm(91.80%)和0—50 cm,但旱季均优先利用表层。(4)土壤表层水对山茶具有一定贡献,但其贡献比例比山鸡椒、蜡瓣花、老鼠矢低,40—50 cm土壤水是其主要来源,与其他树种保持协调生长;但其他3种树种存在一定的水分竞争,且不同海拔的竞争程度不一。综上所述,植物水分来源存在海拔差异、季节效应以适应不同环境因子的限制,山茶具有与山鸡椒、蜡瓣花、老鼠矢协同的水分利用模式,山鸡椒、蜡瓣花、老鼠矢三者间存在水分竞争,且在各个海拔的竞争程度不一。本研究对亚热带地区生态系统树种配置及保护、庐山植被生态水文耦合模型的建立提供科学的理论参考。

季节性淹水对长江滩地杨树林土壤理化性质和酶活性及微生物群落的影响

为了探明季节性淹水对林分地力的影响,以安徽沿江地区滩地杨树林土壤为研究对象,对季节性淹水前后,土壤(0<深度(h)≤60 cm)的养分质量分数、物理性质及酶活性进行测定;采用高通量测序技术对土壤微生物群落组成、多样性、空间结构及功能类群等进行测定,分析环境因子与土壤微生物群落的相互作用及其潜在关系。结果表明:季节性淹水后,滩地杨树林土壤0<h≤60 cm土层的pH显著升高;除全磷、速效钾、水解氮养分外,其他养分质量分数均极显著降低;田间持水量极显著增加;土壤脲酶、酸性磷酸酶的活性均有所下降,其中酸性磷酸酶活性降幅达99.68%;过氧化氢酶活性总体上升。季节性淹水改变了土壤细菌、真菌优势菌群的相对丰度,未显著提高微生物群落的丰富性和多样性,但改变了土壤真菌群落多样性在各土层间的变化趋势。非度量多维尺度分析(NMDS)和相似性分析(ANOSIM)发现,淹水前的细菌群落结构与淹水后具有显著差异;淹水前的真菌群落结构与淹水后具有极显著差异;且淹水后各土层间的细菌、真菌群落均呈显著差异。功能预测结果表明:土壤细菌生态功能以化能异养、好氧化能异养、硝化作用、氨氧化作用功能类群为主,季节性淹水后,土壤40 cm<h≤60 cm土层中,细菌群落的亚硝酸盐呼吸、硝化、亚硝态氮反硝化功能较为丰富。土壤真菌群落主要功能在淹水后,由病理-腐生-共生过渡型(33.13%)向病理营养型(20.74%)转变。淹水前后,土壤0<h≤20 cm土层真菌群落的植物病原菌相对丰度差异显著。冗余分析和相关性分析结果表明:pH、酸性磷酸酶、脲酶、过氧化氢酶、水解氮、全钾是影响微生物群落的主要环境因子。

旱地全膜覆土穴播对春小麦耗水、产量和土壤水分平衡的影响

目的干旱、降水供需错位和春季低温是制约西北黄土高原丘陵沟壑区春小麦生产的主要因子,如何最大限度保蓄自然降水、实现水分的跨季节利用,则是该区春小麦产量稳定提高的根本途径。本文在大田定位观测的基础上,揭示全膜覆土穴播对西北黄土高原旱作春小麦季节性耗水特征、产量、水分利用效率和休闲期土壤水分补给的影响,并评判其年际土壤水分平衡效应。方法试验于2011—2013年在西北黄土高原半干旱区的甘肃省农业科学院定西试验站进行(104°36′E,35°35′N),以春小麦陇春27号为试验材料,设全膜覆土穴播(FMS)、地膜覆盖穴播(FM)和露地穴播(CK)3个处理,测定春小麦不同生育时期的土壤含水量、生物量、产量和产量构成因子,计算休闲效率、耗水量、水分利用效率、收获指数等指标。结果 2011和2012年3个处理的春小麦耗水量无显著差异,但2013年FMS耗水量显著高于CK。FMS和FM可增加春小麦苗期到孕穗期耗水,且此阶段的耗水量在干旱年份分别较CK增加27.2%和9.6%,在丰水年份分别较CK增加52.2%和44.6%。虽然FMS和FM在各生育期的耗水量无显著差异,但FMS在丰水年(2012年和2013年)的耗水量较FM有增加趋势,且这一效果在2013年尤为明显。FMS和FM在休闲期可补充0—80 cm土层土壤水分25.4和18.3 mm,比CK分别低2.2和9.3 mm;补充80—200 cm土层土壤水分78.0和71.0 mm,比CK分别高30.0和23.1 mm;与2011年播前相比,种植3年春小麦后0—200 cm土层的土壤贮水量FMS增加了23.8 mm、FM增加了22.5 mm、CK增加了12.4 mm。FMS的休闲效率为30.5%—52.6%,比CK高12.8%—109.5%,比FM高4.5%—40.9%。FMS的穗粒数、千粒重等产量构成因子均显著高于CK(P<0.05);收获指数为0.4—0.5,比CK高32.5%。FMS的产量为1 750—3 180 kg·hm-2,水分利用效率为5.5—11.5 kg·hm-2·mm-1,分别比CK增加40%—220%、27%—239%,而且干旱年份的增加幅度更高。在干旱的2011年,FMS处理的产量较FM增加26.2%,水分利用效率提高28.2%;在丰水的2013年,FMS处理的产量较FM增加20.9%,水分利用效率提高14.8%,两年均达到显著差异水平,表明FMS较FM具有更明显的丰水年份增产、干旱年份适应干旱胁迫的潜力,能够实现该区春小麦生产稳产高产的目标。结论西北黄土高原半干旱区FMS种植模式有效提高了春小麦播前和生长前期的土壤贮水量,并使春小麦苗期—孕穗期的作物耗水量显著升高,增加春小麦穗粒数,扩大籽粒产量库容和促进灌浆,显著提高春小麦产量和水分利用效率;并在休闲期完全补充春小麦生育期消耗的0—200 cm土壤水分,保持春小麦田的土壤水分年际平衡。

岩溶地区地下水位变动带隧道涌水问题的思考

通过鸡冠山隧道涌水实例及广泛收集岩溶地区隧道涌水案例,总结出岩溶地区隧道季节变动带涌水具有反应时间快、水量大、泥沙重的特点,并综合分析地下水季节变动带隧道的水文地质特征,将其划分为一般山岭隧道及向斜构造地下水位变动带两种类型,且对两种类型涌水机理进行了阐述。岩溶地区隧道前期勘察应重点划分隧道岩溶地下水系统及地下水动力分带,查明岩溶发育特征与规律;施工期和运行期应结合岩溶揭露情况和涌水情况开展针对性的补充勘察,做好降雨、涌水过程和涌水压力监测,判断和预测最大外水压力和涌水量。针对涌水问题,提出封堵和排泄两种处理思路:施工开挖揭露的岩溶现象不可盲目封堵,需尽可能维持原通道的通畅,针对可能涌水的隧道衬砌设计不可仅考虑围岩结构,应充分考虑外水压力,做好围岩固结灌浆;常规隧道"环形排水系统+中心沟"排水系统可靠性差,针对大流量涌水,多采用泄水洞排水。

不同生态条件对人工林杨树木材物理力学性质的影响

在施肥与未施肥、淹水与未淹水两种生态条件下,以杨树人工林木材I-69杨为对象,对木材年轮宽度、基本密度、干缩性质、主要力学性质进行了测试,并对数据进行了统计、对比和分析.结果表明,施肥处理后,木材年轮宽度、静态抗弯弹性模量和顺纹抗压强度分别增大0.99%、2.73%和1.06%;全干时和气干时的径向、弦向、体积全干干缩率分别降低了4.2%、7.7%、6.6%、15.6%、6.3%和11.1%;木材密度、抗弯强度、动态抗弯弹性模量则分别降低了2%、1.79%、8.13%.与未淹水相比,季节性淹水对I-69杨木材密度、木材干缩率和力学性质的影响较大,二者差异显著(P<0.05).其中木材密度、全干时和气干时的径向、弦向、体积干缩率、抗弯强度、抗弯弹性模量以及顺纹抗压强度分别降低了5.5%、11.1%、9.2%、9.6%、16.7%、10.9%、8.5%、24.29%、18.18%和16.81%.

Seasonal dynamics of wintering waterbirds in two shallow lakes along Yangtze River in Anhui Province

The shallow lake wetlands in the middle and lower Yangtze River floodplain are important wintering and stopover habitats for migratory waterbirds on the East Asia-Australia Flyway.With increasing fishery practices in recent years,however,the wetlands have deteriorated significantly and now threaten wintering waterbirds.To gain insight into the influence of deteriorating wetlands on waterbirds,we conducted a survey of wintering waterbird species,population size,and distribution across 11 belt transects in Caizi Lake and Shengjin Lake,two shallow lakes along the Yangtze River in Anhui Province from November 2007-April 2008 and from November 2008-April 2009,respectively.The impacts of different fishery patterns on the distribution of waterbirds were also analyzed.A total of 43 waterbirds species belong to 7 orders of 12 families were counted during the surveys,of which 38 were found in Caizi Lake with a density of 8.2 ind./hm2,and 42 in Shengjin Lake with a density of 3.5 ind./hm2.Geese（Anser cygnoides）,bean geese（Anser fabalis）,tundra swan（Cygnus columbianus）,and dunlin（Calidris alpina） were the dominant species in the two shallow lakes.Species number and individual assemble reached maximum at the end of December and in early January of the following year,without coincidence of the largest flock for different ecological groups.Based on waterbird diversity across the 11 belt transects and the fishery patterns,habitats could be divided into three groups.Gruiformes,Anseriformes and Charadriiformes had relatively higher densities in the natural fishery zones and lower densities in the cage fishery zones;whereas,the density of Ardeidae showed little change across all lake zones.It is important to develop sustainable fishery patterns in shallow lakes along the middle and lower Yangtze River floodplain to better protect resources of wintering waterbirds.

The Influence of Seasonal Snow on Soil Thermal and Water Dynamics under Different Vegetation Covers in a Permafrost Region

Seasonal snow is one of the most important influences on the development and distribution of permafrost and the hydrothermal regime in surface soil. Alpine meadow, which constitutes the main land type in permafrost regions of the Qinghai-Tibet Plateau, was selected to study the influence of seasonal snow on the temperature and moisture in active soil layers under different vegetation coverage. Monitoring sites for soil moisture and temperature were constructed to observe the hydrothermal processes in active soil layers under different vegetation cover with seasonal snow cover variation for three years from 2010 to 2012. Differences in soil temperature and moisture in areas of diverse vegetation coverage with varying levels of snow cover were analyzed using active soil layer water and temperature indices. The results indicated that snow cover greatly influenced the hydrothermal dynamics of the active soil layer in alpine meadows. In the snow manipulation experiment with a snow depth greater than 15 cm, the snow cover postponed both the freeze-fall and thawrise onset times of soil temperature and moisture in alpine LC(lower vegetation coverage) meadows and of soil moisture in alpine HC(higher vegetation coverage) meadows; however, the opposite response occurred for soil temperatures of alpine HC meadows,where the entire melting period was extended by advancing the thaw-rise and delaying the freeze-fall onset time of the soil temperature. Snow cover resulted in a decreased amplitude and rate of variation in soil temperature, for both alpine HC meadows and alpine LC meadows, whereas the distinct influence of snow cover on the amplitude and rate of soil moisture variation occurred at different soil layers with different vegetation coverages. Snow cover increased the soil moisture of alpine grasslands during thawing periods. The results confirmed that the annual hydrothermal dynamics of active layers in permafrost were subject to the synergistic actions of both snow cover and vegetation coverage.

Interannual and Interdecadal Variability of Atmospheric Water Vapor Transport in the Haihe River Basin

The seasonal mean atmospheric precipitable water and water vapor transport over the Haihe River Basin （HRB） in North China with a focus on their interannual to interdecadal variability, and then the relationships of the interannual and interdecadal variability of the water cycle over the HRB to the Pacific Decadal Oscillation （PDO） and E1 Nino-Southern Oscillation （ENSO） phenomena were investigated using the observational and National Centers for Environmental Prediction （NCEP） reanalysis data. There was a strong interdecadal variability for the water cycle （such as precipitation and water vapor transport） over the region, with an abrupt change occurring mostly in the mid 1970s. The intensity of the East Asian summer monsoon largely affected the atmospheric water vapor transport. Generally, the net meridional convergence of the water vapor flux over the region was relatively large before 1965, and it declined gradually from then on with a further notable decrease since mid 1970s. Zonal water vapor transport was similar to meridional, but with a much smaller magnitude and no noteworthy turning in the mid 1970s. Results also suggested that the wind field played an important role in the water vapor transport over the HRB before the mid 1960s, and the interdecadal variability of the water cycle （precipitation, water vapor transport, etc.） in the summer was related to the PDO; however, interannual variation of the water vapor transport could also be related to the ENSO phenomena.

Remediation Effects of Water Management and Lime Application on Seasonally-Fallowed Cd-Contaminated Paddy Fields

In the light of the national policy of fallow, this study was conducted to determine how the different water management and lime application would affect soil physical and chemical properties, rice yield and cadmium （Cd） content of rice in fallow season. The results showed that, compared with the arid fallow, the waterlogging fallow decreased the soil pH value whereas signifcantly increased the soil organic matter content and the cation exchange quantity, and reduced the soil effective cadmium content and the rice cadmium content whereas could increase the rice yield to a certain extent. In the fooded fallow or the dry fallow, the application of lime mainly depended on the alkali conditioning of lime and the antagonistic effect of Ca2＋, which could signifcantly reduce the cadmium content of rice, and its effect would increase linearly with the increase of lime dosage, whereas had no significant effect on soil organic matter content and cation exchange quantity. In order to establish a linear equation of lime dosage and related indexes under the condition of waterlogging fallow or dry fallow, calculations showed that each application of lime at 1 000 kg/hm2 or kg/hmss2 could improve soil pH value by 0.238 2 or 0.246 5units respectively, and reduce the effective Cd content to 0.007 5 mg/kg both in the arid fallow and the waterlogging fallow conditions. The lime theoretic application rate for the lowest Cd content of late rice in the arid fallow was 5 120 kg/hm2, and the minimum limit of the Cd content in rice was 0.124 2 mg/kg; and the lime theoretic application rate for the highest yield of late rice in the submerged water fallow was 4 636 kg/hm2, the minimum theoretic Cd content in rice is 0.100 7 mg/kg, and it could reduce the Cd content in rice under the condition of submerged fallow and decrease the dosage of lime.

Analysis of seasonal variation of water masses in East China Sea

Seasonal variations of water masses in the East China Sea(ECS) and adjacent areas are investigated, based on historical data of temperature and salinity( T-S). Dynamic and thermodynamic mechanisms that affect seasonal variations of some dominant water masses are discussed, with reference to meteorological data. In the ECS above depth 600 m, there are eight water masses in summer but only five in winter. Among these, Kuroshio Surface Water(KSW), Kuroshio Intermediate Water(KIW), ECS Surface Water(ECSSW), Continental Coastal Water(CCW), and Yellow Sea Surface Water(YSSW) exist throughout the year. Kuroshio Subsurface Water(KSSW), ECS Deep Water(ECSDW), and Yellow Sea Bottom Water(YSBW) are all seasonal water masses, occurring from May through October. The CCW, ECSSW and KSW all have significant seasonal variations, both in their horizontal and vertical extents and their T-S properties. Wind stress, the Kuroshio and its branch currents, and coastal currents are dynamic factors for seasonal variation in spatial extent of the CCW, KSW, and ECSSW, whereas sea surface heat and freshwater fl uxes are thermodynamic factors for seasonal variations of T-S properties and thickness of these water masses. In addition, the CCW is affected by river runoff and ECSSW by the CCW and KSW.

Impact of seasonal tide variation on saltwater intrusion in the Changjiang River estuary

An improved 3-D ECOM-si model was used to study the impact of seasonal tide variation on saltwater intrusion into the Changjiang River estuary, especially at the bifurcation of the North Branch （NB） and the South Branch （SB）. The study assumes that the fiver discharge and wind are constant. The model successfully reproduced the saltwater intrusion. During spring tide, there is water and salt spillover （WSO and SSO） from the NB into the SB, and tidally averaged （net） water and salt fluxes are 985 m3/s and 24.8 ton/s, respectively. During neap tide, the WSO disappears and its net water flux is 122 m3/s. Meanwhile, the SSO continues, with net salt flux of 1.01 ton/s, much smaller than during spring tide. Because the tidal range during spring tide is smaller in June than in March, overall saltwater intrusion is weaker in June than in March during that tidal period. However, the WSO and SSO still exist in June. Net water and salt fluxes in that month are 622 m3/s and 15.35 ton/s, respectively, decreasing by 363 m3/s and 9.45 ton/s over those in March. Because tidal range during neap tide is greater in June than in March, saltwater intrusion in June is stronger than in March during that tidal period. The WSO and SSO appear in June, with net water and salt fluxes of 280 m3/s and 8.55 ton/s, respectively, increasing by 402 m3/s and 7.54 ton/s over those in March. Saltwater intrusion in the estuary is controlled by the fiver discharge, semi-diurnal flood-ebb tide, semi-monthly spring or neap tide, and seasonal tide variation.

Seasonal variability of salinity budget and water exchange in the northern Indian Ocean from HYCOM assimilation

Based on HYbrid Coordinate Ocean Model (HYCOM) assimilation and observations, we analyzed seasonal variability of the salinity budget in the southeastern Arabian Sea (AS) and the southern part of the Bay of Bengal (BOB), as well as water exchange between the two basins. Results show that fresh water flux cannot explain salinity changes in salinity budget of both regions. Oceanic advection decreases salinity in the southeastern AS during the winter monsoon season and increases salinity in the southern BOB during the summer monsoon season. In winter, the Northeast Monsoon Current (NMC) carries fresher water from the BOB westward into the southern AS; this westward advection is confined to 4°-6°N and the upper 180 m south of the Indian peninsula. Part of the less saline water then turns northward, decreasing salinity in the southeastern AS. In summer, the Southwest Monsoon Current (SMC) advects high-salinity water from the AS eastward into the BOB, increasing salinity along its path. This eastward advection of high-salinity water south of the India Peninsula extends southward to 2°N, and the layer becomes shallower than in winter. In addition to the monsoon current, the salinity difference between the two basins is important for salinity advection.

Phytoplankton community structure in reservoirs of different trophic status, Northeast China

The aim of this study was to determine the phytoplankton community structures of reservoirs of different trophic status, located in a cold region. Physical and chemical variables and the phytoplankton communities were investigated in two reservoirs (Xiquanyan Reservoir and Taoshan Reservoir) in Northeast China in 2009. The two reservoirs showed strong seasonal fluctuations in their physical and chemical composition. Results of the trophic status index indicated that Xiaquanyan Reservoir was mesotrophic, whilst Taoshan Reservoir was eutrophic. Diatoms were the dominant phytoplankton group in Xiquanyan Reservoir throughout all seasons of the study, while in Taoshan Reservoir, diatoms dominated in spring, and cyanobacteria dominated in summer and autumn. This difference was resulted from differences in local environmental factors, including nutrients and hydrology. This study suggests that in mesotrophic reservoirs, nutrients played a key role in controlling seasonal phytoplankton successions, whereas in eutrophic reservoirs water temperature was the key factor in a cold region. Notably, the dominant species in summer in the Taoshan Reservoir was Microcystis, which may produce toxins depending on the ambient conditions, and presenting a risk of local toxin contamination.