为了探究不同藻竞争利用不同形态磷对浮游植物群落结构影响,分别以楯形多甲藻不等变种(Peridinium umbonatum var.inaequale)和铜绿微囊藻(Microcystis aeruginosa)进行PM4A板多磷源单培养实验,并向原位水样添加其两藻种进行5'-单磷酸腺苷(5'-AMP)和磷酸氢二钾(K2HPO4)增殖模拟实验.结果表明:不同的藻种对不同形态磷的竞争利用具有选择性,楯形多甲藻不等变种和铜绿微囊藻分别能够利用溶解性有机磷(DOP)35种和25种,两种藻能够较好的利用氨基酸和核苷酸.当以楯形多甲藻不等变种调控起始生物量占比(绿藻:甲藻:硅藻:蓝藻为38％:26％:20％:7％),无论以有机磷还是无机磷为磷源,甲藻的竞争优势明显,生物量占比达37.11％～50.19％;当以铜绿微囊藻调控起始生物量占比(绿藻:蓝藻:硅藻:甲藻为38％:29％:20％:4％),蓝藻竞争优势明显,生物量占比达52.25％～53.44％.在温度和光照等环境条件一定的情况下,磷源形态和藻类起始生物量结构共同影响浮游植物群落结构演替.

本文以福建省福清市东张水库为例,采集2016-2017年间包含水华期间在内的共295组的水质(水温、pH、电导率、浊度、溶解氧)和气象(气温、风速)数据,以80％的数据进行模型演算,20％的数据进行模型验证,以叶绿素a浓度作为输出参数,应用BP人工神经网络模型进行演算.通过输入不同的参数组合,将结果与实际测定的叶绿素a值比较,挑选出最优的参数组合.结果 表明,当以水温、溶解氧、电导率和气温作为组合变量输入时,输出的结果最优,输出数据的预测值与实测值拟合度R2为0.83,均方根误差(RMSE)为0.08μg/L,均方根-实测值标准偏差比(RSR)为0.43,且模型稳定性较好.表明该参数组合作为输入参数建立的BP人工神经网络预警模型,有望未来用于预测东张水库富营养化的发生.

磷是浮游植物生长的必要元素,也是调控水体富营养化的重要因子之一.在无机磷缺乏的水域,能够有效利用有机磷的藻类有可能成为浮游植物群落的优势种.为了研究有机磷对浮游植物群落结构演替的影响,分别从3个水库采集表层水样,西陂水库(硅藻70.3％,甲藻19.1％,绿藻9.3％)、山美水库(硅藻31.3％,甲藻59.2％,绿藻3.5％)、三十六脚湖(硅藻43.1％,甲藻50.5％,绿藻5.0％),选用有机磷单磷酸腺苷(Adenosine monophosphate,AMP)作为磷源进行实验室模拟实验,并与无机磷(NaH2PO4·2H2O)作为磷源实验组做同步对比,探讨有机磷源条件下浮游植物竞争及群落结构演替规律.结果显示:AMP培养20 d后,西陂水库、山美水库和三十六脚湖的浮游植物生物量分别增加了6.5倍,2.1倍和1.9倍,浮游植物群落结构都演替为以甲藻门和绿藻门为优势藻,所占比例分别为81.8％和16.7％、55.2％和33.5％、73.2％和24.3％,其中西陂水库甲藻门拟多甲藻对有机磷AMP的利用能力强,其所占比例达到81.8％.表明有机磷AMP能有效地促进甲藻门拟多甲藻属的增殖,进而改变水体浮游植物群落结构.

We studied the zooplankton in different seasons during the period from 1996-1997,2006-2007,2011-2012 in Shanzi Reservoir and analyzed the characteristics of distribution and abundance of zooplankton in the early stage of dam construction and after the algal controlling by fish.The result showed that the dominant species of rotifers in the early stage of dam construction from 1996 to 2012 were Synchaeta stylata,Polyarthra vulgaris,Keratella cochlearis ect.The proportion of rotifers in zooplankton species increased from 70.11％ in 1996 to 92.31％ in 2012,and the average density increased first and then decreased.From the seasons,the zooplankton in Shanzi Reservoir was the largest in winter,followed by spring,then summer and autumn.The population density was the highest in spring,followed by winter then summer and autumn.The spatial distribution of zooplankton in Shanzi Reservoir was generally characterized by the entrance ＞ reservoir center ＞ the front of dam.The richness index and diversity index of each section of Shanzi Reservoir were as follows the entrance ＞ reservoir center ＞ the front of dam.And different seasons generally showed winter ＞ spring ＞ summer and autumn.The number of zooplankton species decreased continuously,the biodiversity gradually decreased,and the average density increased first and then decreased,and the eutrophication and algal controlling had some influence on the zooplankton community structure and density of Shanzi Reservoir.Eutrophication increased the average density of zooplankton,while algal controlling caused the average density of zooplankton decreased,and the number and density of rotifer species increased,and the zooplankton showed a trend of miniaturization.

To reveal the effects of different phosphorus forms on the growth and succession of phytoplankton community,we investigated the phytoplankton community change at sediment-water interface in Xipi Reservoir,Jiulong River,with different phosphorus sources,as inorganic phosphate (IP,NaH2PO4 · 2H20),organic phosphorus (adenosine monophosphate,AMP),sediment phosphorus extracted by SMT methods (SMT-TP),fresh sediment (Sediment) and original water (OW).The phytoplankton abundance in Xipi Reservoir is 7.2 × 104 cells· L-1,dominated by Diatom (49.16％),Chlorophyta (32.40％) and Cyanobacteria (17.32％).Our results show a significant higher growth rate of phytoplankton in IP and AMP treatments (N ∶P =20∶1),where the dominant phyla in phytoplankton community changed to Cyanobacteria and Chlorophyta,accounting for 76.67％ and 23.34％ of total population,respectively.The phytoplankton community in AMP treatment was dominated by Chlorophyta (92.51％).In treatments of low phosphorus (N ∶P-25∶1),OW (N ∶ P =17∶ 1) and SMT-TP (N ∶ P =10∶1),the dominant phyla in phytoplankton community were Diatoms,Chlorophyta and Cyanobacteria,consistent with the results in IP treatment.However in Sediment treatment (N ∶ P =10∶1,contain both inorganic and organic phosphorus),the dominant phyla changed to Cyanobacteria,accounting for 71.80％ of total population.The results indicate the significant impacts of phosphorus forms on phytoplankton community structure.In all the IP,AMP and SMT-TP treatments,the diversity of phytoplankton community declined and Diatom gradually became rare phylum.On the contrast,the diversity of phytoplankton community remained stable in Sediment and OW treatments,and Diatom was still the major phylum.It implied that natural sediment can maintain and regulate phytoplankton community structure.The dominancy of Cyanobacteria in Sediment treatment suggested that the release of phosphorus from sediment has an important contribution to the cyanobacteria bloom.

于2011年不同季节对山仔水库水体物理和化学指标、浮游植物和浮游动物进行监测,分析了蓝藻门微囊藻属在水平和垂向空间上的分布规律,探索了微囊藻属生物量与环境因子的相关关系.结果表明,不同季节山仔水库大坝断面微囊藻属细胞丰度在105～107L-1之间变化,夏季水体微囊藻属细胞丰度达到107L-1,浮游植物群落中微囊藻属的比例高达95％以上;冬季水体微囊藻属细胞丰度为105L-1,浮游植物群落中微囊藻属的比例在20％～45％.5-9月,表层水体微囊藻属细胞丰度高于底层水体,秋末到冬季水体表层与底层的微囊藻属细胞丰度相差不大,水温与微囊藻属细胞丰度呈显著正相关,轮虫与微囊藻属细胞丰度呈显著负相关.分析可知,水温分层是影响山仔水库微囊藻属垂向分布的重要因素之一.