底栖藻类对氮、磷去除效果研究

通过模拟实验探讨了污水处理中底栖藻类的群落结构、生长状况及其对氮(N)、磷(P)的去除能力。实验期间,被试藻类(丝状绿藻占优势)在污水中生长良好,培养5 d后收获的藻类生物量可达14.36±0.72 g;污水总氮(TN)、总磷(TP)含量分别由36.97±0.26 m g.L-1、2.88±0.02 m g.L-1降至1.44±0.09 m g.L-1、0.07±0.01 m g.L-1,对氨氮(NH4-N)和硝氮(NO3-N)的去除率亦达95%以上;藻体总凯氏氮(TKN)和TP含量分别为5.75±0.20%和1.5±0.22%。实验证明,底栖藻类对污水中的N、P营养有明显的去除效果,在污水的三级处理以及水体富营养化的防治方面具有较大的应用潜力。     

Biological monitoring of eutrophication in rivers

There is an increasing awareness of the need to assess the impact of nutrient enrichment on river ecosystems separately from the impacts of organic effluents. A range of methods have been proposed and some have moved from the development stage to practical use by water management organizations. The methods can be applied to broad surveys or provide baseline information to assess possible future change. In the latter case it is recommended that several different methods are used, especially where it is important to get reliable information on the long-term impact of improvements in effluent quality. Estimates of biomass measured as chlorophyll a have often been used for phytoplankton and sometimes also for benthic communities. However, a lot of care is needed in applying this method, because of the range of factors besides nutrient concentration which can influence values. Approaches based on the whole community have been developed by a number of research groups, usually involving semiquantitative estimates of abundance. There has also been a rapid increase in the use of indices based on the relative proportions of epilithic diatom species. The methodologies used by a number of research groups in Europe are broadly similar, making it possible to compare results between different regions. The development of indices based on macrophyte floristic composition in relation to river nutrient status is also under development, especially in France and UK. However, interpretation of the results is complicated where long-term changes are taking place in nutrient concentrations in the water, because of the varying contributions of sediment and water to different species of rooted plant. Bioassays can be especially helpful where it is desired to establish whether either N or P is limiting for a population of community.     

Quantifying Relationships Among Phosphorus, Agriculture, and Lake Depth at an Inter-Regional Scale

To date, studies examining the impact of agriculture on freshwater systems have been spatially confined (that is, single drainage basin or regional level). Across regions, there are considerable differences in a number of factors, including geology, catchment morphometry, and hydrology that affect water quality. Given this heterogeneity, it is unknown whether agricultural activities have a pervasive impact on lake trophic state across large spatial scales. To address this issue, we tested whether the proportion of agricultural land in a catchment (% Agr) could explain a significant portion of the variation in lake water quality at a broad inter-regional scale. As shallow, productive systems have been shown to be particularly susceptible to eutrophication, we further investigated how lake mean depth modulates the relationship between % Agr and lake total phosphorus (TP) concentration. We applied both traditional meta-analytic techniques and more sophisticated linear mixed-effects models to a dataset of 358 temperate lakes that spanned an extensive spatial gradient (5°E to 73°W) to address these issues. With meta-analytical techniques we detected an across-study correlation between TP and % Agr of 0.53 (one-tailed P-value = 0.021). The across-study correlation coefficient between TP and mean depth was substantially lower (r = −0.38; P = 0.057). With linear mixed-effects modeling, we detected among-study variability, which arises from differences in pre-impact (background) lake trophic state and in the relationship between lake mean depth and lake TP. To our knowledge, this is the first quantitative synthesis that defines the influence of agriculture on lake water quality at such a broad spatial scale. Syntheses such as these are required to define the global relationship between agricultural land-use and water quality.     

淀山湖浮游植物群落特征及其演替规律

为探明淀山湖浮游植物群落结构演变与富营养化之间的关系,于2004-2006年对上海市最大天然淡水湖泊淀山湖的浮游植物进行逐月采样调查,分析其群落结构特征.共采集到淀山湖浮游植物84属205种,主要由绿藻(种类数占50%)、硅藻(20%)、蓝藻(13%)、裸藻(13%)等组成.相邻两月之间种类相似性系数呈现冬春季高、夏秋季低的趋势:优势种为银灰平裂藻(Merismopedia glauca)、小席藻(Phormidium tenus)、铜绿微囊藻(Microcystis aeruginosa)、具缘微囊藻(M.marginata)、湖泊鞘丝藻(Lyngbya limnetica)、微小色球藻(Chroococcus minutus),颗粒直链藻最窄变种(Melosira granulata var.angustissima )、啮蚀隐藻(Cryptomonas erosa)、小球藻(Chlorella vulgate)和四尾栅藻(Scenedesmus quadricauda)等.浮游植物群落细胞数量主要由蓝藻(42.73%)、绿藻(37.75%)、硅藻(12.67%)和隐藻(6.06%)组成;生物量主要由硅藻(36.75%)、蓝藻(16.78%)、绿藻(16.36%)和隐藻03.53%)等组成.淀山湖浮游植物群落结构季节演替模式不同于PEG(Plankton Ecology Group)模型,其中蓝藻从春末开始大量出现,夏季大量繁殖,一直延续到秋初.综合文献资料看出,淀山湖浮游植物群落已从1959年的硅藻一金藻型、1987-1988年的隐藻-硅藻型演变为2004-2006年的蓝藻-绿藻型;数量由1959年的103 ind./L上升至2004-2006年的1.11×107 cells/L.演替的总体趋势表现为:贫中营养型的金藻、甲藻比例下降,富营养型的蓝藻、隐藻和微型绿藻增加.浮游植物数量和群落结构的演变指示了淀山湖水体的富营养化进程.     

灌河口邻近海域春季浮游植物的生态分布及其营养盐限制

2011年4月通过灌河口邻近海域的现场调查及营养加富培养实验,研究了春季灌河口邻近海域浮游植物生态分布特征以及硝酸盐、磷酸盐对浮游植物生长的限制作用,结果表明:共发现浮游植物68种,其中硅藻61种,优势度最高的为中肋骨条藻(Skeletonema costatum,Y=0.53),各个站位浮游植物的丰度介于0.84× 106-2.25×106个/L,均值为1.54×106个/L,种类范围为29-39种,均值为35种,叶绿素a浓度呈现近岸高外海低的特征,在2.66-6.67 μg/L变化,均值为3.89 μg/L,多样性指数介于2.60-3.79,均值为3.20,海域环境基本适宜浮游植物的生长;调查海域磷酸盐浓度的范围为0.35-0.90μmol/L,均值为0.58μmol/L,亚硝酸盐浓度范围为1.57-3.93 μmol/L,均值为3.08 μmol/L,两者分布均具有近岸高外海低的特征;铵盐浓度范围为3.145.43μmol/L,均值为3.95 μmol/L,其分布则是近岸低外海高;硝酸盐浓度严重偏高,在31.21-37.00μmol/L之间变化,均值为34.55 μmol/L,导致调查区域具有高N/P比(42-112),且浮游植物叶绿素a与磷酸盐浓度有显著的正相关(R2=0.80),而与无机氮线性关系不明显(R2=0.11);在P加富培养实验中,磷酸盐在3个培养组(对照,+P,++P)中的比吸收速率分别为0.36、0.43、0.51d-1,加P促进了P本身的吸收,硝酸盐和亚硝酸盐的吸收也得以促进,但没有磷酸盐那么显著,而铵盐浓度基本呈增加趋势,P的添加也促进了藻类的生长,培养结束后叶绿素a浓度最大值分别为77.24、90.57、96.49μg/L.在N加富培养实验中,硝酸盐的比吸收速率分别为0.39、0.049、0.025d-1,加N未促进硝酸盐本身的吸收,磷酸盐浓度在3个实验组变化曲线相似,其吸收也没有得到促进,亚硝酸盐在加N组中浓度是增加的,培养结速后加N组(+N,++N)叶绿素a浓度最大值分别为72.31、69.62μg/L,都小于对照组,N的添加也未促进藻类的生长.上述研究表明了春季灌河口邻近海域浮游植物的生长主要受到P的限制,而不是N限制.     

Relationships between phytoplankton and fish yields in Lake Balaton

Coefficients of determination between fish yields in Lake Balaton (kg/ ha) and different measurements of phytoplankton abundance were: phytoplankton biomass (0.48), chlorophyll a (0.45). The same indices for catch per unit of effort (CUE) proved to be 0.82 and 0.88, respectively. The correlation between fish yields and phytoplankton density has been described in second-degree polynomials.     

南太湖浮游植物特征及其富营养化评价

2008年8-9月对南太湖的浮游植物进行了调查,并对9个采样点水样进行了分析.结果表明:共有浮游植物47种,隶属于7门28属,其中蓝藻门 6属9种,绿藻门10属13种,硅藻门7属18种,裸藻门2属3种,隐藻门 1属2种,金藻门1种,甲藻门1种;南太湖浮游植物的密度为3.56×10~6～7.99×10~6 cells·L~(-1);浮游植物的Shannon-Weaver多样性指数为0.29～2.27,均匀度指数在多数位点<0.5,卡尔森营养状态指数(TSIM)均大于64;根据浮游植物的优势种组成、密度、多样性指数及富营养状态指数的评价结果说明南太湖处于富营养化阶段.

Abstract：

In August-September 2008, an investigation was made on the phytoplankton in south-ern Taihu Lake, and the water quality at nine sampling sites was analyzed. A total of 47 phyto-plankton species belonging to 28 genera and 7 phylums were collected, with 9 species of Cyano-phyta, 13 species of Chlorophyta, 18 species of Diatoms, 3 species of Euglenophyta, 2 species of Cryptophyta, 1 specie of Chrysophyta, and 1 specie of Dinophyta. The phytoplankton density was 3.56×10~6-7.99×10~6 cells·L~(-1), Shannon-Weaver index was 0. 29-2. 77, evenness was low-er than 0. 5, and trophic state index (TSIM) was higher than 64. Based on the evaluation of the dominant species composition, density, and Shannon-Weaver index of phytoplankton, and of the TSIM, the southern Taihu Lake was considered at the stage of eutrophication.     

A Natural Phosphate Source for Lake Waccamaw,North Carolina,USA

A limestone outcrop along the north shore of Lake Waccamaw, North Carolina, is found to contain ca. 0.1 % phosphate by weight. Weathering processes have probably driven steady inputs of phosphate from this source throughout the lake's history, accounting for its near eutrophic state. The sediments of Lake Waccamaw are enriched with phosphate, particularly in the littoral zone near the outcrop. Chemical and biological processes apparently remove phosphate from solution rapidly, making detection of a soluble phosphate signal near the outcrop difficult. Management of nutrient inputs and water quality in Lake Waccamaw requires consideration of the effects of this in-lake source of phosphate. Other sources of phosphate, particularly in the lake's drainage basin, may be less important than previously thought.     

A study of phosphate limitation in Lake Maarsseveen: phosphate uptake kinetics versus bioassays

In order to assess possible phosphate limitation for the phytoplankton community of Lake Maarsseveen, two techniques (phosphate uptake experiments and bioassays) were employed simultaneously in February–March 1982. In that period the ambient phosphate concentration of the lake water was less than 0.03 µM P and the diatom Asterionella formosa constituted more than 90% of the phytoplankton population. The phosphate uptake experiments showed relatively high uptake capacities and low cell phosphorus contents for the natural phytoplankton community. This suggested phosphate limitation throughout the test period. The growth stimulation of the phytoplankton after enrichment with phosphate, however, only revealed phosphate limitation from the beginning of March and bioassays may therefore be regarded as a less sensitive method.