A BROAD SPECTRUM ARTIFICIAL SEA WATER MEDIUM FOR COASTAL AND OPEN OCEAN PHYTOPLANKTON1

A new artificial seawater medium has been tested with 83 strains of coastal and open ocean phytoplankton from 11 different algal classes. The cultures were carried through four transfers, representing a period of eight weeks for most species. Only three species could not be maintained in the enriched artificial seawater, and 16 species, mainly from the Prymnesiophyceae and Dinophyceae, had reduced final cell yields compared to those grown in enriched natural seawater. Since 77% of the species tested grew equally well in enriched artificial or natural seawater and more than 95% could be maintained in the artificial medium, this recipe is useful over a broad spectrum of species. The artificial seawater base was enriched with a modified ES enrichment solution; the primary modifications were the omission of Tris and the addition of Si. Enriched medium was autoclaved without precipitation by lowering the pH before autoclaving. This was accomplished by adding equimolar amounts of Na-HCO₃ and HCl which produced NaCl and CO₂ during the heating process. When no pH buffer was used, precipitation could only be avoided by autoclaving the artificial seawater base as two separate salt solutions (with Ca and Sr separated from CO₃^?2 and SO₄^?2), cooling, mixing and aseptically adding the sterilized enrichment solution.     

渭河流域浮游动物群落结构及其水质评价

分别于2017年10月和2018年6月对渭河流域内12个采样点的浮游动物种类、物种密度、生物量和水温、电导率、溶解氧浓度和pH等水质指标进行调查, 并利用生物多样性指数法对水质进行评价。结果显示, 共鉴定出57种浮游动物(原生动物11种、轮虫33种、枝角类7种、桡足类6种)。优势种为萼花臂尾轮虫Brachionus calyciflorus。枯水期浮游动物密度变化范围在0.72—7.84 ind./L, 平均密度为(2.79±2.11) ind./L; 浮游动物生物量为0.38—6.15 mg/L, 平均生物量为(2.31±2.64) mg/L; CCA分析表明, 水温、溶解氧、海拔和电导率与渭河流域浮游动物群落结构有明显的相关性; Shannon-Wiener多样性指数、Margalef丰富度指数分别为1.07、0.69。丰水期浮游动物密度变化范围在0—179.02 ind./L, 平均密度为(16.66±49.18) ind./L; 浮游动物生物量0—2448.12 mg/L, 平均生物量为(243.96±673.78) mg/L; Shannon-Wiener多样性指数Margalef丰富度指数分别为0.78、1.15。依据浮游动物种类密度和多样性指数对水质进行评价, 结果为渭河水系北道、林家村为中度污染, 魏家堡为重度污染, 咸阳、临潼、华县为轻度污染; 泾河水系杨家坪、雨落坪、张家山为中度污染; 北洛河水系刘家河、交口河、状头为中度污染。     

富营养化湖泊规模化种养的水葫芦与浮游藻类的相互影响

水葫芦(学名凤眼莲,Eichhornia crassipes Solms)是被公认为去除富营养化水体氮、磷效果较好的水生漂浮植物[1—3],也是目前生态修复工程中应用较广的水生漂浮植物[4]。随着《太湖流域控制性种养水葫芦技术规范》的出台,水葫芦安全控养模式在太湖流域的应用相对较为成熟。目前,研究者们对于水葫芦应用的顾虑由最初的影响     

沙颍河流域浮游动物群落结构空间变化特征与水质评价

为了解沙颍河流域浮游动物的群落结构及水质状况, 于2016年秋季对该流域设置了20个采样点, 进行浮游动物群落结构调查, 并利用生物多样性指数对水质进行评价。结果显示: 沙颍河流域共检测出浮游动物36属78种, 其中轮虫20属60种、枝角类10属12种、桡足类6属6种; 浮游动物优势种主要为长肢多肢轮虫(Polyarthra dolichoptera)、裂痕龟纹轮虫(Anuraeopsis fissa)、角突臂尾轮虫(Brachionus angularis)、萼花臂尾轮虫(B. calyciflorus)、曲腿龟甲轮虫(KeratelIa valga)和象鼻溞(Bosmina sp.); 浮游动物密度和生物量最大值出现在沙颍河流域上游, 且从上游至下游, 生物量和密度的空间变化趋势相一致, 大致呈现逐渐降低的趋势; 检测位点Shannon-Wiener 多样性指数的范围为1.03—3.51, Pielou均匀度指数的变化范围为0.26—0.70。综合分析各采样点的种群和多样性指数反映出沙颍河流域上游水体污染较为严重, 中下游水体为中度污染。水质总体呈现出中度-重度污染。     

IRON-MEDIATED CHANGES IN THE GROWTH OF LAKE ERIE PHYTOPLANKTON AND AXENIC ALGAL CULTURES1

The effect of iron enrichment on algal growth and photosynthesis was investigated using natural assemblages of Lake Erie phytoplankton and axenic cultures of Anabaena, Scenedesmus and Selenastrum. Cell yield and photosynthesis were frequently inhibited in the presence of unchelated iron over the range of 3.6 to 53.7 μM iron as FeCl₃. In lake water and in a defined medium with low nutrient concentrations, the degree of inhibition by iron could be reduced by chelating the iron with EDTA or by enriching the cultures with phosphorus. Chemical analyses revealed that the EDTA efectively reduced the ability of the ferric iron to remove soluble phosphorus from the media. EDTA was also observed to reduce rather than enhance iron uptake by axenic cultures of A. flos-aquae. These data support the hypothesis that additions of EDTA to low-nutrient media may serve to stimulate algal growth in the presence of iron by preventing the iron from altering extracellular concentrations of soluble ions essential for algal metabolism. In medium with high nutrient concentrations, the soluble phosphorus concentration was not appreciably altered by either EDTA-chelated or unchelated iron enrichment (0.9 to 53.7 μM). Instead, the observed enhancement of cell yield by EDTA-chelated iron in nutrient-rich media appeared to be due to the direct effect of iron on intracellular metabolic processes.     

火溪河底栖动物现状及水质评价

１９９６年８月,１１月各一次调查火溪河的底栖动物。共采集到到底栖动物３９种,其数量为８７．３ｉｎｄ／ｍ＾２,优势种类为方巢石蚕、四节蜉、小蜉、光石蝇和溪在非议 五种。火溪河底栖运行具有明显的山地型、流水型特点、时空分布一致。应用ＢＭＷＰ记分,ＢＢＩ／ＦＢＩ生物指数和Ｓｙａｎｎｏｎ多样性指数对脂河水质进行评价,表明水质清洁。作者建议以方巢石蚕７０．０ｉｎｄ／ｍ＾２作为火溪河水质清洁与轻污的一个界定值     

杭州西湖水质预测方法和结果分析

本文利用二维对流扩散模型对西湖水质总磷浓度进行预测,给出方程的理论基础,编制FORTRAN77程序,在386微机上实现预测,并对预测结果作了较为详细的分析．本模型对水质环境防治决策具有实际意义．     

DISTRIBUTION AND ALGAL-LYSING ACTIVITY OF FRUITING MYXOBACTERIA IN LAKE SUWA1

The seasonal distribution of fruiting myxobacteria, which are able to lyse cyanobacteria in the water and sediments of eutrophic lakes, was determined periodically in 1985 and 1986. Fruiting myxobacteria isolated from sediments of these sites were found to have a lytic effect on a wide variety of cyanobacteria. The myxobacterium isolate designated as S-1-8 was identified as Myxococcus fulvus Cohn. Lytic activity for cyanobacteria was produced during growth of the organism in a number of complex media. The maximal amount of activity was produced in casitone-yeast media and at the end of the log phase of growth.     

DISTRIBUTION AND ABUNDANCE OF THE AMAZON RIVER DOLPHIN (INIA GEOFFRENSIS) AND THE TUCUXI (SOTALIA FLUVIATILIS) IN THE UPPER AMAZON RIVER

A boat survey was conducted from 5 to 26 June 1993 to estimate the abundance of the Amazon river dolphin ( Inia geoffrensis ) and the tucuxi ( Sotalia fluviatilis ) along ca . 120 km of the Amazon River bordering Colombia, Peru, and Brazil. Two survey methods were used: line transects during 5 d and strip transects during 15 d. The line transects were used to estimate the abundance of both species in the main channels of the Amazon at distances greater than 200 m from river banks and islands, and strip transects were used to estimate abundance in the remainder of the habitat. A total of 29 sightings was obtained using line transects, including 8 of Inia , 15 of Sotalia , and 6 with both species present. The total number of sightings made while using strip transects was 143, including 78 of Inia , 51 of Sotalia , and 14 with both species present. The distributions of sightings with respect to distance from the nearest bank were not significantly different between the two species. Based on the results from the two methods, we estimate that there are 346 (CV = 0.12) Inia and 409 (CV = 0.13) Sotalia in the study area. Overall, the mean group size for Inia was 2.9 individuals and for Sotalia was 3.9 individuals. Inia density (dolphin/km²) was highest in tributaries (4.8), followed by areas around islands (2.7) and along main banks (2.0); while Sotalia density was highest in lakes (8.6), followed by areas along main banks (2.8) and around islands (2.0). These are among the highest densities measured to date for any cetacean.     

DIATOMS AS INDICATORS OF WATER QUALITY IN THE UPPER HENNOPS RIVER (Transvaal,South Africa)

SUMMARY

The water quality of the upper Hennops River was determined by applying the method of Lange-Bertalot (1978; 1979), which is based on groups of diatom species with similar tolerances towards pollution. A definite improvement in the water quality was indicated between the upper reaches of the river, which receives secondary treated sewage effluent discharges, and Rietvlei Dam, some 25 km downstream. According to the water quality classification of Lange-Bertalot, this represented an improvement from class III – IV (α-meso- to polysaprobic) to class II – III (α- to β-mesosaprobic). These results were in general agreement with chemical analyses, which suggests that Lange-Bertalot's method for classifying the quality of running waters can be adapted, to South African conditions. The pollution tolerances of some species not included in Lange-bertalot's classification are suggested.     

东湖沉积物中酸挥发性硫化物的季节、深度分布特征研究

在酸挥发性硫化物AVS存在的情况下,水体沉积物中的重金属的生物有效性将显降低,同步提取金属SEM与AVS的比值SEM/AVS可作为判定重金属生物有效性的良好指标。本通过研究东湖三个不同富营养化水平的站点的AVS的季节、深度变化特征及相关的影响因子,发现AVS的含量夏季要高于冬季,并随深度的加深呈先增高后降低的分布特征,SEM/AVS随深度的变化则呈现出先降低后升高的分布特征。研究结果为正确应用SEM/AYS指标判定沉积物中重金属的生物有效性提供了依据。     

THE INFLUENCE OF P-RETENTION BY SOILS AND SEDIMENTS ON THE WATER QUALITY OF THE LIONS RIVER

SUMMARY

The soils of Midmar dam catchment and the sediments of the Lions river are shown to have high P-retention properties. Present conditions result in little leaching of PO₄ ^?4 from the soils and favour a net transport of P from overlying water to the sediments. P levels in the water are likely to remain low even if the loading rate of P were increased substantially. It is postulated however that other factors may induce a release of P from the sediments and adversely affect the load carried by the water.     

PHOTOINHIBITION OF TEMPERATE LAKE PHYTOPLANKTON BY NEAR-SURFACE IRRADIANCE: EVIDENCE FROM VERTICAL PROFILES AND FIELD EXPERIMENTS1

To evaluate the in situ occurrence of phytoplankton photoinhibition, the light-mediated depression of chlorophyll in vivo fluorescence (IVF) and of the cellular fluorescence capacity (CFC) of phytoplankton was determined in three southeastern United States reservoirs. Vertical profiles of a fluorescence depression index (FDI) and of the CFC for reservoir phytoplankton showed that near-surface photoinhibition of fluorescence properties occurred in association with high surface irradiance and weak vertical mixing of the water column. To characterize the time scales of photochemical and photosynthetic responses to and recovery from exposure to supraoptimal light intensity, phytoplankton IVF responses and ¹⁴C-fixation rates were measured infield experiments. Phytoplankton chlorophyll IVF, CFC, and photosynthetic ¹⁴C fixation were rapidly (20–40 min) depressed when reservoir phytoplankton were exposed to surface irradiances (1700–2000 μE·m^?2·s^?1). Light-mediated increases in the FDI declined rapidly (20–40 min) to pre-exposure levels during a subsequent low-light (75–200 μE·m^?2·s^?1) period, but CFC and ¹⁴C fixation recovered more slowly (>40 min). Exposure of reservoir phytoplankton to a light-intensity gradient revealed both intensity and time thresholds for IVF and CFC depression. Phytoplankton photochemical responses to bright light operate on time scales that, in conjunction with vertical mixing, should limit the occurrence of photoinhibition to extreme irradiance environments. Our results support the hypothesis that the photoinhibition of phytoplankton productivity occurs less commonly than is indicated by fixed-depth incubation measurements.     

PLASTOCHRON INDICES FOR JUVENILE AND MATURE FORMS OF HEDERA HELIX L. (ARALIACEAE)

English ivy (Hedera helix) plants were assessed for the applicability of the plastochron index (PI). Juvenile ivy satisfied all requirements for the use of the PI and showed a plastochron of 4.23 days. Mature ivy grown under long day conditions flowered after 11–12 leaves. Two distinct groups of leaves were produced with different plastochrons (0.83 and 3.2 days, respectively) and leaf morphologies. Long-day-grown ivy did not satisfy the requirements for the use of the PI. Short-day-grown mature ivy continued production of leaves beyond the 12th leaf. Vegetative growth was perpetuated for at least 25 plastochrons. By 19 plastochrons (ca. 41 days after budbreak) a linear PI vs. time relationship was established with a plastochron of 3.16 days. This newly acquired ability to maintain vegetative growth in mature ivy plants may allow a direct comparison with the vegetative indeterminant juvenile in order to assess possible anatomical factors responsible for phase stability and phase change using the PI as a basis for comparison.     

A MODEL APPROACH FOR SIZE-SELECTIVE COMPETITION OF MARINE PHYTOPLANKTON FOR FLUCTUATING NITRATE AND AMMONIUM1

Phytoplankton size-selective competition for fluctuating nutrients was studied with the use of a numerical model, which describes nitrate and ammonium uptake, nitrate reduction to ammonium, and growth as a function of cell she under fluctuating nitrogen limitation. The only size-dependent parameter in the model was the cell nutrient quota. Related to this, the cell surface area per biomass was negatively correlated to cell volume, and the vacuole volume per biomass ratio was positively correlated to cell volume. Simulations showed an inverse correlation between the maximum specific growth rate and cell size under steady-state conditions. With nitrate as the limiting nitrogen source, nitrogen quotas were always higher than with ammonium at the same specific growth rate. Net passive transport of ammonium due to unspecific diffusion of ammonia across the plasma membrane decreased the affinity for ammonium, whereas the affinity for nitrate was not influenced. Transient state-specific ammonium uptake was not dependent on cell size. However, small algae always have the highest specific growth rate in ammonium-controlled systems according to our model. Transient state nitrate uptake rate was positively correlated to cell size because larger algae have a higher vacuole volume per biomass, in which nitrate can be stored. Despite their lower maximum growth rate, larger algae became dominant during simulations under fluctuating nitrate supply when amplitude of and the period between nitrate pulses were high enough. Results from model simulations were qualitatively validated by earlier observations that large diatoms become dominant under fluctuating conditions when nitrate is the main nitrogen source.     

珠三角高产养殖池塘浮游动物群落结构及水质评价

为进一步了解珠三角高产池塘养殖环境状况, 分析珠三角高产池塘浮游动物群落特征及与池塘水质的相关性, 研究于2016年7—8月对珠三角地区6种主要高产养殖模式30口池塘的浮游动物和环境因子进行了调查。研究结果表明: (1)共采集浮游动物55种, 其中原生动物17种、轮虫29种、枝角类4种、桡足类5种。6种养殖模式池塘中, 大口黑鲈S池塘浮游动物种类数最多, 为34种; 草鱼池塘最少, 为18种。(2)30口池塘共记录优势种8种, 其中原生动物和轮虫各4种, 枝角类和桡足类均不占优势。在6种养殖模式池塘中, 优势种也仅包括原生动物和轮虫, 优势种种类数变化范围为5—8种。(3)30口池塘浮游动物平均密度和生物量均较高, 分别为21354 ind./L和9.36 mg/L。方差分析结果表明6种养殖模式池塘浮游动物密度和生物量均不存在显著差异。(4)RDA分析结果表明, TP和pH是影响珠三角池塘浮游动物分布的主要因素。采用浮游动物丰度和生物量对水质的评价结果显示, 6种养殖模式池塘均处于富营养化状态; 运用Shannon-Wiener多样性指数和Margalef多样性指数对水质的评价结果表明, 6种模式养殖池塘均处于α-中污状态, 且以草鱼池塘的污染最为严重。本研究首次利用浮游动物对珠三角高产池塘进行水质评价, 研究结果可为池塘生态修复和管理提供一定的指导意见。     

WATER STATUS AND THE DISTRIBUTION OF CYANIDIUM CALDARIUM IN SOIL1

The size and photosynthetic ability of Cyanidium caldarium populations in soil were related to the water status of the soil, welter soil, areas having larger populations and more extensive photosynthesis. The application of the direct methods used to the study of other soil algae, mosses, and lichens is discussed.     

EFFECTS OF SUSPENDED SEDIMENT ON BIOMASS AND CELL MORPHOLOGY OF CLADOPHORA GLOMERATA (CHLOROPHYTA) IN THE COLORADO RIVER, ARIZONA

This study assessed changes in biomass, filament length, and cell morphology in Cladophora glomerata (L.) Kütz. along a suspended sediment gradient in the Colorado River below Glen Canyon Dam, Arizona. Suspended sediments ranged from 2.0 mg·L⁻¹ at Lees Ferry (Rkm 0.8) to 4.2 mg·L⁻¹ at Gorilla Island (Rkm 352). There was a 74% decrease in Cladophora biomass along the river transect through Grand Canyon National Park and a significant decrease in filament and cell length, but cell width increased. Similar changes in cell morphology occurred after 19 days when C. glomerata was transplanted from a low suspended sediment site (2.0 mg·L⁻¹) at Lees Ferry to a habitat with high suspended sediments (≥20.0 mg·L⁻¹). Cell length increased and cell width decreased when plants were transplanted back to the low suspended sediment habitat for 24 days. In situ studies with reduced light in the absence of suspended sediments showed no change in cell morphology. These in situ experiments imply that changes in cell morphology by C. glomerata in waters with high suspended sediments are adjustments in structural integrity to accommodate the abrasive force of suspended particles. Our study suggests that cell dimensions in Cladophora might be too plastic under varying environmental conditions to be used in taxonomic determinations.     

THE RELATIONSHIP BETWEEN PHOTOSYNTHESIS AND LIGHT FOR NATURAL ASSEMBLAGES OF COASTAL MARINE PHYTOPLANKTON1

In a series of 188 experiments on the, light-saturation curve for natural assemblages of phytoplankton at 3 stations in Nova Scotia coastal waters, it was found that both the initial slope (α) of the curve and the assimilation number (P_m^B) varied about 5-fold throughout the year. No differences could be detected between stations, but both α and P_m^B decreased with depth. The mean value of α for all the experiments was 0.21 mg C[mg Chl a]^?1· h^?1· W^?1· m² with a range from 0.03 to 0.63. An explanation is offered for the nonconstancy of a in terms of the effect of cell-size and shape on self-shading. An estimate is made from first principles of the physiological maximum-attainable value of α. This estimate corresponds, within the limits of experimental error, to the highest values of α observed in the study. It is deduced that on the average the phytoplankton were photosynthesizing at only 44% maximum capacity. The mean value of P_m^B for all experiments was 4.9 mg C[mg Chl a]^?1· h^?1, with a range from 0.73 to 24.8. In the matrix of partial correlation coefficients, α and P_m^B were positively correlated with each other; α was correlated with mean solar radiation averaged over the 3 days prior to the experiment, but uncorrelated with temperature; P_m^B was correlated strongly with temperature but uncorrelated with recent solar radiation. The results show that P_m^B could be estimated from α and temperature using an empirical multiple regression equation, independent of depth. It is suggested that α and P_m^B are both correlated with some other factor not measured in the study, perhaps the mean cell-size of the populations, or the nutrient status of the cells. The predictability of primary production is discussed in the light of this evidence.     

长江中游典型草型湖泊与藻型湖泊鲫种群结构和生长比较(英文)

浅水湖泊牛山湖和月湖均位于长江中游武汉市境内,前者水质清澈、沉水植物茂盛,属典型的草型湖泊;后者长期受生活污水和工业废水排放的影响,水质恶劣、沉水植物稀少,属典型的藻型湖泊。文章选择这两个湖泊的共同优势鱼类——鲫(Carassius auratus)作为研究对象,通过比较两类不同湖泊环境条件下鲫种群结构和生长上的差异,评估人类活动引起的水环境改变对鱼类种群生存状况的影响。2006年春季(3—5月),于牛山湖和月湖各采集鲫种群样本713尾和641尾,研究结果表明:(1)牛山湖和月湖鲫种群的全长频数分布经kolmogorov-Smirnov检验均符合正态分布,但前者的分布范围(63—271 mm)大于后者(72—191 mm),前者的全长峰值(190 mm)亦大于后者(110 mm);(2)牛山湖鲫种群的年龄组成(6个年龄组)较月湖(仅3个年龄组)完整,但月湖各龄鲫的全长均显著大于牛山湖(P<0.05);(3)两个湖泊性成熟鲫的雌、雄鱼比均随全长的增长而增加,即小个体性成熟鲫以雄鱼为主,大个体性成熟鲫以雌鱼为主,该现象在月湖更为明显;(4)牛山湖和月湖鲫全长–体重回归关系(W=a Lb)分别为W=0.00001 L3.060(R2=0.989)和W=0.000006 L3.246(R2=0.971),协方差分析表明两个湖泊鲫种群的b值差异极显著(P<0.01);另一方面,月湖鲫种群各全长组雌、雄鱼的肥满度均显著大于牛山湖(P<0.05)。作者认为影响牛山湖和月湖鲫生长和种群结构的主要因素是两个湖泊饵料组成和捕捞压力等方面的差异。