Preliminary Investigation of the Effect of Select Pollutants on Marine Phytoplankton Using Multidimensional Fluorescence Measurements

Abstract

The use of multidimensional fluorescence for detecting the effects of select pollutants on algal fluorescence and production is demonstrated. Multidimensional fluorescence is ideally suited to rapidly measure algal fluorescence generated by both chlorophyll a and accessory pigments, as well as any changes induced by pollutants. Laboratory cultured and natural algae samples from classes Chlorophyceae, Bacillariophyceae, and Cyanophyceae were exposed to substituted nitroaromatics and fluorescence spectra of the algae recorded. Notable spectroscopic changes and fluorescence quenching were observed. In addition, a novel method for rapidly preconcentrating dilute natural marine samples is described.     

Environmental sources and sinks of alkyllead compounds

Evidence is presented in favour of a natural environmental alkylation process as a source of atmospheric vapour-phase alkyllead. Several species of marine flora have been cultured under laboratory conditions with added doses of inorganic lead, and production of alkyllead, predominantly trimethyllead (Me₃Pb⁺), has been measured. Atmospheric concentrations and ratios of alkyl and inorganic lead at urban, rural and remote sites suggest that differential decay and deposition processes for different species, together with an environmental alkylation source, may explain enhanced ratios of total alkyllead/total lead in maritime air masses.     

THE EXTINCTION OF A NON-AUTONOMOUS ALLELOPATHIC PHYTOPLANKTON MODEL WITH FEEDBACK CONTROLS

A non-autonomous allelopathic phytoplankton model with feedback controls is considered in this paper. By constructing some suitable Lyapunov type extinction functions, some sufficient conditions for the extinction of the system are obtained. For the autonomous case, by constructing a suitable Lyapunov function, we show that one species is extinct and the rest species is globally attractive. Our results supplement some known results.     

粤东柘林湾浮游植物与生态因子的灰关联-回归分析

应用灰关联方法对 2 0 0 1年 1 0月至 2 0 0 2年 7月柘林湾海域的海水采样结果进行数据分析 ,在磷酸盐、硅酸盐等 1 1项生态因子中找出影响浮游植物密度的关键因子 .根据这个结果 ,进一步建立了以这些关键因子为自变量的线性回归模型 ,模型最后的分析结果和灰关联分析的结果一致 ,即 Fe、水温、浊度是影响柘林湾浮游植物密度的关键因子 .     

Dynamics of arsenic speciation in surface waters: As(III) production by algae

Algae reduce and methylate arsenate [As(V)]. The end product of the overall transformation reaction can be arsenite [As(III)] or methylated arsenic. Field and laboratory data suggest a strong correlation between the end product of the reaction and the growth rate of the algae, with As(III) only produced during log (exponential, fast) growth. The result is a peak in As(III) concentration preceding or coincident with the algal bloom. This paper analyzes data from 18 different water bodies (five lakes, one river, six estuary/marine sites, six experimental sites). Algal blooms, As(III) peaks and algal blooms with preceding or coincident As(III) peaks were identified. In total, 80 algal blooms were identified, 49 (61%) of which were associated with As(III) peaks. In 78% of water bodies algal blooms were typically (>50%) associated with As(III) peaks. The average time lag between As(III) peaks and algal blooms was 20 days (standard deviation 18 days). Copyright © 2005 John Wiley & Sons, Ltd.     

Seasonality in estuarine sources of methylated arsenic

The effect of seasonal temperature change on the release of methylated arsenic from macroalgae, phytoplankton and sediment porewaters has been investigated by a series of controlled laboratory experiments. The appearance of dissolved arsenic species in the overlying waters was monitored using a coupled hydride generation/GC AA analytical technique. The liberation of dissolved arsenic species by the macroalgae Ascophyllum nodosum was examined under estuarine conditions at 5 °C and 15 °C. At the lower temperature the release rates were 0.2 μg kg^?1 h^?1 (wet weight of material) for monomethylarsenic (MMA) and 0.5 μg kg^?1 h^?1 for dimethylarsenic (DMA), whereas at 15 °C the rates were 0.4 μg kg^?1 h^?1 and 3.2 μg kg^?1h^?1, respectively. Incubation experiments were also carried out at 15 °C using the diatom Skeletonema costatum. During the log growth phase, when chlorophyll a concentrations were in the range 1-5 μg dm^?3, the rate of appearance of DMA in the water was ～3 ng dm^?3 h^?1. Sediment samples from the freshwater and seawater end-members of the Tamar Estuary, UK, were incubated under natural conditions at 5 °C and 15 °C. The freshwater sediments released DMA in preference to MMA; the concentrations of both species increased exponentially and reached a steady state in the overlying water after 250 h. Considerably more DMA was produced at 15 °C than at 5 °C, whilst the amount of MMA produced appeared to be insensitive to the temperature increase. In contrast, the seawater sediments always produced more MMA than DMA and the increase in temperature had little effect on the production of either MMA or DMA. The results of the laboratory experiments were compared with field observations in temperate estuaries, including the Tamar Estuary. The implications of changes of water temperature on the fate of arsenic in estuaries is discussed and modifications to the estuarine arsenic cycle are proposed.     

Study on patterns and chemical features of NO effect on marine phytoplankton growth

With supernatural bioactivation, nitric oxide (NO), which was first regarded as an endothelium- derived relaxing factor, was recognized by Science as the “Molecule of the Year” in 1992. The Nobel Prize of Physiology & Medicine in 1998 was awarded jointly to Furchgatt, Ignarro, and Murad for their discoveries concerning the NO effects in the cardiovascular sys- tem. From then on, researchers have paid more and more attention to the special and diverse functions of NO in organism[1―18].…     

Analysis of Natural Phytoplankton Populations by Pattern Recognition of Two-Dimensional Fluorescence Spectra

Two-dimensional Fourier-transform-based pattern recognition is used to characterize natural populations of marine algae by their two-dimensional, in vivo fluorescence spectra. The two dimensional fluorescence spectrum, termed an excitation-emission matrix (EEM), is acquired using a portable, multichannel fluorescence spectrophotometer (PMFS). Natural populations in the Gulf of Mexico south of Louisiana and the coastal area near Savannah, Georgia are characterized by their measurement of in situ fluorescence. Characterization of unknown populations is achieved by comparing the unknown EEMs to a collection of standard EEMs acquired from 23 species (6 classes) of marine algae. Pattern recognition results from data collected along the Georgia coast indicating diatom populations were confirmed by microscopic examination of selected samples.     

龙须菜与缢蛏单养或混养对对虾集约化养殖尾水净化的效果

为了降低对虾集约化养殖尾水的富营养化程度以及对水域环境的影响, 采用龙须菜和缢蛏单养和混养方式来研究对海水养殖尾水中营养物质的去除效率及处理过程中的浮游植物群落动态变化. 结果表明, 应用大型藻类龙须菜以及龙须菜和滤食性贝类缢蛏混养处理海水对虾养殖尾水均能取得明显效果, 其中龙须菜和缢蛏混养24h对水体中氨氮、硝态氮、亚硝态氮、磷酸盐、总氮和总磷的去除率可分别达到76.92%、77.97%、77.88%、80.00%、71.67%和71.95%. 缢蛏对水体浮游植物和总磷也有明显的去除效果, 但在实验时间内未能观察到对其他营养盐含量的明显去除效果; 且实验期间浮游植物种类没有发生显著变化, 但进行过程中混养组浮游植物丰度不断增大.     

Separation of chlorophylls and their degradation products in marine phytoplankton by reversed-phase high-performance liquid chromatography

Summary An RP-HPLC procedure which separates chlorophylls and their degradation products is described. By employing an amonium acetate buffered mobile phase and a linear gradient elution, complex mixtures of chloroand phaeopigments are separated in less than 30 minutes. The method has been applied to the control of chlorophyll enzymatic degradation in cultures of two algal species, and has also been successfully used in the analysis of algal xanthophylls.