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1.
This research aimed to evaluate the alga Scenedesmus obliquus toxicity induced by textiledyeing effluents(TDE).The toxicity indicator of TDE in alga at the physiological(algal growyth),biochemical(chlorophyll-a(Chl-a) synthesis and superoxide dismutase(SOD) activity) and structural(cell membrane integrity) level were investigated.Then we further study the relationship among toxicity indicators at physiological and biochemical level,and supplemented by research on algal biomacromolecules.According to the analysis of various endpoints of the alga,the general sensitivity sequence of toxicity endpoints of Scenedesmus obliquus was:SOD activity Chl-a synthesis algal growth.The stimulation rate of SOD activity increased from day 3(57.25%~83.02%) to day 6(57.25%~103.81%),and then decreased on day 15(-4.23%~-32.96%),which indicated that the antioxidant balance system of the algal cells was destroyed.The rate of Chl-a synthesis inhibition increased gradually,reaching19.70%~79.39% on day 15,while the rate of growth inhibition increased from day 3(-12.90%~10.16%) to day 15(-21.27%~72.46%).Moreover,the algal growth inhibition rate was positively correlated with the inhibition rate of SOD activity or Chl-a synthesis,with the correlation coefficients were 0.6713 and 0.5217,respectively.Algal cells would be stimulating to produce excessive reactive oxygen species,which would cause peroxidation in the cells,thereby destroying chloroplasts,inhibiting chlorophyll synthesis and reducing photosynthesis.With increasing exposure time,irreversible damage to algae can lead to death.This study is expected to enhance our understanding of the ecological risks through algal tests caused by TDE. 相似文献
2.
Van Hoecke K De Schamphelaere KA Van der Meeren P Smagghe G Janssen CR 《Environmental pollution (Barking, Essex : 1987)》2011,159(4):970-976
The influence of pH (6.0-9.0), natural organic matter (NOM) (0-10 mg C/L) and ionic strength (IS) (1.7-40 mM) on 14 nm CeO2 NP aggregation and ecotoxicity towards the alga Pseudokirchneriella subcapitata was assessed following a central composite design. Mean NP aggregate sizes ranged between 200 and 10000 nm. Increasing pH and IS enhanced aggregation, while increasing NOM decreased mean aggregate sizes. The 48 h-ErC20s ranged between 4.7 and 395.8 mg CeO2/L. An equation for predicting the 48 h-ErC20 (48 h-ErC20 = −1626.4 × (pH) + 109.45 × (pH)2 + 116.49 × ([NOM]) − 14.317 × (pH) × ([NOM]) + 6007.2) was developed. In a validation study with natural waters the predicted 48 h-ErC20 was a factor 1.08-2.57 lower compared to the experimental values. 相似文献
3.
The macro-algae communities observed in the south lake of Tunis are characterized by the predominance of nitrophilous algae
which are in the order of biomass importance:Ulva, Cladophora andEnteromorpha. We have noted seasonal changes of alga distribution. The wind appears to be one of the most important factors influencing
this distribution. The total biomass reaches a maximum in the spring. Rapid decomposition of the biomass leads to a severe
ecological imbalance, resulting in crises of anoxia and fish death.
A restoration project has already started. It aims at removal of contaminated muds and the introduction of a new circulation
system.
The main objectives of this work were to collect information on the distribution and biomass of the phytobenthic communities
as a first step in the constitution of a database for further comparison. 相似文献
4.
5.
Termination of harmful algal blooms (HABs) and coexistence of phytoplankton–zooplankton populations are of great importance to human health, ecosystem, environment, tourism and fisheries. In this paper, we propose a three component model consisting of non-toxic phytoplankton (NTP), toxin producing phytoplankton (TPP) and zooplankton (Z). The growth of zooplankton species is assume to reduce due to toxic chemicals released by TPP population. We have extended the model proposed by Chattopadhyay et al. [Chattopadhyay, J., Sarkar, R.R., Pal, S., 2004. Mathematical modelling of harmful algal blooms supported by experimental findings. Ecol. Comp. 1, 225–235] by including competition terms between TPP and NTP. We observe the effect of competition factors both in the presence and absence of the environmental fluctuation. From our field as well as model analysis we observe that competition helps in the coexistence of the species, but if the effect of competition is very high on the TPP population, it results in planktonic bloom. It is shown that the coexistence equilibrium loses its stability when the competition coefficient crosses a critical value and resulting Hopf-bifurcation around the positive equilibrium depicting oscillations phenomena of the populations. 相似文献
6.
镍对纤维藻(Ankistrodesmus.sp.)毒性作用研究 总被引:1,自引:0,他引:1
本文研究了重金属镍对一种淡水绿藻──纤维藻(Ankistrodesmus.sp.)的毒性作用.结果表明:纤维藻对镍毒作用反应敏感.镍对纤维藻的半数有效浓度96EC50为0.33μg/mL镍,当镍浓度≥0.4μg/mL时,纤维藻的生长受到明显抑制,生长滞期延长,光合作用受阻,细胞膜透性增加.当镍浓度为3.2μg/mL时,其蛋白质氨基酸含量明显下降. 相似文献
7.
Critical review of actually available chemical compounds for prevention and management of cyanobacterial blooms 总被引:3,自引:0,他引:3
Cyanobacteria proliferation is among the most threatening consequences of freshwater pollution. Health risks from human and other-organism exposure to cyanobacteria have led to an effort to find practical methods for cyanobacterial water-bloom reduction. Hence, methods and techniques have been developed in order to reduce the amount of phosphorus or to decrease the abundance of nuisance phytoplankton species directly in the water bodies (in-lake measures). Although these “acute” methods do not solve the problem of catchment area eutrophication, they are cheaper, easier to manage, and for some areas they are the only way to protect human and environmental health against massive cyanobacterial proliferation. This review summarizes the extent of knowledge and published data about the management using metals (Al, Fe, Cu, Ag, Ca), photosensitizers (hydrogen peroxide, phthalocyanines, TiO2), herbicides and chemicals derived from natural compounds as fast and efficient removal agents of cyanobacteria. This review concludes that some compounds, when non-persistent and ecotoxicologically acceptable may help to manage cyanobacterial blooms in an efficient way compared to previous methods (e.g. copper sulfate). 相似文献
8.
Faouzi Herzi Natacha Jean Huiyu Zhao Stéphane Mounier Hassine Hadj Mabrouk Asma Sakka Hlaili 《Chemosphere》2013
In this study, metal contamination experiments were conducted to investigate the effects of copper and cadmium on the growth of the marine toxic dinoflagellate Alexandrium catenella and on the production of dissolved organic matter (Dissolved Organic Carbon: DOC; Fluorescent Dissolved Organic Matter: FDOM). This species was exposed to increasing concentrations of Cu2+ (9.93 × 10−10–1.00 × 10−7 M) or Cd2+ (1.30 × 10−8–4.38 × 10−7 M), to simulate polluted environments. The drastic effects were observed at pCu2+ = 7.96 (Cu2+: 1.08 × 10−8 M) and pCd2+ = 7.28 (Cd2+: 5.19 × 10−8 M), where cyst formation occurred. Lower levels of Cu2+ (pCu2+ > 9.00) and Cd2+ (pCd2+ > 7.28) had no effect on growth. However, when levels of Cu2+ and Cd2+ were beyond 10−7 M, the growth was totally inhibited. The DOC released per cell (DOC/Cell) was different depending on the exposure time and the metal contamination, with higher DOC/Cell values in response to Cu2+ and Cd2+, comparatively to the control. Samples were also analyzed by 3D-fluorescence spectroscopy, using the Parallel Factor Analysis (PARAFAC) algorithm to characterize the FDOM. The PARAFAC analytical treatment revealed four components (C1, C2, C3 and C4) that could be associated with two contributions: one, related to the biological activity; the other, linked to the decomposition of organic matter. The C1 component combined a tryptophan peak and a characteristic humic substances response, and the C2 component was considered as a tryptophan protein fluorophore. The C3 and C4 components were associated to marine organic matter production. 相似文献
9.
通过对Bloom分类学,即对教育活动三个领域划分方法的研究,从心理学角度详细分析了教育活动中认知、情感学习、运动三个领域子层面的内涵,指出该方法对教育工作者科学有效地开展教育活动具有重要的现实指导意义。 相似文献
10.
稳定塘中氧传递规律研究 总被引:2,自引:0,他引:2
在稳定塘污水处理过程中,氧是有机物好氧分解的重要组成部分,稳定塘中氧的来源有藻类光合放氧和大气复氧。本研究通过有光无光对比试验、大气复氧试验及对实际稳定塘中运行数据进行总结研究,定量分析藻类光合产氧和大气复氧量,计算在稳定塘中有机物的总去除量中各部分所占的比例,确定出大气复氧是稳定塘中氧传递的主要方式。 相似文献