Environmental hormone pollution is becoming more and more serious in marine environment recently. In order to evaluate the impact of environmental hormones on marine eco-system, the acute toxic effect of three environmental hormones on four marine microalgae was investigated. Results showed that the growth of microalgae including Chlorella sp., Nannochloropsis ocutala, Phaeocystis globosa and Prorocentrum donghaiense was significantly inhibited by the three environmental hormones. The 96 h median effective concentrations (96 h-EC50) of triclocarban for Chlorella sp., N. ocutala, P. globosa and P. donghaiense were 108.19 μg·L-1, 63.21 μg·L-1, 60.73 μg·L-1 and 57.58 μg·L-1, respectively. The values of 96 h-EC50 of dibutyl phthalate for four microalgae were 1.42 mg·L-1, 1.02 mg·L-1, 1.47 mg·L-1 and 1.21 mg·L-1, and those of tributyl tin chloride for four microalgae were 3.5 μg·L-1, 4.36 μg·L-1, 0.6 μg·L-1 and 0.6 μg·L-1, respectively. The toxic intensity of the three environmental hormones to marine microalgae was in the order of tributyl tin chloride > triclocarban > dibutyl phthalate.
Based on the data collected from three cruises during spring (May), summer (August) and autumn (November) of 2009, the species composition, community structure, abundance and biomass of zooplankton in the Jiulongjiang Estuary were analyzed. The results showed that in total 119 species were identified. The zooplankton community was mainly composed of copepods (35 species) and jellyfish (31 species). The dominant species mainly included Schmackeria poplesia, Pseudeuphausia sinica, Blackfordia virginica, Zoea larvae and Macrura larva, of which S. poplesia, P. sinica and B. virginica were predominant in spring, Z. larvae and M. larva in summer, and S. poplesia and A. sinensis in autumn. Both the abundance and biomass showed significant seasonal fluctuation, with the highest in spring and the lowest in autumn. However, their spatial distributions were uneven and the dense center shifted from offshore to estuary area. Compared with historic data, a significant change was found in the abundance, and composition of dominant species in Jiulongjiang Estuary in the past 20 years. Our results showed that the average abundance in this survey was the lowest and the main dominant species were also significantly different from other years.
Physiological changes of the seedlings of Duranta repens cv. ‘Dwarf Yellow', Pueraria lobata, Thunbergia erecta, Duranta repens and Tephrosia candida were observed under drought stress. The results showed that during drought stress period, the water content of the five seedlings declined; their chlorophyll, free proline, soluble sugar and MDA contents and SOD activity increased; the content of soluble protein of D. repens slightly fluctuated, whereas that of other seedlings increased gradually. These physiological indices generally recovered to the control level after rewatering. Seedlings' physiological properties were evaluated using principal component analysis, and their drought resistance was sequenced as T. candida>D. repens>T. erecta>D. repens cv. Dwarf Yellow>P. lobata.
Toxicity and interference effects of dibutyl phthalate (DBP) on the growth of Pavlova viridis were studied. The exposure concentrations of DBP were 0, 2.5, 3.0, 3.5, 4.0, 5.0, 7.5 mg·L-1. The cell density, photosynthetic pigment content, chlorophyll fluorescence characteristics and malondialdehyde (MDA) content were examined. The results showed that DBP inhibited the growth of P. viridis, and the cells were completely killed at the high concentrations (5 and 7.5 mg·L-1). The contents of chlorophyll a and carotenoids significantly decreased with the increase of DBP concentrations. Photochemical efficiency of PSII (Fv/Fm), potential activity of PSII (Fv/Fo), actual photochemical efficiency of PSII in the light (Yield) and the electron transport rate (ETR) significantly decreased with increasing concentrations of DBP, while the content of MDA increased. The results confirm that the DBP has toxic effects on the population of the microalgae.
Cd bioaccumulation in Sinonovacula constricta under different Cd concentrations (0.005 mg·L-1, 0.025 mg·L-1, 0.05 mg·L-1 and 0.1 mg·L-1) was investigated using microwave digestion-graphite furnace atomic absorption spectrometry. The result showed that S. constricta had the ability to accumulate Cd2+ in seawater. The amount and rate of Cd bioaccumulation in soft tissue of S. constricta increased with increasing Cd2+ concentration in seawater; meanwhile, during the period of 168 h exposure time, Cd bioaccumulation and biological concentration multiples (BCM) in the mollusks were positively related to the exposure time (P<0.01). Furthermore, there were discrepancies of accumulation abilities, such as bioaccumulation amount, bioaccumulation rate and BCM. In different tissues of S. constricta, Cd accumulation in gills was more significant than in muscle, but less than in digestive glands. S. constricta is not a species with strong Cd-bioaccumulation ability as compared with other mollusks.
The woody plant species richness, community diversity and spatial distribution features were analyzed based on sampling plots in Xingdoushan Nature Reserve, Hubei, China. The research also took Rapoport's altitude rule as a case study. Results showed that the forests in Xingdoushan consisted of multi-species dominant communities. The trees whose importance values were more than 15 included Cunninghamia lanceolata, Phoebe zhennan, Tetracentron sinense, and Cyclobalanopsis glauca. The physiognomy of the community changed with elevations. The α diversity, presented by the Simpson and Shannon-Weiner indices, decreased for both the tree and shrub layers with increasing altitude. The β diversity, which was indicated by the Cody index, declined with increasing altitude. These patterns supported Rapoport's altitude rule. Furthermore, the species diversity was significantly different among aspects. The Simpson index was the highest in the east and northeast aspect, followed by west, and the lowest in north aspect. The species diversity of shrub layer was higher than the tree layer at same forest community due to environment differences in canopy layers.
The antioxidant activities of Ulva lacyuca L. aqueous extracts against DPPH and ABTS free radicals were evaluated using spectrometric methods. The results showed that the detection wavelength and stable time for ABTS system were 734 nm and 6 min respectively, while those for DPPH system were 515 nm and 30 min, respectively. The extracts effectively and rapidly removed ABTS and DPPH free radicals, and showed a dose- and time-dependent manner, indicating the potent antioxidant activities under both hydrophilic and hydrophobic conditions. Under the optimized systems, the IC50 values for Se-PPC, PPC and VC against ABTS free radical were 76.40, 54.11 and 60.69 μg/ml, respectively. Se-PPC exhibited significantly higher activities than the VC. For DPPH free radicals, the IC50 values of Se-PPC, PPC and VC were 123.29, 76.83 and 24.79 μg/ml, respectively. Our results suggest selenium-enrichment cultured U. lacyuca L. has potential value of applications to be functional food with antioxidation.
Effects of dibutyl phthalate (DBP) with different concentrations on related enzyme activities and tissue of Portunus trituberculatus were researched. Crabs were sampled at 0, 5, 10, 15 and 20 d after stressing by three different concentrations. The results showed that the mortality increased with the increasing of DBP concentration. In 0.03 mg/L DBP treatment, SOD CAT and AKP activities showed an alternate fluctuation of increase and decrease. POD activity was lower than the control group at 10 d (P<0.05) and was equivalent to the control group in other times. However, ACP activity was significantly higher than the control group at 5 d (P<0.05) and maintained the level of the control group until the end of the experiment. Nevertheless, SOD activity was first increased and then showed a downward trend while the concentration was 0.2 mg/L. Although POD activity almost remained at the same level with the control group, CAT activity first decreased and then increased, and finally restored to same level of control group. ACP activity increased to the highest value in 15 d and was equal to the control group in other times. However, AKP activity first raised then recovered, showing a fluctuating trend. When the concentration was 0.4 mg/L, SOD, CAT and AKP activities showed a trend of first increasing and then decreasing. POD and ACP activities were lower than those in the control group in 20 d (P<0.05), but were equivalent to the control group in other times. Furthermore, histological examination indicated that the hepatopancreas and gill of P. trituberculatus were damaged by DBP. In addition, the higher the concentration was and longer the stress time was, the more obvious the damage was.
A submergence simulation experiment was conducted using four particular plants including Paspalum distichum, Alternanthera philoxeroides, Hemarthria altissima and Cynodon dactylon collected from the water-level-fluctuation-zone of Baihua Reservoir from July to October in 2011. To understand their adaptability traits, growth and chlorophyll contents were investigated under controlled condition. The results are as follows. Firstly, P. distichum, A. philoxeroides and H. altissima had significantly higher growth rate, whereas C. dactylon had significantly lower growth rate in submergence condition. Meanwhile, the shoots and leaves of four species which were not adapted to the submergence condition were reduced. Secondly, the growth strategies of P. distichum, H. altissima and C. dactylon were primarily the developments of caudex, while those of A. philoxeroides were primarily growth of caudex and shoot. When the top of plant protruded water, submergence significantly enhanced the leaves growth rates of P. distichum, A. philoxeroides and H. altissima. Thirdly, complete submergence condition significantly reduced contents of both chlorophyll a and chlorophyll b of the four species, but the reduction was more prominent in chlorophyll b than in chlorophyll a. Chlorophyll a/chlorophyll b ratio increased significantly in four species. When the top of plant protruded water, the contents of both chlorophyll a and chlorophyll b of P. distichum, A. philoxeroides and H. altissima increased, but chlorophyll a/chlorophyll b ratio of them reduced significantly. At last, we concluded that the four species were adaptable to submergence or complete submergence.
Isolation of allelochemicals is an important step to study allelopathy. Our previous work demonstrated that Streptomyces strain 4903 showed allelopathic effects on both plants and plant fungal pathogens. In this study four macroporous resins (X-5, NKA-II, AB-8 and HP-20) were used to collect herbicidal substances from fermentation broth of Streptomyces strain 4903. Among the four resins, AB-8 macroporous resin had the highest adsorption capacity for herbicidal compounds from the fermentation broth. The static saturation adsorption capacity was 7 times that of resin volume. The optimal eluant eluted herbicidal compounds of Streptomyces strain 4903 from AB-8 resin was 80% (v/v) ethanol–water. All herbicidal compounds of Streptomyces strain 4903 were able to be desorbed by 2-3 times that of its resin volume. The AB-8 resin can be used for extraction and purification of herbicidal compounds from fermentation broth of Streptomyces strain 4903.
The effects of UV-B irradiation on the growth, physiological and biochemical characteristics including chlorophyll, Car, MDA, soluble protein contents and antioxidant enzyme activity of Phaeodactylum tricornutum and Chaetoceros minutissimus were studied by using experimental ecology and biochemical methods. The results are as follows. (1) UV-B irradiation could inhibit the growth of two marine microalgae species; however, low-dose of UV-B irradiation (0.75 J/m2) could stimulate the growth of P. tricornutum. (2) Two microalgal species exposed to UV-B radiation had lower content of chlorophyll than the control. The chlorophyll content of P. tricornutum increased first and then decreased; C. minutissimus showed a decreasing trend with increasing dose of UV-B radiation. The MDA contents of two microalgal species increased with increasing dose of UV-B radiation. (3) The soluble protein content of P. tricornutum under enhanced UV-B irradiation increased first and then decreased; C. minutissimus showed a decreasing trend from the beginning to the end. (4) The SOD, POD and CAT activities of two marine microalgae increased first and then decreased, whereas C. minutissimus showed a relatively stable change under UV-B irradiation.
In order to make a quantitative analysis about ecological capacity change of mangrove in the development of Guangxi Beibu Gulf Economic Zone, Zhenzhu Bay, Tieshan Bay, Qinzhou Bay and Lianzhou Bay were chosen as study sites. The data of remote sensing images in 2004, 2006, 2008 and 2010 were obtained by using RS and GIS techniques, combining the state-space model as well as the indicator system of ecological capacity assessment of mangrove. The changes of ecological capacity and the correlation about ecological capacity of mangrove with the resources supply, ecosystem resilience, environmental tolerance and human activities potential of mangrove were analyzed. The results showed that the trend of ecological capacity of mangrove improved gradually in Guangxi Beibu Gulf. Resources supply and environmental tolerance of mangrove declined gradually. Environmental tolerance was influenced by the development of Beibu Gulf Economic Zone, but the ecological capacity of mangrove was not influenced. The human activities potential is the key factor determining the ecological capacity of mangrove.
We made an investigation on the Ormosia saxatilis in the Ormosia saxatilis community in the natural forest of Guizhou, studying the niche breadth values, niche proportional similarity values and niche overlapping values of the major tree species at different levels through the method of quantitative analysis. The results are as follows. 1) There is a large difference in the niche breadth of the tree layers of Ormosia saxatilis, Carpinus pubescens, Celtis sinensis, Cyclobalanopsis glauca etc, measured with Levins and Shannon-Wiener indexes, but the sequences of the first ones are basically the same. 2) In the arborous layers, the trees have a large niche breadth. Their B(SW)i and B(H)i are as following: 0.6559, 0.5113, 0.3635, 0.3369 and 0.9086, 0.4545, 0.4071, 0.3298. 3) In the shrub layers, O. saxatilis, Platycarya longipes and other species have large niche breadth as well. 4) The niche breadth can reflect the species' adaptive norm, that is to say, the larger the niche breadth is, the stronger the species is. 5) The niche breadth and the niche overlap are closely linked. Generally speaking, species with a larger niche breadth own larger overlap values. Besides, the species and other species have more similarities and larger overlap values. In a word, the larger overlap values they have, the more similarities they have in utilizing resources, and the more intense the competiveness will become.
Total nitrogen (TN) and total phosphorus (TP) of two pumping stations and seven pumped storage reservoirs were monitored in Zhuhai City from the year of 2006 to 2011. Results showed that nutrients level of Xijiang River was significantly higher than that of the seven reservoirs. Pumping water from Xijiang River resulted in a sharp rise of nutrients level in the reservoirs in the short term, and a following cyanobacteria bloom in some reservoirs. The lowest TN and TP concentrations were detected in three middle-sized reservoirs and the highest in two small reservoirs; the main reasons were that small reservoirs showed a less buffer, self-purification and capacity of pollutant. Effective approaches to relieving eutrophication process included setting up reasonable pumping water quality standards and constructing ecological engineering. Moreover, we suggest that optimal pumping through adjusting hydraulic retention time could reduce or avoid the risk of cyanobacterial blooms.
Seasonal variations in the species composition and quantity distribution characteristics of zooplankton were investigated in the Ningbo port sea area from autumn of 2009 to summer of 2010. The results showed 70 kinds of zooplanktons belonging to 3 phylum and 35 genera. Among them, copepod accounted for 73.54%. The dominant species were mainly Acartiella sinensis, Keratella quadrata, Oithona fallax, Microsetella norvegica, Microsetella sp.,Acrocalanus gibber, Oithona brevicornis, etc. The abundance of zooplankton was in the order of summer >autumn >spring >winter. The mean abundance of the four seasons was 2.50×103 ind/m3, 40.16×103 ind/m3, 3.72×103 ind/m3 and 1.20×103 ind/m3. The biomass of zooplankton ranked as summer> spring >autumn >winter. The mean biomass was 88.94 mg/m3, 931.22 mg/m3, 58.74 mg/m3 and 24.49 mg/m3. By comparing with historical information and adjacent sea area, we found that zooplankton biomass was greater [D1] than the East China Sea or equal. The biological diversity (H') in the summer and spring, autumn and winter was significantly different (P <0.05), and a higher biological diversity was found in the summer. Shannon-Wiener diversity index (H'), Species richness (D), Pielou evenness index (J), and the largest diversity index (H'max) basically showed the trend of summer> spring> autumn> winter. Compared with the adjacent sea area, the diversity index (H'max), species richness (D) and the largest diversity index (H'max) displayed the trend of declining.
The seasonal variation and spatial distribution of silicate and Chl. a during May to October in 2009 were analyzed by taking Nandaihe coastal waters as a case study, and the relationship between them and the picophytoplankton algal bloom was also discussed. Results showed that the average concentration was 0.67±0.31 mg·L-1 for silicate, and 2.06±1.16 ug·L-1 for Chl. a during the research. The spatial distribution of silicate and Chl. a both decreased from inshore to offshore area. The average concentration of silicate was the highest in September, and the lowest in May, while that of Chl. a was the highest during August to September, and the lowest during May to June. During the period of picophytoplankton algal bloom, the average concentrations of silicate and Chl. a were significantly higher than those in the same period of 2008 when the picophytoplankton algal bloom didn't occur. It showed positive correlations between distribution features of silicate and Chl. a, which was more obvious in the course of picophytoplankton algal bloom. It was analyzed that the mass propagation of picophytoplankton inhibited the normal reproduction of the phytoplankton such as diatom which utilized silicate for growth.
Cadmium is a non-degradable metal pollutant and widely exists in the environment. It is a non-essential element for plants and one of the most toxic heavy metals in the environment. It mainly comes from mining, thermal power, mechanical processing, automobile exhaust emissions, and phosphate fertilizer production, etc. Cd can be absorbed into the body by rice roots, transported to the above ground part and accumulated. It seriously affects the normal growth of rice, causes Cd pollution in rice, and brings about harm to human health through the food chain. The paper summarizes research progress on Cd pollution in rice, including the influence factors that affect the Cd absorption, such as soil pH, Eh, ionic concentration, etc., and the mechanism of Cd absorption, transport and accumulation. The tolerance and molecular mechanisms to Cd stress in rice are discussed, and existing problems and future research directions are also pointed out.
The rapid development of tourism industry and unreasonable land use have brought about potential threats to the sustainable development of resources and environment, causing certain destruction of ecosystem and pollution to the environment, and negative effects on the ecological system. It is urgently needed to establish evaluation and supervision system of ecological effect of tourism land programs for tourism industry. In present, study on ecological effect is still in the preliminary stage. It is lack of in-depth systematic research on basic theory and application practice, and the theory system is not mature. Tourism science urgently needs building theoretical research frame system to systematically plan the research contents and explore the ecological effect and its regulation mechanism of tourism land use. In this paper we design an outline of the research, based on the need of theory study and practice, composing the framework of tourist land use ecological effect and regulation mechanism research system (basic research level, the technical level, policy advice level) and the research content plan (tourism land classification system, tourism land ecological effect mechanism, ecological effect regulation and control mechanism, and tourism land ecological effect regulation policy proposals, achievement presentation and promotion), expecting to give some suggestions to research on land use ecological effect of tourism industry with theoretical enlightenment.
