The long term variation of nutrient structure in the southwest part of Daya Bay from 1982 to 2002 is analyzed in this study. The dissolved inorganic nitrogen (DIN) has increased steadily, phosphate has a trend of decrease from the 1980s to the end of 1990s and slightly increased after 2000, while silicate fluctuated at high level ~20μmol·L^-1 in different years. The nutrient atomic ratios also changed in this period: N/P ratio had a trend of increase, Si/N ratio decreased, and Si/P ratio increased slightly. These long term variations of the nutrient concentrations and their atomic ratios suggested that the nutrient limiting factor for phytoplankton growth could turn to phosphate limitation from nitrogen limitation in the last decade. The growth of phytoplankton is likely limited by nitrogen in spring and winter while by phosphate in summer and autumn. The spatial distribution in the southwest Daya bay shows the higher DIN concentration inside the Dapeng'Ao cove than that outside the cove, and phosphate concentration inside the cove is lower than that outside since 1997.

Microsystin-detoxifizyme gene plays an important role in microcystin detoxication in freshwater fishes. cDNA fragments that encoding partial sequences of microsystin-detoxifizyme gene were successfully amplified by RT-PCR using degenerate primers from the liver of the main Chinese freshwater fishes, including silver carp, bighead carp, grass carp, goldfish, Chinese perch and Tilapia. Homologous analysis show that the deduced amino acid sequences of the microsystin-detoxifizyme gene in silver carp, bighead carp, grass carp, goldfish, Chinese perch and Tilapia were 50%-60% homologus to the glutathione S-transferase gene of mammals, such as human, mouse, rat, cow, pig and sheep. The homologous analysis results indicate a big difference between the microcystin-detoxifizyme gene of freshwater fishes and the glutathione S-transferase gene of mammals, which may explain the special function of this gene in freshwater fishes for microcystin detoxication.

The extraction of chlorophyll a from phytoplankton was by freezing-thawing was assessed in this study. Filters containing alga cells were frozen and thawed repeatedly, then were steeped in 90% acetone solution for ~20 hours. Compared to the standard rubbing method, the freezing-thawing method had the improvements on small artificial error, high consistency, high accuracy, and operational simplicity. The filteration volume had no significant effect on the results for the mono-species algal cultures (P>0.05), but Bur the results for the lake water were significantly affected by filteration volume (P<0.01). For the water samples from eutrophic waterbodies, the 100ml water volume was suggested to be filtered.The data analysis showed there was no significant difference between Acetate Fiber Filter, Tiny Aperture Filter and Glass Fiber Filter.

The ecological resources in Zhaoqing city are abundant and the environment is in good condition, and there is a great potential for eco-environment construction. However, ecology and economy can not be developed harmoniously without reasonable planning. The current ecological environmental condition of Zhaoqing city was analyzed and evaluated in this paper. The whole city is divided into three eco-function areas and the landscape was designed. The research was aimed to provide useful information on the city planning and landscape designing of Zhaoqing city.

Effects of different starvation duration on survival rate and development of zoeaⅠ larvae of Chinese mitten handed crab,Eriocheir sinensis,were studyed. The results showed that starvation can significantly decrese the survival rate of the larvae and prolong the development time. A positive relationship(D=4.6648+1.3344t γ=0.978 p<0.01)between the starving time(t) and the larval development time(D) was observed. As to the zoea of Chinese mitten handed crab, if the duration of starvation exceeds 4 d, the larvae cannot recover from starvation and have normal development and exuviate function. So the point of no-return (PNR) for Chinese mitten handed crab is ~4 d, and PNR₅₀, another indicator for the resistance of the larvae to starvation, is ~48h. The results suggested that in the commercial rearing of larvae of the crab, efforts should be made to fed larvae as soon as possible after the hatching.

Biofiltration removal of odor emitted from grit-water separator in a municipal sewage plant was studied. The height and volume of biofilter media were 1.5m and 55 m³ respectively, and the volume of odor gas to be treated was 12 000 m³·h^-1. The 120d observation showed that the initial concentration of H₂S and NH₃ was 1.96~4.63 mg·m^-3, 2.21~5.68 mg·m^-3. After treatment, the concentration was reduced to 0.03~0.97 mg·m^-3 for H₂S and under 0.46 mg·m^-3 for NH₃. The removal ratio of H₂S exceeded 80%, and the concentration of NH₃ in outflux was better than level 1 National Standard. Odor removal strains consisted of bacteria, yeast and mould, such as Bacillus, Pseudomonas, Zoogloea, Acinetobacter, Thiobacillus, Saceharomyces, Candida, Aspergillus, Penicillium,and Rhizopus, among which bacteria was dominant and reached 1.8~3.1×10⁸ CFU per gram dry filter media.

The Nanjiang Industrial Park, which is located near the north branch of the Peal River, has many metals machining, plating factories. The sound environment around Nanjiang Industrial park was investiaged to assess the noise impacts to the surrounding areas. Result showed that the noise from the Industrial Park had certain impacts to the surrounding areas. During construction period, the noise had exceeded the national standard and had certain impacts to the surrounding villages and primary schools with the maximum impact at night. During operation period, noise level in three villages and one primary school had exceeded the national standard 2 and 1 respectively. The percentage of exceeding the national standard were 7.5%～17.2% in daytime, and 19.2%～33.3% at night.

Eco-tourism, a new approach for exploiting tourism resources, unites the efficacy of ecology, economy, and society. Based on the natural environment, the landscape feature and the distribution of the Shantou Nature Reserves, it is necessary to appropriately develop the eco-tourism for sustainable development.The comprehensive investigation revealed that there were many touring resources in the coastal wetlands, such as the attractive ecological scenses, the superior location and the diversified landscapes. This paper gave a comprehensive plan for the nature reserve's eco-tourism, suggested that the testing area, about 834.89hm², between Xinjinhekou and Nangangkou, should develop eco-tourism. And we also analyzed the environmental capability and eco-tourism benefit of this testing area. Eco-tourism not only can strengthen the development potential of the reserve but also can improve the service commercial around the reserve and then it can sequentially increase the avenue and the employment in the surrounding areas.

A greenhouse experiment was conducted to investigate the cycling of lead in an artificial mangrove wetland system receiving Pb-containing "wastewater". Avicennia marina was selected as the only tested mangrove plant species, which grew in tanks containing soils collected from a mangrove tidal wetland in Shenzhen, South China. Artificial seawater with salinity of 15‰ was pumped into and out of the tanks at regular intervals to simulated semi-diurnal tidal conditions. Synthetic wastewater containing various levels of lead (control, NW, FW and TW) was discharged into the artificial wetland twice a week for a year. The results show that large amounts of lead in the "wastewater" were removed by the soil after entering the artificial wetland system and the amount of soil-retained lead increased with increasing content of lead in the importing wastewater although the amount of lead remained in the artificial tidal water also increased with increasing content of lead in the importing wastewater. In general, the concentration of lead in roots is higher than it in stems and leaves. The study demonstrated that artificial wetland system had high efficiency to remove lead from the synthetic wastewater. The removal rates were 97.97%,97.86% and 98.06% for treatments NW, FW and TW, respectively. As the environmental capacity of lead in soil subsystem is calculated according to the model of matter balance, the simulated wetland has a high capacity for bearing the heavy metal pollution of lead, which has implications for the management of wastewater using mangrove wetlands.

Based on the conserved 16S rDNA sequence of Microcystis, Cyanobacteria and microcystin synthetase gene B(mcyB), three pairs of specific primer 209F/409R, 27F1/409R and MTR/MTF are selected. The primer 409R is shared in two pairs. A duplex PCR to detect Microcystis and Cyanobacteria and a triplex PCR to detect Microcystis, Cyanobacteria and mcyB are optimized. The threshold of primers for cell concentration is also studied to detect the sensitivity of these primers. Results showed that the optimal concentrations for duplex PCR and for triplex PCR are from 10⁵ cells·mL^-1 to 10³ cells·mL^-1, and the duplex PCR could be used directly to detect crude water samples from reservoirs. This study suggested that the multiplex PCR is a simple and practical approach, and could play an important role on monitoring of microcystin in water.

Jinjiang oysters, Crassostrea ariakensis, were subjected to heat shock at various temperatures (38℃、39℃、40℃、 41℃、42℃、43℃) for 1.5h, and then transferred to the ambient temperature seawater for 3 days. The results showed the 50% mortality (LT50) temperature for Jinjiang oyster was 40℃, sublethal temperature was 36℃ and lethal temperature was 42℃.The experiments also indicated that exposure to sublethal temperature dramatically enhances thermotolerance. Oysters both exposed to a single nonlethal heat shock (36℃ for 1.5 h) and subsequently recovered for 6 h in ambient temperature seawater acquired a tolerance to a subsequent exposure previously determined to be lethal (42℃ for 1.5h), i.e., the oysters pretreated with nonlethal heat shock were in a survival rate of 96.7% which was significantly higher than that the control treatment.

The acute toxicities of tow strains of Phaeocystis globosa scherffel isolated respectively from the coastal waters of Hong Kong (HK) in June 1998 and Shantou (ST) of Guangdong Province in October 1997 were studied under laboratory conditions. The results showed that two strains were pernicious to Artemia sinica. 1) Media Lethal concentration (MLC) for HK strain of logarithmic phase was 2.9×10⁵ cell·mL^-1.Median Lethal Time (MLT) was 20.91 hours. 2) MLC was 9.89×10⁶ cell·mL^-1 for ST strain of decline phase, and MLT was 26.62 hours. 3) The cell-free liquids of tow stains of Phaeocystis globosa scherffel were also pernicious to Artemia sinica, but the adverse effect of them were not so remarkable as whole cells culture medias. MLT was 26.56 hours for cell-free liquids of HK strain, and 28.02 hours for ST strain. MLC for them respectively were 7.1×10⁵ cell·mL^-1 and 1.457×10⁷ cell·mL^-1.The experimental results showed that the toxicities of cell and cell-free liquids of HK strain were more remarkable than ST strain, and the toxicities of cell liquids were more acute than cell-free liquids.

Global warming caused by increasing GHG seriously affected social and economic development around the world. Because forest can absorb CO₂ from the atmosphere and mitigate global warming, The Bonn Agreements and the Marrakesh Accord reached in 2001 approved afforestation and reforestation projects as eligible projects under the Clean Development Mechanism (CDM) in the first commitment period. These actions have been developing in many countries but not in China. In order to give guideline on this projects in our country, this paper analysize the consequences of developing forest carbon sequestration in China. The conclusion is that we can properly develop it in order to promote the sustainable development of economy and society, strengthen the international station of our country.

The tourism industry in Bao-an District, Shen-zhen City is underdeveloped. Bao-an District should aim to develop the eco-tourism based on the world tourism tendency, and local tourism resources. Through integrating its existing tourism resources, Bao-an District can form a macro-framework of eco-tourism. It is possible for Bao-an District to establish the wetland eco-tourism attractions based on 3 Wetland ecosystems: the agro-eco-tourism attractions based on Guangming Farm, the natural eco-tourism attractions based on the Yang Tai Mountain and the Fenghuang Mountain, the historical culture eco-tourism attractions based on Shajing Town,Fuyang Town,and Xixing Town. Some experienced companies inside or outside country must be absorbed to take part in the management of Bao-an tourism. The paper also suggests that Bao-an District can register a company called "Bao-an Tourism Group Co., Ltd" to manage all the tourism related industries in the District, including tourism transportation, tourism hotel, and travel agency according to international tourism market regulations. It is very important for Bao-an eco-tourism industry to build some high-level "green hotels" and the basic installations such as "green transportation".

Integrated rice-duck farming technology, as an environmental friendly technology, has been applied and practiced in many countries in Asia and in many provinces or areas in China. In order to promote this technology more effectively and scientifically, Some problems or issues should be addressed: (1) selection of rice species and duck species suitable for rice-duck farming system; (2) structure optimization of rice-duck farming system; (3) scientific issues related to ecological processes and functions of duck and linked mechanisms in paddy ecosystem; (4) integrated pest and disease management in paddy ecosystem; (5)sustainability of soil fertility of paddy field; (6)improvement of routine field management; (7) new sources of fodder for ducks; (8) prevention and cure of epidemic diseases of ducks; (9) standardization of integrated rice-duck farming system; (10) improvement of economic benefits of integrated rice-duck farming system.

The oriental fruit fly, Bactrocera (Bactrocera) dorsalis(Hendel) is a serious quarantine pest of fruits in tropical and subtropical countries. This paper reviews the researches on biology and ecology of this fruit fly, including its distribution, host, morphological characteristics, duration and its effecting factors, life history, population dynamics, and control measures etc.. Some suggestions for the further study on this pest are also proposed.

The side effect of allelopathy could casue few billions dollars lose to worldly agriculture annually. It's important that its negative and positive influence to agriculture should be studied. A review is given on the types of allelopathy, the mechanism, the affecting factors to allelopathy, and its application in agriculture. Some subjects should be addressed for the agro-forestry systems in the middle and lower reaches of the Yangtze River: study on different crop species for poplar-corps system, sieving "the mutual plants" to utilize in the biological controlling for the longhorn beetle, the autotoxicity of poplar and its influence to the succeeding crops, the effects of poplar on the content of microflora and enzymatic activities in soil.

This paper reviewed the advance in researches on rehabilitation technique of mangrove wetland based on seedling raising and reforestation technique, reformation of second forest, tree introduction and provenance screening. Based on the current condition in China, following researches should be emphasized:Rresearch on the principle of tree introduction to recover vegetation and enhance quality of ecological engineering; ②monitoring on ecological effects of non-indigenous species introduction on mangrove wetlands of China; ③effects of semi-mangrove on engineering construction of coastal shelterbelts; ④the adaptability of mangrove plants on the tidal level in flats; ⑤synthetically located research on ecological recovery of mangrove plantation; and so on.

Watercolor is an important index for aquatic environmental assessment. Watercolor was affected remarkably by phytoplankton community. The effects of predominant algal species on watercolor and relationship between algae and watercolor were reviewed. The mechanism of fertilization affecting watercolor was also analyzed and regulating methods on watercolor were advised. Method on how to distinguish the predominant algae from different watercolor was put forward in this paper to instruct the water management and relative aquatic industry.

In recent decades, the frequency of exotic plants invasions has reached to an unprecedented level. It is very important to investigate the mechanism for exotic plant invasion. There are several hypotheses to explain the plant invasion. The previous researches were reviewed in this paper, and the explaintation of exotic plant invasion from the allelopathic perspective was further addressed. Compared to exotic plants, native species are more sensitive to the chemical compounds released by exotic plants, exotic plants may use "chemical weapon" to interfere with native plants, avoid predation by herbivores and prevent infection from pathogenic microbe so that they hold advantage relative to native species, extend distribution area, and finally achieve successful invasion. Furthermore, the theoretic and applied implications from the chemical mechanism were discussed, and some suggestions were also proposed.

With the development of remote sensing technology, vegetation indices(VI), which is a quantitative indicator for ivegetation canopy and growth conditions, has been widely applied in the fields such as environmental, ecological and agricultural studies. Different types of VI have been developed during last thirty years to enhance vegetation and minimize the effects of the factors. This paper reviews the formation mechanism and the factors of VI such as vegetation conditions, atmosphere, soil, sensor calibration, sensor viewing conditions. The VI with technical innovation are discussed and analyzed for the advantages and limitations. In general, the vegetation indices are classified into airborne and satelliate VI according to the sensor platform. The satelliate vegettion indices consist of three sorts of VI: simple linear combination of the spectral bands, eliminating the effects of the factors and aiming at hyperspectral remote sensing technology and thermal infrared multi-spectral remote sensing technology. Several issues in VI future development are also addressed: Firstly, Standardization and classification of different types of VI are necessary. Secondly, the applied fields of various VI are different so that the choice of VI should be careful. Thirdly, Because of many factors of affecting VI, modification should be made before application in practice. Also, the complex formula of VI prevent its application. Finally, new VI should be developed based on the advance of remote sensing technology.

The research of microbial preparation for aquaculture is increasing rapidly with the demand for environment-friendly aquaculture. The probiotics applications were shown to improve human and terrestrial animals nutrition and reduce pathogenic problems. Now some commercial products as treating to altitude propagation are designing to treat in aquaculture. The usage of probiotics is gaining acceptance to substitute of antibiotics to control potential pathogens in aquaculture. This paper reviewed the formation and development of microbial preparation concept, explained microbial preparation applications in aquaculture in the three aspects: nutrition characteristic, immune characteristic and the aspect of improving ecological environment. The application of probiotics in aquaculture shows promise, but yet it is at early stage of development and further research is still needed. This paper further expounded the production technology of microbial preparation and principle of using, put forward author's own view on the application of microbial preparation at last.

Self-detoxification in agricultural soil is a very complicated eco-chemical process and important in sustaining and improving soil quality. Thus, adsorptive detoxification, non-biological degradative detoxification, microbiological degradative detoxification, soil-enzyme detoxification, degradative and transformative detoxification in rhizospheric environment and phytoaccumulative immobility were reviewed, and reactive mechanisms involved in various detoxicated processes were discuessed.

Biodegradation is the key factor that determines the fate of microcystin in aquatic ecosystem and its toxicological effects on aquatic organisms. This paper reviewed the studies on biodegradation of microcystin by aquatic bacteria, plants, invertebrates and fishes. Different groups of aquatic organisms showed different pathways of microcystin degradation. Aquatic bacteria Sphingomonas sp, Pseudomonas aeruginosa and Ralstonia solanacearum had the ability of biodegradation of microcystin. Degradation of microcystin-LR in Sphingomonas sp was carried out by at least three intracellular hydrolytic enzymes, one of them was termed microcystinase. While the degradation of microcystin in Pseudomonas aeruginosa was carried out by alkaline protease. The pathway of microcystin degradation in Ralstonia solanacearum was unclear. For aquatic plants, invertebrates and fishes, microcystin was mainly biotransformed into a conjugate product with GSH, which is catalyzed by glutathione S-transferases. This paper also discussed the bioremediation strategies of microcystin in aquatic environments.