Effectsof Combined Ecological Restorationon theMicrobial Diversityin Watercourse

TANG Xiang-chen

（College of Chemical and Environmental Engineering,Qingdao University，Qingdao Shandong 266071，China）

0 Introduction

Ecological restoration was one of the main functions of locating water ecological restoration techniques which could promote aquatic ecosystems recovery and purify the river water.

At present, ecological restoration technology included bioremediation,aquatic plant purification,artificial wetland and biological membrane,biological control,oxidation pond,and river aeration technology(Qu J etal,2010),they were widely used in riverway treatment.Then aquatic plant purification technology were composed of plants absorb,microbial metabolism and the microenvironment of the plant roots of adsorption,filtration,precipitation,etc(Reddy and Debusk,1987).

In the artificial wetland,plants could directly absorb the nitrogen，phosphorus and other nutrients,and plant roots biofilm microbial catabolism could also effectively remove organic pollutants and other nutrients in the river water(Yang Qing-hai.2008).Biological control,also known as the food web manipulation，its main role was to improve the function of aquatic food chains Celsius and aquatic ecosystems.Aquatic animals and benthic filter-feeding fish could increase algae for food of intake and reduce algae levels and improve water quality.Gifford et al(2005)studied the removal of nutrients and heavy metals which used the oyster in water.The results show that these aquatic animals could actually make a difference for TN,ammonia， TP，etc.

The main principle of the biofilm technology was use of bioaccumulation layer attached to the carrier in some natural and artificial carrier formed above， after contacted with water， they could be achieved by removing water contaminants purpose metabolism of microorganisms(Dre N Ner RW,1999)；for example the contact between the oxide gravel，artificial fillers etc belonged to this type of contact oxidation technology. Biofilm organisms included bacteria， fungi， algae， protozoa，metazoa and some visible worms,insects,larvae and the like.When Xiao Yu-tang etal (2005)used the three-dimensional elastic filler,microporous aeration enriched biological contact oxidation to repair Chuanyang Watercourse in Shanghai，they observed that the aerobic biofilm had play the major role for pollutant removal which was through to enrich in biological membranes.

But now the research and evaluation for the ecological impact of these technologies were very scarce(Hu M,2010).As anthropogenic interference with the ecological reconstruction，whether to promote the healthy development of the ecosystem，would have adverse ecological impact?What evaluation methods could be sensitived to judge the effect of ecological restoration and warn the adverse trends?What factors could be regulated its ecological impact?How to design and control?These unresolved issues increased water ecological restoration blindness.

The study relied on a south typical river which had been practiced all kinds of ecological restoration techniques(Ma Ke-xing,Wu Hai-qing,2011).During the trial,we carried out around the demonstration area corresponding to zooplankton， phytoplankton,benthic fauna observation，and had embarked much resolution on habitat physicochemical properties and microbial functional diversity(Nduwimana A,Yang X-L,Wang L-R.,2007).Then we had started a long-term observational study for phytoplankton， zooplankton,benthos， fish,plants and even microbes and other large aquatic ecosystems(Li X N,Song H L,Li W,Lu X W,Nishimura O.2010),in order to identify the key factors,set up the sensitivity monitoring method and evaluation indicators of environmental evaluation factors，assess the effect of ecological restoration,warn the ecological adverse trends timely and guide to design the ecological restoration techniques(Rana S,Bag SK,Golder D,Jana B B,2011).

1 Materials and methods

1.1 Experiment design

Ecological restoration technology had introduced a variety of largescale directly aquatic plants，which had provide a suitable habitat to survive and multiply for animals becamea polluted river in the “ Oasis.”(Zhu L D,Li Z H,Ketola T 2011).To assess the ecological effects from the ecological restoration of the river，we had choosed an example of a city river ecology project,in the round coins grass，plant rhizosphere poly floating islands of grass，artificial vector,plant water section,we could find fish(mainly carp)and other animals，a variety of aquatic biological indicators were regularly carried out ecological monitoring before and after for the implementation of ecological projects.

1.2 Sampled frequency

In the river，we had set three long-term monitoring sections to monitor from 2011 to 2012,sampling one time in every quarterly，monitored chlorophyll-a,algae density，the biological acute toxicity of water,observed benthic organisms， phytoplankton， zooplankton， fish,other aquatic plants.Until December 2012.we had proceed six times sampling in three sections of the river.

1.3 Analyzed methods

Community diversity was an important yardstick community stability，currently,the species diversity index biome diversity index could be divided intoα，βandγdiversity index categories，the paper had opted these for the index and measured using CCA analysis.

1.4 Monitored methods

Chlorophyll-a,algae density， benthic organisms， phytoplankton，zooplankton，fish were used biological monitoring methods of the water and wastewater monitoring and analysis methods fourth edition，the biological acute toxicity of water was used bright light-emitting bacteria T3 method for measuring.

2 Results and Discussion

In previous samples，we had not found the plant in the river except which planted in the floating aquatic beds and wetlands，so it showed that plants could be well controlled for growing,and they had no diffusion or intrusion hazards.The number of fish had Increased，but the type were too small and the dominant species were stain fish，this diversity had no significant change in two years.Benthic biomass increased significantly,but the type was also too small and the dominant species were stain species,Hope-LIMNODRILUS were the dominant species，this diversity also had no significant change in two years.In contrast,the phytoplankton community composition had highly sensitivity.After the project implementation of ecological restoration,plankton communities had constituted a significant change，and the changes had a certain correlation with water quality.Changes of phytoplankton diversity index in different sections in Fig 1，CCA biplot of main phytoplankton species and environmental variables in the river in Fig 2，Changes of zooplankton diversity index in different sections in Fig 3，CCA biplot of main zooplankton species and environmental variables in the river in Fig 4.

Fig.1 Changes of phytoplankton diversity index in three river sections

Fig.2 CCA biplot of main phytoplankton species and environmental variables in the river

Fig.3 Changes of zooplankton diversity index in three river sections

Fig.4 CCA biplot of main zooplankton species and environmental variables in the river

Changes of phytoplankton diversity index in different sections in Fig 1，through the shannon analysis,we found that the diversity index had changed significantly after the treatment.As the season changes，the diversity index had significantly increase,particularly in the the downstream area，the diversity had significantly improved(Sun L P,Liu Y,Jin H,2009).Judging from the composition of the population although it still dominated by Cyanophyta， green algae， diatoms were significantly increased in the midstream and downstream area.

Through CCA analysis,CCA biplot of main phytoplankton species and environmental variables in the river in Fig 2。 The ecology of phytoplankton had significantly changed，it had a high correlation to the TN、TP、pH、COD and other factors in ecology rehabilitation engineer.In this paper，phytoplankton diversity were significantly correlated with temperature，seasons and plant diversity;TN,TP and other pollutants affected the distribution of phytoplankton species，monitoring data showed that the river phytoplankton community had become more stable after two years(Song H L,Lu X W,2011).

In Fig 3,it showed the changes of zooplankton diversity index in different sections,after the implementation of the project，zooplankton diversity had no significantly changed in species composition in the river， but the number of protozoa had increase， it indirectly indicated that river had become better and better.CCA biplot of main zooplankton species and environmental variables in the river in Fig 4,we found that zooplankton diversity were significantly correlated with TN、pH and transparency ;,monitoring data showed that the river zooplankton community had also become more stable after two years.

Used the many techniques like floating island，wetland,floating plants and benthic animals which put in a variety of ways to build habitats， it could significantly improve the river landscape， inhibit water odor and promote aquatic ecosystem restoration(Li M,Wu Y J,2007).While improving the flow of the river and making in situ oxygenation and oxygen hydrodynamic conditions，it had played a large role in inhibit the occurrence of black-odor，enhance plant-microbe system,protect the ecosystem restoration(Fang Yi-feng,2005).When we had integrated these techniques like ecological construction, manufacturing flow and oxygenation,sediment pollution control and rapid purification technologies，which were built an integrated system of urban river water purification technology and ecological restoration，This project had used many technicals(Zhang Tongqi,2011)(Wang Wen-lin,2008)，by the phytoplankton and animal diversity as a factor indicating in the technology analysis,the results showed that the coupling could significantly improve the water quality and diversity，which also provided for drawing river management technical in future.

2 Conclusion

After the demonstration project fully implemented in the river,the area of high pollutant concentration had been reduced efficiently.The water quality compared with the contrast section had been obviously improved，COD,ammonia nitrogen,TP， DO increased significantly,the phenomenon of black-odor river had been controlled,landscape of urban river channels had been improved,the diversity of phytoplankton had been increased，and then cyanobacteria， such as indicator species for water pollution had also been reduced， fish， benthic biomass increased significantly。

Compared with the contrast section，the river and sediment microbial composition had obvious differences in the restoration area.Especially，the diversity of microbial species in restoration area were significantly higher than the contrast area.the biological diversity of plant roots in floating gate bed and microbial biofilm carrier were significantly higher than in the river and sediment.Studied on the differences of microflora and quantity in different environment,it had a high correlation to the TN、TP、COD and other factors in ecology rehabilitation engineer.S

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