Comparative Study on Purification Characteristics of ...

11

［Japanese Journal of Water Treatment Biology Vol.49 No.1 11－19 2013］

Comparative Study on Purification Characteristics of Various Submerged

Macrophyte Species in Different SeasonsZHIJIANG LU1＊, JIEMING LI2, RYUHEI INAMORI3, KAIQIN XU4,5,

NORIO SUGIURA1, and YUHEI INAMORI3

1Graduate School of Life and Environmental Sciences, University of Tsukuba/Tsukuba 305－8572, Japan2College of Resources and Environmental Sciences, China Agricultural University/Beijing 100193, China

3Japan Faculty of Symbiotic Systems Science, Fukushima University/Fukushima 960－1296, Japan4National Institute for Environmental studies/Tsukuba 305－8506, Japan

5School of Environmental Science and Engineering, Shanghai Jiao Tong University/Shanghai 200240, China

Abstract Based on macrophyte-buffering improvement methods, this study compared thecapability of water quality purification among seven submerged macrophytes throughcontinuous tests.No significant difference in nitrogen andphosphorus removal for eachsubmergedmacrophytespeciesatthewatertemperaturerangingfrom15℃to25℃,whileslight reduction in removal capability was observed at the water temperature less than15℃andmorethan25℃.Theresultsshowedthattheremovalcapabilitieswerestableinthe constructed biological system (CBS) with Ceratophyllum demersum. At low watertemperature, the removal capability remained within a certain level in the CBSs withPotamogeton malaianus,Ceratophyllum demersum,Myriophyllum spicatum, Potamogeton oxyphyllus.Amongthesevenmacrophytespecies, thestrongestaffinitywithzooplanktonwasobservedforCeratophyllum demersum.Accrordingtotheeologicalinsight,cultivationofCeratophyllum demersumisofprimeimportanceduringinitialmacrophyte-plantingineutrophicwaters,becauseofitsstrongpurificationcapabilityandaffinitywithzooplankton.

Keywords: Submerged macrophytes, water quality, eutrophication, microorganisms, aquatic animals

＊Corresponding author E－mail: [email protected]. Tel./Fax: +81－29－886－0362

INTRODUCTION Excessive inputs of nutrients, especially nitrogen and phosphorus originated from domestic, municipal and agriculture effluents, accelerate eutrophication in closed waters, favoring serious environmental problems including toxic cyanobacterial bloom, exhaustion in drinking-water source and reduction in aquaculture applicable areasin aquatic ecosystems1－4). In Japan, Water quality standards have been established for several lakes by the Ministry of the Environment5), and water source safety is

also considered as an important issue by regional governments. Although continuous efforts have been made to alleviate and control the loading inputs of nutrients from bodies of water, the rate of achieving the environmental standards for lakes still remains at a low level over the past few decades6). Nowadays, deterioration of water quality presents a large concern to water management authorities and requires an urgent need to purify the water quality in lakes, ponds and reservoirs. Compared with traditional physic-chemical methods in industry, flexible

12 Japanese J. Wat. Treat. Biol. Vol.49 No.1

application of environmental technologies is becoming increasingly attractive as a cost-effective, energy-saving and sustainable strategy for water purification2－3). According to the regulation of ecological theory, macrophyte-based restoration technology (MRT), developed as constructed wetland method and biogeofilter, has been arresting social attention in recent years and emphasizes on the omnibus research in aquatic ecosystems7－13). As compared to phytoplankton-dominated ecosystem, macrophyte-dominated ecosystem is usually structured with much higher biodiversity and larger total biomass. Submerged macrophytes build an ecotone horizontally between land and open water and vertically between sediments and overlying water, which can structurally and functionally form the “underwater forest7－13), creating a habitat that highly meets the need of aquatic organisms. So far, MRT has been proposed as crucial for remediation of the eutrophic water bodies and the functions exerted by macrophytes have been extensively studied. Many researches have demonstrated that the submerged macrophytes play an important roles in maintaining the total biomass of aquatic organisms and water purification by several mechanisms, such as assimilating and binding nutrient substances, competing with algae for nutrients and sunlight, providing a refuge for zooplankton14－16), serving as food source for invertebrate and vertebrate aquatic animals17－18) and suppressing algal growth by releasing allelopathic compounds3,19). Thus, previous related studies always focused on testing the relationships between phytoplanktons and macrophytes during macrophyte-cultivation in laboratory water-tank experiment. Although a few of large-scale studies have also been conducted, yet the detailed examination was restrained because of the multiple impact factors in natural ecosystems. Unlike previous studies which mainly aimed at the test regarding the relationships between phytoplanktons and macrophytes, this study was conducted by simulating natural ecosystems via additional drawing large aquatic animals including fishes and scallops into experimental system. In this

study, seven indigenous submerged macrophytes were used as experimental plants. The objective of this study was (1) to compare the effects of various submerged macrophytes on the water quality improvement in constructed aquatic ecosystem; (2) to compare the effects of various temperature on purification efficiency of each macrophyte, through continuous examination at different temperatures; 3) to test the DO, pH, growth of macrophytes, species distribution and biomass of zooplankton attached on different macrophytes species, in order to compare the affinities between related zooplankton species and macrophytes.

MATERIALS AND METHODSTestaquaticorganisms Considering that

the macrophytes species indigenous to Japan can be practically employed in remediation of native aquatic habitat, avoiding the problems of exotic species invasion, thus seven indigenous submerged macrophytes, including Vallisneria denseserrulata, Potamogeton malaianus, Ceratophyllum demersum, Myriophyllum spicatum, Potamogeton oxyphyllus, Hydrilla verticillata and Potamogeton perfoliatu, were selected as test submerged macrophytes. Five types of animals including Rhodeus ocellatus, Caridina multidentata, Sinanodonta woodiana, Rhinogobius sp., Radix auricularia japonica were employed as test aquatic animals to better simulate natural ecosystems.Design of Experimental Set-up Con

structed biological system (CBS) was set up in a rectangular transparent glass-tank (24cm in length, 24cm in width and 29.5cm in height). A hole with diameter of 1 cm was made on the vertical center line of glass-tank wall, locating at the height of 24.5 cm from the bottom. The sediment of CBS consisted of three zones: lake sludge, humic soil-black earth combination and fine sand, which were vertically arranged from the lower to the upper, and was spread on the bottom of the glass flume. After filling natural eutrophic water from Lake Kasumigaura into a glass-tank, one of seven different macrophyte species was cultivated in the sediment and aquatic animals were subsequently added

13Comparative Study on Purification Characteristics of Various Submerged Macrophyte Species in Different Seasons

into the system. Within every CBS, the animals included 4 Rhodeus ocellatus ocellatus with the fresh weight of 8 g for each, 4 Sinanodonta woodiana with the weight of 18 g for each, 4 Caridina multidentata with the weight of 6g for each, 8 Radix auricularia japonica with the weight of 6g for each and 4 Rhinogobius with the weight of 10g for each. To establish a stable habitat for the macrophytes, the CBS was left aside for 10 days. Next, artificial sewage with biological oxygen demand (BOD) of 30 mg l－1, total organic carbon (TOC) of 4.2 mg l－1, total nitrogen (T－N) of 4.9 mg l－1 and total phosphorous (T－P) of 1.4 mg l－1, dissolved oxygen (DO) of 4－5 mg l－1, pH of 5.5－6.0 was daily injected in CBS by an automatic electromagnetic device. The daily influent volume of sewage was 1.26 l, which was successively injected in CBS for 96 times. Hydraulic retention time (HRT) was set as 8 days. To conserve natural environmental conditions for continuous tests, all the CBSs were incubated within large transparent glasshouse to avoid any limit in exposure to natural temperature and light intensity.

SAMPLING AND ANALYSESWater quality The values of DO, water

temperature, illuminance intensity, pH, oxidation reduction potential (ORP), BOD, TOC, T－N and T－P, of the water in CBS were determined twice a week. Among these, DO, illuminance intensity, water temperature, pH value and ORP were also analyzed in the effluent from each CBS by a portable monitor. Prior to PO4－P, NH4－N, NO2－N and NO3－N determination, the sample was filtered through a GF/C and the value were determined by GF/C filtering methods. DO was determined by diaphragm type of dry battery method, pH and ORP were determined by glass electrode methods. The analyses were conducted in six replicates during daytime. The removal capability for parameters and the effect of DO can be calculated by the following equations:

A = [(c’－c)－(c’0－c0)] V × 103　　　　　　　　　　　　

WT (1)

B = (c－c0)V　　　　

W (2)

where A is the removal capability µgd－1g－1, B is the influence on the average value per day for DO value mgd－1g－1, V is the total water volume, l; W is the fresh weight of macrophytes, g; T is the time interval, day. In equation (1), c’ is the initial values of parameters in CBS, mg l－1, c’0 is the initial values of parameters in control, mg l－1; c is the monitored values of parameters in effluent from CBS, mg l－1; c0 is the monitored values of parameters in effluents from control, mg l－1. In equation (2), c is average values within one day in CBS, mg l－1; c0 is average values within one day in control, mg l－1.Zooplanktoncounting Two hundreds ml

effluent water and 6 leaves of macrophyte were sampled from each glass CBS. Each leaf was divided into two parts without being rinsed and placed on a glass slide (22cm × 24cm). One hundred µl effluent water was dropped on to the cut leaf surface. Then, the leaf was covered by a coverslip and left aside for 30 min. Next, the coverslip was removed by tweezers and the zooplankton attached on the leaf was counted directly using microscopy.

RESULTS AND DISCUSSIONPurification characteristics of different

submergedmacrophytesconcentrationofT－N,T－P, suspend solid,TOC in the effluentwaterfrom each CBS Comparing the values of T－N and T－P in effluent water between CBS and control, the T－N and T－P values in CBS fluctuated within a specific range (ANOVA F=(T－N)28.3・(T－P) 12.8, df=7, p<0.0001, Post Hoc test: Turkey HSD) (Figs. 1 and 2). Also, suspend solid (SS) values in CBS fluctuated within a specific range (ANOVA F=3.5, df=7, p<0.0014, Post Hoc test: Turkey HSD) (Fig. 3).Nitrogen and phosphorous removal

characteristicsofeachmacrophyteatdifferentwater temperatures As shown in Fig. 4, no obvious difference in purification of nitrogen was observed among different submerged macrophytes at 15－25℃. When the water temperature was below 15℃ or beyond 25℃, the Myriophyllum spicatum presented the strongest capability for nitrogen removal and the Hydrilla verticillata


exhibited the worst, as compared with other macrophyte species. This result suggested that at the changing water temperature with alternate seasons, cultivation of different macrophytes will ensure a changeable nitrogen removal from eutrophic water. The Myriophyllum spicatum afforded high purification capability for nitrogen irrespective of the water temperature, thereby implying

that it can be selected as a major functional macrophyte in the engineering of eutrophication treatment. The elimination ability of different submerged macrophytes seems almost the same at 15－25℃, but the removal quantity of Potamogeton malaianus, Ceratophyllum demersum, Myriophyllum spicatum and Potamogeton oxyphyllus for phosphorus is obviously better than others when the temperature was below 15℃ or beyond 25℃ (Fig. 5).Comparison between characteristics of

macrophytes growth, SS, DO and pHvalues All the seven macrophytes were subjected to detection of growth biomass (recovery of biomass included stem and root). All the seven macrophytes have a weight of 80g before cultivation. Among the seven macrophytes, different growth biomass was evident between different species, the order

Fig. 1 Average concentration of T－N in the water effluent from each CBS.

Fig. 2 Average concentration of T－P in the water effluent from each CBS.

Fig. 3 Average concentration of TOC in the water effluent from each CBS.

Fig. 4 T－N removal characteristics for each macrophyte at different water temperatures.

Fig. 5 T－P removal characteristics of each macrophyte at different water temperatures.


in congruent with Ceratophyllum demersum (639.2 g) > Hydrilla verticillata (459.7 g) > Myriophyllum spicatum (354.8 g) > Potamogeton perfoliatu (306.5 g) > Potamogeton malaianus (191.7 g) > Potamogeton oxyphyllus (131.3 g) > Vallisneria denseserrulata (100.6 g) (Fig. 6), suggesting different uptake capabilities of nitrogen and phosphorous, and namely, different purification capability. The specific concentration of SS was lower in effluent water in CBS than that in control (ANOVA F=3.5, df=7, p<0.0014). Average concentration of DO in each CBS is shown in Fig. 7. Since the bodies of emerged macrophytes can provide DO into system at daytime through photosynthesis, the activity of aquatic organisms can be improved within the system due to the existence of macrophytes. In the CBSs with macrophytes, the average values of DO concentrations were 8.5 mg l－1, which was close to the saturated DO concentration value in water (8.8 mg l－1, 20℃). Also, during night the increased respiratory activities of macrophytes can be revealed in this study. The pH values of waters in each CBS are show in Fig. 8. The influence of the bloom of macrophytes on pH value can be attributed to the fact that photosynthesis of macrophytes impacted the CO2－joined ionization equilibrium.The following CO2－joined ionization equilibrium can be found in water environment:

H2O+CO2 =H2CO3 (1)

H2CO3 =H+ +HCO3－ (2)

HCO3－=H+ +CO3

2－ (3)

Moreover, the ionization equilibrium for water itself was true, which can be shown as:

H2O=H+ +OH－ (4)

The pH value was regulated by the concentration of H+ and OH－

During the phase of exuberant growth, the macrophytes strongly consumed CO2 in water via photosynthesis. The consumption of CO2 affected the CO2－joined ionization equilibrium and allowed the equilibriums shown in the reaction equations (1), (2) and (3) to shift

left, which further consume H+. Simultaneously, the consumption of H+ influenced the ionization equilibrium for water and allowed the equilibriums shown in the reaction equations (4) to shift right. Therefore, the OH－ concentration increased, finally resulting in the increased pH value in water.The correlationbetween species distribution

of co-existing microorganisms habitants associated with different macrophytes and puri

Fig. 6 The growth mass of each macrophyte.

Fig. 7 Average values of DO in each CBS.

Fig. 8 Average values of pH in each CBS.


ficationcapability The species distribution of zooplantktons attached on the surface of macrophyte leaves was monitored through the microscopy. The species included Vorticella sp., Paramecium sp., Limnodrilus sp., Stentor sp., Philodina sp. They are classified into protozoa, rotifer and oligochaetes, etc, and attached to the leave surface of macrophytes in the form of biofilm. The leaves of macrophytes exerted nitrogen-uptake function to improve the growth. Simultaneously, the macrophytes can produce DO through photosynthesis, Hence, the swift reproducing of zooplanktons can be achieved due to the aerobic conditions and enough food source. This suggested that the macrophytes in CBSs can not only uptake nitrogen and phosphorous, but also sustain the living space, thus forming a food chain/web in aquatic habitat where the zooplanktons and macrophytes can consume nitrogen and phosphorous as food source. Finally, the purification function can be largely elevated22). Table 1 summarizes the species distribution and biomass of zooplanktons attached on different macrophytes. The results indicated that Ceratophyllum demersum and Myriophyllum spicatum have higher zooplankton biomass (ANOVA F=15.8 (DO), p<0.00001, Post Hoc test: Turkey HSD). The DO concentration in CBS with

Ceratophyllum demersum was higher than other CBSs, and the pH value in CBS with Ceratophyllum demersum was stable at 8.3. Moreover, Ceratophyllum demersum and Myriophyllum spicatum maintain higher biomass of attached zooplanktons. Compared with Ceratophyllum demersum, the DO concentration in CBS with Myriophyllum spicatum possess a lower range (ANOVA F=22.5 (pH), p<0.00001, Post Hoc test: Turkey HSD). It can be inferred that the number of active animals per unit existed animals is high in CBS with Ceratophyllum demersum but low in CBS with Myriophyllum spicatum. Additionally, less than 2.0 mg l－1 of T－N concentration and less than 0.1 mg l－1 of T－P phosphorous in effluent water from CBS with Ceratophyllum demersum were evident. As for other CBSs, including the CBS with Myriophyllum spicatum, T－N and T－P concentrations were less than 2.5 and 0.3 mg l－1, respectively, the pH value was around 8.0, DO concentration ranged from 6.5－10.5 mg l－1. These results suggested that macrophytes’ purification capabilities of water quality were positively proportional with their affinities with zooplanktons. From these results, Ceratophyllum demersum can be most suitably used in sustaining the safety of aquatic habitat.

Table 1 The species distribution of co-existing zooplanktons habitants associated with different macrophytes

None Vallisneria denseserrulata

Potamogeton malaianus

Ceratophy.demersum

Myriophyllum spicatum

Potamogeton oxyphyllus

Hydrilla verticillata

Potamogeton perfoliatu

Vorticella sp + +++ ++++ +++ +++ ++ +++Paramecium sp +++ ++++ ++++ ++++ ++ ++ +++Limnodrilus sp ++ ++ +++ ++ +++ ++ +++

Stentor sp + +++ +++++ ++++ ++ ++++ ++++Philodina sp +++ +++ + +

Note: +: 1～10; ++: 10～20; +++: 20～35; ++++: 35～50

Table 2 Submerged macrophytes and types of animals

None Vallisneria denseserrulata

Potamogeton malaianus

Ceratophy.demersum

Myriophyllum spicatum

Potamogeton oxyphyllus

Hydrilla verticillata

Potamogeton perfoliatu

Rhodeus ocellatus ○ ○ ○ ○ ○ ○ ○ ○Caridina multidentata ○ ○ ○ ○ ○ ○ ○ ○Sinanodonta woodiana ○ ○ ○ ○ ○ ○ ○ ○

Rhinogobius sp ○ ○ ○ ○ ○ ○ ○ ○Radix auricularia japonica ○ ○ ○ ○ ○ ○ ○ ○


From above results, it can be seen that the submerged macrophytes exerted important effects for water quality safety in eutrophic lakes. Comparing the control and CBS, we can infer that the submerged macrophytes were able to uptake nitrogen and phosphorous from ecosystems, and sustain the living space for aquatic organisms. Based on comparing CBSs with different macrophytes in this study, the results demonstrated that the removal capability for nitrogen and phosphorous of Ceratophyllum demersum was strongest among the seven different species. While the zooplankton and macrophytes biomass increased, the Ceratophyllum demersum and Myriophyllum spicatum exerted relatively high efficiency in nitrogen and phosphorous removal. Furthermore, Ceratophyllum demersum do not grow in the sediment. Therefore, Ceratophyllum demersum can survive under both emerged and submerged conditions. In other words, the exuberant growth of Ceratophyllum demersum can be achieved by simply being introduced into still water without planting, Moreover, no requirement for habitat structure, quality and depth in eutrophic waters is present in Ceratophyllum demersum cultivation. Judged from the ecological theory, the application of Ceratophyllum demersum is of high convenience and cost-efficiency in engineering process. The range of pH values of 6.5－8.5 has been recommended as the water quality standard in China. Water samples from the lake with cyanobacterial bloom are always alkali, with the pH value that beyond 10. Through this study, we envisaged that the aquatic area with exuberant growth of Ceratophyllum demersum can be developed by manual transplant or planting, so that the pH values can be adjusted and nitrogen/phosphorous can be removed in eutrophic waters, further the biodiversity of aquatic organisms can be sustained and the aquatic quality can be improved. Moreover, aquatic area with exuberant growth of Ceratophyllum demersum can maintain a healthy habitat for aquaculture resources. The function exerted by submerged macrophytes in improvement of eutrophic

water quality has been reported. This study indicated that the introduction of Ceratophyllum demersum into ecosystem palys a positive role in water safety. We can inferred that besides the utilization of Ceratophyllum demersum in alleviating eutrophication, application of submerged macrophytes community with multiple species including Ceratophyllum demersum can achieve a successful induction and of practical significance. To avoid the interference on local genetic information originated from species invasion, the introduction of exotic species is needed to be strictly conducted23). This suggests even if the introduced species has ever existed in one region, the species was necessarily regarded as an exotic species, subsequently the investigation can be carried out with respected to indigenous species, this can be considered as an issue in the future. Efficient exploitation and application of indigenous species via seed bank in soil could lead to a developed area with exuberant growth of submerged macrophytes24).

CONCLUSIONS The following conclusions can be drawn from the results obtained from this study:(1) No influence was observed in removal capability for nitrogen and phosphorous of each macrophytes at water temperature between the range from 15－25℃.(2) The difference in removal capability for nitrogen and phosphorous can be observed between different macrophytes species at water temperature that less than 15℃ and more than 25℃. However, the optimal temperature was also influenced by the adaptive capacities and the regional specific of hereditary factors of macrophytes species.(3) The order of nitrogen and phosphorous removal capability in congruent with Ceratophyllum demersum > Myriophyllum spicatum > Hydrilla verticillata > Potamogeton perfoliatu > Potamogeton malaianus > Potamogeton oxyphyllus > Vallisneria denseserrulata was observed.(4) The strongest buffer capability for pH was observed in CBS with Ceratophyllum demersum among all the seven macrophyte species.


(5) The strongest affinity with zooplankton was observed in CBS with Ceratophyllum demersum among all the seven macrophyte species.(6) The Ceratophyllum demersum, which can grow no matter roots are in soil or not, is very easy for transplanting and planting.(7) Considering the water purifying ability and the affinity for attached microbiology, among 7 selected submerged macrophytes, the Ceratophyllum demersum can be inferred to be the best suitable plant for managing eutrophication for lakes and swamps.

REFERENCES

　1）Codd G. A.: Cyanobacterial toxins, the perception of water quality, and the prioritisation of eutrophication control. Ecol. Eng., 16, 51－60 (2000)

　2）Song H., Li X., Lu X., and Inamori Y.: Investigation of microcystin removal from eutrophic surface water by aquatic vegetable bed. Ecol. Eng., 35, 1589－1598 (2009)

　3）WangG.,Zhang,L.,ChuaH.,LiX.,XiaM.,andPuP.: A mosaic community of macro-phytes for the ecological remediation of eutrophic shallow lakes. Ecol. Eng., 35, 582－590 (2009)

　4）Wu Y., Kerr P. G., Hu Z., and Yang L.: Removal of cyanobacterial bloom from a biopond-wetland system and the asso-ciated response of zoobenthic diversity. Bioresour. Technol., 101, 3903－3908 (2010)

　5）Taguchi K., and Nakata K.: Evaluation of biological water purification functions of inland lakes using an aquatic ecosystem model. Ecol. Model., 220, 2255－2271 (2009)

　6）Ministry of the Environment: The environmental white paper, Ed. of the year 2005. Gyousei, Japan (2006)

　7）QiuD.,WuZ.,LiuB.,DengJ.,FuG.,andHeF.: The restoration of aquatic macrophytes for improving water quality in a hypertrophic shallow lake in Hubei Province, China. Ecol. Eng., 18, 147－156 (2001)

　8）Sooknah R. D. andWilkieA. C.: Nutrient removal by floating aquatic macrophytes

cultured in anaerobically digested flushed dairy manure wastewater. Ecol. Eng., 22, 27－42 (2004)

　9）Nahlik A. M. and Mitsch W. J.: Tropical treatment wetlands dominated by free-floating macrophytes for water quality improvement in Costa Rica. Ecol. Eng., 28, 246－257 (2006)

10）Wang S., Jin X., Zhao H., and Wu F.: Phosphate biosorption characteristics of a submerged macrophyte Hydrilla verti-cillata. Aquat. Bot., 89, 23－26 (2008)

11）Gao J., Xiong Z., Zhang J., ZhangW., andMbaF.O.: Phosphorus removal from water of eutrophic Lake Donghu by five submerged macrophytes. Desalination, 242, 193－204 (2009)

12）WangY.,ZhangJ.,KongH.,InamoriY.,XuK.,InamoriR.,andKondoT.: A simulation model of nitrogen transformation in reed constructed wetlands. Desalination, 235, 93－101 (2009)

13）LiX.,SongH.,LiW.,LuX., andNishinuraO.: An integrated ecological floating-bed employing plant, freshwater clam and biofilm carrier for purification of eutrophic water. Ecol. Eng., 36, 382－390 (2010)

14）Moss B.: Engineering and biological approaches to the restoration from eutrophication of shallow lakes in which aquatic plant communities are important components. Hydrobiologia, 200/201, 367－378 (1990)

15）JeppensenE., Jensen J. P., SondergaardM.,LauridsenT.,PedersenL. J., andJensenL.: Top-down control in freshwater lakes: the role of nutrient state, submerged macro-phytes and water depth. Hydrobiologia, 342, 151－164 (1997)

16）Meijer M. L. and Hosper H.: Effects of biomanipulation in the large and Shallow Lake Wolderwijd, The Netherlands. Hydrobiologia, 342/343, 335－349 (1997)

17）Lamberti G. A. and Moore J. W.: Aquatic insects as primary consumers. In: Resh V.H., Rosenberg D.M. (Eds.), The Ecology of Aquatic Insects. Praeger Scientific, New York, pp.164－195 (1984)

18）MaceinaM. J., Bettoli P.W.,KlussmannW.G.,BetsillR.K., andNobleR.L.: Effect of aquatic macrophyte removal on recruit-ment and growth of black crappies and white crappies in Lake Conroe, Texas. N.


Am. J. Fish. Manage., 11, 556－563 (1991)19）NakaiS.,InoueY.,HosomiM.,andMurakami

A.: Myriophllum spicatum-released allelopathic polyphenols inhibiting growth of blue-green algae Microcystis aeruginosa. Water Res., 34, 3026－3032 (2000)

20）QiuD.R.,WuZ.B.,LiuB.Y.,DengJ.Q.,FuG.P.,andHeF.: The restoration of aquatic macrophytes for improving water quality in a hypertrophic shal-low lake in Hubei Province, China, Ecol. Eng., 18, 147－156 (2001)

21）Chen H.: Studies on productivity of Potamogeton crispus L, Acta Hydrobiol. Sin, 13, 152－159 (1989)

22）HayashiN.,OzakiY., and Sakai F.: Role of

aquatic animals for water purification on aquatic plant purification system. J. Jpn. Biol. Soc. Water Waste, 47, 119－129 (2011)

23）Nishihiro J. andWashitani I. : The Future Studies of Water Environment in “Biodiversity and Ecosystem Restoration”. J. Jpn. Soc. Water Environ., 27, 240－241 (2004)

24）Kushiro,K.,HayashiN.,andNishihiroJ.: A restoration of submerged vegetations from propagule banks by making small ponds at the shore of Lake Imba-numa, Japan. Ecol. Civil Eng. 12, 141－147 (2009)

(Submitted 2012. 12. 13)(Accepted 2012. 12. 31)

Comparative Study on Purification Characteristics of ...

Documents

Transcript of Comparative Study on Purification Characteristics of ...