The microscale distribution of oxygen,the nitrogen flux and the denitrification rates in sediment inhabited by chironomid larvae（Tanypus chinensis） were measured in eutrophic Lake Taihu,China.The presence of the chi...The microscale distribution of oxygen,the nitrogen flux and the denitrification rates in sediment inhabited by chironomid larvae（Tanypus chinensis） were measured in eutrophic Lake Taihu,China.The presence of the chironomids in the sediment increased the oxygen diffusional flux from 10.4 ± 1.4 to 12.7 ± 2.5 mmol O 2 /（m 2 ·day）.The burrows of the larvae represented ＂hot spots＂ and strongly influenced the nitrogen cycles and diagenetic activity in the sediment.The results indicate that the bioturbation effects of Tanypus chinensis chironomid larvae increased the capacity of the sediment as a sink for nitrate and a source for ammonium.Nitrate influx and ammonium outflux were increased 8.8 and 1.7 times,respectively.Under bioturbation,the amount of nitrate consumed was greater than the amount of ammonium released.The total denitrification rate was also enhanced from 0.76 ± 0.34 to 5.50 ± 1.30 mmol N/（m 2 ·day）.The net effect was that the bioturbated sediments acted as a net sink for inorganic nitrogen under direct and indirect bioturbation effects compared to the control.展开更多
Chironomid larvae propagated excessively in eutrophic water body and could not be effectively inactivated by the conventional disinfection process like chlorination due to its stronger resistance to oxidation. In this...Chironomid larvae propagated excessively in eutrophic water body and could not be effectively inactivated by the conventional disinfection process like chlorination due to its stronger resistance to oxidation. In this paper, a pilot-scale study of chlorine dioxide preoxidation cooperating with routine clarification process for Chironomid larvae removal was conducted in Shenzhen Waterworks in Guangdong Province, China. The experimental results were compared with that of the existing prechlorination process in several aspects, including the Chironomid larvae removal efficiencies of water samples taken from the outlets of sedimentation tank, sand filter, the security of drinking water and so on. The results showed that chlorine dioxide might be more effective to inactivate Chironomid larvae than chlorine and Chironomid larvae could be thoroughly removed from water by pre-dosing chlorine dioxide process. The GC-MS examination and Ames test further showed that the sort and amount of organic substance in the treated water by chlorine dioxide preoxidation were evidently less than that ofprechlorination and the mutagenicity of drinking water treated by pre-dosing chlorine dioxide was substantially reduced compared with prechlorination.展开更多
The Taihu Lake,a large shallow lake in the floodplain of the Changjiang(Yangtze) River in the eastern China,is faced with challenging ecological problems resulting from eutrophication,which has affected the regional f...The Taihu Lake,a large shallow lake in the floodplain of the Changjiang(Yangtze) River in the eastern China,is faced with challenging ecological problems resulting from eutrophication,which has affected the regional freshwater supply of a large population.Although efforts have been made to assess the nutrient evolution histories in the northern bays,little is known regarding nutrient histories in different parts across the entire lake basin.In this paper,we present nutrient histories for different parts of the lake based on chironomid transfer functions applied to four short cores obtained from the northern,western and eastern regions of the lake.The chironomid-inferred total phosphorus(CI-TP) concentrations were compared with the phosphorus concentrations obtained by using instrumental and sedimentary data.The results suggest that trophic evolution histories were asynchronous throughout the lake during the past decades in response to different ecological regimes controlled by the nutrient input,wind direction and shoreline topography.The restoration of aquatic plants may be an effective option for the management of lake rehabilitation to ′natural′ conditions.Given the multiple factors controlling the biotic communities in such a large and complex lake,combined analyses among the multi-proxies encountered in the sediments are necessary for comprehensive insight into paleolimnological studies.The spatial heterogeneity in the ecological trajectories within this complicated ecosystem suggests that different management practices should be undertaken for specific lake zones in the Taihu Lake.展开更多
Objective:Rice fields are dynamic mosquito larval habitats with assemblage of different predator taxa,including the larva of the mosquitoes Lutzia.Entomological surveillance in the ricefields is essential to evaluate ...Objective:Rice fields are dynamic mosquito larval habitats with assemblage of different predator taxa,including the larva of the mosquitoes Lutzia.Entomological surveillance in the ricefields is essential to evaluate the potential of these predators as biological resource to regulate vector mosquito population.In view of this,a survey of ricefields for immatures of different mosquito species including Lutzia was conducted.Methods:Survey of selected ricefields was carried out to evaluate the species composition of mosquitoes.Laboratory evaluation of the immatures of Lutzia mosquitoes was carried out to assess its predation potential using mosquitoes and chironomid as preys.Results:The survey revealed the presence of five mosquito species belonging to the genera Anopheles and Culex and the predatory immatures of the mosquito Lutzia Juscana(Wiedemann,1820).The ratio of prey and predatory larva ranged between 1.46 and 4.78 during the study period,with a significant correlation on the relative abundance of the larval stages of Lt.Juscana and Anopheles and Culex larvae.Under laboratory conditions,a single IV instar larvae of Lt.fuscana was found to consume on an average 5 to 15 equivalent instars of Anopheles sp.and Culex sp.larvae per day depending on its age.The prey consumption reduced with the larval stage approaching pupation.When provided with equal numbers of chironomid and Anopheles or Culex larvae,larva of Lt.fuscana consumed mosquito larvae significantly more compared to chironomids.Conclusion: The survey results and the preliminary study on predation are suggestive of the role of Lt.Juscana in the regulation of vector mosquito populations naturally in the ricefields.Since Lt.Juscana is common in many Asian countries,further studies on bioecology will be helpful to justify their use in mosquito control programme.展开更多
Chironomid larvae propagate prolifically in eutrophic water body and they cannot be exterminated by conventional disinfection process. The inactivation effects of chlorine and chlorine dioxide on Chironomid larvae wer...Chironomid larvae propagate prolifically in eutrophic water body and they cannot be exterminated by conventional disinfection process. The inactivation effects of chlorine and chlorine dioxide on Chironomid larvae were investigated and some bourdary values in practice were determined under .conditions of various oxidaat dosage, organic precursor concentmtion and pH value. In addition, removal effect of different pre-oxidation cambined with coagulation process on Chironomid larvae in raw water was evaluated. It was found that chlorine dioxide possessed better inactivation effect than chlorine. Complete inactivation of Chironomid larvae in raw water was resulted by 1.5 mg/L of chlorine dioxide with 30 min of contact ＇time. Additionally, the organic precursor concentration, pH value had little influence on the inactivation effect. The coagulation jar test showed that Chironomid larvae in the raw water could be completely removed by chlorine dioxide pre-oxidation in combination with the coagulation process at chlorine dioxide dosage of 0.8 mg/L.展开更多
To investigate the use of a biomarker for assessment of the effects on the tropical chironomid, Chironomus javanus (C. javanus), Kiffer of sediment contaminated with an insecticide (chlorpyrifos).MethodsA wide range o...To investigate the use of a biomarker for assessment of the effects on the tropical chironomid, Chironomus javanus (C. javanus), Kiffer of sediment contaminated with an insecticide (chlorpyrifos).MethodsA wide range of biological responses to the tropical chironomid exposed were measured, including survival, growth rate and Acetylcholinesterase (AChE) activity.ResultsThe measured median lethal concentration (96 h LC<sub>50</sub>) of chlorpyrifos to C. javanus was 0.056 (95% CI 0.024-0.124) μg/kg. For sub-chronic levels of chlorpyrifos between 0.001 and 0.25 μg/kg administered for 10 days, the effects on the growth of C. javanus were reduced (larva size, head structure width and dry weight) at the significance level (P < 0.01) and the effects were concentration dependent. Following exposure to chlorpyrifos at the level of 0.001 μg/kg for 48 and 96 h, the AChE activity in C. javanus was inhibited compared with control samples (P < 0.05).ConclusionsThis study demonstrated that C. javanus was sensitive when exposed to chlorpyrifos. This species could serve as a potential biomarker for assessing pesticide contamination at low environmental persistence and provides limited effects data on the sensitivity of tropical biota to contaminants for ecological risk assessment of organophosphate pesticides in the tropical aquatic ecosystem.展开更多
Starvation metabolism is one of the important parts of respiration for normal activities of chironomids. During April 1996 to March 1997, the relationships of starvation metabolism and temperature, body weight of two ...Starvation metabolism is one of the important parts of respiration for normal activities of chironomids. During April 1996 to March 1997, the relationships of starvation metabolism and temperature, body weight of two common chironomids in Biandantang Lake were carefully investigated. The results showed relationship between starvation metabolism （R, mgO2/ind.d） and body weight （Ww, mg wet wt） was： Chironomus plumosus, 1gR=-2.573＋1.0211gWw （5℃）, 1gR=-2.710＋1.3541gWw （10℃）, 1gR= -1.824＋0.8231gWw （15℃）, 1gR=-1.364＋0.4421gWw （20℃）, 1gR=-2.763＋1.5171gWw （25℃）; and Tokunagayusurika akamusi, 1gR=-2.390＋0.7521gWw （5℃）, 1gR=-1.978＋0.7101gWw （10℃）, 1gR=-1.676＋ 0.6481gWw （15℃）, 1gR=-1.517＋0.6501gWw （20℃）, 1gR=-2.434＋1.2901gWw （25℃）. Relationship of starvation metabolism and temperature （T, ℃） was： C. plumosus, R = -0.051 ＋ 0.021T- 0.0006T^2 ; akamusi, R= -0.051 ＋ 0.021T- 0.0006T^2. The complex relationship of the three parameters was： C. plumosus, R=0.0098Ww^0.3882e^0.1068T; T. akamusi, R=0.0012Ww^1.1936e^0.0711r. With the above regressions, the estimated annual starvation metabolisms of the two chironomid species in Biandantang Lake were： C. plumosus, 24.2791 kJ/m^2.a; T. akamusi, 8.7864 kJ/m^2.a, respectively. This provides a firm foundation for the comparative study of bioenergetics of the chironomids.展开更多
To study the influence of human activity on natural lake, chironomid fauna change in the 700-560cm lake sediment in Quidenham Mere of England associated with chironomid inferred TP presented that the lake experienced ...To study the influence of human activity on natural lake, chironomid fauna change in the 700-560cm lake sediment in Quidenham Mere of England associated with chironomid inferred TP presented that the lake experienced a whole eutrophication process due to human hemp-retting in Post-Medieval based on the history record and pollen analysis, which was confirmed by mollusc and ostracod analysis. However, the response of chironomid and mollusc to retting was the strongest with ostracod a little behind. It proved that cultural eutrophication existed in history and could be recovered by itself despite of some long-term unachievahle destroy. And it was most important for external nutrient to be cut off during lake restoration even in ancient times.展开更多
Two holotypes of the orthoclad genus Nanocladius from Japan were redescribed and illustrated:Nanocladius(Plecopteracoluthus) asiaticus Hayashi and Nanocladius(Nanocladius) tamabicolor Sasa.A key to the males of Nanocl...Two holotypes of the orthoclad genus Nanocladius from Japan were redescribed and illustrated:Nanocladius(Plecopteracoluthus) asiaticus Hayashi and Nanocladius(Nanocladius) tamabicolor Sasa.A key to the males of Nanocladius from the East Asia was provided.展开更多
基金supported by the National Natural Science Foundation of China (No. 41271468,40971253,40903031)the Basic Research Program of Jiangsu Province (No. BK2011879)the Key Project of"One Three Five" Strategic Developing Plan (No. NIGLAS2012135008
文摘The microscale distribution of oxygen,the nitrogen flux and the denitrification rates in sediment inhabited by chironomid larvae（Tanypus chinensis） were measured in eutrophic Lake Taihu,China.The presence of the chironomids in the sediment increased the oxygen diffusional flux from 10.4 ± 1.4 to 12.7 ± 2.5 mmol O 2 /（m 2 ·day）.The burrows of the larvae represented ＂hot spots＂ and strongly influenced the nitrogen cycles and diagenetic activity in the sediment.The results indicate that the bioturbation effects of Tanypus chinensis chironomid larvae increased the capacity of the sediment as a sink for nitrate and a source for ammonium.Nitrate influx and ammonium outflux were increased 8.8 and 1.7 times,respectively.Under bioturbation,the amount of nitrate consumed was greater than the amount of ammonium released.The total denitrification rate was also enhanced from 0.76 ± 0.34 to 5.50 ± 1.30 mmol N/（m 2 ·day）.The net effect was that the bioturbated sediments acted as a net sink for inorganic nitrogen under direct and indirect bioturbation effects compared to the control.
文摘Chironomid larvae propagated excessively in eutrophic water body and could not be effectively inactivated by the conventional disinfection process like chlorination due to its stronger resistance to oxidation. In this paper, a pilot-scale study of chlorine dioxide preoxidation cooperating with routine clarification process for Chironomid larvae removal was conducted in Shenzhen Waterworks in Guangdong Province, China. The experimental results were compared with that of the existing prechlorination process in several aspects, including the Chironomid larvae removal efficiencies of water samples taken from the outlets of sedimentation tank, sand filter, the security of drinking water and so on. The results showed that chlorine dioxide might be more effective to inactivate Chironomid larvae than chlorine and Chironomid larvae could be thoroughly removed from water by pre-dosing chlorine dioxide process. The GC-MS examination and Ames test further showed that the sort and amount of organic substance in the treated water by chlorine dioxide preoxidation were evidently less than that ofprechlorination and the mutagenicity of drinking water treated by pre-dosing chlorine dioxide was substantially reduced compared with prechlorination.
基金Under the auspices of National Basic Research Program of China(No.2012CB9561002008CB418103)National Natural Science Foundation of China(No.41072267)
文摘The Taihu Lake,a large shallow lake in the floodplain of the Changjiang(Yangtze) River in the eastern China,is faced with challenging ecological problems resulting from eutrophication,which has affected the regional freshwater supply of a large population.Although efforts have been made to assess the nutrient evolution histories in the northern bays,little is known regarding nutrient histories in different parts across the entire lake basin.In this paper,we present nutrient histories for different parts of the lake based on chironomid transfer functions applied to four short cores obtained from the northern,western and eastern regions of the lake.The chironomid-inferred total phosphorus(CI-TP) concentrations were compared with the phosphorus concentrations obtained by using instrumental and sedimentary data.The results suggest that trophic evolution histories were asynchronous throughout the lake during the past decades in response to different ecological regimes controlled by the nutrient input,wind direction and shoreline topography.The restoration of aquatic plants may be an effective option for the management of lake rehabilitation to ′natural′ conditions.Given the multiple factors controlling the biotic communities in such a large and complex lake,combined analyses among the multi-proxies encountered in the sediments are necessary for comprehensive insight into paleolimnological studies.The spatial heterogeneity in the ecological trajectories within this complicated ecosystem suggests that different management practices should be undertaken for specific lake zones in the Taihu Lake.
文摘Objective:Rice fields are dynamic mosquito larval habitats with assemblage of different predator taxa,including the larva of the mosquitoes Lutzia.Entomological surveillance in the ricefields is essential to evaluate the potential of these predators as biological resource to regulate vector mosquito population.In view of this,a survey of ricefields for immatures of different mosquito species including Lutzia was conducted.Methods:Survey of selected ricefields was carried out to evaluate the species composition of mosquitoes.Laboratory evaluation of the immatures of Lutzia mosquitoes was carried out to assess its predation potential using mosquitoes and chironomid as preys.Results:The survey revealed the presence of five mosquito species belonging to the genera Anopheles and Culex and the predatory immatures of the mosquito Lutzia Juscana(Wiedemann,1820).The ratio of prey and predatory larva ranged between 1.46 and 4.78 during the study period,with a significant correlation on the relative abundance of the larval stages of Lt.Juscana and Anopheles and Culex larvae.Under laboratory conditions,a single IV instar larvae of Lt.fuscana was found to consume on an average 5 to 15 equivalent instars of Anopheles sp.and Culex sp.larvae per day depending on its age.The prey consumption reduced with the larval stage approaching pupation.When provided with equal numbers of chironomid and Anopheles or Culex larvae,larva of Lt.fuscana consumed mosquito larvae significantly more compared to chironomids.Conclusion: The survey results and the preliminary study on predation are suggestive of the role of Lt.Juscana in the regulation of vector mosquito populations naturally in the ricefields.Since Lt.Juscana is common in many Asian countries,further studies on bioecology will be helpful to justify their use in mosquito control programme.
基金The National Natural Science Foundation of China(NO.503780262)Supporting Certificate of China Postdoctoral Science Foundation(No.20070420882)Heilongjiang Postdoctorial Financial Assistance(No.LBH-Z06115)
文摘Chironomid larvae propagate prolifically in eutrophic water body and they cannot be exterminated by conventional disinfection process. The inactivation effects of chlorine and chlorine dioxide on Chironomid larvae were investigated and some bourdary values in practice were determined under .conditions of various oxidaat dosage, organic precursor concentmtion and pH value. In addition, removal effect of different pre-oxidation cambined with coagulation process on Chironomid larvae in raw water was evaluated. It was found that chlorine dioxide possessed better inactivation effect than chlorine. Complete inactivation of Chironomid larvae in raw water was resulted by 1.5 mg/L of chlorine dioxide with 30 min of contact ＇time. Additionally, the organic precursor concentration, pH value had little influence on the inactivation effect. The coagulation jar test showed that Chironomid larvae in the raw water could be completely removed by chlorine dioxide pre-oxidation in combination with the coagulation process at chlorine dioxide dosage of 0.8 mg/L.
基金funded by the Higher Education Research Promotion and National Research University Project of Thailand(Grant number:W-2553-Ph.D.-05)
文摘To investigate the use of a biomarker for assessment of the effects on the tropical chironomid, Chironomus javanus (C. javanus), Kiffer of sediment contaminated with an insecticide (chlorpyrifos).MethodsA wide range of biological responses to the tropical chironomid exposed were measured, including survival, growth rate and Acetylcholinesterase (AChE) activity.ResultsThe measured median lethal concentration (96 h LC<sub>50</sub>) of chlorpyrifos to C. javanus was 0.056 (95% CI 0.024-0.124) μg/kg. For sub-chronic levels of chlorpyrifos between 0.001 and 0.25 μg/kg administered for 10 days, the effects on the growth of C. javanus were reduced (larva size, head structure width and dry weight) at the significance level (P < 0.01) and the effects were concentration dependent. Following exposure to chlorpyrifos at the level of 0.001 μg/kg for 48 and 96 h, the AChE activity in C. javanus was inhibited compared with control samples (P < 0.05).ConclusionsThis study demonstrated that C. javanus was sensitive when exposed to chlorpyrifos. This species could serve as a potential biomarker for assessing pesticide contamination at low environmental persistence and provides limited effects data on the sensitivity of tropical biota to contaminants for ecological risk assessment of organophosphate pesticides in the tropical aquatic ecosystem.
基金Supported by NSFC (No. 30270278, 39430101 and 3960019)
文摘Starvation metabolism is one of the important parts of respiration for normal activities of chironomids. During April 1996 to March 1997, the relationships of starvation metabolism and temperature, body weight of two common chironomids in Biandantang Lake were carefully investigated. The results showed relationship between starvation metabolism （R, mgO2/ind.d） and body weight （Ww, mg wet wt） was： Chironomus plumosus, 1gR=-2.573＋1.0211gWw （5℃）, 1gR=-2.710＋1.3541gWw （10℃）, 1gR= -1.824＋0.8231gWw （15℃）, 1gR=-1.364＋0.4421gWw （20℃）, 1gR=-2.763＋1.5171gWw （25℃）; and Tokunagayusurika akamusi, 1gR=-2.390＋0.7521gWw （5℃）, 1gR=-1.978＋0.7101gWw （10℃）, 1gR=-1.676＋ 0.6481gWw （15℃）, 1gR=-1.517＋0.6501gWw （20℃）, 1gR=-2.434＋1.2901gWw （25℃）. Relationship of starvation metabolism and temperature （T, ℃） was： C. plumosus, R = -0.051 ＋ 0.021T- 0.0006T^2 ; akamusi, R= -0.051 ＋ 0.021T- 0.0006T^2. The complex relationship of the three parameters was： C. plumosus, R=0.0098Ww^0.3882e^0.1068T; T. akamusi, R=0.0012Ww^1.1936e^0.0711r. With the above regressions, the estimated annual starvation metabolisms of the two chironomid species in Biandantang Lake were： C. plumosus, 24.2791 kJ/m^2.a; T. akamusi, 8.7864 kJ/m^2.a, respectively. This provides a firm foundation for the comparative study of bioenergetics of the chironomids.
基金Under the auspices of Knowledge Innovation Program of Chinese Academy of Sciences (No. KZCX1-SW-12-I)Pre-research Project of Major Basic Program of Ministry of Science and Technology (No. 2004CCA02900)
文摘To study the influence of human activity on natural lake, chironomid fauna change in the 700-560cm lake sediment in Quidenham Mere of England associated with chironomid inferred TP presented that the lake experienced a whole eutrophication process due to human hemp-retting in Post-Medieval based on the history record and pollen analysis, which was confirmed by mollusc and ostracod analysis. However, the response of chironomid and mollusc to retting was the strongest with ostracod a little behind. It proved that cultural eutrophication existed in history and could be recovered by itself despite of some long-term unachievahle destroy. And it was most important for external nutrient to be cut off during lake restoration even in ancient times.
基金supported by the National Natural Science Foundation of China(NSFC)(31460572,31101624)the Natural Science Foundation of Education Bureau of Hubei Province,China(B2016102)+1 种基金the Fourth Open Foundation of Key Laboratory of Biological Resources Protection and Utilization of Hubei Province(PKLHB1305,PKLHB1326)the First Level Disciplines of Forestry of Hubei University for Nationalities
文摘Two holotypes of the orthoclad genus Nanocladius from Japan were redescribed and illustrated:Nanocladius(Plecopteracoluthus) asiaticus Hayashi and Nanocladius(Nanocladius) tamabicolor Sasa.A key to the males of Nanocladius from the East Asia was provided.
