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
A chironomid larvae images recognition method based on wavelet energy feature and improved KNN is developed. Wavelet decomposition and color information entropy are selected to construct vectors for KNN that is used t...A chironomid larvae images recognition method based on wavelet energy feature and improved KNN is developed. Wavelet decomposition and color information entropy are selected to construct vectors for KNN that is used to classify of the images. The distance function is modified according to the weight determined by the correlation degree between feature and class, which effectively improves classification accuracy. The result shows the mean accuracy of classification rate is up to 95.41% for freshwater plankton images, such as chironomid larvae, cyclops and harpacticoida.展开更多
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
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
A 1000-year high-resolution(～10 years) chironomid record from varved sediments of Sugan Lake,Qaidam Basin on the northern Tibetan Plateau,is presented.The chironomid assemblages are mainly composed of the relatively ...A 1000-year high-resolution(～10 years) chironomid record from varved sediments of Sugan Lake,Qaidam Basin on the northern Tibetan Plateau,is presented.The chironomid assemblages are mainly composed of the relatively high-saline-water taxa Psectrocladius barbimanus-type and Orthocladius/Cricotopus,and the relatively low-saline-water taxa Procladius and Psectrocladius sordidellus-type.Variations in the chironomid fauna and inferred salinities suggest that over the last millennium,the Sugan Lake catchment has alternated between contrasting climatic conditions,having a dry climate during the period 990―1550 AD,a relatively humid climate during the Little Ice Age(LIA)(1550―1840 AD),and a dry climate again from 1840 AD onwards.At the decadal to centennial scale,a wet event around 1200―1230 AD,interrupting the generally arid period(990―1550 AD),and a dry event around 1590―1700 AD,punctuating the generally humid period(1550―1840 AD),are clearly documented.Trends in the chironomid-based salinity time series indicate a highly unstable climate during the LIA when salinity fluctuations were of greater magnitude and higher frequency.The effective moisture evolution in the Sugan Lake catchment during the last millennium reconstructed by chironomid analysis is in broad agreement with previous palaeo-moisture data derived from other sites in arid Northwest China(ANC).The LIA,characterized by generally humid conditions over the west-erly-dominated ANC was distinctly different from that in monsoonal China,implying an "out-of-phase" relationship between moisture evolution in these two regions during the past 1000 years.展开更多
The results of an investigation into the relationship between surface sediment subfossil chi- ronomid distribution and water quality are presented. Data from 30 lakes in the middle and lower reaches of the Yangtze Riv...The results of an investigation into the relationship between surface sediment subfossil chi- ronomid distribution and water quality are presented. Data from 30 lakes in the middle and lower reaches of the Yangtze River indicate that the nutrient gradi- ent was the major factor affecting the distribution of chironomids across these sites. Canonical corre- spondence analysis (CCA) revealed that of 12 sum- mer water environmental variables, total Phosphorus was most important, accounting for 20.1% of the variance in the chironomid data. This was significant enough to allow the development of quantitative in- ference models. A TP inference model was devel- oped using weighted averaging (WA), partial least squares (PLS) and weighted averaging partial least squares (WA-PLS). An optimal two-component WA-PLS model provided a high jack-knifed coeffi- cient of prediction for conductivity r 2jack = 0.76, with a low root mean squared error of prediction (RMSEPjack = 0.13). Using this model it is possible to produce long-term quantitative records of past water quality for lacustrine sites across the middle and lower reaches of the Yangtze River, which has important implications for future lake management and eco- logical restoration.展开更多
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.
基金Supported by the National Natural Science Foundation of China(50778048)(60803096)the Natural Science Foundation of Hei-longjiang Province(E200812)China Postdoctoral ScienceFoundation Funded Project(20070420882)~~
文摘A chironomid larvae images recognition method based on wavelet energy feature and improved KNN is developed. Wavelet decomposition and color information entropy are selected to construct vectors for KNN that is used to classify of the images. The distance function is modified according to the weight determined by the correlation degree between feature and class, which effectively improves classification accuracy. The result shows the mean accuracy of classification rate is up to 95.41% for freshwater plankton images, such as chironomid larvae, cyclops and harpacticoida.
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Supported by the Fund for Creative Research Groups,National Natural Science Foundation of China (Grant No. 40721061)Research Fund for the Doctoral Program of Higher Education (Grant No. 20060730003)
文摘A 1000-year high-resolution(～10 years) chironomid record from varved sediments of Sugan Lake,Qaidam Basin on the northern Tibetan Plateau,is presented.The chironomid assemblages are mainly composed of the relatively high-saline-water taxa Psectrocladius barbimanus-type and Orthocladius/Cricotopus,and the relatively low-saline-water taxa Procladius and Psectrocladius sordidellus-type.Variations in the chironomid fauna and inferred salinities suggest that over the last millennium,the Sugan Lake catchment has alternated between contrasting climatic conditions,having a dry climate during the period 990―1550 AD,a relatively humid climate during the Little Ice Age(LIA)(1550―1840 AD),and a dry climate again from 1840 AD onwards.At the decadal to centennial scale,a wet event around 1200―1230 AD,interrupting the generally arid period(990―1550 AD),and a dry event around 1590―1700 AD,punctuating the generally humid period(1550―1840 AD),are clearly documented.Trends in the chironomid-based salinity time series indicate a highly unstable climate during the LIA when salinity fluctuations were of greater magnitude and higher frequency.The effective moisture evolution in the Sugan Lake catchment during the last millennium reconstructed by chironomid analysis is in broad agreement with previous palaeo-moisture data derived from other sites in arid Northwest China(ANC).The LIA,characterized by generally humid conditions over the west-erly-dominated ANC was distinctly different from that in monsoonal China,implying an "out-of-phase" relationship between moisture evolution in these two regions during the past 1000 years.
基金This study was supported by the National Natural Science Foundation of China （Grant No. 40402015） the State Key Basic Research and Development Plan of China （Grant No. 2004CB720205）the Knowledge Innovation Project of the CAS （Grant No. KZCX1-SW-12）.
文摘The results of an investigation into the relationship between surface sediment subfossil chi- ronomid distribution and water quality are presented. Data from 30 lakes in the middle and lower reaches of the Yangtze River indicate that the nutrient gradi- ent was the major factor affecting the distribution of chironomids across these sites. Canonical corre- spondence analysis (CCA) revealed that of 12 sum- mer water environmental variables, total Phosphorus was most important, accounting for 20.1% of the variance in the chironomid data. This was significant enough to allow the development of quantitative in- ference models. A TP inference model was devel- oped using weighted averaging (WA), partial least squares (PLS) and weighted averaging partial least squares (WA-PLS). An optimal two-component WA-PLS model provided a high jack-knifed coeffi- cient of prediction for conductivity r 2jack = 0.76, with a low root mean squared error of prediction (RMSEPjack = 0.13). Using this model it is possible to produce long-term quantitative records of past water quality for lacustrine sites across the middle and lower reaches of the Yangtze River, which has important implications for future lake management and eco- logical restoration.
