Xu Sun, P. C. Mwagona, I. E. Shabani, Wen-jie Hou, Xiaoyu Li, F. Zhao, Qing Chen, Yuxi Zhao, Di Liu, Xingchun Li, Chengxue Ma, Hongxian Yu
The present study was carried out in the biggest tributary of Ussuri River of boundary between China and Russia. The Muling River basin has undergone a long-term dredging works, and waterbody became seriously turbid. The succession of phytoplankton functional groups succession and environmental factors in the river were sampled in 2015. We totally identified 83 species, belonging to 17 functional groups which 5 were predominant, including group F, M, MP, P and Y. The seasonal succession of phytoplankton functional groups was M/P-F/MP/P-MP/P. Results of Spearman correlation analysis and canonical correspondence analysis (CCA) revealed that phytoplankton functional groups were mainly influenced by nutrient concentrations and light availability including total nitrogen (TN), ammonium nitrogen (NH4+–N), nitrate nitrogen (NO3−–N), N:P ratio (N:P), water depth (D) and transparency (SD) in the basin.
{"title":"Phytoplankton functional groups response to environmental parameters in Muling River basin of northeast China","authors":"Xu Sun, P. C. Mwagona, I. E. Shabani, Wen-jie Hou, Xiaoyu Li, F. Zhao, Qing Chen, Yuxi Zhao, Di Liu, Xingchun Li, Chengxue Ma, Hongxian Yu","doi":"10.1051/limn/2019014","DOIUrl":"https://doi.org/10.1051/limn/2019014","url":null,"abstract":"The present study was carried out in the biggest tributary of Ussuri River of boundary between China and Russia. The Muling River basin has undergone a long-term dredging works, and waterbody became seriously turbid. The succession of phytoplankton functional groups succession and environmental factors in the river were sampled in 2015. We totally identified 83 species, belonging to 17 functional groups which 5 were predominant, including group F, M, MP, P and Y. The seasonal succession of phytoplankton functional groups was M/P-F/MP/P-MP/P. Results of Spearman correlation analysis and canonical correspondence analysis (CCA) revealed that phytoplankton functional groups were mainly influenced by nutrient concentrations and light availability including total nitrogen (TN), ammonium nitrogen (NH4+–N), nitrate nitrogen (NO3−–N), N:P ratio (N:P), water depth (D) and transparency (SD) in the basin.","PeriodicalId":7903,"journal":{"name":"Annales De Limnologie-international Journal of Limnology","volume":"10 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87724429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Khaoula Ayati, Ramzi Hadjab, Hichem Khammar, S. Dhaouadi, C. Piscart, E. Mahmoudi
Northern Africa, although one of the world hotpots of biodiversity, is poorly studied and the freshwater fauna living in this part of the world remains partly unknown. This study focused on the diversity and distribution of the poorly known epigean freshwater amphipods. We performed an exhaustive analysis of the literature on this group of crustaceans and sampled 106 additional localities from the eastern part of Algeria and in Tunisia. Our results showed an important diversity with 25 species (including the presence of at least three new undescribed species) and a very high rate of endemism with 52% of species occurring at on only 1 or 2 sites. We also highlighted a very low diversity on each site with only 4.4% of sites harboring more than 1 species. The comparative distribution of certain species between Europe and Maghreb and also between the western and eastern part of Northern Africa allow us to discuss some hypotheses about the factors underlying this endemism and the biogeographical origin of species. However, our study revealed a general lack of knowledge in the region, especially in the South of Morocco and Algeria. Hence, more information would be needed to propose adapted conservation strategies of freshwater fauna in Maghreb.
{"title":"Origin, diversity and distribution of freshwater epigean amphipods in Maghreb","authors":"Khaoula Ayati, Ramzi Hadjab, Hichem Khammar, S. Dhaouadi, C. Piscart, E. Mahmoudi","doi":"10.1051/LIMN/2019012","DOIUrl":"https://doi.org/10.1051/LIMN/2019012","url":null,"abstract":"Northern Africa, although one of the world hotpots of biodiversity, is poorly studied and the freshwater fauna living in this part of the world remains partly unknown. This study focused on the diversity and distribution of the poorly known epigean freshwater amphipods. We performed an exhaustive analysis of the literature on this group of crustaceans and sampled 106 additional localities from the eastern part of Algeria and in Tunisia. Our results showed an important diversity with 25 species (including the presence of at least three new undescribed species) and a very high rate of endemism with 52% of species occurring at on only 1 or 2 sites. We also highlighted a very low diversity on each site with only 4.4% of sites harboring more than 1 species. The comparative distribution of certain species between Europe and Maghreb and also between the western and eastern part of Northern Africa allow us to discuss some hypotheses about the factors underlying this endemism and the biogeographical origin of species. However, our study revealed a general lack of knowledge in the region, especially in the South of Morocco and Algeria. Hence, more information would be needed to propose adapted conservation strategies of freshwater fauna in Maghreb.","PeriodicalId":7903,"journal":{"name":"Annales De Limnologie-international Journal of Limnology","volume":"63 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79229217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wenzhi Wei, Hang Zhuang, Yingying Zhang, Liufu Wang
The relationship between crustacean zooplankton community and environmental factors remains a hot topic in eutrophication bio-monitoring subject. Most water bodies in the Yangtze River delta are mesotrophic/eutrophic, which has attracted much attention from ecologists. Nevertheless, previous studies on crustacean zooplankton community in this region only focused on their relation to physicochemical factors excluding phytoplankton. In this study, the crustacean zooplankton abundance and environmental factors (physicochemical factors and phytoplankton abundance) were investigated in Spring, Summer, Autumn and Winter in 13 waterbodies (8 lakes and 5 reservoirs) located in the Yangtze River delta. Results showed that NO2−–N and TN in Spring, SD and TP in Summer had significant difference (P < 0.05) between 8 lakes and 5 reservoirs. That may be related to microbial communities and macrophytes. All 13 studied water bodies were dominated by cyanophyta, whose Microcystis may determine the dominance of Bosmina fatalis. Moreover, eutrophic level should be in relation to the significant difference of plankton between 8 lakes and 5 reservoirs. Finally, five factors (cyanophyta, SD, WT, pH and DO) were significantly correlated with crustacean zooplankton abundance. That indicated the metabolism, reproduction, development and competitors of crustacean zooplankton were affected by these five factors. This research provided basic data of the 13 water bodies and studied the relationship between zooplankton and physicochemical factors as well as phytoplankton, providing scientific basis for the monitoring of eutrophic waterbodies located in the Yangtze river delta.
{"title":"Crustacean zooplankton community in relation to physicochemical factors and phytoplankton of 13 waterbodies located in the Yangtze River delta","authors":"Wenzhi Wei, Hang Zhuang, Yingying Zhang, Liufu Wang","doi":"10.1051/LIMN/2019016","DOIUrl":"https://doi.org/10.1051/LIMN/2019016","url":null,"abstract":"The relationship between crustacean zooplankton community and environmental factors remains a hot topic in eutrophication bio-monitoring subject. Most water bodies in the Yangtze River delta are mesotrophic/eutrophic, which has attracted much attention from ecologists. Nevertheless, previous studies on crustacean zooplankton community in this region only focused on their relation to physicochemical factors excluding phytoplankton. In this study, the crustacean zooplankton abundance and environmental factors (physicochemical factors and phytoplankton abundance) were investigated in Spring, Summer, Autumn and Winter in 13 waterbodies (8 lakes and 5 reservoirs) located in the Yangtze River delta. Results showed that NO2−–N and TN in Spring, SD and TP in Summer had significant difference (P < 0.05) between 8 lakes and 5 reservoirs. That may be related to microbial communities and macrophytes. All 13 studied water bodies were dominated by cyanophyta, whose Microcystis may determine the dominance of Bosmina fatalis. Moreover, eutrophic level should be in relation to the significant difference of plankton between 8 lakes and 5 reservoirs. Finally, five factors (cyanophyta, SD, WT, pH and DO) were significantly correlated with crustacean zooplankton abundance. That indicated the metabolism, reproduction, development and competitors of crustacean zooplankton were affected by these five factors. This research provided basic data of the 13 water bodies and studied the relationship between zooplankton and physicochemical factors as well as phytoplankton, providing scientific basis for the monitoring of eutrophic waterbodies located in the Yangtze river delta.","PeriodicalId":7903,"journal":{"name":"Annales De Limnologie-international Journal of Limnology","volume":"2 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74040216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
There is no place on Earth where plastic debris could not be found. Impacts of plastics on aesthetics, biota and ecosystems are dependent on how long plastic items last, and what degradation products are released, in recipient environments. As bio-based plastics tend to replace petroleum-based plastics in everyday life, it is important to upgrade knowledge on the degradation of new polymers in natural environments. Single-use plastic carrier bags are nowadays made of bio-plastics certified as biodegradable and compostable. It is unclear, however, whether claims of biodegradability and compostability can be taken as evidence of rapid degradation of plastic bags outside recycling/composting facilities. This study sought to provide quantified information about the degradation of compostable plastic carrier bags in streams and riparian zones. We found that plastic samples enclosed in different types of mesh bags lost weight at extremely slow rates, albeit significant when submerged in a stream. 95% of initial plastic mass remained after 77 days spent in water whereas alder leaf litter allowed to decompose under the same condition had completely disappeared before the end of the study. Determination of respiration rate and invertebrate abundance in plastic samples showed a greater decomposer activity in the stream than in the riparian environment. However, biotically-mediated degradation by decomposers was probably overridden by dissolution processes in mediating plastic mass loss. Our findings suggest that mismanaged plastic carrier bags could impact recipient ecosystems even when they are claimed as biodegradable or compostable.
{"title":"Slow degradation of compostable plastic carrier bags in a stream and its riparian area","authors":"Maxime Artru, A. Lecerf","doi":"10.1051/limn/2019017","DOIUrl":"https://doi.org/10.1051/limn/2019017","url":null,"abstract":"There is no place on Earth where plastic debris could not be found. Impacts of plastics on aesthetics, biota and ecosystems are dependent on how long plastic items last, and what degradation products are released, in recipient environments. As bio-based plastics tend to replace petroleum-based plastics in everyday life, it is important to upgrade knowledge on the degradation of new polymers in natural environments. Single-use plastic carrier bags are nowadays made of bio-plastics certified as biodegradable and compostable. It is unclear, however, whether claims of biodegradability and compostability can be taken as evidence of rapid degradation of plastic bags outside recycling/composting facilities. This study sought to provide quantified information about the degradation of compostable plastic carrier bags in streams and riparian zones. We found that plastic samples enclosed in different types of mesh bags lost weight at extremely slow rates, albeit significant when submerged in a stream. 95% of initial plastic mass remained after 77 days spent in water whereas alder leaf litter allowed to decompose under the same condition had completely disappeared before the end of the study. Determination of respiration rate and invertebrate abundance in plastic samples showed a greater decomposer activity in the stream than in the riparian environment. However, biotically-mediated degradation by decomposers was probably overridden by dissolution processes in mediating plastic mass loss. Our findings suggest that mismanaged plastic carrier bags could impact recipient ecosystems even when they are claimed as biodegradable or compostable.","PeriodicalId":7903,"journal":{"name":"Annales De Limnologie-international Journal of Limnology","volume":"86 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89346809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Global climatic changes and local disturbances may alter composition and distribution of spring invertebrates in mountains. In this study, we compared the effects of elevation, landscape and local characteristics on spring biodiversity. At 16 springs (from 570 to 1650 m a.s.l.) in The Chartreuse Range (French Alps) benthic, vegetation, and interstitial habitats were sampled in summer for aquatic invertebrate assemblage structure (abundances, richness, reproduction and dispersal traits, functional feeding groups). Assemblages were related to geographic location (elevation), landscape characteristics and local variables. Elevation was the major driver of the fauna: taxonomic richness and the percentage of scrapers decreased with elevation, while the proportion of predators and species with an asexual reproduction increased with elevation. The landscape characteristics around the spring had a weak influence on the benthic taxonomic richness which increased with the percentage of forest and decreased with the proportion of grassland. Finally, the habitat characteristics had no effect on taxonomic richness, but partially control the abundances of benthic assemblages and sediment-feeder organisms that both decreased with increasing sediment grain size. Current and future changes in the temperature patterns would affect alpine spring fauna, but disturbance of the local characteristics of springs must not be neglected.
{"title":"Relative effects of elevational and habitat constraints on alpine spring biodiversity","authors":"C. Claret, P. Marmonier","doi":"10.1051/limn/2019021","DOIUrl":"https://doi.org/10.1051/limn/2019021","url":null,"abstract":"Global climatic changes and local disturbances may alter composition and distribution of spring invertebrates in mountains. In this study, we compared the effects of elevation, landscape and local characteristics on spring biodiversity. At 16 springs (from 570 to 1650 m a.s.l.) in The Chartreuse Range (French Alps) benthic, vegetation, and interstitial habitats were sampled in summer for aquatic invertebrate assemblage structure (abundances, richness, reproduction and dispersal traits, functional feeding groups). Assemblages were related to geographic location (elevation), landscape characteristics and local variables. Elevation was the major driver of the fauna: taxonomic richness and the percentage of scrapers decreased with elevation, while the proportion of predators and species with an asexual reproduction increased with elevation. The landscape characteristics around the spring had a weak influence on the benthic taxonomic richness which increased with the percentage of forest and decreased with the proportion of grassland. Finally, the habitat characteristics had no effect on taxonomic richness, but partially control the abundances of benthic assemblages and sediment-feeder organisms that both decreased with increasing sediment grain size. Current and future changes in the temperature patterns would affect alpine spring fauna, but disturbance of the local characteristics of springs must not be neglected.","PeriodicalId":7903,"journal":{"name":"Annales De Limnologie-international Journal of Limnology","volume":"129 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83030880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
O. Chamsi, E. Pinelli, Bruno Faucon, Annie Perrault, L. Lacroix, J. Sánchez-Pérez, J. Charcosset
Freshwater microalgae are primary producers and cosmopolitan species subjected to the effects of herbicides. In this work, the in vitro algal growth inhibitory effects of 11 agrochemicals (9 herbicides, 1 metabolite, and 1 safener) were quantified. Chemical compounds were applied singly and in specific mixtures. Three species were used in axenic condition: the green alga Desmodesmus subspicatus (Chodat), the diatoms Nitzschia palea (Kützing) W. Smith and Navicula pelliculosa (Kützing) Hilse. When exposed to single compounds, N. palea and N. pelliculosa were only sensitive to atrazine/desethylatrazine and the safener benoxacor (BE), respectively. D. subspicatus was equally sensitive to four herbicides including atrazine and its metabolite and significantly more sensitive to iodosulfuron-methyl-sodium (IODO). The mixture of these five compounds induced a significantly higher growth inhibition of about 1.5-fold than IODO alone, which could be attributed to the four other herbicides. The mixture of all compounds was twofold less toxic than IODO on D. subspicatus. A halogen atom is present in IODO as in the herbicides to which the safener BE − known to induce glutathione-S-transferases − is associated in agrochemical preparations. We then showed that IODO was less toxic when combined with non-toxic concentrations of BE. These results indicated that the toxicity of the most active herbicide studied was decreased by a non-herbicide compound present in agrochemical formulations of other herbicides. These results suggest the importance to take into account the chemistry and the mechanisms of action for each compound in a risk assessment approach of a complex mixture.
淡水微藻是受除草剂影响的初级生产者和世界性物种。本研究对11种农药(9种除草剂、1种代谢物和1种安全剂)的体外抑藻效果进行了定量研究。化合物可以单独使用，也可以混合使用。在无性条件下选用3种:绿藻Desmodesmus subspicatus (Chodat)，硅藻Nitzschia palea (k tzing) W. Smith和Navicula pelliculosa (k tzing) Hilse。当暴露于单一化合物时，古孢螨和褐皮孢螨分别仅对阿特拉津/去乙基拉津和安全剂苯氧苄啶敏感。对阿特拉津及其代谢物等4种除草剂均敏感，对碘磺隆-甲基钠(IODO)敏感。这五种化合物的混合对生长的抑制作用明显高于单独使用碘化碘的1.5倍，这可能是其他四种除草剂的作用。所有化合物的混合物对细纹田鼠的毒性均比碘化多(IODO)低2倍。碘碘中存在卤素原子，就像农药制剂中与安全剂BE(已知能诱导谷胱甘肽- s -转移酶)相关的除草剂一样。然后我们发现，当与无毒浓度的BE结合使用时，IODO的毒性较低。这些结果表明，所研究的最有效除草剂的毒性被其他除草剂的农化配方中存在的非除草剂化合物所降低。这些结果表明，在复杂混合物的风险评估方法中，考虑每种化合物的化学和作用机制的重要性。
{"title":"Effects of herbicide mixtures on freshwater microalgae with the potential effect of a safener","authors":"O. Chamsi, E. Pinelli, Bruno Faucon, Annie Perrault, L. Lacroix, J. Sánchez-Pérez, J. Charcosset","doi":"10.1051/LIMN/2019002","DOIUrl":"https://doi.org/10.1051/LIMN/2019002","url":null,"abstract":"Freshwater microalgae are primary producers and cosmopolitan species subjected to the effects of herbicides. In this work, the in vitro algal growth inhibitory effects of 11 agrochemicals (9 herbicides, 1 metabolite, and 1 safener) were quantified. Chemical compounds were applied singly and in specific mixtures. Three species were used in axenic condition: the green alga Desmodesmus subspicatus (Chodat), the diatoms Nitzschia palea (Kützing) W. Smith and Navicula pelliculosa (Kützing) Hilse. When exposed to single compounds, N. palea and N. pelliculosa were only sensitive to atrazine/desethylatrazine and the safener benoxacor (BE), respectively. D. subspicatus was equally sensitive to four herbicides including atrazine and its metabolite and significantly more sensitive to iodosulfuron-methyl-sodium (IODO). The mixture of these five compounds induced a significantly higher growth inhibition of about 1.5-fold than IODO alone, which could be attributed to the four other herbicides. The mixture of all compounds was twofold less toxic than IODO on D. subspicatus. A halogen atom is present in IODO as in the herbicides to which the safener BE − known to induce glutathione-S-transferases − is associated in agrochemical preparations. We then showed that IODO was less toxic when combined with non-toxic concentrations of BE. These results indicated that the toxicity of the most active herbicide studied was decreased by a non-herbicide compound present in agrochemical formulations of other herbicides. These results suggest the importance to take into account the chemistry and the mechanisms of action for each compound in a risk assessment approach of a complex mixture.","PeriodicalId":7903,"journal":{"name":"Annales De Limnologie-international Journal of Limnology","volume":"47 3 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87688651","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chunni Zhong, Guijun Yang, Boqiang Qin, S. Wilhelm, Liu Yu, Han Lihua, Rui Zheng, Hongwei Yang, Zhang Zhou
Mixing is an integral environmental factor that affects lake ecosystems. For the cyanobacterium Microcystis, colony size is important with respects to migration velocity, how cells respond to grazing pressure, light attenuation, nutrient uptake and growth. To understand how mixing shapes colony size and the growth of Microcystis, we measured the effects of different current velocities (0, 0.16, 0.32, 0.64, and 1.28 m s−1) on M. aeruginosa in Lake Taihu. After 24 h of continuous mixing, the mean colony sizes of M. aeruginosa in the controls, 0.16, 0.32, 0.64, and 1.28 m s−1 groups were 23.6, 50.1, 92.9, 67.8, and 37.3 μm, respectively. Colony sizes of M. aeruginosa in all treatment groups were significantly larger than those in controls. As well, the concentration of soluble extracellular polysaccharide and bound extracellular polysaccharides of M. aeruginosa in all treatment groups were significantly higher than those in controls. Except for the highest level of mixing (1.28 m s−1), the growth rate of M. aeruginosa was significantly higher than that in controls. This study suggested that mixing intensity over short time periods can significantly influence colony size and the growth of M. aeruginosa.
混合是影响湖泊生态系统的重要环境因子。对于微囊蓝藻来说，菌落大小对于迁移速度、细胞对放牧压力、光衰减、营养吸收和生长的反应是重要的。为了了解混合如何影响微囊藻的菌落大小和生长，我们测量了不同流速(0、0.16、0.32、0.64和1.28 m s - 1)对太湖铜绿假单胞菌的影响。连续搅拌24 h后，对照组、0.16、0.32、0.64和1.28 m s−1组铜绿假单胞菌平均菌落大小分别为23.6、50.1、92.9、67.8和37.3 μm。各处理组铜绿假单胞菌菌落大小均显著大于对照组。各处理组铜绿假单胞菌的可溶性胞外多糖和结合胞外多糖浓度均显著高于对照组。除最高混合水平(1.28 m s−1)外，铜绿假单胞菌的生长速度显著高于对照。本研究表明，短时间的混合强度可以显著影响菌落大小和铜绿假单胞菌的生长。
{"title":"Effects of mixing intensity on colony size and growth of Microcystis aeruginosa","authors":"Chunni Zhong, Guijun Yang, Boqiang Qin, S. Wilhelm, Liu Yu, Han Lihua, Rui Zheng, Hongwei Yang, Zhang Zhou","doi":"10.1051/LIMN/2019011","DOIUrl":"https://doi.org/10.1051/LIMN/2019011","url":null,"abstract":"Mixing is an integral environmental factor that affects lake ecosystems. For the cyanobacterium Microcystis, colony size is important with respects to migration velocity, how cells respond to grazing pressure, light attenuation, nutrient uptake and growth. To understand how mixing shapes colony size and the growth of Microcystis, we measured the effects of different current velocities (0, 0.16, 0.32, 0.64, and 1.28 m s−1) on M. aeruginosa in Lake Taihu. After 24 h of continuous mixing, the mean colony sizes of M. aeruginosa in the controls, 0.16, 0.32, 0.64, and 1.28 m s−1 groups were 23.6, 50.1, 92.9, 67.8, and 37.3 μm, respectively. Colony sizes of M. aeruginosa in all treatment groups were significantly larger than those in controls. As well, the concentration of soluble extracellular polysaccharide and bound extracellular polysaccharides of M. aeruginosa in all treatment groups were significantly higher than those in controls. Except for the highest level of mixing (1.28 m s−1), the growth rate of M. aeruginosa was significantly higher than that in controls. This study suggested that mixing intensity over short time periods can significantly influence colony size and the growth of M. aeruginosa.","PeriodicalId":7903,"journal":{"name":"Annales De Limnologie-international Journal of Limnology","volume":"9 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81090022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The allelopathically inhibitory effects of submerged macrophytes on phytoplankton have been extensively studied and are utilised as an effective strategy for water restoration. However, this technique has been minimally implemented in natural in situ water bodies because of the unclear and complex interactions involved. Our study considered the uneven density distribution of algae in natural aquatic ecosystems and the biomass-dependent effects of submerged macrophytes on target algae. Ceratophyllum demersum methanol extracts of gradient concentration on Chlorella vulgaris with different initial algal density were conducted in the present laboratory study. Results indicated that methanol extracts of C. demersum could not only inhibit the growth of but also promote colony formation of C. vulgaris. C. vulgaris of a low density exerted increased inhibition and colony proportion responses to C. demersum extracts. By 0.42 g/mL C. demersum treatment, the inhibition rate on C. vulgaris under 0.02 IAD (Initial Alagal Density) and 0.05 IAD (p < 0.05) was 88.7%, 70.9%, respectively. We also suggested that the effects of C. demersum were biomass dependent, such that extracts with high concentration could produce increased inhibitory effects on C. vulgaris. According to GC-MS analysis, the study revealed five potential compounds (i.e. hexanoic, acetoacetic, azelaic, palmitic and stearic acid) in the C. demersum methanol extracts. However, the individual or combined effects of those compounds require further exploration. This study proposed certain theoretical basis for future water restoration by submerged macrophytes, that the biomass of the macrophytes and the density of the algae should both be taken into account.
{"title":"Growth and morphological responses of Chlorella vulgaris at different initial algal densities to treatment with Ceratophyllum demersum methanol extracts","authors":"Jing Dong, Mengyang Chang, Chenlu Li, Dujuan Dai","doi":"10.1051/LIMN/2019015","DOIUrl":"https://doi.org/10.1051/LIMN/2019015","url":null,"abstract":"The allelopathically inhibitory effects of submerged macrophytes on phytoplankton have been extensively studied and are utilised as an effective strategy for water restoration. However, this technique has been minimally implemented in natural in situ water bodies because of the unclear and complex interactions involved. Our study considered the uneven density distribution of algae in natural aquatic ecosystems and the biomass-dependent effects of submerged macrophytes on target algae. Ceratophyllum demersum methanol extracts of gradient concentration on Chlorella vulgaris with different initial algal density were conducted in the present laboratory study. Results indicated that methanol extracts of C. demersum could not only inhibit the growth of but also promote colony formation of C. vulgaris. C. vulgaris of a low density exerted increased inhibition and colony proportion responses to C. demersum extracts. By 0.42 g/mL C. demersum treatment, the inhibition rate on C. vulgaris under 0.02 IAD (Initial Alagal Density) and 0.05 IAD (p < 0.05) was 88.7%, 70.9%, respectively. We also suggested that the effects of C. demersum were biomass dependent, such that extracts with high concentration could produce increased inhibitory effects on C. vulgaris. According to GC-MS analysis, the study revealed five potential compounds (i.e. hexanoic, acetoacetic, azelaic, palmitic and stearic acid) in the C. demersum methanol extracts. However, the individual or combined effects of those compounds require further exploration. This study proposed certain theoretical basis for future water restoration by submerged macrophytes, that the biomass of the macrophytes and the density of the algae should both be taken into account.","PeriodicalId":7903,"journal":{"name":"Annales De Limnologie-international Journal of Limnology","volume":"46 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80348654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Danek, J. Musil, Petr Vlašánek, J. Svobodová, Tereza Barteková, David Štrunc, Miroslav Barankiewicz, E. Bouše, E. Svobodová, S. Johnsen, Oddgeir Andersen
This article reports on the results of the first radiotelemetric field study comparing the movement patterns of juvenile and adult noble crayfish (Astacus astacus) over the 24-h cycle. During our study (in summer, outside the reproduction period), juveniles moved over significantly longer distances than adults; upstream movements prevailed in both groups. The longest distance covered by an individual crayfish during a three-hour interval was 110 m (in the upstream direction). Adults moved most frequently at dusk and least frequently during daytime. Among juveniles, the likelihood of movement did not significantly differ between the times of day; however, distances covered by juveniles were the longest at night and significantly shorter during daytime and at dusk. Juveniles and adults exhibited very similar local activity (motion within a single place) with high values at night and low values during daytime.
{"title":"Movement patterns of juvenile and adult noble crayfish (Astacus astacus) in a small stream, determined by radiotelemetry","authors":"T. Danek, J. Musil, Petr Vlašánek, J. Svobodová, Tereza Barteková, David Štrunc, Miroslav Barankiewicz, E. Bouše, E. Svobodová, S. Johnsen, Oddgeir Andersen","doi":"10.1051/limn/2019018","DOIUrl":"https://doi.org/10.1051/limn/2019018","url":null,"abstract":"This article reports on the results of the first radiotelemetric field study comparing the movement patterns of juvenile and adult noble crayfish (Astacus astacus) over the 24-h cycle. During our study (in summer, outside the reproduction period), juveniles moved over significantly longer distances than adults; upstream movements prevailed in both groups. The longest distance covered by an individual crayfish during a three-hour interval was 110 m (in the upstream direction). Adults moved most frequently at dusk and least frequently during daytime. Among juveniles, the likelihood of movement did not significantly differ between the times of day; however, distances covered by juveniles were the longest at night and significantly shorter during daytime and at dusk. Juveniles and adults exhibited very similar local activity (motion within a single place) with high values at night and low values during daytime.","PeriodicalId":7903,"journal":{"name":"Annales De Limnologie-international Journal of Limnology","volume":"12 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84964069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Intensive interspecific competition for limited resource often can result in the exclusion of inferior competitors, decrease the species diversity and alter the structure of the zooplankton community. Competitive experiments between Brachionus calyciflorus and Brachionus angularis were conducted at three Scenedesmus densities (0.5 × 106, 1.0 × 106 and 2.0 × 106 cells ml−1) and four initial inoculation densities (numerically, 100% B. calyciflorus, 75% B. calyciflorus and 25% B. angularis, 50% each of the two species, 25% B. calyciflorus and 75% B. angularis, and 100% B. angularis). The results showed that at the low food level, B. angularis outcompeted B. calyciflorus and vice versa at the high food levels. At the intermediate food level, B. angularis was displaced by B. calyciflorus at nearly all the initial inoculation densities except for 75% B. angularis, at which both species coexisted until the termination of the experiment. When grown alone at 0.5 × 106, 1.0 × 106 and 2.0 × 106 cells ml−1 of Scenedesmus, B. calyciflorus reached the peak abundance values of 34 ± 4, 69 ± 5 and 101 ± 9 individuals ml−1 and had population growth rates of 0.608 ± 0.032, 0.654 ± 0.033 and 0.518 ± 0.039 d−1, respectively. The corresponding values for B. angularis were 265 ± 8, 330 ± 30 and 802 ± 87 individuals ml−1 and 0.623 ± 0.020, 0.770 ± 0.036 and 0.871 ± 0.013 d−1. The results suggest that the outcome of competition depends not only on the size of the competing species and food availability but also on their colonizing density.
对有限资源的激烈的种间竞争往往会导致劣势竞争者的排斥，减少物种多样性并改变浮游动物群落结构。在3种场景蝇密度(0.5 × 106、1.0 × 106和2.0 × 106细胞ml - 1)和4种初始接种密度(数值上为100%花萼轮虫、75%花萼轮虫和25%角轮虫、两种各50%、25%花萼轮虫和75%角轮虫、100%角轮虫)下进行萼轮虫和角轮虫的竞争实验。结果表明:在低摄食水平下，角小蠊优于萼花小蠊;在高摄食水平下，角小蠊优于萼花小蠊;在中间食物水平上，除75%角小蠊与萼花小蠊共存外，角小蠊几乎在所有初始接种密度下都被萼花小蠊取代。在花萼草0.5 × 106、1.0 × 106和2.0 × 106 cells ml - 1条件下，花萼草的丰度峰值分别为34±4、69±5和101±9个个体ml - 1，种群生长率分别为0.608±0.032、0.654±0.033和0.518±0.039 d - 1。角棘球蚴的对应值分别为265±8、330±30和802±87个体ml - 1和0.623±0.020、0.770±0.036和0.871±0.013 d - 1。结果表明，竞争的结果不仅取决于竞争物种的大小和食物供应，还取决于它们的殖民密度。
{"title":"Competition between Brachionus calyciflorus and Brachionus angularis (Rotifera) in relation to algal food level and initial population density","authors":"Kun Zhang, Quan Wan, Y. Xi","doi":"10.1051/LIMN/2019001","DOIUrl":"https://doi.org/10.1051/LIMN/2019001","url":null,"abstract":"Intensive interspecific competition for limited resource often can result in the exclusion of inferior competitors, decrease the species diversity and alter the structure of the zooplankton community. Competitive experiments between Brachionus calyciflorus and Brachionus angularis were conducted at three Scenedesmus densities (0.5 × 106, 1.0 × 106 and 2.0 × 106 cells ml−1) and four initial inoculation densities (numerically, 100% B. calyciflorus, 75% B. calyciflorus and 25% B. angularis, 50% each of the two species, 25% B. calyciflorus and 75% B. angularis, and 100% B. angularis). The results showed that at the low food level, B. angularis outcompeted B. calyciflorus and vice versa at the high food levels. At the intermediate food level, B. angularis was displaced by B. calyciflorus at nearly all the initial inoculation densities except for 75% B. angularis, at which both species coexisted until the termination of the experiment. When grown alone at 0.5 × 106, 1.0 × 106 and 2.0 × 106 cells ml−1 of Scenedesmus, B. calyciflorus reached the peak abundance values of 34 ± 4, 69 ± 5 and 101 ± 9 individuals ml−1 and had population growth rates of 0.608 ± 0.032, 0.654 ± 0.033 and 0.518 ± 0.039 d−1, respectively. The corresponding values for B. angularis were 265 ± 8, 330 ± 30 and 802 ± 87 individuals ml−1 and 0.623 ± 0.020, 0.770 ± 0.036 and 0.871 ± 0.013 d−1. The results suggest that the outcome of competition depends not only on the size of the competing species and food availability but also on their colonizing density.","PeriodicalId":7903,"journal":{"name":"Annales De Limnologie-international Journal of Limnology","volume":"11 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87657062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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