Tanja Maksimović, D. Hasanagić, Ivan Samelak, B. Kukavica
In this study, changes in Class III peroxidase (POX) and polyphenol oxidase (PPO) activity in Phragmites australis (Cav.) Trin. Ex Steud. Utricularia vulgaris L. and Salvinia natans (L.) from the Bardača wetland during one vegetation season (June-October) were monitored. The highest activities of soluble and ionic cell wall bound peroxidases (solPOX and ionPOX, respectively) were measured for Phragmites communis (leaf > root > rhizome), followed by Utricularia vulgaris (whole plant), then Salvinia natans (whole plant). The results showed that during the vegetation period (August-September) the activity of solPOX, ionPOX and PPO in Phragmites communis increased, but the activity decreased drastically in October. For Salvinia natans and Utricularia vulgaris, a different seasonal distribution was obtained in the PPO activity, i.e. with a maximum activity during July and a minimum one during September. Different seasonal trends in enzyme activities are probably the result of abiotic stress caused by changing physic-chemical environmental conditions and different adaptive capacities of the studied species to habitat conditions. Correlations between physicochemical environmental parameters and enzyme activities indicate the possibility of using POX and PPO activities as an important bioindicatos of environmental status.
{"title":"Class III peroxidase and polyphenol oxidase activities in aquatic macrophytes during vegetative period in Bardača a wetland","authors":"Tanja Maksimović, D. Hasanagić, Ivan Samelak, B. Kukavica","doi":"10.1051/limn/2022009","DOIUrl":"https://doi.org/10.1051/limn/2022009","url":null,"abstract":"In this study, changes in Class III peroxidase (POX) and polyphenol oxidase (PPO) activity in Phragmites australis (Cav.) Trin. Ex Steud. Utricularia vulgaris L. and Salvinia natans (L.) from the Bardača wetland during one vegetation season (June-October) were monitored. The highest activities of soluble and ionic cell wall bound peroxidases (solPOX and ionPOX, respectively) were measured for Phragmites communis (leaf > root > rhizome), followed by Utricularia vulgaris (whole plant), then Salvinia natans (whole plant). The results showed that during the vegetation period (August-September) the activity of solPOX, ionPOX and PPO in Phragmites communis increased, but the activity decreased drastically in October. For Salvinia natans and Utricularia vulgaris, a different seasonal distribution was obtained in the PPO activity, i.e. with a maximum activity during July and a minimum one during September. Different seasonal trends in enzyme activities are probably the result of abiotic stress caused by changing physic-chemical environmental conditions and different adaptive capacities of the studied species to habitat conditions. Correlations between physicochemical environmental parameters and enzyme activities indicate the possibility of using POX and PPO activities as an important bioindicatos of environmental status.","PeriodicalId":7903,"journal":{"name":"Annales De Limnologie-international Journal of Limnology","volume":"14 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81918065","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}
H. Fazli, Fatemeh Satadat Tahami, H. Nasrollahzadeh Saravi, Aboulghasem Roohi, Elif Eker-Develi, G. Daryanabard, F. Vahedi
Seasonal variations of phytoplankton abundance, species composition, and their interaction with environmental parameters were investigated in the Azad Dam Lake, in the West of Iran during 2015–2016. Sampling was conducted seasonally at five stations in the lake. Multivariate statistical analyses were carried out to define the abiotic variables influencing phytoplankton community composition. A total of 51 taxa of phytoplankton belonging to six phyla were identified. Bacillariophyta (diatoms) were most diverse with 22 taxa, comprised more than 90% of the total density. Despite the low Shannon–Wiener index (H ′) diversity (0.10–1.54), pointing out the dominant density of Bacillariophyta resulted in high water quality. Statistical analysis showed seasonal phytoplankton assemblages differences indicating a biogeographical gradient. Distance-based Linear Model (DisTLM) analysis displayed six environmental variables showing significant relationships with the phytoplankton abundance in the resemblance matrix (p < 0.05). Based on Akaike's information criterion (AIC), the combination of total phosphorus (TP), water temperature (WT), Secchi disc depth (SD), total nitrogen (TN), nitrite (NO2−), and dissolved oxygen (DO) by the DisTLM model elucidated 63.1% of the total variability. Since the dam is newly constructed and has not yet been exploited, and the factors caused by human activities that threaten the lake have not yet spread much, findings of the present study suggest Azad Dam Lake appears to have been not highly affected by anthropogenic activities up to now.
{"title":"The response of phytoplankton assemblages to environmental parameters in the Azad Dam Lake in the west of Iran","authors":"H. Fazli, Fatemeh Satadat Tahami, H. Nasrollahzadeh Saravi, Aboulghasem Roohi, Elif Eker-Develi, G. Daryanabard, F. Vahedi","doi":"10.1051/limn/2022014","DOIUrl":"https://doi.org/10.1051/limn/2022014","url":null,"abstract":"Seasonal variations of phytoplankton abundance, species composition, and their interaction with environmental parameters were investigated in the Azad Dam Lake, in the West of Iran during 2015–2016. Sampling was conducted seasonally at five stations in the lake. Multivariate statistical analyses were carried out to define the abiotic variables influencing phytoplankton community composition. A total of 51 taxa of phytoplankton belonging to six phyla were identified. Bacillariophyta (diatoms) were most diverse with 22 taxa, comprised more than 90% of the total density. Despite the low Shannon–Wiener index (H ′) diversity (0.10–1.54), pointing out the dominant density of Bacillariophyta resulted in high water quality. Statistical analysis showed seasonal phytoplankton assemblages differences indicating a biogeographical gradient. Distance-based Linear Model (DisTLM) analysis displayed six environmental variables showing significant relationships with the phytoplankton abundance in the resemblance matrix (p < 0.05). Based on Akaike's information criterion (AIC), the combination of total phosphorus (TP), water temperature (WT), Secchi disc depth (SD), total nitrogen (TN), nitrite (NO2−), and dissolved oxygen (DO) by the DisTLM model elucidated 63.1% of the total variability. Since the dam is newly constructed and has not yet been exploited, and the factors caused by human activities that threaten the lake have not yet spread much, findings of the present study suggest Azad Dam Lake appears to have been not highly affected by anthropogenic activities up to now.","PeriodicalId":7903,"journal":{"name":"Annales De Limnologie-international Journal of Limnology","volume":"44 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90739284","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}
Çağatay Çapraz, O. Külköylüoğlu, D. Akdemir, M. Yavuzatmaca
page 5, the caption of Table be: Tolerance (Tol) and optimum (Opt) values for the nine most common species against the variables measured from each sampling site. Abbreviations: Count (numbers of species occurrence), Max (maximum numbers of individuals), N2 (Hill ’ s coef fi cient or measure of effective number of occurrences), dissolved oxygen (DO, mg l-1), electrical conductivity (EC, mS cm-1), water temperature (Tw, °C), redox potential (ORP), elevation (Elev), sodium (Na 2+, ppm) in water, magnesium (Mg2+, ppm) in water, calcium (Ca2+, ppm) in water, fl uoride (F – , ppm) in water, chloride (Cl – , ppm) in water, total phosphate (T.PO43 – , ppm) in sediment.
{"title":"Erratum to: Determining effective environmental factors and ecology of non-marine Ostracoda (Crustacea) in Giresun, Turkey","authors":"Çağatay Çapraz, O. Külköylüoğlu, D. Akdemir, M. Yavuzatmaca","doi":"10.1051/limn/2022010","DOIUrl":"https://doi.org/10.1051/limn/2022010","url":null,"abstract":"page 5, the caption of Table be: Tolerance (Tol) and optimum (Opt) values for the nine most common species against the variables measured from each sampling site. Abbreviations: Count (numbers of species occurrence), Max (maximum numbers of individuals), N2 (Hill ’ s coef fi cient or measure of effective number of occurrences), dissolved oxygen (DO, mg l-1), electrical conductivity (EC, mS cm-1), water temperature (Tw, °C), redox potential (ORP), elevation (Elev), sodium (Na 2+, ppm) in water, magnesium (Mg2+, ppm) in water, calcium (Ca2+, ppm) in water, fl uoride (F – , ppm) in water, chloride (Cl – , ppm) in water, total phosphate (T.PO43 – , ppm) in sediment.","PeriodicalId":7903,"journal":{"name":"Annales De Limnologie-international Journal of Limnology","volume":"25 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78241538","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}
Unlike most saline lakes, the Chinese ones were formed in depressions entirely by runoff from the surrounding topography, hence greatly affected by seasons and variation in salinity, with microbial composition and functions being the most influenced. Determining the nature of key environmental drivers such as microbial dynamics is necessary. Therefore, the current study applied metagenomics study approach to determining the microbial community diversity and functions across sediment regimen (clay [NT], sandstone [FS] and salt-bearing [SY]) of the East Taijinar Salt Lake, China. The result indicated that members of Actinobacterium did not exhibit variability across the sediment types while members of Firmicutes and Proteobacteria showed some variabilities, and had highest dominance in clay (NT) and sandstone (FS) sediment type as compared to the salt-bearing (SY) sediment type. Based on UniFrac, STAMP analyses there was significant differences (P < 0.05), with the weighted-UniFrac approach indicating the highest abundance under the clay sediment type. According to NMDS analysis, there was closer similarity in microbial composition between the clays sediment type (NT) and sandstone (FS). Furthermore, through the cladogram, it was visualized that there was very low representation of bacterial species from the salt-bearing (SY) sediment type as compared to other sediment types. More COG and KEGG pathways were dominant under the clays (NT) sandstone (FS) sediment types as opposed to the salt-based (SY) sediment type. Based on this result, in-depth studies on spatial and temporal variability in microbial community diversity and eco-genomics functions across the sediments of the East Taijinar Salt Lake is recommended.
{"title":"Microbial community diversity and eco-genomics functions across sediment regimen of a saline lake","authors":"Chen Deng, O. Donde, Ze Qing Li","doi":"10.1051/limn/2022008","DOIUrl":"https://doi.org/10.1051/limn/2022008","url":null,"abstract":"Unlike most saline lakes, the Chinese ones were formed in depressions entirely by runoff from the surrounding topography, hence greatly affected by seasons and variation in salinity, with microbial composition and functions being the most influenced. Determining the nature of key environmental drivers such as microbial dynamics is necessary. Therefore, the current study applied metagenomics study approach to determining the microbial community diversity and functions across sediment regimen (clay [NT], sandstone [FS] and salt-bearing [SY]) of the East Taijinar Salt Lake, China. The result indicated that members of Actinobacterium did not exhibit variability across the sediment types while members of Firmicutes and Proteobacteria showed some variabilities, and had highest dominance in clay (NT) and sandstone (FS) sediment type as compared to the salt-bearing (SY) sediment type. Based on UniFrac, STAMP analyses there was significant differences (P < 0.05), with the weighted-UniFrac approach indicating the highest abundance under the clay sediment type. According to NMDS analysis, there was closer similarity in microbial composition between the clays sediment type (NT) and sandstone (FS). Furthermore, through the cladogram, it was visualized that there was very low representation of bacterial species from the salt-bearing (SY) sediment type as compared to other sediment types. More COG and KEGG pathways were dominant under the clays (NT) sandstone (FS) sediment types as opposed to the salt-based (SY) sediment type. Based on this result, in-depth studies on spatial and temporal variability in microbial community diversity and eco-genomics functions across the sediments of the East Taijinar Salt Lake is recommended.","PeriodicalId":7903,"journal":{"name":"Annales De Limnologie-international Journal of Limnology","volume":"20 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81328570","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}
J. Pereira da Silva, Aingeru Martínez, A. L. Gonçalves, F. Bärlocher, C. Canhoto
Freshwater salinization is a world-wide phenomenon threatening stream communities and ecosystem functioning. In these systems, litter decomposition is a main ecosystem-level process where fungi (aquatic hyphomycetes) play a central role linking basal resource and higher levels of food-web. The current study evaluated the impact of aquatic hyphomycete richness on leaf litter decomposition when subjected to salinization. In a microcosm study, we analysed leaf mass loss, fungal biomass, respiration and sporulation rate by fungal assemblages at three levels of species richness (1, 4, 8 species) and three levels of salinity (0, 8, 16 g NaCl L‑1). Mass loss and sporulation rate were depressed at 8 and 16 g NaCl L‑1, while fungal biomass and respiration were only negatively affected at 16 g L‑1. A richness effect was only observed on sporulation rates, with the maximum values found in assemblages of 4 species. In all cases, the negative effects of high levels of salinization on the four tested variables superimposed the potential buffer capacity of fungal richness. The study suggests functional redundancy among the fungal species even at elevated salt stress conditions which may guarantee stream functioning at extreme levels of salinity. Nonetheless, it also points to the possible importance of salt induced changes on fungal diversity and identity in salinized streams able to induce bottom-up effects in the food webs.
淡水盐碱化是威胁河流群落和生态系统功能的世界性现象。在这些系统中，凋落物分解是一个主要的生态系统水平过程，真菌(水生菌丝菌)在连接基础资源和更高水平的食物网中起着核心作用。本研究评估了盐渍化条件下水生菌丝丰富度对凋落叶分解的影响。在微观环境研究中，我们分析了3种物种丰富度水平(1、4、8种)和3种盐度水平(0、8、16 g NaCl L - 1)下真菌组合的叶片质量损失、真菌生物量、呼吸和产孢率。8和16 g NaCl L - 1抑制了质量损失和产孢率，而16 g NaCl L - 1仅对真菌生物量和呼吸产生负影响。丰度效应仅在产孢率上存在，在4种组合中达到最大值。在所有情况下，高水平盐碱化对四个测试变量的负面影响叠加了真菌丰富度的潜在缓冲能力。该研究表明，即使在高盐胁迫条件下，真菌物种之间的功能冗余也可能保证溪流在极端盐度水平下的功能。尽管如此，它也指出了盐引起的真菌多样性和特征变化的可能重要性，这些变化能够在食物网中引起自下而上的效应。
{"title":"Fungal richness does not buffer the effects of streams salinization on litter decomposition","authors":"J. Pereira da Silva, Aingeru Martínez, A. L. Gonçalves, F. Bärlocher, C. Canhoto","doi":"10.1051/LIMN/2021003","DOIUrl":"https://doi.org/10.1051/LIMN/2021003","url":null,"abstract":"Freshwater salinization is a world-wide phenomenon threatening stream communities and ecosystem functioning. In these systems, litter decomposition is a main ecosystem-level process where fungi (aquatic hyphomycetes) play a central role linking basal resource and higher levels of food-web. The current study evaluated the impact of aquatic hyphomycete richness on leaf litter decomposition when subjected to salinization. In a microcosm study, we analysed leaf mass loss, fungal biomass, respiration and sporulation rate by fungal assemblages at three levels of species richness (1, 4, 8 species) and three levels of salinity (0, 8, 16 g NaCl L‑1). Mass loss and sporulation rate were depressed at 8 and 16 g NaCl L‑1, while fungal biomass and respiration were only negatively affected at 16 g L‑1. A richness effect was only observed on sporulation rates, with the maximum values found in assemblages of 4 species. In all cases, the negative effects of high levels of salinization on the four tested variables superimposed the potential buffer capacity of fungal richness. The study suggests functional redundancy among the fungal species even at elevated salt stress conditions which may guarantee stream functioning at extreme levels of salinity. Nonetheless, it also points to the possible importance of salt induced changes on fungal diversity and identity in salinized streams able to induce bottom-up effects in the food webs.","PeriodicalId":7903,"journal":{"name":"Annales De Limnologie-international Journal of Limnology","volume":"6 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90179205","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}
It is widely known that pesticides generally do not show target specificity, and off-target species are strikingly affected by these chemicals. In the current work, histological changes in skeletal muscles of zebrafish (Danio rerio) caused by fonofos, an acetylcholinesterase (AChE) inhibitor organophosphate insecticide, were examined. Zebrafish were treated with 1 mg/L, 2 mg/L and 4 mg/L of fonofos for 96 hours. Skeletal muscle samples were removed from the pectoral region and embedded in paraffin. Sections were stained with Mayer's Hematoxylin and Eosin, Gomori's Trichrome and Periodic Acid Schiff techniques. Histopathological alterations were investigated by light microscopy. Fibrosis, intramyofibrillar vacuoles, disintegrated myofibrils, splitting of myofibers, atrophic and disappeared fibers, histoarchitectural loss, necrosis and progressive decrement in glycogen content were noted. Muscle fiber diameter measurements were also performed. Statistical analysis showed that measured fiber diameters of all fonofos exposed groups were significantly different from the control group, and they decreased in a concentration-dependent manner. These results suggested that fonofos caused significant myoarchitectural impairments in non-target freshwater zebrafish.
{"title":"Impact of acute fonofos exposure on skeletal muscle of zebrafish: Histopathological and biometric analyses","authors":"Sezgi Arman, S. I. Üçüncü","doi":"10.1051/limn/2021023","DOIUrl":"https://doi.org/10.1051/limn/2021023","url":null,"abstract":"It is widely known that pesticides generally do not show target specificity, and off-target species are strikingly affected by these chemicals. In the current work, histological changes in skeletal muscles of zebrafish (Danio rerio) caused by fonofos, an acetylcholinesterase (AChE) inhibitor organophosphate insecticide, were examined. Zebrafish were treated with 1 mg/L, 2 mg/L and 4 mg/L of fonofos for 96 hours. Skeletal muscle samples were removed from the pectoral region and embedded in paraffin. Sections were stained with Mayer's Hematoxylin and Eosin, Gomori's Trichrome and Periodic Acid Schiff techniques. Histopathological alterations were investigated by light microscopy. Fibrosis, intramyofibrillar vacuoles, disintegrated myofibrils, splitting of myofibers, atrophic and disappeared fibers, histoarchitectural loss, necrosis and progressive decrement in glycogen content were noted. Muscle fiber diameter measurements were also performed. Statistical analysis showed that measured fiber diameters of all fonofos exposed groups were significantly different from the control group, and they decreased in a concentration-dependent manner. These results suggested that fonofos caused significant myoarchitectural impairments in non-target freshwater zebrafish.","PeriodicalId":7903,"journal":{"name":"Annales De Limnologie-international Journal of Limnology","volume":"17 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76642604","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}
Triclosan (TCS) is a broad-spectrum antimicrobial agent found in personal care, household, veterinary, medical, and industrial products. TCS has been detected in soil, sediment, and surface water. In the current work, the effects of acute exposure to TCS on gill and liver tissues of zebrafish were evaluated. Adult zebrafish were treated with sublethal concentrations of TCS (34, 85, and 170 μg/L) for 120 h. Gill and liver samples were removed and embedded in paraffin for histopathological investigations. TCS induced aneurysm, capillary dilation, lamellar disorganization, hyperplasia, epithelial lifting, and desquamation in the gills. Liver specimens showed sinusoidal dilation, congestion, vacuolization, hepatocellular degeneration, and necrosis. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay was performed to observe the apoptotic effect of TCS. Accordingly, no apoptotic cells were detected in the specimens of 34 μg/L of TCS exposed gills, while the slides of 85 and 170 μg/L of TCS treated gills showed a high number of TUNEL-positive cells. In the liver, no TUNEL-positive cells were identified in 34 μg/L of TCS treated samples of zebrafish. 85 and 170 μg/L of TCS exposed livers showed few hepatic parenchymal cells undergoing apoptosis.
{"title":"Effects of acute triclosan exposure on gill and liver tissues of zebrafish (Danio rerio)","authors":"Sezgi Arman","doi":"10.1051/LIMN/2021004","DOIUrl":"https://doi.org/10.1051/LIMN/2021004","url":null,"abstract":"Triclosan (TCS) is a broad-spectrum antimicrobial agent found in personal care, household, veterinary, medical, and industrial products. TCS has been detected in soil, sediment, and surface water. In the current work, the effects of acute exposure to TCS on gill and liver tissues of zebrafish were evaluated. Adult zebrafish were treated with sublethal concentrations of TCS (34, 85, and 170 μg/L) for 120 h. Gill and liver samples were removed and embedded in paraffin for histopathological investigations. TCS induced aneurysm, capillary dilation, lamellar disorganization, hyperplasia, epithelial lifting, and desquamation in the gills. Liver specimens showed sinusoidal dilation, congestion, vacuolization, hepatocellular degeneration, and necrosis. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay was performed to observe the apoptotic effect of TCS. Accordingly, no apoptotic cells were detected in the specimens of 34 μg/L of TCS exposed gills, while the slides of 85 and 170 μg/L of TCS treated gills showed a high number of TUNEL-positive cells. In the liver, no TUNEL-positive cells were identified in 34 μg/L of TCS treated samples of zebrafish. 85 and 170 μg/L of TCS exposed livers showed few hepatic parenchymal cells undergoing apoptosis.","PeriodicalId":7903,"journal":{"name":"Annales De Limnologie-international Journal of Limnology","volume":"72 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75113156","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}
Chengxue Ma, Chang Zhao, P. C. Mwagona, Ziyu Li, Zixuan Liu, H. Dou, Xuehong Zhou, J. Bhadha
The debates about the extent to which phytoplankton in freshwater ecosystems are regulated by top-down or bottom-up forces have been ongoing for decades. This study examines the effects of bottom-up and top-down factors on the phytoplankton functional groups in a eutrophic lake. Phytoplankton and zooplankton were sampled and physical-chemical variables measured from May 2019 to October 2019 in Lake Hulun, China. Approximately 43 phytoplankton species were observed and grouped into 23 functional groups. For the zooplankton, about 27 species were observed and classified into 8 functional groups. The study revealed that the bottom-up effects of physical-chemical variables on some phytoplankton functional groups was stronger than the top-down effects of zooplankton. Water temperature (WT), total phosphorus (TP), total nitrogen (TN), conductivity (Cond), water transparency (SD), and dissolved oxygen (DO) significant influence the biomass of the phytoplankton functional groups. The biomass of phytoplankton functional groups was influenced positively by nutrient availability likely because nutrients influence the growth and reproduction of phytoplankton in freshwater. WT and DO had a positive influence on biomass of phytoplankton functional groups. Conversely, phytoplankton biomass revealed a decreasing trend when SD and Cond significantly increased. This study showed that zooplankton functional groups were positively correlated with phytoplankton biomass implying that the top-down control of phytoplankton by the zooplankton in the lake is not strong enough to produce a negative effect. It is evident that the zooplankton functional groups in Lake Hulun are controlled more by bottom-up force than top-down.
{"title":"Bottom-up and top-down effects on phytoplankton functional groups in Hulun Lake, China","authors":"Chengxue Ma, Chang Zhao, P. C. Mwagona, Ziyu Li, Zixuan Liu, H. Dou, Xuehong Zhou, J. Bhadha","doi":"10.1051/LIMN/2020028","DOIUrl":"https://doi.org/10.1051/LIMN/2020028","url":null,"abstract":"The debates about the extent to which phytoplankton in freshwater ecosystems are regulated by top-down or bottom-up forces have been ongoing for decades. This study examines the effects of bottom-up and top-down factors on the phytoplankton functional groups in a eutrophic lake. Phytoplankton and zooplankton were sampled and physical-chemical variables measured from May 2019 to October 2019 in Lake Hulun, China. Approximately 43 phytoplankton species were observed and grouped into 23 functional groups. For the zooplankton, about 27 species were observed and classified into 8 functional groups. The study revealed that the bottom-up effects of physical-chemical variables on some phytoplankton functional groups was stronger than the top-down effects of zooplankton. Water temperature (WT), total phosphorus (TP), total nitrogen (TN), conductivity (Cond), water transparency (SD), and dissolved oxygen (DO) significant influence the biomass of the phytoplankton functional groups. The biomass of phytoplankton functional groups was influenced positively by nutrient availability likely because nutrients influence the growth and reproduction of phytoplankton in freshwater. WT and DO had a positive influence on biomass of phytoplankton functional groups. Conversely, phytoplankton biomass revealed a decreasing trend when SD and Cond significantly increased. This study showed that zooplankton functional groups were positively correlated with phytoplankton biomass implying that the top-down control of phytoplankton by the zooplankton in the lake is not strong enough to produce a negative effect. It is evident that the zooplankton functional groups in Lake Hulun are controlled more by bottom-up force than top-down.","PeriodicalId":7903,"journal":{"name":"Annales De Limnologie-international Journal of Limnology","volume":"106 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76695214","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}
L. Velho, Suzana de Fátima Rodrigues de Castro, F. Lansac‐Tôha, B. R. Meira, Felipe Rafael de Oliveira, G. M. Alves, F. Lansac-Tôha
The aim of this study was to investigate the spatial and temporal patterns in species composition of ciliates, in rural streams, affected by agricultural activities, and urban streams, impacted by domestic wastewater. Samplings were taken in two different periods of the year, in the headwater, middle and mouth stretch of ten streams. We recorded 143 species of ciliates, distributed in 14 groups, standing out Hymenostomatia, Peritrichia and Hypotrichia. Our results showed significant spatial (between rural and urban streams) and, especially, temporal differences (between winter and summer periods) in the ciliates taxonomic composition. Such differences seem to be not related to the organic load that was quite similar among streams and periods sampled. Rather, the changes in ciliates composition are probably driving mainly by other enviromental variables such as resources, determined by the spatial diferences in light availability, and flow water velocity and discharge, which present high temporal dissimilarity.
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Samples of 5, 10 or 20 adult Galba truncatula each were introduced into 25 slope rush beds and 24 road ditches on acid soil to study the colonization of these new sites by the snail. Surveys were conducted over the following eight years to determine the area where these G. truncatula colonized in these new stations and to count the number of overwintering snails in April or May. Snail populations were present in about 50% of the sites where samples of 5 snails each were introduced and in all sites when each sample included 10 or 20 snails. The average area of these habitats showed a peak before decreasing in the following years and this peak was all the more late as the sample introduced into the station increased in size. In contrast, snail abundance in all cases peaked in the second or third year after introduction and gradually decreased thereafter. In all cases, a concentration of snails was noted in the most upstream zone, whereas the number of individuals decreased gradually towards the downstream zone. These results demonstrate that a small number of snails (10 or 20 adults per sample) allow the development of a new population of G. truncatula in new acid soil stations.
{"title":"Galba truncatula (O.F. Müller, 1774) (Gastropoda, Lymnaeidae): the colonization of new stations on acid soil by low numbers of snails","authors":"G. Dreyfuss, P. Vignoles, D. Rondelaud","doi":"10.1051/limn/2021024","DOIUrl":"https://doi.org/10.1051/limn/2021024","url":null,"abstract":"Samples of 5, 10 or 20 adult Galba truncatula each were introduced into 25 slope rush beds and 24 road ditches on acid soil to study the colonization of these new sites by the snail. Surveys were conducted over the following eight years to determine the area where these G. truncatula colonized in these new stations and to count the number of overwintering snails in April or May. Snail populations were present in about 50% of the sites where samples of 5 snails each were introduced and in all sites when each sample included 10 or 20 snails. The average area of these habitats showed a peak before decreasing in the following years and this peak was all the more late as the sample introduced into the station increased in size. In contrast, snail abundance in all cases peaked in the second or third year after introduction and gradually decreased thereafter. In all cases, a concentration of snails was noted in the most upstream zone, whereas the number of individuals decreased gradually towards the downstream zone. These results demonstrate that a small number of snails (10 or 20 adults per sample) allow the development of a new population of G. truncatula in new acid soil stations.","PeriodicalId":7903,"journal":{"name":"Annales De Limnologie-international Journal of Limnology","volume":"1 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79924925","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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