Enes Dalgakıran, O. Külköylüoğlu, M. Yavuzatmaca, D. Akdemir
To explore the relationship between ostracods carapace (body) size and altitude, 117 non-marine aquatic habitats were sampled from Mersin province (Turkey) during 03–09 October 2015. A total of 36 species and 14 sub-fossils were detected from 66 of 117 sites located between −3 m and 1630 m a.s.l. Thirty-four of the species are previously unknown in the province. In addition, four of the taxa were new records for the Turkish Ostracoda fauna. Five species (Ilyocypris bradyi, Heterocypris salina, H. incongruens, Psychrodromus olivaceus, Potamocypris fallax ) were the most common among all habitats with relatively wide ecological and altitudinal ranges. Canonical correspondence analyses revealed 72.6% of the relationship between 12 ostracods and five environmental variables. Water temperature and pH were the two most influential variables (p = 3980) at all altitudinal ranges. A strong tendency of changes in valve height with increasing altitude seems to be more prominent (p < 0.05) than the changes in length for some species. Our results do not support some ecological rules but rather, suggest that a linear relationship between carapace size and altitude may only be applicable for some ostracods.
{"title":"Correlational analyses of the relationships between altitude and carapace size of Ostracoda (Crustacea)","authors":"Enes Dalgakıran, O. Külköylüoğlu, M. Yavuzatmaca, D. Akdemir","doi":"10.1051/limn/2019025","DOIUrl":"https://doi.org/10.1051/limn/2019025","url":null,"abstract":"To explore the relationship between ostracods carapace (body) size and altitude, 117 non-marine aquatic habitats were sampled from Mersin province (Turkey) during 03–09 October 2015. A total of 36 species and 14 sub-fossils were detected from 66 of 117 sites located between −3 m and 1630 m a.s.l. Thirty-four of the species are previously unknown in the province. In addition, four of the taxa were new records for the Turkish Ostracoda fauna. Five species (Ilyocypris bradyi, Heterocypris salina, H. incongruens, Psychrodromus olivaceus, Potamocypris fallax ) were the most common among all habitats with relatively wide ecological and altitudinal ranges. Canonical correspondence analyses revealed 72.6% of the relationship between 12 ostracods and five environmental variables. Water temperature and pH were the two most influential variables (p = 3980) at all altitudinal ranges. A strong tendency of changes in valve height with increasing altitude seems to be more prominent (p < 0.05) than the changes in length for some species. Our results do not support some ecological rules but rather, suggest that a linear relationship between carapace size and altitude may only be applicable for some ostracods.","PeriodicalId":7903,"journal":{"name":"Annales De Limnologie-international Journal of Limnology","volume":"28 1","pages":"2"},"PeriodicalIF":1.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83397697","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}
M. D. H. J. Senavirathna, Nilnuwani Ashika Wijesinghe, Zhao-pu Liu, T. Fujino
Sea-level rise caused by global warming is leading to increased freshwater salinization, which causes significant stress on aquatic ecosystems and species, including macrophytes. To form a better understanding of the responses of macrophytes to salinity stress, we assessed biochemical, pigmentation and growth responses of Myriophyllum spicatum L. and Ceratophyllum demersum L. exposed to different salinity levels (0, 1.5, 2.5, 5.0, and 10 ppt). For both species, elongation rates decreased, and levels of photosynthetic pigments (chlorophyll a and chlorophyll b) increased at higher salinities (5 ppt and 10 ppt). Anthocyanin and H2O2 concentrations increased in M. spicatum but decreased in C. demersum with the increase in salinity. The activities of antioxidant enzymes (guaiacol peroxidase, catalase, and ascorbate peroxidase) were different between two species and fluctuated along the salinity gradient. M. spicatum and C. demersum exhibit species-specific salinity sensitivities, reaching different physiological statuses at each salinity level. Elongation rates were significantly correlated with several biochemical parameters in a species-specific manner. These correlations can be used in evaluating the expected responses of these two species to salinity changes. The species-specific responses of most parameters measured in the present study suggests the inapplicability of common biochemical responses across species.
{"title":"Effects of short-term exposure to different salinity levels on Myriophyllum spicatum and Ceratophyllum demersum and suitability of biomarkers to evaluate macrophyte responses to salinity stress","authors":"M. D. H. J. Senavirathna, Nilnuwani Ashika Wijesinghe, Zhao-pu Liu, T. Fujino","doi":"10.1051/limn/2020021","DOIUrl":"https://doi.org/10.1051/limn/2020021","url":null,"abstract":"Sea-level rise caused by global warming is leading to increased freshwater salinization, which causes significant stress on aquatic ecosystems and species, including macrophytes. To form a better understanding of the responses of macrophytes to salinity stress, we assessed biochemical, pigmentation and growth responses of Myriophyllum spicatum L. and Ceratophyllum demersum L. exposed to different salinity levels (0, 1.5, 2.5, 5.0, and 10 ppt). For both species, elongation rates decreased, and levels of photosynthetic pigments (chlorophyll a and chlorophyll b) increased at higher salinities (5 ppt and 10 ppt). Anthocyanin and H2O2 concentrations increased in M. spicatum but decreased in C. demersum with the increase in salinity. The activities of antioxidant enzymes (guaiacol peroxidase, catalase, and ascorbate peroxidase) were different between two species and fluctuated along the salinity gradient. M. spicatum and C. demersum exhibit species-specific salinity sensitivities, reaching different physiological statuses at each salinity level. Elongation rates were significantly correlated with several biochemical parameters in a species-specific manner. These correlations can be used in evaluating the expected responses of these two species to salinity changes. The species-specific responses of most parameters measured in the present study suggests the inapplicability of common biochemical responses across species.","PeriodicalId":7903,"journal":{"name":"Annales De Limnologie-international Journal of Limnology","volume":"1 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89844251","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}
In the genus Rhyncholimnochares, a total of 11 species new to science is described, 10 representatives of the subgenus Rhyncholimnochares s. str. − R. ursula sp. n., R. minuta sp. n., R. cooki sp. n., R. jicotea sp. n., R. lundbladi sp. n. and R. monikae sp. n. from Costa Rica; R. expansipalpis sp. n., R. petaliseta sp. n, R. tapiarum sp. n., R. glabra sp. n. from Ecuador (the latter recorded also from Brazil and Chile), and one representative of the subgenus Paralimnochares, R. chilensis sp. n. from Chile. New records are given for R. (s. str.) lamellipalpis (O. Lundblad 1936. Dritte Mitteilung über neue Wassermilben aus Santa Catharina in Südbrasilien. Zool Anz 116 (7-8): 200–211.) from Chile. A determination key is given for all known species at the adult/deutonymphal stage.
{"title":"New water mite species of the genus Rhyncholimnochares Lundblad (Acariformes, Limnocharidae) from Central and South America, with a key to all known species of the genus","authors":"P. Tuzovskij, R. Gerecke","doi":"10.1051/limn/2020013","DOIUrl":"https://doi.org/10.1051/limn/2020013","url":null,"abstract":"In the genus Rhyncholimnochares, a total of 11 species new to science is described, 10 representatives of the subgenus Rhyncholimnochares s. str. − R. ursula sp. n., R. minuta sp. n., R. cooki sp. n., R. jicotea sp. n., R. lundbladi sp. n. and R. monikae sp. n. from Costa Rica; R. expansipalpis sp. n., R. petaliseta sp. n, R. tapiarum sp. n., R. glabra sp. n. from Ecuador (the latter recorded also from Brazil and Chile), and one representative of the subgenus Paralimnochares, R. chilensis sp. n. from Chile. New records are given for R. (s. str.) lamellipalpis (O. Lundblad 1936. Dritte Mitteilung über neue Wassermilben aus Santa Catharina in Südbrasilien. Zool Anz 116 (7-8): 200–211.) from Chile. A determination key is given for all known species at the adult/deutonymphal stage.","PeriodicalId":7903,"journal":{"name":"Annales De Limnologie-international Journal of Limnology","volume":"55 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84733557","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}
This study explores the seasonal variation in functional composition, diversity and redundancy of Cladocera from an Indian lotic eutrophic habitat using two-year sampling data. Two seasonal clusters distinguishable by faunal and functional diversity patterns were obtained. Cluster A comprised of four functional groups while the ctenopod filter feeders were absent in cluster B. Cluster A had more number of species, higher functional divergence and lower redundancy than cluster B. Relatively, higher divergence values observed during the cluster A time period could be associated with set of functionally varied species occurring throughout the season. Decline in redundancy values seen within cluster A might be explained by the loss of littoral and benthic species in the peak of summer due to disappearance of submerged macrophytes and an increased nutrient load. Peculiar occurrence of Moina species in the most polluted months needs further investigation as a potential local pollution indicator.
{"title":"Seasonal variation in functional composition and diversity of cladoceran zooplankton of a lotic eutrophic habitat from India","authors":"Sameer M. Padhye","doi":"10.1051/limn/2020011","DOIUrl":"https://doi.org/10.1051/limn/2020011","url":null,"abstract":"This study explores the seasonal variation in functional composition, diversity and redundancy of Cladocera from an Indian lotic eutrophic habitat using two-year sampling data. Two seasonal clusters distinguishable by faunal and functional diversity patterns were obtained. Cluster A comprised of four functional groups while the ctenopod filter feeders were absent in cluster B. Cluster A had more number of species, higher functional divergence and lower redundancy than cluster B. Relatively, higher divergence values observed during the cluster A time period could be associated with set of functionally varied species occurring throughout the season. Decline in redundancy values seen within cluster A might be explained by the loss of littoral and benthic species in the peak of summer due to disappearance of submerged macrophytes and an increased nutrient load. Peculiar occurrence of Moina species in the most polluted months needs further investigation as a potential local pollution indicator.","PeriodicalId":7903,"journal":{"name":"Annales De Limnologie-international Journal of Limnology","volume":"74 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82464090","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}
This study aimed at investigating the effects of the urban wastewater treatment plant (WTP) discharges on the metabolism of Büyüksu Stream (Bolu, Turkey), and modelling the metabolism components as a function of measured environmental variables. Dissolved oxygen (DO) and water temperatures (Tw) were measured to estimate montly stream metabolism in the four reaches: Before and after discharges of the WTP, and the headwaters of Abant Creek and Mudurnu Creek feeding Büyüksu Stream. The DO and Tw measurements were performed for 17 months between August 2015 and December 2016. Metabolism components of community respiration (Rc), gross primary production (GPP) and net ecosystem metabolism (NEM) were estimated by using the two-station method. According to naturality gradient (reach disturbance gradients: before and after discharges, and headwaters of the creeks), mean metabolism components were compared by performing the one-way analysis of variance. The comparison results showed that the WTP discharges increased the average Rc from −30.6 g O2 m−2 day−1 to −130.9 g O2 m−2 day−1, and had no significant impact on the average GPP, statistically (15.6 and 9.1 g O2 m−2 day−1 before and after discharges, respectively). Validations of the multiple non-linear regression models of NEM and Rc gave coefficients of determination of 74.9% and 66.6%, respectively.
本研究旨在调查城市污水处理厂(WTP)排放对b y ksu溪流(土耳其Bolu)代谢的影响，并将代谢成分建模为测量环境变量的函数。通过测量溶解氧(DO)和水温(Tw)来估算WTP排放前后以及Abant Creek和Mudurnu Creek源源饲喂b yy ksu溪前后4个河段的月溪流代谢。从2015年8月到2016年12月，进行了17个月的DO和Tw测量。采用双站法估算了群落呼吸(Rc)、总初级生产量(GPP)和净生态系统代谢(NEM)的代谢组分。根据自然梯度(到达扰动梯度:排放前后和源头)，采用单因素方差分析比较平均代谢成分。对比结果表明，WTP排放使平均Rc从- 30.6 g O2 m−2 day−1增加到- 130.9 g O2 m−2 day−1，对平均GPP无显著影响(排放前后分别为15.6 g O2 m−2 day−1和9.1 g O2 m−2 day−1)。经多元非线性回归模型验证，NEM和Rc的决定系数分别为74.9%和66.6%。
{"title":"Quantifying spatiotemporal rhythm of stream metabolism along human disturbance gradients","authors":"M. Eryiğit, F. Evrendilek, N. Karakaya","doi":"10.1051/limn/2020014","DOIUrl":"https://doi.org/10.1051/limn/2020014","url":null,"abstract":"This study aimed at investigating the effects of the urban wastewater treatment plant (WTP) discharges on the metabolism of Büyüksu Stream (Bolu, Turkey), and modelling the metabolism components as a function of measured environmental variables. Dissolved oxygen (DO) and water temperatures (Tw) were measured to estimate montly stream metabolism in the four reaches: Before and after discharges of the WTP, and the headwaters of Abant Creek and Mudurnu Creek feeding Büyüksu Stream. The DO and Tw measurements were performed for 17 months between August 2015 and December 2016. Metabolism components of community respiration (Rc), gross primary production (GPP) and net ecosystem metabolism (NEM) were estimated by using the two-station method. According to naturality gradient (reach disturbance gradients: before and after discharges, and headwaters of the creeks), mean metabolism components were compared by performing the one-way analysis of variance. The comparison results showed that the WTP discharges increased the average Rc from −30.6 g O2 m−2 day−1 to −130.9 g O2 m−2 day−1, and had no significant impact on the average GPP, statistically (15.6 and 9.1 g O2 m−2 day−1 before and after discharges, respectively). Validations of the multiple non-linear regression models of NEM and Rc gave coefficients of determination of 74.9% and 66.6%, respectively.","PeriodicalId":7903,"journal":{"name":"Annales De Limnologie-international Journal of Limnology","volume":"1 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86553562","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. Tunca, Ali Doǧru, F. Kockar, Burçin Önem, T. O. Sevindik
Azadirachtin (Aza) used as insecticide due to inhibiting growth of insects and preventing them from feeding on plants. To understand the effects of contamination of this insecticide on phototrophs, and to determine the responses of these organisms against these insecticides are extremely important in understanding how the ecosystem is affected. In this study, chlorophyll-aamount, OD 560 and antioxidant parameters (total SOD, APX, GR, Proline, MDA and H2O2) were determined in order to understand the effect of Aza onArthrospira platensisGomont. Aza was applied between 0–20 μg mL−1concentrations for 7 days in the study. Enzyme analysis was conducted at the end of the 7th day. There was a statistically significant decrease in the absorbance of OD560 and the chlorophyll-acontent inA. platensiscultures exposed to the Aza (0–20 μg mL−1) during 7 days due to the increase in pesticide levels. SOD activity decreased at 8, 16 and 20 μg mL−1concentrations; GR enzyme activity showed a significant decrease compared to the control at a concentration of 20 μg mL−1. APX activity did not change significantly compared to control. The MDA content increased significantly at 16 and 20 μg mL−1concentrations. The H2O2content significantly increased at 12, 16 and 20 μg mL−1concentrations (p< 0.05) while the free proline content decreased at 4 μg mL−1concentration (p< 0.05). As a result, regarding the Aza concentrations used in this study may be a step to prevent pesticide pollution in the environment.
{"title":"Evaluation of Azadirachtin onArthrospira plantensisGomont growth parameters and antioxidant enzymes","authors":"H. Tunca, Ali Doǧru, F. Kockar, Burçin Önem, T. O. Sevindik","doi":"10.1051/limn/2020008","DOIUrl":"https://doi.org/10.1051/limn/2020008","url":null,"abstract":"Azadirachtin (Aza) used as insecticide due to inhibiting growth of insects and preventing them from feeding on plants. To understand the effects of contamination of this insecticide on phototrophs, and to determine the responses of these organisms against these insecticides are extremely important in understanding how the ecosystem is affected. In this study, chlorophyll-aamount, OD 560 and antioxidant parameters (total SOD, APX, GR, Proline, MDA and H2O2) were determined in order to understand the effect of Aza onArthrospira platensisGomont. Aza was applied between 0–20 μg mL−1concentrations for 7 days in the study. Enzyme analysis was conducted at the end of the 7th day. There was a statistically significant decrease in the absorbance of OD560 and the chlorophyll-acontent inA. platensiscultures exposed to the Aza (0–20 μg mL−1) during 7 days due to the increase in pesticide levels. SOD activity decreased at 8, 16 and 20 μg mL−1concentrations; GR enzyme activity showed a significant decrease compared to the control at a concentration of 20 μg mL−1. APX activity did not change significantly compared to control. The MDA content increased significantly at 16 and 20 μg mL−1concentrations. The H2O2content significantly increased at 12, 16 and 20 μg mL−1concentrations (p< 0.05) while the free proline content decreased at 4 μg mL−1concentration (p< 0.05). As a result, regarding the Aza concentrations used in this study may be a step to prevent pesticide pollution in the environment.","PeriodicalId":7903,"journal":{"name":"Annales De Limnologie-international Journal of Limnology","volume":"351 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80038510","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}
C. Nguyen, A. Vila-Gispert, X. Quintana, Au Van Hoa, Thanh‐Phuong Nguyen, N. Vu
The area surrounding the Hau River is one of the most important aquaculture and fisheries areas in the Mekong Delta, Vietnam. Fish, shrimp farms and fishers rely of the natural zooplankton production in the incoming water to sustain production. Zooplankton samples were collected from July 2017 to June 2018 using a zooplankton net with mesh size of 60 μm at 3 sites on Hau river at Tran De (river mouth), Dai Ngai (midpoint) and Cai Con (farthest salt intrusion area on Hau river). Qualitative and quantitative samples of zooplankton together with salinity level were determined monthly at each sites. The salinity was found to fluctuate from 0 to 20‰ in the study area. A total of 137 zooplankton species were recorded including 26 species of Protozoa (19%), 47 species of Rotifera (34%), 12 species of Cladocera (9%), 44 species of Copepoda (32%) and 8 other taxon (6%). Copepod and rotifer prevailed with high densities (19.9 × 103 ind m−3 and 19.7 × 103 ind m−3, respectively), whereas protozoa and cladocera were less abundant with 6.8 × 103 ind m−3 and 4.9 × 103 ind m−3, respectively. When salinity increased to more than 5, protozoa and copepods were more abundant and reached a peak at 20 with 25.0 × 1036 ind m−3 and 53.0 × 103 ind m−3, respectively. Regression analysis indicated that the density of zooplankton was significantly correlated to salinity variation. Protozoa and copepod were positively correlated with salinity, whereas cladocera and rotifer were negatively correlated with salinity. The impacts of climate change could exacerbate the seasonal fluctuations in salinity and zooplankton composition.
口河周边地区是越南湄公河三角洲最重要的水产养殖和渔业地区之一。养鱼场、虾场和渔民依靠流入水中的天然浮游动物来维持生产。2017年7月至2018年6月，在河口Tran De、中点Dai Ngai和盐侵最远区Cai Con 3个地点，采用60 μm网目采集浮游动物样本。每个站点每月测定浮游动物的定性和定量样本以及盐度水平。研究区盐度在0 ~ 20‰之间波动。共记录到浮游动物137种，其中原生动物26种(19%)，轮虫目47种(34%)，枝目12种(9%)，桡足目44种(32%)，其他8种(6%)。桡足类和轮虫密度较高，分别为19.9 × 103和19.7 × 103和m - 3，原生动物和枝类密度较低，分别为6.8 × 103和4.9 × 103和m - 3。当盐度大于5时，原生动物和桡足动物数量较多，在20时达到峰值，分别为25.0 × 1036和53.0 × 103 ind m - 3。回归分析表明，浮游动物密度与盐度变化呈显著相关。原生动物和桡足动物与盐度呈显著正相关，枝纲动物和轮虫与盐度呈显著负相关。气候变化的影响可能加剧盐度和浮游动物组成的季节性波动。
{"title":"Effects of salinity on species composition of zooplankton on Hau River, Mekong Delta, Vietnam","authors":"C. Nguyen, A. Vila-Gispert, X. Quintana, Au Van Hoa, Thanh‐Phuong Nguyen, N. Vu","doi":"10.1051/limn/2020018","DOIUrl":"https://doi.org/10.1051/limn/2020018","url":null,"abstract":"The area surrounding the Hau River is one of the most important aquaculture and fisheries areas in the Mekong Delta, Vietnam. Fish, shrimp farms and fishers rely of the natural zooplankton production in the incoming water to sustain production. Zooplankton samples were collected from July 2017 to June 2018 using a zooplankton net with mesh size of 60 μm at 3 sites on Hau river at Tran De (river mouth), Dai Ngai (midpoint) and Cai Con (farthest salt intrusion area on Hau river). Qualitative and quantitative samples of zooplankton together with salinity level were determined monthly at each sites. The salinity was found to fluctuate from 0 to 20‰ in the study area. A total of 137 zooplankton species were recorded including 26 species of Protozoa (19%), 47 species of Rotifera (34%), 12 species of Cladocera (9%), 44 species of Copepoda (32%) and 8 other taxon (6%). Copepod and rotifer prevailed with high densities (19.9 × 103 ind m−3 and 19.7 × 103 ind m−3, respectively), whereas protozoa and cladocera were less abundant with 6.8 × 103 ind m−3 and 4.9 × 103 ind m−3, respectively. When salinity increased to more than 5, protozoa and copepods were more abundant and reached a peak at 20 with 25.0 × 1036 ind m−3 and 53.0 × 103 ind m−3, respectively. Regression analysis indicated that the density of zooplankton was significantly correlated to salinity variation. Protozoa and copepod were positively correlated with salinity, whereas cladocera and rotifer were negatively correlated with salinity. The impacts of climate change could exacerbate the seasonal fluctuations in salinity and zooplankton composition.","PeriodicalId":7903,"journal":{"name":"Annales De Limnologie-international Journal of Limnology","volume":"123 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77006599","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}
Fish biodiversity on Hau (Bassac) river was investigated to assess the status of species composition and fishing by fishing gears during a year. Sampling was implemented monthly at the upper part (An Giang province), middle part (Can Tho City) and lower part (Soc Trang province) of Hau River using trawl net as main sampling gear. Additionally, fish composition was also recorded from four other most popular fishing gears including cast net, gill net, fixed net and hook operated in the study sites. Fish species composition was determined by fishing gears and their abundance (CPUE) was calculated only from the main sampling gear (trawl net). The results showed that a total of 176 fish species belonging to 16 orders and 49 families was recorded. Perciformes was the most abundant group with 51 species followed by Cypriniformes with 46 species. The number of fish species was decreasing from upper part to lower part. Trawl net was considered the most destructive gear as up to 145 fish species caught by this device, followed by gill net with 98 species, fixed net 75, cast net 57, and hooks 16 species. CPUE was very low ranging from 0.53 kg.ha−1 h−1 to 26.30 kg.ha−1 h−1. Higher CPUE was recorded at lower part in compared to upper part and middle part, and at dry season in compared to rainy season. Regulation on fishing gears, fishing ground and season should be taken into consideration to protect and conserve the resources.
{"title":"Status of fish biodiversity and fishing on Hau River, Mekong Delta, Vietnam","authors":"V. Ut, Au Van Hoa, Huỳnh Phước Vinh","doi":"10.1051/limn/2020012","DOIUrl":"https://doi.org/10.1051/limn/2020012","url":null,"abstract":"Fish biodiversity on Hau (Bassac) river was investigated to assess the status of species composition and fishing by fishing gears during a year. Sampling was implemented monthly at the upper part (An Giang province), middle part (Can Tho City) and lower part (Soc Trang province) of Hau River using trawl net as main sampling gear. Additionally, fish composition was also recorded from four other most popular fishing gears including cast net, gill net, fixed net and hook operated in the study sites. Fish species composition was determined by fishing gears and their abundance (CPUE) was calculated only from the main sampling gear (trawl net). The results showed that a total of 176 fish species belonging to 16 orders and 49 families was recorded. Perciformes was the most abundant group with 51 species followed by Cypriniformes with 46 species. The number of fish species was decreasing from upper part to lower part. Trawl net was considered the most destructive gear as up to 145 fish species caught by this device, followed by gill net with 98 species, fixed net 75, cast net 57, and hooks 16 species. CPUE was very low ranging from 0.53 kg.ha−1 h−1 to 26.30 kg.ha−1 h−1. Higher CPUE was recorded at lower part in compared to upper part and middle part, and at dry season in compared to rainy season. Regulation on fishing gears, fishing ground and season should be taken into consideration to protect and conserve the resources.","PeriodicalId":7903,"journal":{"name":"Annales De Limnologie-international Journal of Limnology","volume":"1 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83275399","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}
C. R. Cabral, L. P. Diniz, Alef Jonathan da Silva, G. Fonseca, L. Carneiro, Mauro de Melo Júnior, Adriano Caliman
Assessing zooplankton biodiversity is essential to support freshwater management/conservation programs. Here, we investigated the zooplankton community structure from 180 shallow lakes in northeastern Brazil and analyzed them according to biome (Atlantic Forest or Caatinga), the origin of ecosystems (natural or man-made lakes), and habitat type (pelagic or littoral). Additionally, we provided an updated list of zooplankton species. We registered 227 species (137 Rotifera, 65 Cladocera, 25 Copepoda). The most common species of each major group among all lakes were the cladoceran Ceriodaphina cornuta, the rotifers Brachionus havanaensis and Lecane bulla, and the copepod Termocyclops decipiens. Species related to aquatic vegetation, as the Lecanidae rotifers and phytophilous cladocerans, were more frequent along Atlantic Forest biome and natural lakes. On the other hand, species that are bioindicators of eutrophic waters were more common at the Caatinga biome and man-made lakes. Atlantic Forest and Caatinga biomes had similar species richness, but different community compositions for all zooplankton groups, reinforcing the Caatinga significance for the Brazilian aquatic biodiversity. The type of habitat was the most important factor structuring species richness, with higher richness in the littoral region when compared to the pelagic. A result of many unique species of Cladocera and Rotifera associated with the aquatic vegetation were observed. The findings demonstrated that conservation/management plans cannot generalize zooplankton species distribution across different biomes, origins and even within a single lake, between the pelagic and littoral zones.
{"title":"Zooplankton species distribution, richness and composition across tropical shallow lakes: A large scale assessment by biome, lake origin, and lake habitat","authors":"C. R. Cabral, L. P. Diniz, Alef Jonathan da Silva, G. Fonseca, L. Carneiro, Mauro de Melo Júnior, Adriano Caliman","doi":"10.1051/limn/2020023","DOIUrl":"https://doi.org/10.1051/limn/2020023","url":null,"abstract":"Assessing zooplankton biodiversity is essential to support freshwater management/conservation programs. Here, we investigated the zooplankton community structure from 180 shallow lakes in northeastern Brazil and analyzed them according to biome (Atlantic Forest or Caatinga), the origin of ecosystems (natural or man-made lakes), and habitat type (pelagic or littoral). Additionally, we provided an updated list of zooplankton species. We registered 227 species (137 Rotifera, 65 Cladocera, 25 Copepoda). The most common species of each major group among all lakes were the cladoceran Ceriodaphina cornuta, the rotifers Brachionus havanaensis and Lecane bulla, and the copepod Termocyclops decipiens. Species related to aquatic vegetation, as the Lecanidae rotifers and phytophilous cladocerans, were more frequent along Atlantic Forest biome and natural lakes. On the other hand, species that are bioindicators of eutrophic waters were more common at the Caatinga biome and man-made lakes. Atlantic Forest and Caatinga biomes had similar species richness, but different community compositions for all zooplankton groups, reinforcing the Caatinga significance for the Brazilian aquatic biodiversity. The type of habitat was the most important factor structuring species richness, with higher richness in the littoral region when compared to the pelagic. A result of many unique species of Cladocera and Rotifera associated with the aquatic vegetation were observed. The findings demonstrated that conservation/management plans cannot generalize zooplankton species distribution across different biomes, origins and even within a single lake, between the pelagic and littoral zones.","PeriodicalId":7903,"journal":{"name":"Annales De Limnologie-international Journal of Limnology","volume":"75 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77600309","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}
Species distribution models (SDMs) have been used to understand the habitat suitability of key species. Habitat suitability plots, one outcome from SDMs, are valuable for understanding the habitat suitability and behavior of organisms. The sample size is often constrained by budget and time, and could largely influence the reliability of habitat suitability plots. To understand the effect of sample size on habitat suitability plots, the present study utilized random forests (RF) combined with partial dependence function. And the bluegill (Lepomis macrochirus), a main exotic fish species in the Japan rivers, was selected as target species in this study. Total of 1010 samples of bluegill observations along with four environmental variables were surveyed by the National Censuses on River Environments. The area under curves was calculated after generating RF models, to assess the predictive model performance, and this process was repeated 1000 times. To draw habitat suitability plots, we applied partial dependence function to the formulated RF models, and 15 different sample sizes were set to examine the effect on habitat suitability plots. We concluded that habitat suitability plots are affected by sample size and prediction performance. Notably, habitat suitability plots drawn from the sample size of 50 greatly varied among the 1000-time iterations, and they are all different from the observations. Furthermore, to deal with the case of limited samples, we proposed a novel approach “averaged habitat suitability plot” for delineating habitat suitability plots. The proposed approach enables us to assess the habitat suitability even with a small sample size.
{"title":"Effect of sample size on habitat suitability estimation using random forests: a case of bluegill, Lepomis macrochirus","authors":"Risa Shiroyama, Manna Wang, C. Yoshimura","doi":"10.1051/limn/2020010","DOIUrl":"https://doi.org/10.1051/limn/2020010","url":null,"abstract":"Species distribution models (SDMs) have been used to understand the habitat suitability of key species. Habitat suitability plots, one outcome from SDMs, are valuable for understanding the habitat suitability and behavior of organisms. The sample size is often constrained by budget and time, and could largely influence the reliability of habitat suitability plots. To understand the effect of sample size on habitat suitability plots, the present study utilized random forests (RF) combined with partial dependence function. And the bluegill (Lepomis macrochirus), a main exotic fish species in the Japan rivers, was selected as target species in this study. Total of 1010 samples of bluegill observations along with four environmental variables were surveyed by the National Censuses on River Environments. The area under curves was calculated after generating RF models, to assess the predictive model performance, and this process was repeated 1000 times. To draw habitat suitability plots, we applied partial dependence function to the formulated RF models, and 15 different sample sizes were set to examine the effect on habitat suitability plots. We concluded that habitat suitability plots are affected by sample size and prediction performance. Notably, habitat suitability plots drawn from the sample size of 50 greatly varied among the 1000-time iterations, and they are all different from the observations. Furthermore, to deal with the case of limited samples, we proposed a novel approach “averaged habitat suitability plot” for delineating habitat suitability plots. The proposed approach enables us to assess the habitat suitability even with a small sample size.","PeriodicalId":7903,"journal":{"name":"Annales De Limnologie-international Journal of Limnology","volume":"29 4","pages":""},"PeriodicalIF":1.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1051/limn/2020010","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72507856","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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