Phragmites australis, Potamogeton pectinatus, Potamogeton perfoliatus and Ceratophyllum demersum were selected to study concentrations of PAHs in lotic ecosystems. Six sampling sites were selected along Al-Hilla River...Phragmites australis, Potamogeton pectinatus, Potamogeton perfoliatus and Ceratophyllum demersum were selected to study concentrations of PAHs in lotic ecosystems. Six sampling sites were selected along Al-Hilla River and sampling was conducted in 2010 and 2011. Sixteen PAHs listed as priority pollutants were detected in the samples collected, including Naphthalene (Nap), Acenaphthylene (Acpy), Acenaphthene (Acp), Fluorene (Flu), Phenanthrene (Phen), Anthracene (Ant), Fluoranthene (Flur), Pyrene (Py), Benzo (a) Anthracene (B(a)A), Chrysene (Chry), Benzo (b) Fluoranthene (B(b)F), Benzo (k) Fluoranthene (B(k)F), Benzo (a) Pyrene (B(a)P), Dibenzo (a, h) Anthracene (D(b)A), Benzo (ghi) Perylene (B(ghi)P) and Indeno (1,2,3-cd) Pyrene (Ind). The results of the study illustrate that the PAH concentration in macrophytes varies among their species. These variances were as follows: P. australis 0.425 to 299.424 μg/g dry weight (Dw) for B(ghi)P and B(b)F, respectively;P. perfoliatus 0.354 to 235.84 μg/g Dw for B(b)F and B(ghi)P, respectively;C. demersum 0.996 to 162.942 μg/g Dw for Ant and B(ghi)P, respectively;and P. pectinatus 0.383 to 99.87 μg/g Dw for Ant and Nap, respectively. The accumulation potential of PAHs was also investigated by calculating the Bioconcentration Factor (BCF) and Bio-sediment Accumulation Factor (BSAF). The ranges of BCF ratios were 0.05 to 5334.5, 0.08 to 1602.5, 0.01 to 536.6, 0.16 to 1882 in P. australis, P. perfoliatus, P. pectinatus and C. demersum, respectively. The range of BSAF ratios were 3.14 to 1041.6 and 1.5 to 2920.8 in P. australis and P. perfoliatus, respectively.展开更多
Nocturnal invertebrate abundance peaks in lotic systems are usually associated to drift, however, diel migrations other than drift may be important in slow-flowing systems. Then, macroinvertebrate distribution on macr...Nocturnal invertebrate abundance peaks in lotic systems are usually associated to drift, however, diel migrations other than drift may be important in slow-flowing systems. Then, macroinvertebrate distribution on macrophytes may change along the day as result of vertical or horizontal migration from sediments or the water column. My objective was to determine whether macroinvertebrate abundance on macrophytes changes along 24 h. Three Ceratophyllum demersum patches were sampled in late spring from the Las Flores stream (Central Argentina) at 11:20 h, 17:10 h, 23:00 h and 5:00 h. Macroinvertebrates were counted and identified, and relative abundances were estimated for each sampling time. The dominant groups of macroinvertebrates sampled were Oligochaeta, Amphipoda and Cladocera. The relative abundance of macroinvertebrates on macrophytes was the highest at 5:00 h, when dissolved oxygen in water reached its minimum. In conclusion, the abundance of macroinvertebrates on macrophytes in Pampean streams may increase at night, probably as result of nocturnal migration driven by changes in predation risk or dissolved oxygen.展开更多
Background Ushuaia City has experienced much population growth and still lacks secondary treatment for its wastewater.As a result,most of the discharge is directed into the lotic ecosystems that cross the urban enviro...Background Ushuaia City has experienced much population growth and still lacks secondary treatment for its wastewater.As a result,most of the discharge is directed into the lotic ecosystems that cross the urban environment.This paper assesses the relationship between riparian areas and water quality along an urbanization gradient in the city's main watersheds:Pipo River,Buena Esperanza Stream and Arroyo Grande River.Results The Riparian Forest Quality Index adapted for Patagonia showed a positive correlation with the Fuegian Water Quality Index(r=0.83,p<0.05).Differences in the riparian index along the urban gradient were detected in all the studied watersheds.In general,non-urbanized sites in the upper zones showed very good or good quality while urbanized sites showed worse riparian conditions.Furthermore,in relation to the Fuegian Water Quality Index,this work showed spatial and temporal variations.The Pipo River watershed showed no statistically significant differences among sampling sites,although water quality decreased over time at the urbanized site near the outlet of the river(in March 2018 the Fuegian Water Quality Index was 88 and in March 2022 it was 38).In the Buena Esperanza Stream,significant differences were detected among sampling sites;water quality at the non-urbanized zones in the upper section and upper-middle section was higher than at the urbanized sites.In the Arroyo Grande River,despite the lower ranges of the Fuegian Water Quality Index observed at the urban site near the outlet,no significant differences were identified between study sites.Conclusion The relationship of both indices supports the relevance of the environmental surroundings of the watercourses and how their ecological integrity affects water quality in urban lotic ecosystems.The watersheds studied here are strongly linked to the complex dynamics of a growing city which was reflected by the Fuegian Water Quality.Our findings provide a scientific foundation for sustainable environmental management.We recommend integrated water resources management that not only ceases the direct discharge of wastewater into watercourses but also implements measures to protect and restore the riparian environment as a fundamental measure for the conservation of urban lotic ecosystems.展开更多
The determination of natural variation in physical habitat conditions and the establishment of least-disturbed reference standards is important for ecosystem conservation.Tropical regions hold most of the global fresh...The determination of natural variation in physical habitat conditions and the establishment of least-disturbed reference standards is important for ecosystem conservation.Tropical regions hold most of the global freshwater diversity,nevertheless little is known about the natural conditions of their physical habitats.We calculated 255 physical habitat metrics for 31 stream sites in five protected areas of the Brazilian S~ao Francisco River basin to identify the most variable characteristics among tropical streams in least-disturbed areas.We performed principal components analyses(PCA)to find the most relevant metrics for ordination of streams in the following categories:water quality(2);substrate(7);fish shelter(6);riparian vegetation(9);and channel morphology(7).We used distance-based linear models(DISTLM)to test how much of the variation of these metrics could be explained by geographic position,average elevation,and average discharge of stream sites.The best statistically significant models explained 42%of substrate(33%geographic position;9%average elevation),26%of channel morphology(22%geographic position;4%average discharge),23%of water quality(14%geographic position;9%average discharge),17%of fish shelter(9%geographic position;8%average elevation),and 14%of riparian vegetation(7%geographic position;7%average elevation)variation.Thus,regional features(e.g.geology and climate)related to the geographic position are of greatest importance,followed by average elevation and discharge for determining physical habitat characteristics.Therefore,we suggest that reference sites should be set for tropical streams in the same regional landscape and with similar average elevation and discharge.展开更多
Freshwater gastropods play a pivotal role in the structure and functioning of freshwater ecosystems,but despite their importance,there are still gaps in their ecology.Our goal was to understand what physical habitat f...Freshwater gastropods play a pivotal role in the structure and functioning of freshwater ecosystems,but despite their importance,there are still gaps in their ecology.Our goal was to understand what physical habitat factors are the most important for the distribution of freshwater gastropods in headwater stream ecosystems in the Neotropical Savanna and provide a baseline for conservation and management efforts for freshwater gastropods in this biome.We identified five taxa,each with different environmental prefferences.Littoridina presence related negatively with stream slope,Biomphalaria presence related positively with total dissolved solids and the proportions of cobble,fine sediment and organic matter.Gundlachia presence correlated positively with elevation and the proportion of pools in the site.Physa presence related negatively with total dissolved solids and positively with alkalinity.Melanoides tuberculata presence correlated positively with the proportion of coarse gravel.Our results highlight the challenge for protecting native freshwater gastropod assemblages(and managing non-native invasive species),because environmental preferences vary widely amongst taxa and most are vulnerable to common anthropogenic disturbances.展开更多
文摘Phragmites australis, Potamogeton pectinatus, Potamogeton perfoliatus and Ceratophyllum demersum were selected to study concentrations of PAHs in lotic ecosystems. Six sampling sites were selected along Al-Hilla River and sampling was conducted in 2010 and 2011. Sixteen PAHs listed as priority pollutants were detected in the samples collected, including Naphthalene (Nap), Acenaphthylene (Acpy), Acenaphthene (Acp), Fluorene (Flu), Phenanthrene (Phen), Anthracene (Ant), Fluoranthene (Flur), Pyrene (Py), Benzo (a) Anthracene (B(a)A), Chrysene (Chry), Benzo (b) Fluoranthene (B(b)F), Benzo (k) Fluoranthene (B(k)F), Benzo (a) Pyrene (B(a)P), Dibenzo (a, h) Anthracene (D(b)A), Benzo (ghi) Perylene (B(ghi)P) and Indeno (1,2,3-cd) Pyrene (Ind). The results of the study illustrate that the PAH concentration in macrophytes varies among their species. These variances were as follows: P. australis 0.425 to 299.424 μg/g dry weight (Dw) for B(ghi)P and B(b)F, respectively;P. perfoliatus 0.354 to 235.84 μg/g Dw for B(b)F and B(ghi)P, respectively;C. demersum 0.996 to 162.942 μg/g Dw for Ant and B(ghi)P, respectively;and P. pectinatus 0.383 to 99.87 μg/g Dw for Ant and Nap, respectively. The accumulation potential of PAHs was also investigated by calculating the Bioconcentration Factor (BCF) and Bio-sediment Accumulation Factor (BSAF). The ranges of BCF ratios were 0.05 to 5334.5, 0.08 to 1602.5, 0.01 to 536.6, 0.16 to 1882 in P. australis, P. perfoliatus, P. pectinatus and C. demersum, respectively. The range of BSAF ratios were 3.14 to 1041.6 and 1.5 to 2920.8 in P. australis and P. perfoliatus, respectively.
文摘Nocturnal invertebrate abundance peaks in lotic systems are usually associated to drift, however, diel migrations other than drift may be important in slow-flowing systems. Then, macroinvertebrate distribution on macrophytes may change along the day as result of vertical or horizontal migration from sediments or the water column. My objective was to determine whether macroinvertebrate abundance on macrophytes changes along 24 h. Three Ceratophyllum demersum patches were sampled in late spring from the Las Flores stream (Central Argentina) at 11:20 h, 17:10 h, 23:00 h and 5:00 h. Macroinvertebrates were counted and identified, and relative abundances were estimated for each sampling time. The dominant groups of macroinvertebrates sampled were Oligochaeta, Amphipoda and Cladocera. The relative abundance of macroinvertebrates on macrophytes was the highest at 5:00 h, when dissolved oxygen in water reached its minimum. In conclusion, the abundance of macroinvertebrates on macrophytes in Pampean streams may increase at night, probably as result of nocturnal migration driven by changes in predation risk or dissolved oxygen.
基金funding from Agencia Nacional de Promoción Científica y Tecnológica(ANPCy T PICT 20151152)University of Tierra del Fuego(PIDUNTd F)and PUE 2016 to CADIC(CONICET)Agencia Nacional de Promoción Científica y Tecnológica,PICT 20151152,Patricia Rodriguez
文摘Background Ushuaia City has experienced much population growth and still lacks secondary treatment for its wastewater.As a result,most of the discharge is directed into the lotic ecosystems that cross the urban environment.This paper assesses the relationship between riparian areas and water quality along an urbanization gradient in the city's main watersheds:Pipo River,Buena Esperanza Stream and Arroyo Grande River.Results The Riparian Forest Quality Index adapted for Patagonia showed a positive correlation with the Fuegian Water Quality Index(r=0.83,p<0.05).Differences in the riparian index along the urban gradient were detected in all the studied watersheds.In general,non-urbanized sites in the upper zones showed very good or good quality while urbanized sites showed worse riparian conditions.Furthermore,in relation to the Fuegian Water Quality Index,this work showed spatial and temporal variations.The Pipo River watershed showed no statistically significant differences among sampling sites,although water quality decreased over time at the urbanized site near the outlet of the river(in March 2018 the Fuegian Water Quality Index was 88 and in March 2022 it was 38).In the Buena Esperanza Stream,significant differences were detected among sampling sites;water quality at the non-urbanized zones in the upper section and upper-middle section was higher than at the urbanized sites.In the Arroyo Grande River,despite the lower ranges of the Fuegian Water Quality Index observed at the urban site near the outlet,no significant differences were identified between study sites.Conclusion The relationship of both indices supports the relevance of the environmental surroundings of the watercourses and how their ecological integrity affects water quality in urban lotic ecosystems.The watersheds studied here are strongly linked to the complex dynamics of a growing city which was reflected by the Fuegian Water Quality.Our findings provide a scientific foundation for sustainable environmental management.We recommend integrated water resources management that not only ceases the direct discharge of wastewater into watercourses but also implements measures to protect and restore the riparian environment as a fundamental measure for the conservation of urban lotic ecosystems.
基金Fundaçao Grupo Boticario deProteçao a NaturezaConselho Nacional de Desenvolvimento Científico e Tecnologico,Grant/Award Number:CNPq No.303548/2017-7Coordenaçao de Aperfeiçoamento de Pessoal de Nível Superior.
文摘The determination of natural variation in physical habitat conditions and the establishment of least-disturbed reference standards is important for ecosystem conservation.Tropical regions hold most of the global freshwater diversity,nevertheless little is known about the natural conditions of their physical habitats.We calculated 255 physical habitat metrics for 31 stream sites in five protected areas of the Brazilian S~ao Francisco River basin to identify the most variable characteristics among tropical streams in least-disturbed areas.We performed principal components analyses(PCA)to find the most relevant metrics for ordination of streams in the following categories:water quality(2);substrate(7);fish shelter(6);riparian vegetation(9);and channel morphology(7).We used distance-based linear models(DISTLM)to test how much of the variation of these metrics could be explained by geographic position,average elevation,and average discharge of stream sites.The best statistically significant models explained 42%of substrate(33%geographic position;9%average elevation),26%of channel morphology(22%geographic position;4%average discharge),23%of water quality(14%geographic position;9%average discharge),17%of fish shelter(9%geographic position;8%average elevation),and 14%of riparian vegetation(7%geographic position;7%average elevation)variation.Thus,regional features(e.g.geology and climate)related to the geographic position are of greatest importance,followed by average elevation and discharge for determining physical habitat characteristics.Therefore,we suggest that reference sites should be set for tropical streams in the same regional landscape and with similar average elevation and discharge.
基金This research has been continually funded by Programa Peixe Vivo/Companhia Energetica de Minas Gerais,Programa de Pesquisa e Desenvolvimento Tecnologico do Setor de Energia Eletrica-Companhia Energetica de Minas Gerais(P&D Aneel-Cemig GT-487,GT-550,GT-599,and GT-611)by Fundaçao de Amparoa Pesquisa de Minas Gerais(APQ-01961-15)+2 种基金This study was financed in part by CAPES-Finance Code 001.MC was awarded National Council for Scientific&Technological Development(CNPq)research productivity grants(304060/2020-8)by Fundaçao de Amparoa Pesquisa do Estado de Minas Gerais research grant(PPM 00104-18).DRM received support from CNPq(309763/2020-7)The Coordenaçao de Aperfeiçoamento de Pessoal de Nível Superior-Brasil(CAPES)provided grants to RLM.The team of undergraduate and graduate students of the Laboratorio de Ecologia de Bentos/ICB-UFMG supported the field activities.
文摘Freshwater gastropods play a pivotal role in the structure and functioning of freshwater ecosystems,but despite their importance,there are still gaps in their ecology.Our goal was to understand what physical habitat factors are the most important for the distribution of freshwater gastropods in headwater stream ecosystems in the Neotropical Savanna and provide a baseline for conservation and management efforts for freshwater gastropods in this biome.We identified five taxa,each with different environmental prefferences.Littoridina presence related negatively with stream slope,Biomphalaria presence related positively with total dissolved solids and the proportions of cobble,fine sediment and organic matter.Gundlachia presence correlated positively with elevation and the proportion of pools in the site.Physa presence related negatively with total dissolved solids and positively with alkalinity.Melanoides tuberculata presence correlated positively with the proportion of coarse gravel.Our results highlight the challenge for protecting native freshwater gastropod assemblages(and managing non-native invasive species),because environmental preferences vary widely amongst taxa and most are vulnerable to common anthropogenic disturbances.
