Pub Date : 2021-01-01DOI: 10.4081/jlimnol.2021.2036
A. Marchetto, A. Boggero, D. Fontaneto, A. Lami, A. Lotter, M. Manca, J. Massaferro, R. Mosello, S. Musazzi, U. Nickus, R. Psenner, M. Rogora, Sanna Sorvari Stundet, E. Stuchlík, G. Tartari, H. Thies, M. Tolotti
We publish a data set of environmental and biological data collected in 2000 during the ice-free period in high mountain lakes located above the local timberline in the Alps, in Italy, Switzerland and Austria. Environmental data include coordinates, geographical attributes and detailed information on vegetation, bedrock and land use in lake catchments. Chemical analyses of a sample for each lake collected at the lake surface in Summer 2000 are also reported. Biological data include phytoplankton (floating algae and cyanobacteria), zooplankton (floating animals), macroinvertebrates (aquatic organisms visible to the naked eye living in contact with sediments on lake bottom), benthic diatoms. Diatoms, cladocera and chironomids remains and algal and bacterial pigments were also analysed in lake sediments.
{"title":"Living organisms and sedimentary remains from high mountain lakes in the Alps","authors":"A. Marchetto, A. Boggero, D. Fontaneto, A. Lami, A. Lotter, M. Manca, J. Massaferro, R. Mosello, S. Musazzi, U. Nickus, R. Psenner, M. Rogora, Sanna Sorvari Stundet, E. Stuchlík, G. Tartari, H. Thies, M. Tolotti","doi":"10.4081/jlimnol.2021.2036","DOIUrl":"https://doi.org/10.4081/jlimnol.2021.2036","url":null,"abstract":"We publish a data set of environmental and biological data collected in 2000 during the ice-free period in high mountain lakes located above the local timberline in the Alps, in Italy, Switzerland and Austria. Environmental data include coordinates, geographical attributes and detailed information on vegetation, bedrock and land use in lake catchments. Chemical analyses of a sample for each lake collected at the lake surface in Summer 2000 are also reported. Biological data include phytoplankton (floating algae and cyanobacteria), zooplankton (floating animals), macroinvertebrates (aquatic organisms visible to the naked eye living in contact with sediments on lake bottom), benthic diatoms. Diatoms, cladocera and chironomids remains and algal and bacterial pigments were also analysed in lake sediments.","PeriodicalId":50164,"journal":{"name":"Journal of Limnology","volume":"1 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70280517","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}
Pub Date : 2021-01-01DOI: 10.4081/jlimnol.2021.1987
Tânia C. Dos Santos Ferreira, M. S. Arcifa
Until recently, knowledge of the impact of invertebrate predators on cladocerans in the Brazilian Lake Monte Alegre was limited to a few species. In order to assess the effects of predation on other cladoceran species, experiments were carried out with different pair-wise combinations of prey species. The experiments tested predation by fourth instar larvae of the dipteran Chaoborus brasiliensis Theobald on neonates and adults of the cladocerans Daphnia gessneri Herbst, Diaphanosoma birgei Kořínek, and Ceriodaphnia richardi Sars, and predation by the water mite Krendowskia sp. on neonates and adults of C. richardi and D. gessneri. In replicated treatments, the prey was offered alone or in combination with neonates and adults of two species and kept in bottles on a plankton wheel under controlled temperature, photoperiod, and light conditions. Chaoborus larvae preyed on neonates of D. birgei and D. gessneri and on adults of the former species. They preyed preferentially on neonates and adults of D. birgei over neonates and adults of C. richardi. The mite Krendowskia sp. preyed on only one species: neonates and adults of D. gessneri. Data on the distribution and strategies of prey in the lake are discussed in light of the experimental results, in an attempt to establish a link between laboratory data and field conditions.
{"title":"Experiments on invertebrate predation on cladocerans and its relationships with lake data","authors":"Tânia C. Dos Santos Ferreira, M. S. Arcifa","doi":"10.4081/jlimnol.2021.1987","DOIUrl":"https://doi.org/10.4081/jlimnol.2021.1987","url":null,"abstract":"Until recently, knowledge of the impact of invertebrate predators on cladocerans in the Brazilian Lake Monte Alegre was limited to a few species. In order to assess the effects of predation on other cladoceran species, experiments were carried out with different pair-wise combinations of prey species. The experiments tested predation by fourth instar larvae of the dipteran Chaoborus brasiliensis Theobald on neonates and adults of the cladocerans Daphnia gessneri Herbst, Diaphanosoma birgei Kořínek, and Ceriodaphnia richardi Sars, and predation by the water mite Krendowskia sp. on neonates and adults of C. richardi and D. gessneri. In replicated treatments, the prey was offered alone or in combination with neonates and adults of two species and kept in bottles on a plankton wheel under controlled temperature, photoperiod, and light conditions. Chaoborus larvae preyed on neonates of D. birgei and D. gessneri and on adults of the former species. They preyed preferentially on neonates and adults of D. birgei over neonates and adults of C. richardi. The mite Krendowskia sp. preyed on only one species: neonates and adults of D. gessneri. Data on the distribution and strategies of prey in the lake are discussed in light of the experimental results, in an attempt to establish a link between laboratory data and field conditions.","PeriodicalId":50164,"journal":{"name":"Journal of Limnology","volume":"1 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70279968","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}
Pub Date : 2020-12-07DOI: 10.4081/jlimnol.2020.1974
Massimo Morpurgo, P. Schuchert, S. Vorhauser, R. Alber
The freshwater jellyfish Craspedacusta sowerbii Lankester 1880 is a cryptic cosmopolitan invasive species, which occurs in all continents except Antarctica. Recent molecular studies suggest the existence of at least three very different genetic lineages of Craspedacusta: the “sowerbii”, the “kiatingi”, and the “sinensis” lineages. We report the presence of both medusae and polyps of this alien taxon in the Large Lake of Monticolo / Montiggl, a meso-eutrophic natural lake in the Province of Bolzano / Bozen in Northern Italy. Molecular analyses of mitochondrial 16S sequences showed that this population belongs to a different lineage than that recently described for Sicily (Southern Italy). Therefore, there are two different genetic lineages of C. sowerbii in Italy. In the Large Lake of Monticolo / Montiggl medusae were observed in 6 consecutive summers (2015 – 2020), from July to September. All the examined medusae were males. The stomach content analyses showed that zooplanktonic copepods and cladocerans with size range between 0.3 and 0.8 mm were the preferred prey of medusae. Polyps of C. sowerbii were recorded in the lake on the zebra mussel Dreissena polymorpha in shallow water and on the underside of artificial substrates. The analyses of zebra mussels would Ac ce pte d A rtic le
{"title":"Occurrence of two distinct lineages of the freshwater jellyfish Craspedacusta sowerbii (Hydrozoa: Limnomedusae) in Italy","authors":"Massimo Morpurgo, P. Schuchert, S. Vorhauser, R. Alber","doi":"10.4081/jlimnol.2020.1974","DOIUrl":"https://doi.org/10.4081/jlimnol.2020.1974","url":null,"abstract":"The freshwater jellyfish Craspedacusta sowerbii Lankester 1880 is a cryptic cosmopolitan invasive species, which occurs in all continents except Antarctica. Recent molecular studies suggest the existence of at least three very different genetic lineages of Craspedacusta: the “sowerbii”, the “kiatingi”, and the “sinensis” lineages. We report the presence of both medusae and polyps of this alien taxon in the Large Lake of Monticolo / Montiggl, a meso-eutrophic natural lake in the Province of Bolzano / Bozen in Northern Italy. Molecular analyses of mitochondrial 16S sequences showed that this population belongs to a different lineage than that recently described for Sicily (Southern Italy). Therefore, there are two different genetic lineages of C. sowerbii in Italy. In the Large Lake of Monticolo / Montiggl medusae were observed in 6 consecutive summers (2015 – 2020), from July to September. All the examined medusae were males. The stomach content analyses showed that zooplanktonic copepods and cladocerans with size range between 0.3 and 0.8 mm were the preferred prey of medusae. Polyps of C. sowerbii were recorded in the lake on the zebra mussel Dreissena polymorpha in shallow water and on the underside of artificial substrates. The analyses of zebra mussels would Ac ce pte d A rtic le","PeriodicalId":50164,"journal":{"name":"Journal of Limnology","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2020-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45574140","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}
Pub Date : 2020-11-03DOI: 10.4081/JLIMNOL.2020.1968
Marina Vilenica, M. Kerovec, Ivana Pozojević, Z. Mihaljević
Increasing human pressures have a negative impact on freshwater habitats and their biota worldwide. To protect habitats and the species contained within them, ecological assessments over a gradient of near natural to degraded freshwater habitats are essential. Odonata assemblages were investigated at 46 study sites in Croatia encompassing slightly to heavily modified lowland rivers and streams. Nymphs were sampled between April and September 2016 using a benthos hand net. A total of 19 species was recorded, and Ischnura elegans (Vander Linden, 1820) and Platycnemis pennipes (Pallas, 1771) were most frequently recorded. RDA analysis indicated that water pollution (i.e. levels of chemical oxygen demand and total organic carbon), water temperature and oxygen concentration had the highest influence in the formation of Odonata assemblages at a specific habitat, reflecting their widely recognized bioindicator properties. This study showed that degraded lowland rivers can provide habitat for a relatively low number of species with broad ecological tolerance, while rare and specialist species are generally not able to reproduce there. These results contribute to our knowledge of Odonata occurrence in anthropogenically impacted habitats, and their relationships with such degraded environment.
{"title":"Odonata assemblages in anthropogenically impacted lotic habitats","authors":"Marina Vilenica, M. Kerovec, Ivana Pozojević, Z. Mihaljević","doi":"10.4081/JLIMNOL.2020.1968","DOIUrl":"https://doi.org/10.4081/JLIMNOL.2020.1968","url":null,"abstract":"Increasing human pressures have a negative impact on freshwater habitats and their biota worldwide. To protect habitats and the species contained within them, ecological assessments over a gradient of near natural to degraded freshwater habitats are essential. Odonata assemblages were investigated at 46 study sites in Croatia encompassing slightly to heavily modified lowland rivers and streams. Nymphs were sampled between April and September 2016 using a benthos hand net. A total of 19 species was recorded, and Ischnura elegans (Vander Linden, 1820) and Platycnemis pennipes (Pallas, 1771) were most frequently recorded. RDA analysis indicated that water pollution (i.e. levels of chemical oxygen demand and total organic carbon), water temperature and oxygen concentration had the highest influence in the formation of Odonata assemblages at a specific habitat, reflecting their widely recognized bioindicator properties. This study showed that degraded lowland rivers can provide habitat for a relatively low number of species with broad ecological tolerance, while rare and specialist species are generally not able to reproduce there. These results contribute to our knowledge of Odonata occurrence in anthropogenically impacted habitats, and their relationships with such degraded environment.","PeriodicalId":50164,"journal":{"name":"Journal of Limnology","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2020-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44598295","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}
Pub Date : 2020-10-28DOI: 10.4081/JLIMNOL.2020.1959
P. Ramírez-García, D. Chicalote-Castillo
Changes in cyanobacterial density due to application of Artificial Floating Island model with macrophytes: an experimental case study in a tropical reservoir Pedro Ramírez-García,* David Chicalote-Castillo Laboratorio de Bacteriología, UIICSE, División de Investigación y Posgrado, Universidad Nacional Autónoma de México, Campus Iztacala, Tlalnepantla, Edo. Mex. México, C.P. 54090 *Corresponding author: micro@unam.mx
{"title":"Changes in cyanobacterial density due to application of Artificial Floating Island model with macrophytes: an experimental case study in a tropical reservoir","authors":"P. Ramírez-García, D. Chicalote-Castillo","doi":"10.4081/JLIMNOL.2020.1959","DOIUrl":"https://doi.org/10.4081/JLIMNOL.2020.1959","url":null,"abstract":"Changes in cyanobacterial density due to application of Artificial Floating Island model with macrophytes: an experimental case study in a tropical reservoir Pedro Ramírez-García,* David Chicalote-Castillo Laboratorio de Bacteriología, UIICSE, División de Investigación y Posgrado, Universidad Nacional Autónoma de México, Campus Iztacala, Tlalnepantla, Edo. Mex. México, C.P. 54090 *Corresponding author: micro@unam.mx","PeriodicalId":50164,"journal":{"name":"Journal of Limnology","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2020-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46276592","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}
Pub Date : 2020-10-28DOI: 10.4081/JLIMNOL.2020.1971
E. A. Panarelli, D. Nielsen, Aleicia Holland
Cladocerans are important filter-feeders transferring energy up the food web to different invertebrate and vertebrate predators. Along the flood period, cladocerans are one of the primary food sources for juvenile fish in floodplain. Resting egg banks allow cladoceran populations to overcome the environmental stress, related to several limnological changes, including complete drying of temporary wetlands. After drought, resting egg banks influence cladoceran community attributes during the cyclic and successional processes driven by episodic flood events. In this study we compared the taxonomic richness of active (from the water column) and dormant (from the sediment) Cladocera assemblages and analyzed the structure of resting egg banks, comparing the diversity, abundance and apparent viability/unviability of the eggs, between six temporary and six permanent wetlands, located along the Ovens River Floodplain, Victoria, Australia. The qualitative analysis shows higher taxonomic richness in active assemblages from temporary (24 taxa) than permanent (13 taxa) wetlands compared to dormant assemblages present in resting egg banks (9 taxa) from temporary and permanent wetlands. However, richness was influenced by taxonomic level of identification, with the majority of resting eggs only being identified to the taxonomic level of family (i.e. Chydoridae). Total taxa richness within egg banks was similar between wetland types, however, on average higher Shannon’s diversity of resting eggs was found within permanent (1.53) than temporary (0.82) wetlands. This is likely to be due to more stable wetlands not providing appropriate cues to trigger dormancy induction or breakage for specific populations, leading to higher values of evenness in permanent than temporary wetlands. Comparing permanent and temporary wetlands, higher abundance of resting eggs (more than four times) consisting of higher abundance of unviable eggs and similar viable egg abundance to permanent wetlands, was found within temporary wetlands, suggesting that the increased resting egg abundance in temporary wetlands is balanced by the losses due to factors such as predation, parasitism or other physical damage, during the terrestrial phase. Despite resistant outer shell structure, this study highlights that the damage to egg integrity is intensified in wetlands that undergo dry phases. Cladoceran resting egg banks represent the potential assemblage to recover after disturbance events such as drying, and information about these is important to ensure appropriate management and conservation of floodplain biodiversity. Corresponding author: panarelli1969@gmail.com
{"title":"Cladocera resting egg banks in temporary and permanent wetlands","authors":"E. A. Panarelli, D. Nielsen, Aleicia Holland","doi":"10.4081/JLIMNOL.2020.1971","DOIUrl":"https://doi.org/10.4081/JLIMNOL.2020.1971","url":null,"abstract":"Cladocerans are important filter-feeders transferring energy up the food web to different invertebrate and vertebrate predators. Along the flood period, cladocerans are one of the primary food sources for juvenile fish in floodplain. Resting egg banks allow cladoceran populations to overcome the environmental stress, related to several limnological changes, including complete drying of temporary wetlands. After drought, resting egg banks influence cladoceran community attributes during the cyclic and successional processes driven by episodic flood events. In this study we compared the taxonomic richness of active (from the water column) and dormant (from the sediment) Cladocera assemblages and analyzed the structure of resting egg banks, comparing the diversity, abundance and apparent viability/unviability of the eggs, between six temporary and six permanent wetlands, located along the Ovens River Floodplain, Victoria, Australia. The qualitative analysis shows higher taxonomic richness in active assemblages from temporary (24 taxa) than permanent (13 taxa) wetlands compared to dormant assemblages present in resting egg banks (9 taxa) from temporary and permanent wetlands. However, richness was influenced by taxonomic level of identification, with the majority of resting eggs only being identified to the taxonomic level of family (i.e. Chydoridae). Total taxa richness within egg banks was similar between wetland types, however, on average higher Shannon’s diversity of resting eggs was found within permanent (1.53) than temporary (0.82) wetlands. This is likely to be due to more stable wetlands not providing appropriate cues to trigger dormancy induction or breakage for specific populations, leading to higher values of evenness in permanent than temporary wetlands. Comparing permanent and temporary wetlands, higher abundance of resting eggs (more than four times) consisting of higher abundance of unviable eggs and similar viable egg abundance to permanent wetlands, was found within temporary wetlands, suggesting that the increased resting egg abundance in temporary wetlands is balanced by the losses due to factors such as predation, parasitism or other physical damage, during the terrestrial phase. Despite resistant outer shell structure, this study highlights that the damage to egg integrity is intensified in wetlands that undergo dry phases. Cladoceran resting egg banks represent the potential assemblage to recover after disturbance events such as drying, and information about these is important to ensure appropriate management and conservation of floodplain biodiversity. Corresponding author: panarelli1969@gmail.com","PeriodicalId":50164,"journal":{"name":"Journal of Limnology","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2020-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4081/JLIMNOL.2020.1971","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48271125","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}
Pub Date : 2020-10-01DOI: 10.4081/JLIMNOL.2020.1981
Nicola Ghirardi, Marina Amadori, G. Free, L. Giovannini, M. Toffolon, C. Giardino, M. Bresciani
We investigate the effect of the Adige-Garda spillway opening on the 03/03/2020 on Lake Garda using numerical modelling and maps of Suspended Particulate Matter (SPM) concentration. SPM maps are obtained from Sentinel-2 images processed using the BOMBER bio-optical model. Three satellite images are examined: 28/02/2020, 04/03/2020 and 07/03/2020. Maps indicate a significant increase in SPM concentrations, especially in the northern part of the lake close to the hydraulic tunnel outlet. Results are consistent with the modelled flow field. Remote sensing effectively captures the event’s spatial and temporal variation, while numerical modelling explains and corroborates the observed patterns. Corresponding author: ghirardi.n@irea.cnr.it
{"title":"Using remote sensing and numerical modelling to quantify a turbidity discharge event in Lake Garda","authors":"Nicola Ghirardi, Marina Amadori, G. Free, L. Giovannini, M. Toffolon, C. Giardino, M. Bresciani","doi":"10.4081/JLIMNOL.2020.1981","DOIUrl":"https://doi.org/10.4081/JLIMNOL.2020.1981","url":null,"abstract":"We investigate the effect of the Adige-Garda spillway opening on the 03/03/2020 on Lake Garda using numerical modelling and maps of Suspended Particulate Matter (SPM) concentration. SPM maps are obtained from Sentinel-2 images processed using the BOMBER bio-optical model. Three satellite images are examined: 28/02/2020, 04/03/2020 and 07/03/2020. Maps indicate a significant increase in SPM concentrations, especially in the northern part of the lake close to the hydraulic tunnel outlet. Results are consistent with the modelled flow field. Remote sensing effectively captures the event’s spatial and temporal variation, while numerical modelling explains and corroborates the observed patterns. Corresponding author: ghirardi.n@irea.cnr.it","PeriodicalId":50164,"journal":{"name":"Journal of Limnology","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2020-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4081/JLIMNOL.2020.1981","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45621657","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}
Pub Date : 2020-09-17DOI: 10.4081/JLIMNOL.2020.1982
F. Marrone, V. Pieri, S. Turki, G. Rossetti
Different lines of investigation have recently contributed to increasing the available knowledge about the invertebrates inhabiting inland waters of north Africa, but a comprehensive synopsis on Tunisian Ostracoda is missing to date. An updated checklist of Recent non-marine ostracods from Tunisia and data on their distribution is thus offered here, representing the most extensive survey on this crustacean group ever carried out in inland waters throughout the country. One-hundred-five sites covering various climate zones, from Mediterranean to desert areas, were sampled between 2002 and 2012. Most of the considered water bodies were temporary or ephemeral habitats, but a few permanent sites were sampled as well. Overall, 18 genera and 32 taxa of putative species rank were collected in the frame of this survey, among which nine species and five genera were new to Tunisian fauna. As a result of this study and based on previous investigations, nine families (Candonidae, Cyprididae, Cytherideidae, Darwinulidae, Ilyocyprididae, Leptocytheridae, Limnocytheridae, Loxoconchidae, Paradoxostomatidae), 29 genera and at least 45 species of non-marine ostracods are currently known for Tunisia, which thus prove to host the most diverse ostracod fauna among north African countries. The number of species occurring in a single sample varied from 1 to 4. The Eucypris virens complex was the most widespread taxon (58 records), followed by Heterocypris barbara (30 records), Heterocypris incongruens (22 records), and Sarscypridopsis aculeata (16 records). For some ostracod species, clear distributional gradients associated with different climatic conditions were observed. The affinities with adjacent Maghrebian ostracod faunas are discussed. This study confirms the crucial role played by marginal aquatic habitats for the conservation of biodiversity, in particular in arid and semi-arid regions.
{"title":"The Recent non-marine ostracods of Tunisia: an updated checklist with remarks on their regional distribution patterns and ecological preferences","authors":"F. Marrone, V. Pieri, S. Turki, G. Rossetti","doi":"10.4081/JLIMNOL.2020.1982","DOIUrl":"https://doi.org/10.4081/JLIMNOL.2020.1982","url":null,"abstract":"Different lines of investigation have recently contributed to increasing the available knowledge about the invertebrates inhabiting inland waters of north Africa, but a comprehensive synopsis on Tunisian Ostracoda is missing to date. An updated checklist of Recent non-marine ostracods from Tunisia and data on their distribution is thus offered here, representing the most extensive survey on this crustacean group ever carried out in inland waters throughout the country. One-hundred-five sites covering various climate zones, from Mediterranean to desert areas, were sampled between 2002 and 2012. Most of the considered water bodies were temporary or ephemeral habitats, but a few permanent sites were sampled as well. Overall, 18 genera and 32 taxa of putative species rank were collected in the frame of this survey, among which nine species and five genera were new to Tunisian fauna. As a result of this study and based on previous investigations, nine families (Candonidae, Cyprididae, Cytherideidae, Darwinulidae, Ilyocyprididae, Leptocytheridae, Limnocytheridae, Loxoconchidae, Paradoxostomatidae), 29 genera and at least 45 species of non-marine ostracods are currently known for Tunisia, which thus prove to host the most diverse ostracod fauna among north African countries. The number of species occurring in a single sample varied from 1 to 4. The Eucypris virens complex was the most widespread taxon (58 records), followed by Heterocypris barbara (30 records), Heterocypris incongruens (22 records), and Sarscypridopsis aculeata (16 records). For some ostracod species, clear distributional gradients associated with different climatic conditions were observed. The affinities with adjacent Maghrebian ostracod faunas are discussed. This study confirms the crucial role played by marginal aquatic habitats for the conservation of biodiversity, in particular in arid and semi-arid regions.","PeriodicalId":50164,"journal":{"name":"Journal of Limnology","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2020-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47510583","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}
Pub Date : 2020-09-02DOI: 10.4081/JLIMNOL.2020.1973
Tanner Liang, J. Aherne
Lakes and ponds are a major feature of the Arctic landscape and are recognized as effective ‘sentinels of change’. Here we present water chemistry characteristics of lakes and ponds (n=1300 with 26 variables) across the Canadian Arctic collated from published studies. We also extracted geological and ecoregion data in an attempt to determine the key drivers. In general, most lakes were shallow (85.4%, <10 m), nutrient (phosphorus) poor (oligotrophic = 45.6% and ultra-oligotrophic = 24.8%), located at low elevation (66.5%, <200 m asl), close to coastlines (72.5%, 0-50 km), and underlain by sedimentary geology (66.5%). The first two components from Principal Component Analysis explained 49.3% of the variation in the dataset; the first component was dominated by conductivity/carbonate materials, and the second component suggested allochthonous inputs of phosphorus. In general, bedrock geology is the primary driver of water chemistry; as such, there were major differences between lakes underlain by igneous and sedimentary rocks. Those on sedimentary bedrock tend to have higher pH, nutrients and higher inorganic ion concentrations.
{"title":"Physical and chemical characteristics of 1300 lakes and ponds across the Canadian Arctic","authors":"Tanner Liang, J. Aherne","doi":"10.4081/JLIMNOL.2020.1973","DOIUrl":"https://doi.org/10.4081/JLIMNOL.2020.1973","url":null,"abstract":"Lakes and ponds are a major feature of the Arctic landscape and are recognized as effective ‘sentinels of change’. Here we present water chemistry characteristics of lakes and ponds (n=1300 with 26 variables) across the Canadian Arctic collated from published studies. We also extracted geological and ecoregion data in an attempt to determine the key drivers. In general, most lakes were shallow (85.4%, <10 m), nutrient (phosphorus) poor (oligotrophic = 45.6% and ultra-oligotrophic = 24.8%), located at low elevation (66.5%, <200 m asl), close to coastlines (72.5%, 0-50 km), and underlain by sedimentary geology (66.5%). The first two components from Principal Component Analysis explained 49.3% of the variation in the dataset; the first component was dominated by conductivity/carbonate materials, and the second component suggested allochthonous inputs of phosphorus. In general, bedrock geology is the primary driver of water chemistry; as such, there were major differences between lakes underlain by igneous and sedimentary rocks. Those on sedimentary bedrock tend to have higher pH, nutrients and higher inorganic ion concentrations.","PeriodicalId":50164,"journal":{"name":"Journal of Limnology","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2020-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49232523","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}
Pub Date : 2020-07-01DOI: 10.4081/jlimnol.2020.1964
Andreas Laug, Falko Turner, S. Engels, Junbo Wang, T. Haberzettl, J. Ju, Siwei Yu, Qiangqiang Kou, N. Börner, A. Schwalb
Fluctuating lake levels are an important driver of ecosystem change, and changes in the precipitation/evaporation balance of a region can lead to undesirable changes in ecosystem functioning. Large-scale changes in hydrology will become increasingly more likely as a result of ongoing climate change in the coming century. This is especially true for the Tibetan Plateau, which plays a crucial role as the “Asian water tower” for the surrounding densely populated regions. Chironomids (Diptera: Chironomidae) have proven to be one of the most valuable bioindicators for monitoring and reconstructing the development of aquatic ecosystems. Besides temperature, water depth and salinity are two of the most important environmental factors affecting chironomids. To study the relationship between chironomids and water depth, we analyzed surface sediment samples of two large Tibetan lakes, Selin Co and Taro Co. These lakes have similar environmental conditions (e.g. elevation, temperature and oxygenation) but show strong differences in salinity (7–10 and 0.5 ppt, respectively). Our results show that the chironomid assemblages in both lakes have similar water depths at which the fauna abruptly changes in composition, despite different faunal assemblages. The most important boundaries were identified at 0.8 and 16 m water depth. While the uppermost meter, the “splash zone”, is characterized by distinctly different conditions, resulting from waves and changing water levels, the cause of the lower zone boundary remains enigmatic. Even though none of the measured water depth-related factors, such as water temperature, oxygen content, sediment properties, light intensity or macrophyte vegetation, show a distinct change at 16 m water depth, comparison to other records show that a similar change in the chironomid fauna occurs at 16 m water depth in large, deep lakes around the world. We propose that this boundary might be connected to water pressure influencing the living conditions of the larvae or the absolute distance to the surface that has to be covered for the chironomid larvae to hatch. We conclude that water depth either directly or indirectly exerts a strong control on the chironomid assemblages even under different salinities, resulting in distribution patterns that can be used to reconstruct past fluctuations in water depths.
{"title":"Is there a common threshold to subfossil chironomid assemblages at 16 m water depth? Evidence from the Tibetan Plateau","authors":"Andreas Laug, Falko Turner, S. Engels, Junbo Wang, T. Haberzettl, J. Ju, Siwei Yu, Qiangqiang Kou, N. Börner, A. Schwalb","doi":"10.4081/jlimnol.2020.1964","DOIUrl":"https://doi.org/10.4081/jlimnol.2020.1964","url":null,"abstract":"Fluctuating lake levels are an important driver of ecosystem change, and changes in the precipitation/evaporation balance of a region can lead to undesirable changes in ecosystem functioning. Large-scale changes in hydrology will become increasingly more likely as a result of ongoing climate change in the coming century. This is especially true for the Tibetan Plateau, which plays a crucial role as the “Asian water tower” for the surrounding densely populated regions. Chironomids (Diptera: Chironomidae) have proven to be one of the most valuable bioindicators for monitoring and reconstructing the development of aquatic ecosystems. Besides temperature, water depth and salinity are two of the most important environmental factors affecting chironomids. To study the relationship between chironomids and water depth, we analyzed surface sediment samples of two large Tibetan lakes, Selin Co and Taro Co. These lakes have similar environmental conditions (e.g. elevation, temperature and oxygenation) but show strong differences in salinity (7–10 and 0.5 ppt, respectively). Our results show that the chironomid assemblages in both lakes have similar water depths at which the fauna abruptly changes in composition, despite different faunal assemblages. The most important boundaries were identified at 0.8 and 16 m water depth. While the uppermost meter, the “splash zone”, is characterized by distinctly different conditions, resulting from waves and changing water levels, the cause of the lower zone boundary remains enigmatic. Even though none of the measured water depth-related factors, such as water temperature, oxygen content, sediment properties, light intensity or macrophyte vegetation, show a distinct change at 16 m water depth, comparison to other records show that a similar change in the chironomid fauna occurs at 16 m water depth in large, deep lakes around the world. We propose that this boundary might be connected to water pressure influencing the living conditions of the larvae or the absolute distance to the surface that has to be covered for the chironomid larvae to hatch. We conclude that water depth either directly or indirectly exerts a strong control on the chironomid assemblages even under different salinities, resulting in distribution patterns that can be used to reconstruct past fluctuations in water depths.","PeriodicalId":50164,"journal":{"name":"Journal of Limnology","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45434296","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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