E. Anufriieva, M. Goher, Abd-Ellatif M. Hussian, S. M. El-Sayed, Mahmoud H. Hegab, Usama M. Tahoun, N. Shadrin
The Wadi El-Rayan is a depression in the Fayoum oasis collecting agricultural drainage water from the Fayoum. Since 1973, this drainage water formed two man-made lakes. Twenty years ago, a third lake, called Lake Magic was formed. Since this newly formed lake was not yet studied, in January of 2019 we conducted research related to its physico-chemical (ion composition, nutrients, heavy metals, etc.) and biological (phyto-, bacterio- and zooplankton) characteristics. The depth of the lake ranged from 1.5 to 9.0 m, water transparency was up to 4.0 m, and the water temperature was 13.6 °C. The average salinity was 29.1 g/l, and the salinity of drainage waters from agricultural fields was 2.9 g/l. A total of 28 phytoplankton species was identified belonging to Bacillariophyceae (eight species), Dinophyceae (three species), Cyanobacteria (seven species), Chlorophyceae (nine species) and Conjugatophyceae (one species). Chlorophyllacontent varied from 14.3 to 24.2 μg/l. In zooplankton, there were three species of Ciliophora, five of Rotifera, and two Copepoda as well as Nematoda and Cirripedia larvae. Salinity in Lake Magic was much higher than in drainage waters coming in the lake. This is a result of a strong salinity increase in Lake Magic after its creation due to climate aridity, and salinity may markedly increase during the next 20 years along with the sharp changes of the lake's ecosystem.
{"title":"Ecosystems of artificial saline lakes. A case of Lake Magic in Wadi El-Rayan depression (Egypt)","authors":"E. Anufriieva, M. Goher, Abd-Ellatif M. Hussian, S. M. El-Sayed, Mahmoud H. Hegab, Usama M. Tahoun, N. Shadrin","doi":"10.1051/kmae/2020024","DOIUrl":"https://doi.org/10.1051/kmae/2020024","url":null,"abstract":"The Wadi El-Rayan is a depression in the Fayoum oasis collecting agricultural drainage water from the Fayoum. Since 1973, this drainage water formed two man-made lakes. Twenty years ago, a third lake, called Lake Magic was formed. Since this newly formed lake was not yet studied, in January of 2019 we conducted research related to its physico-chemical (ion composition, nutrients, heavy metals, etc.) and biological (phyto-, bacterio- and zooplankton) characteristics. The depth of the lake ranged from 1.5 to 9.0 m, water transparency was up to 4.0 m, and the water temperature was 13.6 °C. The average salinity was 29.1 g/l, and the salinity of drainage waters from agricultural fields was 2.9 g/l. A total of 28 phytoplankton species was identified belonging to Bacillariophyceae (eight species), Dinophyceae (three species), Cyanobacteria (seven species), Chlorophyceae (nine species) and Conjugatophyceae (one species). Chlorophyllacontent varied from 14.3 to 24.2 μg/l. In zooplankton, there were three species of Ciliophora, five of Rotifera, and two Copepoda as well as Nematoda and Cirripedia larvae. Salinity in Lake Magic was much higher than in drainage waters coming in the lake. This is a result of a strong salinity increase in Lake Magic after its creation due to climate aridity, and salinity may markedly increase during the next 20 years along with the sharp changes of the lake's ecosystem.","PeriodicalId":54748,"journal":{"name":"Knowledge and Management of Aquatic Ecosystems","volume":"12 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89421471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
S. Nagayama, M. Kume, Munehiro Oota, Koichiro Mizushima, Seiichi Mori
The coypu (Myocastor coypus) is a semi-aquatic herbivorous rodent that has been suspected to prey on freshwater unionid mussels in Japan. Fecal DNA metabarcoding that targeted bivalves and terrestrial plants was performed to examine the diet of exotic coypu in the Kiso River, central Japan. Thirty-two fecal samples from four floodplain waterbodies were collected seasonally. In one of the waterbodies, live and dead mussels were investigated to examine the possible effects of coypu predation on mussel population structures. Common coypu predation on unionid mussels was confirmed in two waterbodies. Midden surveys showed that medium- to large-sized mussels tended to be consumed by coypu; possibly resulting in population structures with few large-sized individuals. Seasonal diet selection of terrestrial plants was also detected: two perennial plants were consumed throughout the year, whereas some perennial plants were consumed seasonally. The number of terrestrial plant species/taxa as primary food was higher in summer than in winter, which was attributed to the high consumption of annual plants in the summer. Future studies need to examine the exhaustive diet of coypu including other animals and plants, as well as its effects on freshwater ecosystems in invaded regions.
{"title":"Common coypu predation on unionid mussels and terrestrial plants in an invaded Japanese river","authors":"S. Nagayama, M. Kume, Munehiro Oota, Koichiro Mizushima, Seiichi Mori","doi":"10.1051/kmae/2020029","DOIUrl":"https://doi.org/10.1051/kmae/2020029","url":null,"abstract":"The coypu (Myocastor coypus) is a semi-aquatic herbivorous rodent that has been suspected to prey on freshwater unionid mussels in Japan. Fecal DNA metabarcoding that targeted bivalves and terrestrial plants was performed to examine the diet of exotic coypu in the Kiso River, central Japan. Thirty-two fecal samples from four floodplain waterbodies were collected seasonally. In one of the waterbodies, live and dead mussels were investigated to examine the possible effects of coypu predation on mussel population structures. Common coypu predation on unionid mussels was confirmed in two waterbodies. Midden surveys showed that medium- to large-sized mussels tended to be consumed by coypu; possibly resulting in population structures with few large-sized individuals. Seasonal diet selection of terrestrial plants was also detected: two perennial plants were consumed throughout the year, whereas some perennial plants were consumed seasonally. The number of terrestrial plant species/taxa as primary food was higher in summer than in winter, which was attributed to the high consumption of annual plants in the summer. Future studies need to examine the exhaustive diet of coypu including other animals and plants, as well as its effects on freshwater ecosystems in invaded regions.","PeriodicalId":54748,"journal":{"name":"Knowledge and Management of Aquatic Ecosystems","volume":"46 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72798874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Marion Legrand, Cédric Briand, L. Buisson, Gwenaël Artur, D. Azam, A. Baisez, David Barracou, Nicolas Bourré, L. Carry, A. Caudal, Fabien Charrier, Jérémie Corre, Eric Croguennec, Sophie Der Mikaélian, Q. Josset, L. L. Gurun, Frederick E. Schaeffer, P. Laffaille
The decline and collapse of populations have been reported for a large range of taxa. Diadromous fishes migrate between fresh water and the sea and encounter many anthropogenic pressures during their complex life cycle. In spite of being of ecological, cultural and economic interest, diadromous fishes have been in decline for decades in many parts across the world. In this study, we investigated the change in five diadromous fish counts in France over a 30-year period using 43 monitoring stations located in 29 rivers across 18 catchments. Our hypothesis was that the counts of these species evolved in a contrasting way between catchments. We also tested the effect of five drivers potentially contributing to the observed trends: catchment, latitude, presence of commercial fisheries, improvement of ecological continuity and salmon stocking. We found contrasting trends in fish counts between species at the national scale, with some taxa increasing (Anguilla anguilla and Salmo trutta), some showing a slight increase (Salmo salar) and some decreasing (Alosa spp. and Petromyzon marinus). For each taxon, except Anguilla anguilla, we highlighted a significant catchment effect indicating contrasting trends between catchments and stations. However, we found no significant effect of catchment characteristics for any of the studied taxa.
{"title":"Contrasting trends between species and catchments in diadromous fish counts over the last 30 years in France","authors":"Marion Legrand, Cédric Briand, L. Buisson, Gwenaël Artur, D. Azam, A. Baisez, David Barracou, Nicolas Bourré, L. Carry, A. Caudal, Fabien Charrier, Jérémie Corre, Eric Croguennec, Sophie Der Mikaélian, Q. Josset, L. L. Gurun, Frederick E. Schaeffer, P. Laffaille","doi":"10.1051/kmae/2019046","DOIUrl":"https://doi.org/10.1051/kmae/2019046","url":null,"abstract":"The decline and collapse of populations have been reported for a large range of taxa. Diadromous fishes migrate between fresh water and the sea and encounter many anthropogenic pressures during their complex life cycle. In spite of being of ecological, cultural and economic interest, diadromous fishes have been in decline for decades in many parts across the world. In this study, we investigated the change in five diadromous fish counts in France over a 30-year period using 43 monitoring stations located in 29 rivers across 18 catchments. Our hypothesis was that the counts of these species evolved in a contrasting way between catchments. We also tested the effect of five drivers potentially contributing to the observed trends: catchment, latitude, presence of commercial fisheries, improvement of ecological continuity and salmon stocking. We found contrasting trends in fish counts between species at the national scale, with some taxa increasing (Anguilla anguilla and Salmo trutta), some showing a slight increase (Salmo salar) and some decreasing (Alosa spp. and Petromyzon marinus). For each taxon, except Anguilla anguilla, we highlighted a significant catchment effect indicating contrasting trends between catchments and stations. However, we found no significant effect of catchment characteristics for any of the studied taxa.","PeriodicalId":54748,"journal":{"name":"Knowledge and Management of Aquatic Ecosystems","volume":"23 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85660754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 contribution presents first record of a blue colour morph of spiny-cheek crayfish, Faxonius limosus (Rafinesque, 1817). Two unusually coloured individuals were caught in Poland, in two different locations, separated from each other by approximately 500 km and belonging to different river catchments (Oder and Vistula), within the range of the species occurrence in Europe. Taxonomic identification of collected crayfish has been confirmed by the standard DNA barcoding procedure. Although blue coloured forms of crayfish have been previously described within the Cambaridae family, collected individuals are the first records of blue colouration within F. limosus. It is recommended to supplement identification keys with a new colour form of the species, which, while characteristic dark red bands are not clear, may cause mistakes in recognition of exotic, aquarium as well as native species.
{"title":"First record and DNA barcodes of the invasive blue-coloured spiny-cheek crayfish Faxonius limosus (Rafinesque, 1817) (Decapoda: Cambaridae)","authors":"R. Maciaszek, M. Bonk, W. Sosnowski, A. Jabłońska","doi":"10.1051/kmae/2020014","DOIUrl":"https://doi.org/10.1051/kmae/2020014","url":null,"abstract":"This contribution presents first record of a blue colour morph of spiny-cheek crayfish, Faxonius limosus (Rafinesque, 1817). Two unusually coloured individuals were caught in Poland, in two different locations, separated from each other by approximately 500 km and belonging to different river catchments (Oder and Vistula), within the range of the species occurrence in Europe. Taxonomic identification of collected crayfish has been confirmed by the standard DNA barcoding procedure. Although blue coloured forms of crayfish have been previously described within the Cambaridae family, collected individuals are the first records of blue colouration within F. limosus. It is recommended to supplement identification keys with a new colour form of the species, which, while characteristic dark red bands are not clear, may cause mistakes in recognition of exotic, aquarium as well as native species.","PeriodicalId":54748,"journal":{"name":"Knowledge and Management of Aquatic Ecosystems","volume":"2 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80008583","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Thendo Mutshekwa, Ross N. Cuthbert, R. Wasserman, Florence M. Murungweni, T. Dalu
Lake and reservoir ecosystems are regarded as heterotrophic detritus-based habitats which are dependent on both autochthonous and allochthonous organic matter for the majority of energy inputs. In particular, allochthonous detritus is in particular important for the trophic dynamics of microbial organisms, macroinvertebrates and benthic plants in freshwaters. Here, we assess macroinvertebrate colonisation, and quantify decomposition rates, of leaf litter from species of native and invasive plants in a small agricultural reservoir. Native fig Ficus sycomorus and silver cluster–leaf Terminalia sericea were compared to invasive tickberry Lantana camara and guava Psidium guajava, whereby macroinvertebrate colonisation was assessed over time. Leaf treatments had a significant, group-specific effect on abundances and composition among focal macroinvertebrates. Invasive leaves reduced Physidae and Oligochaeta abundances, yet Ostracoda were significantly more abundant in the presence of invasive P. guajava. Chironomidae relative abundances increased under invasive L. camara treatments, whilst differences among leaf treatment effects on Coenogrionidae abundances were not statistically clear. In turn, macroinvertebrate diversity did not differ significantly among plant treatment groups. The decomposition rate of the leaf litter demonstrated differences among the species, following a decreasing order of L. camara > F. sycomorus > T. sericea > P. guajava. The study results highlight that leaf litter species identity among invasive and native plants plays an important role in the colonisation of macroinvertebrates in small reservoirs, thereby differentially supporting aquatic environments and food webs. However, differences were not uniform across invader-native groupings. Nonetheless, certain invasive leaf litter decomposes faster than native litter, with possible implications for broader nutrient dynamics and subsequent community composition.
{"title":"Macroinvertebrate colonisation associated with native and invasive leaf litter decomposition","authors":"Thendo Mutshekwa, Ross N. Cuthbert, R. Wasserman, Florence M. Murungweni, T. Dalu","doi":"10.1051/kmae/2020025","DOIUrl":"https://doi.org/10.1051/kmae/2020025","url":null,"abstract":"Lake and reservoir ecosystems are regarded as heterotrophic detritus-based habitats which are dependent on both autochthonous and allochthonous organic matter for the majority of energy inputs. In particular, allochthonous detritus is in particular important for the trophic dynamics of microbial organisms, macroinvertebrates and benthic plants in freshwaters. Here, we assess macroinvertebrate colonisation, and quantify decomposition rates, of leaf litter from species of native and invasive plants in a small agricultural reservoir. Native fig Ficus sycomorus and silver cluster–leaf Terminalia sericea were compared to invasive tickberry Lantana camara and guava Psidium guajava, whereby macroinvertebrate colonisation was assessed over time. Leaf treatments had a significant, group-specific effect on abundances and composition among focal macroinvertebrates. Invasive leaves reduced Physidae and Oligochaeta abundances, yet Ostracoda were significantly more abundant in the presence of invasive P. guajava. Chironomidae relative abundances increased under invasive L. camara treatments, whilst differences among leaf treatment effects on Coenogrionidae abundances were not statistically clear. In turn, macroinvertebrate diversity did not differ significantly among plant treatment groups. The decomposition rate of the leaf litter demonstrated differences among the species, following a decreasing order of L. camara > F. sycomorus > T. sericea > P. guajava. The study results highlight that leaf litter species identity among invasive and native plants plays an important role in the colonisation of macroinvertebrates in small reservoirs, thereby differentially supporting aquatic environments and food webs. However, differences were not uniform across invader-native groupings. Nonetheless, certain invasive leaf litter decomposes faster than native litter, with possible implications for broader nutrient dynamics and subsequent community composition.","PeriodicalId":54748,"journal":{"name":"Knowledge and Management of Aquatic Ecosystems","volume":"1 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1051/kmae/2020025","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57906321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
R. Sousa, A. Bogan, D. Gonçalves, J. Lajtner, V. Prié, N. Riccardi, S. Shumka, A. Teixeira, M. Urbańska, S. Varandas, M. Lopes‐Lima
We report for the first time that the freshwater mussel Microcondylaea bonellii (Férussac, 1827) functions as a suitable host for the European bitterling Rhodeus amarus (Bloch, 1782). Given the recent expansion of R. amarus in Europe, the possible physiological cost (e.g. competition for oxygen, reduction in water circulation, and consequent impairment of filter-feeding) of this interaction may further affect the already poor conservation status of M. bonellii populations.
{"title":"Microcondylaea bonellii as a new host for the European bitterling Rhodeus amarus","authors":"R. Sousa, A. Bogan, D. Gonçalves, J. Lajtner, V. Prié, N. Riccardi, S. Shumka, A. Teixeira, M. Urbańska, S. Varandas, M. Lopes‐Lima","doi":"10.1051/kmae/2019047","DOIUrl":"https://doi.org/10.1051/kmae/2019047","url":null,"abstract":"We report for the first time that the freshwater mussel Microcondylaea bonellii (Férussac, 1827) functions as a suitable host for the European bitterling Rhodeus amarus (Bloch, 1782). Given the recent expansion of R. amarus in Europe, the possible physiological cost (e.g. competition for oxygen, reduction in water circulation, and consequent impairment of filter-feeding) of this interaction may further affect the already poor conservation status of M. bonellii populations.","PeriodicalId":54748,"journal":{"name":"Knowledge and Management of Aquatic Ecosystems","volume":"16 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74758316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 biomonitoring great attention has been paid on the selection of the best indices and metrics, often neglecting a simple but fundamental aspect: how reliable are the sampling methodologies? We tested the efficiency of the Surber net in collecting stream macroinvertebrates by comparing two samples collected consecutively on the same plot. We found that substrate particle size and water depth and velocity significantly affected sampling efficiency, especially regarding the total taxa richness, EPT (Ephemeroptera, Plecoptera and Trichoptera) richness and density. This study therefore provides useful insights to collect stream macroinvertebrates using the Surber net under different near-bed conditions.
{"title":"Efficiency of Surber net under different substrate and flow conditions: insights for macroinvertebrates sampling and river biomonitoring","authors":"A. Doretto, T. Bo, F. Bona, S. Fenoglio","doi":"10.1051/kmae/2020001","DOIUrl":"https://doi.org/10.1051/kmae/2020001","url":null,"abstract":"In biomonitoring great attention has been paid on the selection of the best indices and metrics, often neglecting a simple but fundamental aspect: how reliable are the sampling methodologies? We tested the efficiency of the Surber net in collecting stream macroinvertebrates by comparing two samples collected consecutively on the same plot. We found that substrate particle size and water depth and velocity significantly affected sampling efficiency, especially regarding the total taxa richness, EPT (Ephemeroptera, Plecoptera and Trichoptera) richness and density. This study therefore provides useful insights to collect stream macroinvertebrates using the Surber net under different near-bed conditions.","PeriodicalId":54748,"journal":{"name":"Knowledge and Management of Aquatic Ecosystems","volume":"26 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88599632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Rewicz, Jarosław Brodecki, K. Bącela-Spychalska, A. Konopacka, M. Grabowski
Cryptorchestia garbinii Ruffo, Tarocco and Latella, 2014 (Amphipoda: Talitridae), a semiterrestrial amphipod, reported (as Orchestia cavimana Heller, 1865) from the Polish inland waters, e.g., the lowermost Vistula River, for the first time in 2009. Now, we have reported this species from the upper Oder River, which is c.a. 350 km SE from the closest known localities near Berlin, Germany. We confirmed its identity by the DNA barcodes and showed that all individuals found so far in other countries in Central and Western Europe represent the same haplotype, excluding a singleton from the locus typicus of this species in Lake Garda, Italy.
{"title":"Further steps of Cryptorchestia garbinii invasion in Polish inland waters with insights into its molecular diversity in Central and Western Europe","authors":"T. Rewicz, Jarosław Brodecki, K. Bącela-Spychalska, A. Konopacka, M. Grabowski","doi":"10.1051/kmae/2020009","DOIUrl":"https://doi.org/10.1051/kmae/2020009","url":null,"abstract":"Cryptorchestia garbinii Ruffo, Tarocco and Latella, 2014 (Amphipoda: Talitridae), a semiterrestrial amphipod, reported (as Orchestia cavimana Heller, 1865) from the Polish inland waters, e.g., the lowermost Vistula River, for the first time in 2009. Now, we have reported this species from the upper Oder River, which is c.a. 350 km SE from the closest known localities near Berlin, Germany. We confirmed its identity by the DNA barcodes and showed that all individuals found so far in other countries in Central and Western Europe represent the same haplotype, excluding a singleton from the locus typicus of this species in Lake Garda, Italy.","PeriodicalId":54748,"journal":{"name":"Knowledge and Management of Aquatic Ecosystems","volume":"os-5 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87026898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
P. Negus, J. Marshall, A. Steward, G. Mcgregor, Ruth A. O'Connor
Hot springs are characterised by water temperatures above 36.7 °C. Temperature decreases with distance in flow away from spring vents; this natural gradient provides a unique opportunity to investigate the influence of water temperature on aquatic biota. This study investigated the relationship between water temperature and the aquatic invertebrates and benthic diatoms in outflows from a hot spring complex in tropical north Queensland, Australia. Water temperature ranged from 62.7 °C at the vents to 26.0 °C at the location furthest downstream. Richness of benthic diatoms and aquatic invertebrates increased linearly in response to decreasing temperature, with no species present in the hot vents. Multivariate analysis showed that both community assemblages had a response to the temperature gradient. A drop in aquatic invertebrate richness and a change in assemblage composition occurred between 40 °C and 42 °C, indicating a threshold at this temperature. The nearby Einasleigh River has experienced several contemporary peaks in water temperature over 40 °C, which corresponds to this threshold level. The relationships indicate that consistent increases in water temperature expected under climate change could decrease biological richness and precipitate changes in the aquatic invertebrate and benthic diatom taxa of tropical aquatic ecosystems.
{"title":"Aquatic biota in hot water: thermal gradients in rheocrene hot spring discharges as analogues for the effects of climate warming","authors":"P. Negus, J. Marshall, A. Steward, G. Mcgregor, Ruth A. O'Connor","doi":"10.1051/kmae/2020042","DOIUrl":"https://doi.org/10.1051/kmae/2020042","url":null,"abstract":"Hot springs are characterised by water temperatures above 36.7 °C. Temperature decreases with distance in flow away from spring vents; this natural gradient provides a unique opportunity to investigate the influence of water temperature on aquatic biota. This study investigated the relationship between water temperature and the aquatic invertebrates and benthic diatoms in outflows from a hot spring complex in tropical north Queensland, Australia. Water temperature ranged from 62.7 °C at the vents to 26.0 °C at the location furthest downstream. Richness of benthic diatoms and aquatic invertebrates increased linearly in response to decreasing temperature, with no species present in the hot vents. Multivariate analysis showed that both community assemblages had a response to the temperature gradient. A drop in aquatic invertebrate richness and a change in assemblage composition occurred between 40 °C and 42 °C, indicating a threshold at this temperature. The nearby Einasleigh River has experienced several contemporary peaks in water temperature over 40 °C, which corresponds to this threshold level. The relationships indicate that consistent increases in water temperature expected under climate change could decrease biological richness and precipitate changes in the aquatic invertebrate and benthic diatom taxa of tropical aquatic ecosystems.","PeriodicalId":54748,"journal":{"name":"Knowledge and Management of Aquatic Ecosystems","volume":"42 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85321828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 a Chaetomorpha linum high density mat extending over 300 hectares, between 2017 and 2019 samples were collected for C, N, P, S tissue content determination, biomass (b) was estimated, sediment samples collected for labile organic matter (LOM) determination, and water chemical-physical variables measured. The latter showed extreme conditions with a wide range of values and with zero oxygen for long periods. N-NO3:SRP atomic ratio showed extreme P-limitation. Tissue macronutrients showed very variable values, highlighting a strong P-limitation and relatively high level of S. With exception of nitrogen, no significant differences were detected for each macronutrient between the months and between the stations, neither was any correlation found between macronutrients and LOM and b data-set. The growth and survival of the mat occurred despite the scarcity of P, which probably reached with very low frequency the surface layer of the mat, the one capable of performing photosynthesis, where it was quickly re-assimilated and utilised.
{"title":"C, N, P, S content of the Chlorophyta Chaetomorpha linum (Müller) Kützing in a vast high density mat of a Mediterranean non-tidal lagoon","authors":"M. Lenzi, M. Leporatti-Persiano, P. Gennaro","doi":"10.1051/kmae/2020030","DOIUrl":"https://doi.org/10.1051/kmae/2020030","url":null,"abstract":"In a Chaetomorpha linum high density mat extending over 300 hectares, between 2017 and 2019 samples were collected for C, N, P, S tissue content determination, biomass (b) was estimated, sediment samples collected for labile organic matter (LOM) determination, and water chemical-physical variables measured. The latter showed extreme conditions with a wide range of values and with zero oxygen for long periods. N-NO3:SRP atomic ratio showed extreme P-limitation. Tissue macronutrients showed very variable values, highlighting a strong P-limitation and relatively high level of S. With exception of nitrogen, no significant differences were detected for each macronutrient between the months and between the stations, neither was any correlation found between macronutrients and LOM and b data-set. The growth and survival of the mat occurred despite the scarcity of P, which probably reached with very low frequency the surface layer of the mat, the one capable of performing photosynthesis, where it was quickly re-assimilated and utilised.","PeriodicalId":54748,"journal":{"name":"Knowledge and Management of Aquatic Ecosystems","volume":"87 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85881111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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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