Studies on <i>Eurytemora</i>最新文献

{"title":"How many generations does Epischura baikalensis (Copepoda, Calanoida) have in Lake Baikal?","authors":"E. Naumova, V. Alekseev","doi":"10.1163/15685403-00003981","DOIUrl":"https://doi.org/10.1163/15685403-00003981","url":null,"abstract":"\u0000Epischura baikalensis Sars is a dominant pelagic species of the Lake Baikal zooplankton. We empirically determined the duration of the development of Epischura from field data, as it is not possible to determine this experimentally. Based on our data, we conclude that the central pelagic food web of metazoan species in Lake Baikal has not two, as was previously accepted, but three generations during a year and each lasts not 6 but instead 3 to 4 months. The life cycle of the species also possibly includes a 3-months long winter embryonic diapause, starting in November and ending in late February with the start of the under-ice algae bloom. The high nauplii density in spring is not the result of high adult density, suggesting the presence of resting eggs in the E. baikalensis life cycle. We also found a large morphological difference between the pelagic eggs of the species in the winter and in the summertime. The possible participation of diatom algal toxins in the regulation of the seasonal dynamics of their main consumer in Lake Baikal, similar to those known in marine ecosystems, is discussed. The population dynamics in a year with relatively low diatom algae density show four peaks of reproduction, i.e., in February, June, September, and December. In years with significant (more than 15 000 cells/l) diatom blooming we found mass mortality of E. baikalensis juveniles in the plankton, with only two clear peaks of nauplii density. A negative correlation was found between the number of population density peaks for E. baikalensis and the spring-blooming of diatom algae.","PeriodicalId":136416,"journal":{"name":"Studies on <i>Eurytemora</i>","volume":"31 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122168614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Variability of mandible shape in the freshwater glacial relict Eurytemora lacustris (Poppe, 1887) (Copepoda, Calanoida, Temoridae)","authors":"Ł. Sługocki","doi":"10.1163/15685403-00003985","DOIUrl":"https://doi.org/10.1163/15685403-00003985","url":null,"abstract":"\u0000The mandibles of copepods are used to classify the feeding modes of certain species, because these appendages have specific shapes. The number, shape, location, and structure of the mandibular teeth are traits that are related to the feeding preferences of copepods. Therefore, the mandibles have been used as parameters in order to determine the role of the corresponding species in the trophic network. In this study, we aimed to determine the morphological variability of the mandible shape in a rare calanoid, Eurytemora lacustris (Poppe, 1887). The size of the mandibles of E. lacustris is closely related to its body size; however, considering the proportions of the width of the mandibles to that body size, young individuals have relatively larger mandibles. Despite the large body size of males, the females are characterized by larger mandibles than those of males. The teeth of males were found to be smaller, because of intensive abrasion. Moreover, the season and habitat affected the size of the mandibles and also the values of the edge index (EI). The food conditions in the studied lakes fluctuated within seasons, which led to changes in the shape of the dental crowns. Using this index (EI), E. lacustris was classified as an omnivorous species; however, the range of calculated values varied considerably. We note that the values of the EI decrease along with maturation, which suggests that with increase in age, the copepod becomes more herbivorous; however, this contradicts the paradigm that copepods become omnivorous during maturation. All those morphological differences, furthermore, indicate the high phenotypic plasticity of the species, which was found to be related to maturity, sex, phenology, and the environmental conditions of the habitat.","PeriodicalId":136416,"journal":{"name":"Studies on <i>Eurytemora</i>","volume":"67 6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130877179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On time and place of origin of continental calanoid families: a hypothesis","authors":"V. Alekseev, N. Sukhikh","doi":"10.1163/15685403-00004014","DOIUrl":"https://doi.org/10.1163/15685403-00004014","url":null,"abstract":"\u0000Several independent methods: molecular-genetic, biogeographical, and morphological analyses — were applied to explain the origin of the continental calanoid fauna and the distribution of their recent genera. The theory of Continental Drift and the evolution of the Tethys Sea were also used for that purpose. The molecular-genetic-based phylogenetic tree that we constructed, as well as the largest number of genera and species in Diaptomidae, allow us to support the idea that this family of fresh- and brackishwater Copepoda arose earlier than the Temoridae and Centropagidae. The ancestors of the Diaptomidae likely invaded, and were distributed across, the supercontinent Pangaea before its division into two continental plates in the Mesozoic Era, i.e., not later than 180-200 Ma. Therefore, various genera of this family can be found almost everywhere on all continents, except Antarctica. The family Temoridae is known only from Europe, Asia and North America. These three continental plates stayed together long after separation of Pangaea into two parts: Laurasia and Gondwana (until circa 50 Ma). At approximately the same time (50 Ma), the genus Eurytemora should have been created, as its representatives are known from North America and Eurasia. The family Centropagidae seems to have invaded inland waters somewhere between Temoridae and Diaptomidae, as its representatives can be found on all continents except Africa. Also, as a possibly alternative option, this centropagid invasion could have happened independently in the northern and southern Pangaea blocks, by different marine ancestors, at the same time as Temoridae, as is shown herein in the molecular-genetic-based phylogenetic tree. Using the evolution model of the Tethys Sea proved to be very productive for explaining the modern ranges of continental calanoids, both within families and in individual genera, including the genus Eurytemora.","PeriodicalId":136416,"journal":{"name":"Studies on <i>Eurytemora</i>","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117151162","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Representatives of the genus Eurytemora Giesbrecht, 1881 (Calanoida, Temoridae) in aquatic ecosystems of Belarus","authors":"V. Vezhnavets, A. G. Litvinova","doi":"10.1163/15685403-00004008","DOIUrl":"https://doi.org/10.1163/15685403-00004008","url":null,"abstract":"\u0000The main biological features of two species of the genus Eurytemora have been studied: the relict E. lacustris (Poppe, 1887) and the alien E. velox (Lilljeborg, 1853), which can be found in natural environments on the territory of the Republic of Belarus.\u0000The relict species E. lacustris has been found only in two mesotrophic dimictic lakes belonging to the Baltic Sea basin: Volchin (maximum depth 32.9 m) and Vecheliye (35.9 m). E. velox has now colonized the main rivers of the south of Belarus and their accessory reservoirs belonging to the basins of the Baltic and Black seas.\u0000E. lacustris is characterized by an uneven distribution in the water column and location in deep water layers with temperatures below 13°C. Seasonal and daily vertical migrations have been established for E. lacustris. With age, the amplitude of migrations increases, reaching values of more than 10 m of depth for adults. E. velox is recorded in the coastal biotopes of watercourses and shallow water bodies.\u0000In the recent two years, the average density of E. lacustris in Lake Vecheliye has been established as about 2000 ind./m3, while their percentage in the zooplankton was 6%. In Lake Volchin, its density has been 2-5 times lower in the same period, and there this species’ percentage in the plankton did not exceed 2%. The density of E. velox varies from 20 to 12 000 ind./m3, their average density is 1631 ind./m3, and their percentual share in the zooplankton does not exceed 1%.\u0000For E. lacustris, the body length at all stages of development has been determined. It has been established that males have a greater body length in comparison with females, due to the relatively longer male abdomen, which is not typical for other species of freshwater planktonic copepods.\u0000In Belarus, E. lacustris is a bicyclic species, whereas E. velox is polycyclic.","PeriodicalId":136416,"journal":{"name":"Studies on <i>Eurytemora</i>","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131223904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of respiration rate and electron transport system (ETS) enzyme-mediated reduction assay of the invasive copepod Eurytemora carolleeae Alekseev & Souissi, 2011 (Calanoida, Temoridae) in Green Bay, WI, U.S.A.","authors":"A. Timpe, B. Stasio","doi":"10.1163/15685403-00003990","DOIUrl":"https://doi.org/10.1163/15685403-00003990","url":null,"abstract":"\u0000Anthropogenic activities can cause important changes in aquatic ecosystems, such as warming due to climate change, nutrient loading from agricultural runoff and urban areas, and decreased concentrations of oxygen in bottom waters. These changes may lead to impacts on both organism performance and ecosystem functionality. Studying planktonic species that form an aquatic ecosystem’s foundation is an important step towards understanding the entire food web and predicting how it may respond to a changing environment. One important planktonic species in the Laurentian Great Lakes is the invasive calanoid copepod Eurytemora carolleeae (formerly considered part of the Eurytemora affinis species complex). This study analyzes the metabolic activity of E. carolleeae from Green Bay, Lake Michigan, U.S.A. using two different methods, over a range of temperatures from 9 to 26°C. Total oxygen consumption was measured directly using a micropulse oxygen probe system, and the activity of aerobic metabolic enzymes in the electron transport system (ETS) was quantified using in vitro reduction of iodonitrotetrazolium chloride (INT). Respiration rate of E. carolleeae increases approximately linearly from 9 to 26°C. Measurements of ETS activity indicate that the copepod’s metabolic enzymes have an Arrhenius activation energy of 46.5 ± 15.6 kJ/mol with a thermal maximum between 22 and 26°C. Overall, E. carolleeae ETS rates increased by approximately 7% per °C over the range 9 to 22°C. This thermal limit has implications for future performance of this species, as the combination of higher temperatures and disappearance of oxygenated colder-water refuges may limit E. carolleeae’s success in the Green Bay system following warmer climate and increased nutrient conditions.","PeriodicalId":136416,"journal":{"name":"Studies on <i>Eurytemora</i>","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134151263","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Abnormalities in shape and size of Eurytemora affinis (Copepoda, Calanoida) and its eggs under different environmental conditions","authors":"A. Souissi, S. Souissi","doi":"10.1163/15685403-00003989","DOIUrl":"https://doi.org/10.1163/15685403-00003989","url":null,"abstract":"\u0000In this study we examined the morphological anomalies of 2023 ovigerous females of the copepod Eurytemora affinis from laboratory and field samples. Field copepod collections were collected from 10 sites in Europe and North America. Laboratory cultured copepods were reared at 6 experimental conditions during several generations. The observation under the microscope of the ovigerous females’ bodies revealed the presence of a ‘Tumor Like Anomaly’ (TLA) on a few individuals, which were manifested on the urosome. The occurrence of TLA was only noticed on copepods from the field samples. This result shows that under controlled laboratory conditions, E. affinis do not manifest any abnormal morphology, even when temperature and salinity conditions are stressful, which also demonstrates the high plasticity of this copepod species and its capacity to live at a wide range of environmental parameters. In this study, we also confirmed that E. affinis is capable of producing eggs with a wide range of sizes, ranging from very small and abnormal eggs of 75.79 μm only, to very large eggs, reaching a maximal diameter of 128.71 μm. The observed large eggs are abnormal compared to the average size of the other eggs produced within the same clutch. Other abnormalities on eggs, such as deformed eggs or eggs infested by fungi, are only observed from field samples at a few sampling sites. In the Seine estuary, several abnormalities in eggs and adult females were observed during February 2010. The critical period for E. affinis’ development is sampling site-specific and needs to be accurately studied in the future to better explain the causes of the abnormalities described in this work, and their effects at population level.","PeriodicalId":136416,"journal":{"name":"Studies on <i>Eurytemora</i>","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130974561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A multi-year investigation of the Temoridae (Copepoda, Calanoida) assemblage succession within the interplay waters of the northern South China Sea","authors":"L. Tseng, Yanguo Wang, Guang-shan Lian, Jiang‐Shiou Hwang","doi":"10.1163/15685403-00004009","DOIUrl":"https://doi.org/10.1163/15685403-00004009","url":null,"abstract":"\u0000The South China Sea is the largest marginal sea in the world. The northern South China Sea has a complex hydrographic system affected by interplay waters of the Kuroshio Branch Current and the South China Sea waters. To understand the changes in the community structure of the planktonic calanoid copepod family Temoridae in relation to the interplay waters, we collected zooplankton samples in the northern South China Sea from surface waters (0 to 2 m) from November 2001 to January 2007 during 24 research cruises using a standard North Pacific zooplankton net (with a mesh size of 200 μm, a length of 1.8 m, and a mouth diameter of 0.45 m). Among a total of 253 samples, 5 species belonging to 3 genera of Temoridae were identified: Eurytemora pacifica Sato, 1913, Temora discaudata Giesbrecht, 1889, Temora stylifera (Dana, 1849), Temora turbinata (Dana, 1849), and Temoropia mayumbaensis Scott T., 1894. The 3 most abundant species were: T. turbinata (relative abundance, RA: 53.28%; mean density ± standard deviation, MD: 29.33 ± 89.53 ind. m−3), T. stylifera (RA: 36.02%, MD: 19.83 ± 145.22 ind. m−3), and T. discaudata (RA: 7.70%, MD: 4.24 ± 11.82 ind. m−3). The 3 most frequently occurring species were: T. turbinata (occurrence ratio, OR: 52.17%), T. discaudata (OR: 35.18%), and T. stylifera (OR: 9.88%). A noteworthy discovery in our samples was E. pacifica, a marine and brackish water species, collected from 3 stations located near the Kuroshio Branch Current in April 2003. This is the only month when this species was recorded during the investigation period. Variations of dominant species of Temoridae show a clear pattern of seasonal succession. The total abundance was significantly higher in the third quarter (September-November, 116.98 ± 314.49 ind. m−3) than in the fourth quarter (December-February, 24.26 ± 47.72 ind. m−3) (, one-way ANOVA). In general, the present results demonstrate that the assemblages of the Temoridae are very much structured by the water masses of the Kuroshio Current and the South China Sea.","PeriodicalId":136416,"journal":{"name":"Studies on <i>Eurytemora</i>","volume":"149 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121768962","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}