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Christine Cocquyt - One of the best experts on this subject based on the ideXlab platform.
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Reinvestigation of African Surirella taxa (Bacillariophyta) described by B.J. Cholnoky with some remarks on digitization of diatom types
Fottea, 2017Co-Authors: Christine Cocquyt, Jonathan C. Taylor, Wolf-henning KusberAbstract:Cholnoky described several new Surirella taxa from Africa and we have re-investigated this material. As many other of his contemporary authors, especially in the case of description of new African diatoms, Cholnoky did not indicate holotypes. In the present paper original materials are re-evaluated, lectotypes and a holotype are designated and also epitypes whenever it was appropriate. Taxa later transferred to Stenopterobia have not been taken into account. A short description of the seven species concerned (Surirella anassae, S. chasei, S. coei, S. oliffii, S. ostentata = Surirella ovata var. africana, S. pseudotenuis and S. pseudothienemannii) is given based on the original light microscopic descriptions. Additional morphological information based on scanning electron microscopy is added if available. The presently known ecology and distribution of the taxa is given as are other remarks, based on own observations. For each of the seven taxa Cholnoky's original drawings are presented, which were later re-drawn for publication and which are kept in the archive of the South African National Diatom Collection. The results are discussed referring to the outcome of the digitization project of African Surirellaceae (diatoms, microscopic algae) in the frame of the African Plants Initiative.
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Differentiating Iconella from Surirella (Bacillariophyceae): typifying four Ehrenberg names and a preliminary checklist of the African taxa
Pensoft Publishers, 2017Co-Authors: Regine Jahn, Wolf-henning Kusber, Christine CocquytAbstract:To comply with the new phylogeny within the Surirellales as supported by molecular and morphological data, re-evaluations and re-combinations of taxa from and within the genera Surirella, Cymatopleura, and Stenopterobia and with the re-established genus Iconella are necessary. Since the African diatom flora is rich with taxa from these genera, especially Iconella, and the authors have studied these taxa recently, describing also new taxa, a preliminary checklist of African Iconella and Surirella is here presented. 94 names are contained on this list. 57 taxa have been transferred to Iconella; 55 taxa were formerly ranked within Surirella and two taxa within Stenopterobia. 10 taxa have stayed within Surirella and six taxa have been transferred from Cymatopleura to Surirella. 20 Surirella and 1 Stenopterobia names are listed which are either unrevised or unrevisable since morphological data is missing. Four names and taxa described by Ehrenberg are here typified. Two had been transferred to Iconella already: Iconella bifrons (Ehrenb.) Ruck & Nakov and Iconella splendida (Ehrenb.) Ruck & Nakov. Two are re-transferred from Cymatopleura to Surirella: Surirella librile (Ehrenb.) Ehrenb. and Surirella undulata (Ehrenb.) Ehrenb.; both taxa are currently known by their younger synonyms: Cymatopleura solea (Bréb.) W. Smith and Cymatopleura elliptica (Bréb. ex Kützing) W. Smith. Lectotypes for Iconella bifrons, I. splendida, Surirella librile, and S. undulata were designated
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New and interesting Surirella taxa (Surirellaceae, Bacillariophyta) from the Congo Basin (DR Congo)
European Journal of Taxonomy, 2015Co-Authors: Christine Cocquyt, Jonathan C. TaylorAbstract:Two new diatom taxa belonging to the genus Surirella , S. ebalensis and S. congolensis , are described from material of the Congo Basin, downstream Kisangani, DR Congo. The first taxon is a small, rather common species in the studied material; the second a somewhat larger diatom that was only sporadically observed. The morphology of both taxa is examined with light and scanning electron microscopy. The differences between the new and other closely related taxa such as S. agonaensis and S. bonsaensis , and S. takoradiensis , S. tenuissima and S. pseudotenuissima , respectively, are discussed.
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Reinvestigation of West African Surirellaceae (Bacillariophyta) described by Woodhead and Tweed from Sierra Leone
Diatom Research, 2013Co-Authors: Christine Cocquyt, Ingrid Jüttner, Wolf-henning KusberAbstract:Microscope slides containing material from Sierra Leone used by Woodhead and Tweed to describe eight new Surirellaceae taxa in the mid-twentieth century were reinvestigated. Only two taxa were found on the original slides, Surirella approximata Woodhead & Tweed and S. engleri [var. constricta] f. minor Woodhead & Tweed. The valve variability of S. engleri O. Muller includes valves of S. engleri [var. constricta] f. minor which is now regarded as a synonym. As no holotypes were indicated by the authors, types are given here. Comments on S. rudis var. sierra-leonensis Woodhead & Tweed, S. rudis [var. sierra-leonensis] f. constricta Woodhead & Tweed and S. esamangensis Foged are also given. Valves resembling Stenopterobia recta Woodhead & Tweed, Surirella asperrima f. rokuprensis Woodhead & Tweed, S. engleri f. sierra-leonensis Woodhead & Tweed and S. rokuprensis Woodhead & Tweed could not be found on the Woodhead and Tweed original slides.
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The genus Surirella (Bacillariophyta) in the sub-Antarctic and maritime Antarctic region
Diatom Research, 2012Co-Authors: Bart Van De Vijver, Christine Cocquyt, Kateřina Kopalová, Myriam De Haan, Ralitsa ZidarovaAbstract:A revision of taxa from the genus Surirella from the Antarctic region resulted in the description of three new taxa: S. subantarctica Van de Vijver & Cocquyt sp. nov., S. heardensis Van de Vijver & Cocquyt sp. nov. and S. australovisurgis Van de Vijver, Cocquyt, Zidarova & Kopalova sp. nov. Detailed light (LM) and scanning electron microscope (SEM) observations are used to characterize these three new taxa. Comparisons with similar taxa and the ecological preferences of each species are added. The morphological characteristics of a fourth Antarctic Surirella taxon, S. kerguelensis Grunow are illustrated as this taxon was only known from a few hand drawings and LM pictures. Finally, a fifth taxon, S. lapponica A. Cleve was found on South Georgia and likewise illustrated. The revision of these species made clear that the genus Surirella showed similar biogeographical trends as other, previously revised genera indicating that a distinct Antarctic diatom flora exists.
Regine Jahn - One of the best experts on this subject based on the ideXlab platform.
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Differentiating Iconella from Surirella (Bacillariophyceae): typifying four Ehrenberg names and a preliminary checklist of the African taxa
Pensoft Publishers, 2017Co-Authors: Regine Jahn, Wolf-henning Kusber, Christine CocquytAbstract:To comply with the new phylogeny within the Surirellales as supported by molecular and morphological data, re-evaluations and re-combinations of taxa from and within the genera Surirella, Cymatopleura, and Stenopterobia and with the re-established genus Iconella are necessary. Since the African diatom flora is rich with taxa from these genera, especially Iconella, and the authors have studied these taxa recently, describing also new taxa, a preliminary checklist of African Iconella and Surirella is here presented. 94 names are contained on this list. 57 taxa have been transferred to Iconella; 55 taxa were formerly ranked within Surirella and two taxa within Stenopterobia. 10 taxa have stayed within Surirella and six taxa have been transferred from Cymatopleura to Surirella. 20 Surirella and 1 Stenopterobia names are listed which are either unrevised or unrevisable since morphological data is missing. Four names and taxa described by Ehrenberg are here typified. Two had been transferred to Iconella already: Iconella bifrons (Ehrenb.) Ruck & Nakov and Iconella splendida (Ehrenb.) Ruck & Nakov. Two are re-transferred from Cymatopleura to Surirella: Surirella librile (Ehrenb.) Ehrenb. and Surirella undulata (Ehrenb.) Ehrenb.; both taxa are currently known by their younger synonyms: Cymatopleura solea (Bréb.) W. Smith and Cymatopleura elliptica (Bréb. ex Kützing) W. Smith. Lectotypes for Iconella bifrons, I. splendida, Surirella librile, and S. undulata were designated
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Otto Müller’s Surirella taxa (Bacillariophyta) from East Africa, based on a historical collection kept at the Botanic Garden and Botanical Museum Berlin-Dahlem (B)
Afrika Focus, 2008Co-Authors: Christine Cocquyt, Wolf-henning Kusber, Regine JahnAbstract:At the beginning of the 20th century, Otto Müller described over 100 new freshwater diatom taxa from algae samples, collected during the German “Nyassa-See- und Kinga-Gebirgs-Expedition” in East Africa. He published valuable drawings and wrote detailed descriptions of these microalgae, but subsequent authors regarded many of these African taxa to be synonyms or infraspecific of European species. In the last two decades renewed attention to the diatom flora of East Africa has made it evident that Müller’s taxa have to be reinvestigated, in terms of both light as well as scanning electron microscopy, in order to evaluate possible new or endemic species. This was recently done for his Surirella taxa, a typical component of the African Great Lakes diatom flora of which many species are endemic to this area. Additional data, originating from material of later periods in the same region (e.g. Lakes Tanganyika, Malawi, Victoria, Edward), was incorporated in the investigation to study the variability in valve morphology and the African distribution of each species. Otto Müller’s samples thus provide the means to study historical African diatom diversity as a baseline for modern biodiversity assessment Type information and the English description for taxon have been published in international journals and online at the AlgaTerra Information System [www.algaterra.org], a site developed and updated by the Botanic Garden and Botanical Museum Berlin-Dahlem (BGBM). High resolution digital photographs of the Surirella taxa will also be available in the future on the API website [www.aluka.org.
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Otto Müller’s Surirella taxa (Bacillariophyta) from East Africa, based on a historical collection kept at the Botanic Garden and Botanical Museum Berlin-Dahlem (B)
'Ghent University', 2008Co-Authors: Christine Cocquyt, Wolf-henning Kusber, Regine JahnAbstract:At the beginning of the 20th century, Otto Müller described over 100 new freshwater diatom taxa from algae samples, collected during the German “Nyassa-See– und Kinga-Gebirgs-Expedition” in East Africa. He published valuable drawings and wrote detailed descriptions of these micro-algae, but subsequent authors regarded many of these African taxa to be synonyms or infraspecific of European species. In the last two decades renewed attention to the diatom flora of East Africa has made it evident that Müller’s taxa have to be reinvestigated, in terms of both light as well as scanning electron microscopy, in order to evaluate possible new or endemic species. This was recently done for his Surirella taxa, a typical component of the African Great Lakes diatom flora of which many species are endemic to this area. Additional data, originating from material of later periods in the same region (e.g. Lakes Tanganyika, Malawi, Victoria, Edward), was incorporated in the investigation to study the variability in valve morphology and the African distribution of each species. Otto Müller’s samples thus provide the means to study historical African diatom diversity as a baseline for modern biodiversity assessment. Type information and the English description for taxon have been published in international journals and online at the AlgaTerra Information System [www.algaterra.org], a site developed and updated by the Botanic Garden and Botanical Museum Berlin-Dahlem (BGBM). High resolution digital photographs of the Surirella taxa will also be available in the future on the API website [www.aluka.org]. Key words: Algae, Diatoms, Historic Collections, East Afric
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Surirella nyassae O. Muller, S-malombae O. Muller and S-chepurnovii Cocquyt & R. Jahn sp nov (Bacillariophyta) typification and variability of three closely related East African diatoms
Nova Hedwigia, 2007Co-Authors: Christine Cocquyt, Regine JahnAbstract:Three Surirella taxa described by O.Muller from material collected at the beginning of the 20(th) century in Lakes Malawi and Malombe were re-evaluated, and lectotypes are assigned from the original material. One infraspecific taxon, S. nyassae var. sagitta, was synonymized with the nominate variety of S. nyassae and one forma, S. malombae f. acuta, was synonymized with S. malombae. As S. malombae is very rare in the original material from Lake Malombe, an epitype was also assigned from material collected at the end of the 19(th) century in Lake Victoria. Light and scanning electron microscopic information is given for these two taxa; their distribution in Africa and their habitat preference is summarized from the literature. A third, closely related taxon which was regularly observed in Lake Tanganyika is here described as Surirella chepurnovii sp. nov.
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Surirella nyassae o muller s malombae o muller and s chepurnovii cocquyt r jahn sp nov bacillariophyta typification and variability of three closely related east african diatoms
Nova Hedwigia, 2007Co-Authors: Christine Cocquyt, Regine JahnAbstract:Three Surirella taxa described by O.Muller from material collected at the beginning of the 20(th) century in Lakes Malawi and Malombe were re-evaluated, and lectotypes are assigned from the original material. One infraspecific taxon, S. nyassae var. sagitta, was synonymized with the nominate variety of S. nyassae and one forma, S. malombae f. acuta, was synonymized with S. malombae. As S. malombae is very rare in the original material from Lake Malombe, an epitype was also assigned from material collected at the end of the 19(th) century in Lake Victoria. Light and scanning electron microscopic information is given for these two taxa; their distribution in Africa and their habitat preference is summarized from the literature. A third, closely related taxon which was regularly observed in Lake Tanganyika is here described as Surirella chepurnovii sp. nov.
Montoya Moreno Yimmy - One of the best experts on this subject based on the ideXlab platform.
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Sucesión de microalgas perifíticas en tributarios del río Gaira, Sierra Nevada de Santa Marta, Colombia
Universidad Nacional de Colombia - Sede Bogotá - Faculdad de Ciencias - Departamento de Biología, 2015Co-Authors: Osorio Ávila, Farid Jesús, Rodríguez Barrios Javier, Montoya Moreno YimmyAbstract:Las microalgas poseen atributos para la bioindicación, el estudio de algas perifíticas en ecosistemas fluviales tropicales, es de vital importancia ya que permite interpretar la dinámica de estos ecosistemas con importancia ecológica y con vocación para ofrecer servicios de abastecimiento. Para este estudio se seleccionaron tributarios de la cuenca media del río Gaira (SNSM), se evaluó el proceso sucesional de microalgas perifíticas, siguiendo el avance de la comunidad desde enero hasta abril de 2012, mediante la metodología de sustratos artificiales. El propósito fue analizar la variación en la estructura de la comunidad, durante el proceso de sucesión y evaluar los factores ambientales que determinan esta variación en un rio tropical. Los resultados destacan caudal, luz y oxígeno disuelto los cuales presentaron los valores más altos para el tributario C (Jabalí); el pH fue ligeramente básico para todos los sitios, la temperatura y conductividad presentaron valores más altos en el tributario A (Honduras). Durante las primeras semanas de exposición del sustrato Melosira varians y Lyngbya sp. fueron dominantes para los tributarios A y B (La Picúa), mientras que para el tributario C lo fueron Fragilaria sp., Nitzschia sp. y Melosira varians. Después de la cuarta semana de colecta se registraron los mayores valores de diversidad y riqueza de especies. Fueron más notorios los cambios en densidad que en composición de especies, a pesar de esto el proceso de sucesión fue completo y se evidenció la presencia de especies pioneras (Lyngbya sp., Nitzschia sp.), intermedias (Melosira varians, Cocconeis placentula) y tardías (Surirella sp.)Microalgae have attributes for bioindication, the study of periphytic algae in tropical river ecosystems, is vital as it allows interpreting the dynamics of these ecosystems and ecological importance vocation to offer catering services. For this study were selected tributaries of the middle basin of Gaira (SNSM) River, the successional process periphytic microalgae was evaluated following the progress of the community from January to April 2012, using the methodology of artificial substrates. The purpose was to analyze the variation in community structure during the succession process and assess environmental factors that determine this variation in a tropical river. The results highlight flow, light and dissolved oxygen which presented the highest for tax C (Jabalí) values; the pH was slightly basic for all sites, temperature and conductivity showed the highest values in the tax A (Honduras). During the first weeks of exposure of the substrate Melosira varians and Lyngbya sp. were dominant for tributary A and B (La Picúa), while for the tributary C they were Fragilaria sp, Nitzschia sp and Melosira varians. After the fourth week of collecting the highest values of diversity and species richness recorded. Were greatest density changes in species composition, despite this the succession process was complete and the presence of pioneer species (Lyngbya sp, Nitzschia sp), intermediate (Melosira varians, Cocconeis placentula) and late (Surirella sp)
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Succession of microalgae periphytic in tributaries the Gaira river, Sierra Nevada de Santa Marta, Colombia
GeoLimna, 2015Co-Authors: Osorio Ávila, Farid Jesús, Rodríguez Barrios Javier, Montoya Moreno YimmyAbstract:Las microalgas poseen atributos para la bioindicación, el estudio de algas perifíticas en ecosistemas fluviales tropicales, es de vital importancia ya que permite interpretar la dinámica de estos ecosistemas con importancia ecológica y con vocación para ofrecer servicios de abastecimiento. Para este estudio se seleccionaron tributarios de la cuenca media del río Gaira (SNSM), se evaluó el proceso sucesional de microalgas perifíticas, siguiendo el avance de la comunidad desde enero hasta abril de 2012, mediante la metodología de sustratos artificiales. El propósito fue analizar la variación en la estructura de la comunidad, durante el proceso de sucesión y evaluar los factores ambientales que determinan esta variación en un rio tropical. Los resultados destacan caudal, luz y oxígeno disuelto los cuales presentaron los valores más altos para el tributario C (Jabalí); el pH fue ligeramente básico para todos los sitios, la temperatura y conductividad presentaron valores más altos en el tributario A (Honduras). Durante las primeras semanas de exposición del sustrato Melosira varians y Lyngbya sp. fueron dominantes para los tributarios A y B (La Picúa), mientras que para el tributario C lo fueron Fragilaria sp., Nitzschia sp. y Melosira varians. Después de la cuarta semana de colecta se registraron los mayores valores de diversidad y riqueza de especies. Fueron más notorios los cambios en densidad que en composición de especies, a pesar de esto el proceso de sucesión fue completo y se evidenció la presencia de especies pioneras (Lyngbya sp., Nitzschia sp.), intermedias (Melosira varians, Cocconeis placentula) y tardías (Surirella sp.).Microalgae have attributes for bioindication, the study of periphytic algae in tropical river ecosystems, is vital as it allows interpreting the dynamics of these ecosystems and ecological importance vocation to offer catering services. For this study were selected tributaries of the middle basin of Gaira (SNSM) River, the successional process periphytic microalgae was evaluated following the progress of the community from January to April 2012, using the methodology of artificial substrates. The purpose was to analyze the variation in community structure during the succession process and assess environmental factors that determine this variation in a tropical river. The results highlight flow, light and dissolved oxygen which presented the highest for tax C (Jabalí) values; the pH was slightly basic for all sites, temperature and conductivity showed the highest values in the tax A (Honduras). During the first weeks of exposure of the substrate Melosira varians and Lyngbya sp. were dominant for tributary A and B (La Picúa), while for the tributary C they were Fragilaria sp, Nitzschia sp and Melosira varians. After the fourth week of collecting the highest values of diversity and species richness recorded. Were greatest density changes in species composition, despite this the succession process was complete and the presence of pioneer species (Lyngbya sp, Nitzschia sp), intermediate (Melosira varians, Cocconeis placentula) and late (Surirella sp)
Wolf-henning Kusber - One of the best experts on this subject based on the ideXlab platform.
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Reinvestigation of African Surirella taxa (Bacillariophyta) described by B.J. Cholnoky with some remarks on digitization of diatom types
Fottea, 2017Co-Authors: Christine Cocquyt, Jonathan C. Taylor, Wolf-henning KusberAbstract:Cholnoky described several new Surirella taxa from Africa and we have re-investigated this material. As many other of his contemporary authors, especially in the case of description of new African diatoms, Cholnoky did not indicate holotypes. In the present paper original materials are re-evaluated, lectotypes and a holotype are designated and also epitypes whenever it was appropriate. Taxa later transferred to Stenopterobia have not been taken into account. A short description of the seven species concerned (Surirella anassae, S. chasei, S. coei, S. oliffii, S. ostentata = Surirella ovata var. africana, S. pseudotenuis and S. pseudothienemannii) is given based on the original light microscopic descriptions. Additional morphological information based on scanning electron microscopy is added if available. The presently known ecology and distribution of the taxa is given as are other remarks, based on own observations. For each of the seven taxa Cholnoky's original drawings are presented, which were later re-drawn for publication and which are kept in the archive of the South African National Diatom Collection. The results are discussed referring to the outcome of the digitization project of African Surirellaceae (diatoms, microscopic algae) in the frame of the African Plants Initiative.
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Differentiating Iconella from Surirella (Bacillariophyceae): typifying four Ehrenberg names and a preliminary checklist of the African taxa
Pensoft Publishers, 2017Co-Authors: Regine Jahn, Wolf-henning Kusber, Christine CocquytAbstract:To comply with the new phylogeny within the Surirellales as supported by molecular and morphological data, re-evaluations and re-combinations of taxa from and within the genera Surirella, Cymatopleura, and Stenopterobia and with the re-established genus Iconella are necessary. Since the African diatom flora is rich with taxa from these genera, especially Iconella, and the authors have studied these taxa recently, describing also new taxa, a preliminary checklist of African Iconella and Surirella is here presented. 94 names are contained on this list. 57 taxa have been transferred to Iconella; 55 taxa were formerly ranked within Surirella and two taxa within Stenopterobia. 10 taxa have stayed within Surirella and six taxa have been transferred from Cymatopleura to Surirella. 20 Surirella and 1 Stenopterobia names are listed which are either unrevised or unrevisable since morphological data is missing. Four names and taxa described by Ehrenberg are here typified. Two had been transferred to Iconella already: Iconella bifrons (Ehrenb.) Ruck & Nakov and Iconella splendida (Ehrenb.) Ruck & Nakov. Two are re-transferred from Cymatopleura to Surirella: Surirella librile (Ehrenb.) Ehrenb. and Surirella undulata (Ehrenb.) Ehrenb.; both taxa are currently known by their younger synonyms: Cymatopleura solea (Bréb.) W. Smith and Cymatopleura elliptica (Bréb. ex Kützing) W. Smith. Lectotypes for Iconella bifrons, I. splendida, Surirella librile, and S. undulata were designated
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Reinvestigation of West African Surirellaceae (Bacillariophyta) described by Woodhead and Tweed from Sierra Leone
Diatom Research, 2013Co-Authors: Christine Cocquyt, Ingrid Jüttner, Wolf-henning KusberAbstract:Microscope slides containing material from Sierra Leone used by Woodhead and Tweed to describe eight new Surirellaceae taxa in the mid-twentieth century were reinvestigated. Only two taxa were found on the original slides, Surirella approximata Woodhead & Tweed and S. engleri [var. constricta] f. minor Woodhead & Tweed. The valve variability of S. engleri O. Muller includes valves of S. engleri [var. constricta] f. minor which is now regarded as a synonym. As no holotypes were indicated by the authors, types are given here. Comments on S. rudis var. sierra-leonensis Woodhead & Tweed, S. rudis [var. sierra-leonensis] f. constricta Woodhead & Tweed and S. esamangensis Foged are also given. Valves resembling Stenopterobia recta Woodhead & Tweed, Surirella asperrima f. rokuprensis Woodhead & Tweed, S. engleri f. sierra-leonensis Woodhead & Tweed and S. rokuprensis Woodhead & Tweed could not be found on the Woodhead and Tweed original slides.
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Otto Müller’s Surirella taxa (Bacillariophyta) from East Africa, based on a historical collection kept at the Botanic Garden and Botanical Museum Berlin-Dahlem (B)
Afrika Focus, 2008Co-Authors: Christine Cocquyt, Wolf-henning Kusber, Regine JahnAbstract:At the beginning of the 20th century, Otto Müller described over 100 new freshwater diatom taxa from algae samples, collected during the German “Nyassa-See- und Kinga-Gebirgs-Expedition” in East Africa. He published valuable drawings and wrote detailed descriptions of these microalgae, but subsequent authors regarded many of these African taxa to be synonyms or infraspecific of European species. In the last two decades renewed attention to the diatom flora of East Africa has made it evident that Müller’s taxa have to be reinvestigated, in terms of both light as well as scanning electron microscopy, in order to evaluate possible new or endemic species. This was recently done for his Surirella taxa, a typical component of the African Great Lakes diatom flora of which many species are endemic to this area. Additional data, originating from material of later periods in the same region (e.g. Lakes Tanganyika, Malawi, Victoria, Edward), was incorporated in the investigation to study the variability in valve morphology and the African distribution of each species. Otto Müller’s samples thus provide the means to study historical African diatom diversity as a baseline for modern biodiversity assessment Type information and the English description for taxon have been published in international journals and online at the AlgaTerra Information System [www.algaterra.org], a site developed and updated by the Botanic Garden and Botanical Museum Berlin-Dahlem (BGBM). High resolution digital photographs of the Surirella taxa will also be available in the future on the API website [www.aluka.org.
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Otto Müller’s Surirella taxa (Bacillariophyta) from East Africa, based on a historical collection kept at the Botanic Garden and Botanical Museum Berlin-Dahlem (B)
'Ghent University', 2008Co-Authors: Christine Cocquyt, Wolf-henning Kusber, Regine JahnAbstract:At the beginning of the 20th century, Otto Müller described over 100 new freshwater diatom taxa from algae samples, collected during the German “Nyassa-See– und Kinga-Gebirgs-Expedition” in East Africa. He published valuable drawings and wrote detailed descriptions of these micro-algae, but subsequent authors regarded many of these African taxa to be synonyms or infraspecific of European species. In the last two decades renewed attention to the diatom flora of East Africa has made it evident that Müller’s taxa have to be reinvestigated, in terms of both light as well as scanning electron microscopy, in order to evaluate possible new or endemic species. This was recently done for his Surirella taxa, a typical component of the African Great Lakes diatom flora of which many species are endemic to this area. Additional data, originating from material of later periods in the same region (e.g. Lakes Tanganyika, Malawi, Victoria, Edward), was incorporated in the investigation to study the variability in valve morphology and the African distribution of each species. Otto Müller’s samples thus provide the means to study historical African diatom diversity as a baseline for modern biodiversity assessment. Type information and the English description for taxon have been published in international journals and online at the AlgaTerra Information System [www.algaterra.org], a site developed and updated by the Botanic Garden and Botanical Museum Berlin-Dahlem (BGBM). High resolution digital photographs of the Surirella taxa will also be available in the future on the API website [www.aluka.org]. Key words: Algae, Diatoms, Historic Collections, East Afric
Osorio Ávila, Farid Jesús - One of the best experts on this subject based on the ideXlab platform.
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Sucesión de microalgas perifíticas en tributarios del río Gaira, Sierra Nevada de Santa Marta, Colombia
Universidad Nacional de Colombia - Sede Bogotá - Faculdad de Ciencias - Departamento de Biología, 2015Co-Authors: Osorio Ávila, Farid Jesús, Rodríguez Barrios Javier, Montoya Moreno YimmyAbstract:Las microalgas poseen atributos para la bioindicación, el estudio de algas perifíticas en ecosistemas fluviales tropicales, es de vital importancia ya que permite interpretar la dinámica de estos ecosistemas con importancia ecológica y con vocación para ofrecer servicios de abastecimiento. Para este estudio se seleccionaron tributarios de la cuenca media del río Gaira (SNSM), se evaluó el proceso sucesional de microalgas perifíticas, siguiendo el avance de la comunidad desde enero hasta abril de 2012, mediante la metodología de sustratos artificiales. El propósito fue analizar la variación en la estructura de la comunidad, durante el proceso de sucesión y evaluar los factores ambientales que determinan esta variación en un rio tropical. Los resultados destacan caudal, luz y oxígeno disuelto los cuales presentaron los valores más altos para el tributario C (Jabalí); el pH fue ligeramente básico para todos los sitios, la temperatura y conductividad presentaron valores más altos en el tributario A (Honduras). Durante las primeras semanas de exposición del sustrato Melosira varians y Lyngbya sp. fueron dominantes para los tributarios A y B (La Picúa), mientras que para el tributario C lo fueron Fragilaria sp., Nitzschia sp. y Melosira varians. Después de la cuarta semana de colecta se registraron los mayores valores de diversidad y riqueza de especies. Fueron más notorios los cambios en densidad que en composición de especies, a pesar de esto el proceso de sucesión fue completo y se evidenció la presencia de especies pioneras (Lyngbya sp., Nitzschia sp.), intermedias (Melosira varians, Cocconeis placentula) y tardías (Surirella sp.)Microalgae have attributes for bioindication, the study of periphytic algae in tropical river ecosystems, is vital as it allows interpreting the dynamics of these ecosystems and ecological importance vocation to offer catering services. For this study were selected tributaries of the middle basin of Gaira (SNSM) River, the successional process periphytic microalgae was evaluated following the progress of the community from January to April 2012, using the methodology of artificial substrates. The purpose was to analyze the variation in community structure during the succession process and assess environmental factors that determine this variation in a tropical river. The results highlight flow, light and dissolved oxygen which presented the highest for tax C (Jabalí) values; the pH was slightly basic for all sites, temperature and conductivity showed the highest values in the tax A (Honduras). During the first weeks of exposure of the substrate Melosira varians and Lyngbya sp. were dominant for tributary A and B (La Picúa), while for the tributary C they were Fragilaria sp, Nitzschia sp and Melosira varians. After the fourth week of collecting the highest values of diversity and species richness recorded. Were greatest density changes in species composition, despite this the succession process was complete and the presence of pioneer species (Lyngbya sp, Nitzschia sp), intermediate (Melosira varians, Cocconeis placentula) and late (Surirella sp)
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Succession of microalgae periphytic in tributaries the Gaira river, Sierra Nevada de Santa Marta, Colombia
GeoLimna, 2015Co-Authors: Osorio Ávila, Farid Jesús, Rodríguez Barrios Javier, Montoya Moreno YimmyAbstract:Las microalgas poseen atributos para la bioindicación, el estudio de algas perifíticas en ecosistemas fluviales tropicales, es de vital importancia ya que permite interpretar la dinámica de estos ecosistemas con importancia ecológica y con vocación para ofrecer servicios de abastecimiento. Para este estudio se seleccionaron tributarios de la cuenca media del río Gaira (SNSM), se evaluó el proceso sucesional de microalgas perifíticas, siguiendo el avance de la comunidad desde enero hasta abril de 2012, mediante la metodología de sustratos artificiales. El propósito fue analizar la variación en la estructura de la comunidad, durante el proceso de sucesión y evaluar los factores ambientales que determinan esta variación en un rio tropical. Los resultados destacan caudal, luz y oxígeno disuelto los cuales presentaron los valores más altos para el tributario C (Jabalí); el pH fue ligeramente básico para todos los sitios, la temperatura y conductividad presentaron valores más altos en el tributario A (Honduras). Durante las primeras semanas de exposición del sustrato Melosira varians y Lyngbya sp. fueron dominantes para los tributarios A y B (La Picúa), mientras que para el tributario C lo fueron Fragilaria sp., Nitzschia sp. y Melosira varians. Después de la cuarta semana de colecta se registraron los mayores valores de diversidad y riqueza de especies. Fueron más notorios los cambios en densidad que en composición de especies, a pesar de esto el proceso de sucesión fue completo y se evidenció la presencia de especies pioneras (Lyngbya sp., Nitzschia sp.), intermedias (Melosira varians, Cocconeis placentula) y tardías (Surirella sp.).Microalgae have attributes for bioindication, the study of periphytic algae in tropical river ecosystems, is vital as it allows interpreting the dynamics of these ecosystems and ecological importance vocation to offer catering services. For this study were selected tributaries of the middle basin of Gaira (SNSM) River, the successional process periphytic microalgae was evaluated following the progress of the community from January to April 2012, using the methodology of artificial substrates. The purpose was to analyze the variation in community structure during the succession process and assess environmental factors that determine this variation in a tropical river. The results highlight flow, light and dissolved oxygen which presented the highest for tax C (Jabalí) values; the pH was slightly basic for all sites, temperature and conductivity showed the highest values in the tax A (Honduras). During the first weeks of exposure of the substrate Melosira varians and Lyngbya sp. were dominant for tributary A and B (La Picúa), while for the tributary C they were Fragilaria sp, Nitzschia sp and Melosira varians. After the fourth week of collecting the highest values of diversity and species richness recorded. Were greatest density changes in species composition, despite this the succession process was complete and the presence of pioneer species (Lyngbya sp, Nitzschia sp), intermediate (Melosira varians, Cocconeis placentula) and late (Surirella sp)