Balasubramanian Karthick | Agharkar Research Institute (original) (raw)
Papers by Balasubramanian Karthick
Fottea
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Phytotaxa
A new species belonging to the genus Hippodonta is described, Hippodonta mudumalaiensis, from Mud... more A new species belonging to the genus Hippodonta is described, Hippodonta mudumalaiensis, from Mudumalai, Tamil Nadu, India. This paper analysed a detailed morphology and ultrastructure of H. mudumalaiensis based on LM and SEM observations and compared it with similar species within the genus. The new species belongs to group two of Hippodonta, with the characteristic features of narrow lanceolate valve outline, protracted to broadly rounded apices and rhombic to panduriform central area. The described species is our prime effort to report genus Hippodonta from India, aiding in microbial biodiversity assessment of the country. Additionally, Hippodonta of the Indian Subcontinent is also discussed.
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Diversity, 2022
Myristica swamps are one of the rarest wetland ecosystems within the sub-tropical evergreen fores... more Myristica swamps are one of the rarest wetland ecosystems within the sub-tropical evergreen forests of the Western Ghats, India. As their name indicates, they harbor trees belonging to the ancient family Myristicaceae. Due to the waterlogged conditions and high humic decomposition, these swamps are acidic, harbor rare and endemic biotas, and provide ecosystem services to humans. Monitoring this rare ecosystem is crucial because the swamps that once formed a large hydrological network across the Western Ghats are now confined to isolated patches due to human disturbance such as agricultural interventions, roads, and dam construction. Due to the change in land use, there is also a drastic change in water chemistry and associated biodiversity. Biomonitoring is more precise than physical and chemical monitoring. So, the current study aimed to undertake a comprehensive analysis of the physical, chemical, and biological assessment of these swamps. The diatom assemblages are strongly affec...
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Limnetica, 2019
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This paper describes two new Gomphonema species from the lesser Himalayas, India, with their valv... more This paper describes two new Gomphonema species from the lesser Himalayas, India, with their valve morphology using light and scanning electron microscopy. The two species, Gomphonema juettnerii sp. nov. and G. doonensis sp. nov., were found in Nalota stream in Doon Valley of Uttarakhand State. Main features of G. juettnerii are valve outline, shape of the areolae and striae pattern and presence of stigma. Main features of G. doonensis are rounded headpole, striae made by doubly punctate striae and features in central area. A detailed discussion on doubly punctate striae in members of gomphonemoid diatoms is presented.
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Water Practice and Technology, 2021
The freshwater rockpools support high endemic biodiversity but are poorly studied habitats in the... more The freshwater rockpools support high endemic biodiversity but are poorly studied habitats in the Western Ghats biodiversity hotspot. These freshwater rock pools are situated on outcrops at various elevations in the Western Ghats and are composed of different bedrocks such as laterite and basalt. We aimed to analyze the water quality, geographical position based differences in the water chemistry and the role of bedrock in determining the water chemistry of the rock pools. Our study showed a wide range of water quality variables such as pH, conductivity, and ionic contents that attributed to the natural variation. We observed a drastic variation in the anions and cations at low elevation pools. Rock type and precipitation are influencing the ionic concentration; for example, Calcium and Bromide could be attributed to the seasonal precipitation and geomorphology. This documentation of physicochemical properties of the Western Ghats rock pools can form a baseline for further detailed ...
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Fottea, 2020
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Fottea, 2021
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European Journal of Phycology, 2021
ABSTRACT Stauroneis Ehrenberg is a species-rich genus that is common and widespread with some var... more ABSTRACT Stauroneis Ehrenberg is a species-rich genus that is common and widespread with some variation in frustule morphology. Recently, studies have explored the molecular diversity of the Stauroneis from the temperate region, but there are no molecular data for tropical species. In the present study, four species of Stauroneis were investigated using morphological and molecular data. Morphological characters were analysed using light microscopy (LM) and scanning electron microscopy (SEM), and the features of each taxon were compared with similar species within the genus. For the molecular analyses, Stauroneis strains were isolated, cultured, DNA was extracted, and sequences from rbcL and 18S genes were analysed to determine phylogenetic relationships. Our analysis describes three new species and records one previously known species. The new species are: (1) Stauroneis lateritica Wadmare, Kociolek & B.Karthick, characterized by small frustules with elliptical lanceolate valves and short subrostrate apices, broad central bow-tie shaped stauros, and few moderate striae centrally becoming strongly radiate towards the poles; (2) Stauroneis sholaii Wadmare, Kociolek & B.Karthick, which has broad lanceolate valves with short rectangular stauros and radiate striae; and (3) Stauroneis bartii Wadmare, Kociolek & B.Karthick, which has large, lanceolate valves with rounded apices, a stauros with 4–7 shortened striae and radiate striae. Ultrastructure and molecular data from India for the previously known, widespread species Stauroneis gracilis Ehrenberg are presented. The combined morphological and molecular approach supports recognition of S. lateritica, S. sholaii and S. bartii as new species. This study is the first-ever attempt at molecular species discovery of diatoms from the Indian subcontinent.
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Phytotaxa, 2020
A new species of Navicula sensu stricto is described from a small stream from the Kaas Plateau in... more A new species of Navicula sensu stricto is described from a small stream from the Kaas Plateau in the northern part of the Western Ghats of India. The species is presented with light and scanning electron microscopy, and compared with similar species like Navicula reinhardtii, N sovereignii, N. aurora and N. gogorevii. This taxon is characterized by rhomboid shape, elongated lineolae, short striae at the central area giving a distinctive shape, and narrowly-rounded apices. The discovery of this taxon signifies that a significant number of species to be discovered in this biodiverse region of peninsular India, especially unique habitats like lateritic plateaus.
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Issues of modern algology (Вопросы современной альгологии), 2019
Two new species of Gomphonema Ehrenberg are described on the basis of light and scanning electron... more Two new species of Gomphonema Ehrenberg are described on the basis of light and scanning electron microscopical observations. These are Gomphonema kallarensis sp. prov., a species found in India, and G. kezlyae sp. prov., which have been found in India and Vietnam. We also document the morphology and variability of G. doonensis B. Karthick, R. Nautiyal et Kociolek from Vietnam. This species was described originally from India based on a limited number of valves. Both G. doonensis and G. kallarensis have biseriate striae composed of areolae without occlusions, while G. kezlyae have striae with single row of areolae that have external occlusions giving the impression of C-shaped openings. Our investigation shows that India and Vietnam share some species in common, and adding additional evidence that the biogeography of freshwater diatoms from the Tropics warrants future investigation.
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Nova Hedwigia, Beihefte, 2018
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Phytotaxa, 2019
New diatom species from the genus Cymbella is described, Cymbella pavanaensis from the Pavana Riv... more New diatom species from the genus Cymbella is described, Cymbella pavanaensis from the Pavana River situated in Pimpri-Chinchwad, Pune, Maharashtra, India. The new species description is based on detailed LM and SEM morphological observations. Comparison of the new species with similar, previously-described taxa is made. C. pavanaensis belongs to a group of small-celled species of the genus, which lack differentiated, rounded porelli comprising the apical pore fields. This taxon is reported from a moderately to the highly-polluted urban lotic system, which signifies that even the diatom flora of easily accessible habitats of India is yet to be fully documented.
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Phytotaxa, 2018
Light and scanning electron microscope observations of Cymbella sagarensis Gandhi are presented. ... more Light and scanning electron microscope observations of Cymbella sagarensis Gandhi are presented. Morphological peculiarities of this species show that it belongs to the genus Oricymba Jüttner, Krammer, Cox, Van de Vijver & Tuji. Based on our observations, the new taxonomic combination, Oricymba sagarensis (Gandhi) C.Radhakrishnan, Kociolek & B.Karthick, comb. nov. is proposed. Morphological comparison of this species with other known members of Oricymba is given. A second taxon described by Gandhi, C. sagarensis f. gracilis Gandhi, is suggested to be a synonym of the nominate forma. Distribution of this species and other Oricymba taxa is discussed.
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Springer Earth System Sciences, 2015
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Resonance, 2008
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Industrial & Engineering Chemistry Research, 2009
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ABSTRACT Community diversity and the population abundance of a particular group of species are co... more ABSTRACT Community diversity and the population abundance of a particular group of species are controlled by immediate environment, inter- and intra-species interactions, landscape conditions, historical events and evolutionary processes. Nestedness is a measure of order in an ecological system, referring to the order in which the number of species is related to area or other factors. In this study we have studied the nestedness pattern in stream diatom assemblages in 24 stream sites of central Western Ghats, and report 98 taxa from the streams of central Western Ghats region. The communities show highly significant nested pattern. The Mantel test of matrix revealed a strong relationship between species assemblages and environmental conditions at the sites. A significant relationship between species assemblage and environmental condition was observed. Principal component analysis (PCA) indicated that environmental conditions differed markedly across the sampling sites, with the first three components explaining 78% of variance. Species composition of diatoms is significantly correlated with environmental distance across geographical extent. The current pattern suggests that micro-environment at regional levels influences the species composition of epilithic diatoms in streams. The nestedness shown by the diatom community was highly significant, even though it had a high proportion of idiosyncratic species, characterized with high numbers of cosmopolitan species, whereas the nested species were dominated by endemic species. PCA identifies ionic parameters and nutrients as the major features which determine the characteristics of the sampling sites. Hence the local water quality parameters are the major factors in deciding the diatom species assemblages.
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Magnesium, 2007
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Fottea
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Phytotaxa
A new species belonging to the genus Hippodonta is described, Hippodonta mudumalaiensis, from Mud... more A new species belonging to the genus Hippodonta is described, Hippodonta mudumalaiensis, from Mudumalai, Tamil Nadu, India. This paper analysed a detailed morphology and ultrastructure of H. mudumalaiensis based on LM and SEM observations and compared it with similar species within the genus. The new species belongs to group two of Hippodonta, with the characteristic features of narrow lanceolate valve outline, protracted to broadly rounded apices and rhombic to panduriform central area. The described species is our prime effort to report genus Hippodonta from India, aiding in microbial biodiversity assessment of the country. Additionally, Hippodonta of the Indian Subcontinent is also discussed.
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Diversity, 2022
Myristica swamps are one of the rarest wetland ecosystems within the sub-tropical evergreen fores... more Myristica swamps are one of the rarest wetland ecosystems within the sub-tropical evergreen forests of the Western Ghats, India. As their name indicates, they harbor trees belonging to the ancient family Myristicaceae. Due to the waterlogged conditions and high humic decomposition, these swamps are acidic, harbor rare and endemic biotas, and provide ecosystem services to humans. Monitoring this rare ecosystem is crucial because the swamps that once formed a large hydrological network across the Western Ghats are now confined to isolated patches due to human disturbance such as agricultural interventions, roads, and dam construction. Due to the change in land use, there is also a drastic change in water chemistry and associated biodiversity. Biomonitoring is more precise than physical and chemical monitoring. So, the current study aimed to undertake a comprehensive analysis of the physical, chemical, and biological assessment of these swamps. The diatom assemblages are strongly affec...
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Limnetica, 2019
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This paper describes two new Gomphonema species from the lesser Himalayas, India, with their valv... more This paper describes two new Gomphonema species from the lesser Himalayas, India, with their valve morphology using light and scanning electron microscopy. The two species, Gomphonema juettnerii sp. nov. and G. doonensis sp. nov., were found in Nalota stream in Doon Valley of Uttarakhand State. Main features of G. juettnerii are valve outline, shape of the areolae and striae pattern and presence of stigma. Main features of G. doonensis are rounded headpole, striae made by doubly punctate striae and features in central area. A detailed discussion on doubly punctate striae in members of gomphonemoid diatoms is presented.
Bookmarks Related papers MentionsView impact
Water Practice and Technology, 2021
The freshwater rockpools support high endemic biodiversity but are poorly studied habitats in the... more The freshwater rockpools support high endemic biodiversity but are poorly studied habitats in the Western Ghats biodiversity hotspot. These freshwater rock pools are situated on outcrops at various elevations in the Western Ghats and are composed of different bedrocks such as laterite and basalt. We aimed to analyze the water quality, geographical position based differences in the water chemistry and the role of bedrock in determining the water chemistry of the rock pools. Our study showed a wide range of water quality variables such as pH, conductivity, and ionic contents that attributed to the natural variation. We observed a drastic variation in the anions and cations at low elevation pools. Rock type and precipitation are influencing the ionic concentration; for example, Calcium and Bromide could be attributed to the seasonal precipitation and geomorphology. This documentation of physicochemical properties of the Western Ghats rock pools can form a baseline for further detailed ...
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Fottea, 2020
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Fottea, 2021
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European Journal of Phycology, 2021
ABSTRACT Stauroneis Ehrenberg is a species-rich genus that is common and widespread with some var... more ABSTRACT Stauroneis Ehrenberg is a species-rich genus that is common and widespread with some variation in frustule morphology. Recently, studies have explored the molecular diversity of the Stauroneis from the temperate region, but there are no molecular data for tropical species. In the present study, four species of Stauroneis were investigated using morphological and molecular data. Morphological characters were analysed using light microscopy (LM) and scanning electron microscopy (SEM), and the features of each taxon were compared with similar species within the genus. For the molecular analyses, Stauroneis strains were isolated, cultured, DNA was extracted, and sequences from rbcL and 18S genes were analysed to determine phylogenetic relationships. Our analysis describes three new species and records one previously known species. The new species are: (1) Stauroneis lateritica Wadmare, Kociolek & B.Karthick, characterized by small frustules with elliptical lanceolate valves and short subrostrate apices, broad central bow-tie shaped stauros, and few moderate striae centrally becoming strongly radiate towards the poles; (2) Stauroneis sholaii Wadmare, Kociolek & B.Karthick, which has broad lanceolate valves with short rectangular stauros and radiate striae; and (3) Stauroneis bartii Wadmare, Kociolek & B.Karthick, which has large, lanceolate valves with rounded apices, a stauros with 4–7 shortened striae and radiate striae. Ultrastructure and molecular data from India for the previously known, widespread species Stauroneis gracilis Ehrenberg are presented. The combined morphological and molecular approach supports recognition of S. lateritica, S. sholaii and S. bartii as new species. This study is the first-ever attempt at molecular species discovery of diatoms from the Indian subcontinent.
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Phytotaxa, 2020
A new species of Navicula sensu stricto is described from a small stream from the Kaas Plateau in... more A new species of Navicula sensu stricto is described from a small stream from the Kaas Plateau in the northern part of the Western Ghats of India. The species is presented with light and scanning electron microscopy, and compared with similar species like Navicula reinhardtii, N sovereignii, N. aurora and N. gogorevii. This taxon is characterized by rhomboid shape, elongated lineolae, short striae at the central area giving a distinctive shape, and narrowly-rounded apices. The discovery of this taxon signifies that a significant number of species to be discovered in this biodiverse region of peninsular India, especially unique habitats like lateritic plateaus.
Bookmarks Related papers MentionsView impact
Issues of modern algology (Вопросы современной альгологии), 2019
Two new species of Gomphonema Ehrenberg are described on the basis of light and scanning electron... more Two new species of Gomphonema Ehrenberg are described on the basis of light and scanning electron microscopical observations. These are Gomphonema kallarensis sp. prov., a species found in India, and G. kezlyae sp. prov., which have been found in India and Vietnam. We also document the morphology and variability of G. doonensis B. Karthick, R. Nautiyal et Kociolek from Vietnam. This species was described originally from India based on a limited number of valves. Both G. doonensis and G. kallarensis have biseriate striae composed of areolae without occlusions, while G. kezlyae have striae with single row of areolae that have external occlusions giving the impression of C-shaped openings. Our investigation shows that India and Vietnam share some species in common, and adding additional evidence that the biogeography of freshwater diatoms from the Tropics warrants future investigation.
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Nova Hedwigia, Beihefte, 2018
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Phytotaxa, 2019
New diatom species from the genus Cymbella is described, Cymbella pavanaensis from the Pavana Riv... more New diatom species from the genus Cymbella is described, Cymbella pavanaensis from the Pavana River situated in Pimpri-Chinchwad, Pune, Maharashtra, India. The new species description is based on detailed LM and SEM morphological observations. Comparison of the new species with similar, previously-described taxa is made. C. pavanaensis belongs to a group of small-celled species of the genus, which lack differentiated, rounded porelli comprising the apical pore fields. This taxon is reported from a moderately to the highly-polluted urban lotic system, which signifies that even the diatom flora of easily accessible habitats of India is yet to be fully documented.
Bookmarks Related papers MentionsView impact
Phytotaxa, 2018
Light and scanning electron microscope observations of Cymbella sagarensis Gandhi are presented. ... more Light and scanning electron microscope observations of Cymbella sagarensis Gandhi are presented. Morphological peculiarities of this species show that it belongs to the genus Oricymba Jüttner, Krammer, Cox, Van de Vijver & Tuji. Based on our observations, the new taxonomic combination, Oricymba sagarensis (Gandhi) C.Radhakrishnan, Kociolek & B.Karthick, comb. nov. is proposed. Morphological comparison of this species with other known members of Oricymba is given. A second taxon described by Gandhi, C. sagarensis f. gracilis Gandhi, is suggested to be a synonym of the nominate forma. Distribution of this species and other Oricymba taxa is discussed.
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Springer Earth System Sciences, 2015
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Resonance, 2008
Bookmarks Related papers MentionsView impact
Industrial & Engineering Chemistry Research, 2009
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
ABSTRACT Community diversity and the population abundance of a particular group of species are co... more ABSTRACT Community diversity and the population abundance of a particular group of species are controlled by immediate environment, inter- and intra-species interactions, landscape conditions, historical events and evolutionary processes. Nestedness is a measure of order in an ecological system, referring to the order in which the number of species is related to area or other factors. In this study we have studied the nestedness pattern in stream diatom assemblages in 24 stream sites of central Western Ghats, and report 98 taxa from the streams of central Western Ghats region. The communities show highly significant nested pattern. The Mantel test of matrix revealed a strong relationship between species assemblages and environmental conditions at the sites. A significant relationship between species assemblage and environmental condition was observed. Principal component analysis (PCA) indicated that environmental conditions differed markedly across the sampling sites, with the first three components explaining 78% of variance. Species composition of diatoms is significantly correlated with environmental distance across geographical extent. The current pattern suggests that micro-environment at regional levels influences the species composition of epilithic diatoms in streams. The nestedness shown by the diatom community was highly significant, even though it had a high proportion of idiosyncratic species, characterized with high numbers of cosmopolitan species, whereas the nested species were dominated by endemic species. PCA identifies ionic parameters and nutrients as the major features which determine the characteristics of the sampling sites. Hence the local water quality parameters are the major factors in deciding the diatom species assemblages.
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Magnesium, 2007
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