Balasubramanian Karthick - Profile on Academia.edu (original) (raw)

Papers by Balasubramanian Karthick

Fottea

A new aerophilic diatom species, Humidophila manipurensis sp. nov., is described from the Sadu Ch... more A new aerophilic diatom species, Humidophila manipurensis sp. nov., is described from the Sadu Chiru waterfalls, Manipur, India, a part of the Indo-Burma hotspot region. This species is characterized by having its valve shape slightly inflated at middle, terminal raphe ends that are slightly deflected, round areolae and a central depression. Further, we also recorded Humidophila bigibba from Meghalaya State, Northeast India, and this population is compared with the type population from Indonesia and Chinese populations. Fine structural details of both taxa were examined using light and scanning electron microscopy and compared with morphologically similar taxa in this genus. Addition of new species from this region will further add to the biodiversity richness of the Indo-Burma biodiversity hotspot. Further, this study confirms the presence of H. bigibba for the first time in India. This species has a deep constriction in the middle of the valve which is not found in the populations from the Indonesia and China.

A new species of Hippodonta Lange-Bertalot, Metzeltin & Witkowski (Bacillariophyceae, Naviculales) from the Western Ghats, India

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.

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...

Limnetica, 2019

Biogeography and morphology of a poorly known diatom Dorofeyukea rostellata (Hustedt) Kulikovskiy... more Biogeography and morphology of a poorly known diatom Dorofeyukea rostellata (Hustedt) Kulikovskiy & Kociolek Dorofeyukea rostellata is a rare and poorly known representative of Dorofeyukea genus. To date, this taxon has only been recorded only outside of Europe. In two Croatian lakes, we found a diatom in appearance similar to Dorofeyukea rostellata and within corresponding physical and chemical conditions. Due to the uncertain taxonomical position of this taxon, type material of Dorofeyukea rostellata and a closely related species, Navicula grimmeioides, were analysed by means of light and scanning electron microscopy. Upon a detailed investigation, we could clearly distinguish the Croatian population from N. grimmeioides. However, the Croatian population and the type material of D. rostellata differed only in minor characteristics. The most obvious difference is the shape of areolae. Nevertheless, differences between the shapes of the areolae can be caused by the degree of silicification, which often depends on the environmental conditions. Since almost every other characteristic of the Croatian population overlapped with that of the type material of D. rostellata we identified it as D. rostellata. Additionally, scanning electron microscopy analyses also revealed that N. grimmeioides belongs to the genus Dorofeyukea, so its new combination was proposed.

Two new species of Gomphonema (Bacillariophyceae) from Doon Valley, Uttarakhand, India

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.

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 ...

Fottea, 2020

A new freshwater diatom species, Gomphonema adhikarii sp. nov., is described from a small roadsid... more A new freshwater diatom species, Gomphonema adhikarii sp. nov., is described from a small roadside pool from the alpine region of Arunachal Pradesh, Eastern Himalayas, India. Detailed valve morphological features, based on both light and scanning electron microscopy, is presented and this taxon is compared with similar species. Gomphonema adhikarii has a distinct asymmetry about the apical axis and slightly bent foot pole area. The outline of the valve is slightly undulate, the valve centre is swollen and both apices are broadly rounded. This new species described from the Eastern Himalayas supports the idea of the area being rich in biodiversity, even with respect to the freshwater diatom flora.

Fottea, 2021

Three new species of the genus Stauroneis Ehrenberg are discovered from the Northern Western Ghat... more Three new species of the genus Stauroneis Ehrenberg are discovered from the Northern Western Ghats of India-Stauroneis datarii sp. nov., Stauroneis bahlsii sp. nov., and Stauroneis hamiltonii sp. nov. Based on light microscopy (LM) and scanning electron microscopy (SEM) observations, detailed morphological features are presented and each taxon is discussed in comparison with similar species within the genus. Features of linear-lanceolate valves with median constriction, rounded apices, bow-tie shaped stauros, and radiating striae characterize Stauroneis datarii. Stauroneis bahlsii has large, lanceolate valves, with obtusely-rounded apices, a bow-tie shaped stauros that may have isolated areolae in some valves. Stauroneis hamiltonii possesses linear-lanceolate valves, broadly rostrate apices, characteristic bow-tie shaped stauros, and radiate striae. All of the taxa share a characteristic pseudoseptum at the apices. The recent discoveries of many novel taxa from the terrestrial and semi-aquatic environments of the Northern Western Ghats highlight the role of non-aquatic habitats in unmasking the diatom diversity of the Indian subcontinent.

Description and phylogenetic position of three new species of Stauroneis Ehrenberg (Bacillariophyceae: Stauroneidaceae) from the Indian Subcontinent

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.

Navicula watveae sp. nov. (Bacillariophyceae) a new diatom species from the Western Ghats, India

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.

Morphological investigation and description of two new Gomphonema Ehrenberg (Bacillariophyta) species from India and Vietnam with biogeographical comments

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.

Three new species of Gomphonema Ehrenberg (Bacillariophyta), from Eastern Himalayas, with a note on the unique girdle band structure

Nova Hedwigia, Beihefte, 2018

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.

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.

Springer Earth System Sciences, 2015

The Western Ghats is the primary catchment for most of the rivers in peninsular India. Pristine f... more The Western Ghats is the primary catchment for most of the rivers in peninsular India. Pristine forests in this region are rich in biodiversity but are under environmental stress due to unplanned developmental activities. This has given rise to concerns about land use/land cover changes with the realization that the land processes influence the climate. Rapid and unscientific land-use changes undermine the hydrological conditions, and deteriorate all the components in the hydrological regime. The developmental programs, based on ad-hocdecisions, are posing serious challenges to the conservation of fragile ecosystems. Considerable changes in the structure and composition of land use and land cover in the region have been very obvious during the last four decades. Pressure on land for agriculture, vulnerability of degraded ecosystems, the vagaries of high intensity rainfall and consequent occurrences of accelerated erosion and landslides, lack of integrated and coordinated land use planning become some of the reasons for rapid depletion of natural resource base. These changes have adversely affected the hydrological regime of river basins, resulting in diminished river/stream flows. This necessitates conservation of ecosystems in order to sustain their biodiversity, hydrology and ecology. In this situation, for resolving present problems and to avoid any future crisis, a comprehensive assessment of land use changes, its spatial distribution and its impact on hydrological regime were carried out. Accordingly, appropriate remedial methods have been explored for the sustainable utilization of the land and water resources in the catchment. The current research, focusing on five rivers located in the central Western Ghats, monitors water quality along with that of diatoms, land use in the catchment and threats faced by these ecosystems.

Industrial & Engineering Chemistry Research, 2009

In the face of increasing CO 2 emissions from conventional energy (gasoline), and the anticipated... more In the face of increasing CO 2 emissions from conventional energy (gasoline), and the anticipated scarcity of crude oil, a worldwide effort is underway for cost-effective renewable alternative energy sources. Here, we review a simple line of reasoning: (a) geologists claim that much crude oil comes from diatoms; (b) diatoms do indeed make oil; (c) agriculturists claim that diatoms could make 10-200 times as much oil per hectare as oil seeds; and (d) therefore, sustainable energy could be made from diatoms. In this communication, we propose ways of harvesting oil from diatoms, using biochemical engineering and also a new solar panel approach that utilizes genomically modifiable aspects of diatom biology, offering the prospect of "milking" diatoms for sustainable energy by altering them to actively secrete oil products. Secretion by and milking of diatoms may provide a way around the puzzle of how to make algae that both grow quickly and have a very high oil content.

The Bellandur Lake catchment has been subjected to extreme environmental stress mainly due to the... more The Bellandur Lake catchment has been subjected to extreme environmental stress mainly due to the rampant unplanned developmental activities in the catchment in recent years. Part of catchment area also falls under the Bangalore city municipal limits, which is mainly responsible for most of the sewage that flows into the lake apart from the natural storm water that drains into the lake. Of late, with the increasing pressures on land in the municipal limits, the land belonging to the lakebed has also been subjected to ad-hoc development approaches as evinced from the field investigations. The functional ability of the ecosystem is impaired due to structural changes in the ecosystem. This is evident from poor water quality, breeding of disease vectors, contamination of ground water in the catchment, frequent flooding in the catchment due to topography alteration, decline in ground water table, erosion in lake bed, etc. The development plans of the region (current as well as the proposed) ignore the integrated planning approaches considering all components of the ecosystem. Serious threats to the sustainability of the region due to lack of holistic approaches in aquatic resources management are: 1. Land use changes: Conversion of watershed area of the lake to residential and commercial layouts has altered the hydrological regime while enhancing the silt movement-lowering water yield in the catchment affecting the ground water recharge.

Nestedness Pattern in Stream Diatom Assemblages of Central Western Ghats

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.

Magnesium, 2007

Social, economic and political development of a region is dependent on the health and quantity of... more Social, economic and political development of a region is dependent on the health and quantity of the natural resources. Integrated approaches in the management of natural resources would ensure sustainability, which demands inventorying, mapping and monitoring of resources considering all components of an ecosystem. The monitoring of hydrological and catchment landscape of river resources have a vital role in the conservation and management of aquatic resources. This paper presents a case study Venkatapura river basin in Uttara Kannada district of Karnataka State, India based on stream hydrology and landuse analyses. The results revealed variations in dissolved oxygen and free carbon dioxide according to the flow nature of the water, and increased amount of phosphates and coliform contamination in streams closer to anthropogenic activities.