Papers by Nallamuthu Godhantaraman
Journal of Marine Science: Research & Development, Sep 23, 2013
Dr. Nallamuthu has made significant contributions to research in the field of biological oceanogr... more Dr. Nallamuthu has made significant contributions to research in the field of biological oceanography with special reference to population and production ecology of microzooplankton, climate change impacts on marine ecosystem and published over 25 research articles in refereed journals and chapters in books. Dr. Nallamuthu participated and delivered lectures in various national and international symposia/conferences/workshops (over 30) and visited countries like Japan, USA,
Indian Journal of Marine Sciences, 2001
Seasonal abundance and the relationship of microzooplankton with higher trophic levels were studi... more Seasonal abundance and the relationship of microzooplankton with higher trophic levels were studied in the tropical estuarine and mangrove waters, from Parangipettai (11° 29' N; 79° 46' E). Taxonomic composition and abundance of microzooplankton exhibited clear seasonal variations, being highest in summer and lowest in monsoon. The overall mean abundance in summer was 4.0 fold (estuary) and 2.5 fold (mangrove) higher than in monsoon. Over the study period, tintinnid ciliates overwhelmingly dominated the microzooplankton community both in terms of species diversity (mean 62%) and abundance (mean 65%). The remaining taxa included rotifers, copepod nauplii, naked ciliates, metazoan larval forms and veliger larvae. Their position in the food web was assumed from the gut content of the common secondary and tertiary consumers. The food web relationships closely followed the existing seasonal pattern of microzooplankton abundance, i.e. tintinnids, cirriped nauplii, veliger larvae, ...
Oceanography & Fisheries Open access Journal, Apr 6, 2017
participantGlobal warming and the subsequent events of climate change and variability may have ev... more participantGlobal warming and the subsequent events of climate change and variability may have even greater repercussions for marine ecosystems than for terrestrial ecosystems, because temperature influences, water column stability, nutrient enrichment, and changes in the biodiversity of plankton communities and its reproductive cycles. Any change in the plankton diversity and abundance would affect the marine food-web and other trophic levels. In order to understand the impacts of climate change and its variability on the tropical coastal and marine ecosystems, study has been undertaken to investigate the diversity and trophic structure of plankton in the most important tropical estuarine system, a unique coastal marine environment in South India, as it is connected with mangrove ecosystem, brackish water and Bay of Bengal. The long term continuous monitoring survey showed (20 years of intensive study from 1988 to 2008) remarkable variations in environmental parameters, chlorophyll...
CLEAN - Soil, Air, Water, 2016
The study first investigated the spatial distribution, diversity, and biomass of the planktonic c... more The study first investigated the spatial distribution, diversity, and biomass of the planktonic choreotrich ciliate tintinnids inhabiting the biosphere reserve, the core region of Indian Sundarban mangrove wetland. A total of 21 species (eight genera and six families) were recorded including agglomerated and non-agglomerated or hyaline forms from these intricate estuarine network systems. Maximum mean abundance (2747 ± 111 individuals L−1) and species diversity (H′ = 2.32) of tintinnid ciliate were recorded at the sampling site located towards the Bay of Bengal whereas lower abundance (666 ± 56 individuals L−1) and diversity (H′ = 1.55) were encountered towards inner part of the estuary. Tintinnopsis represented the most dominant agglutinated genus comprising of Tintinnopsis beroidea, Tintinnopsis fimbriata, Tintinnopsis cylindrica, Tintinnopsis tocantinensis, and Tintinnopsis radix, accounting ∼52% of total tintinnid community. The agglomerated forms Amphorellopsis tetragona, Eutintinnus apertus, Codonellopsis lusitanica, and T. fimbriata were recorded for the first time in this region. The biomass value exhibited wide range of variations (0.03 ± 0.09 to 12.4 ± 1.1 μg C L−1), accounting maximum value towards seaward region. The small-sized tintinnid (lorica length <40 μm) contributed the most dominant group (sharing ∼85% of total species abundance) in this core region and their presence was mainly governed by factors, namely, chlorophyll α, salinity, and nutrients (nitrate and silicate). The results of combining multivariate methods (RELATE and BIOENV analyses) reveal that chl a and nitrate were the potential significant factors for tintinnid abundance and distribution.
CLEAN - Soil, Air, Water, 2013
An intense monospecies bloom of the centric diatom Hemidiscus hardmannianus (Greville) Mann. (Bac... more An intense monospecies bloom of the centric diatom Hemidiscus hardmannianus (Greville) Mann. (Bacillariophyceae) occurred in the coastal waters of Sundarban mangrove wetland, India on 22 July, 2010. The species was abruptly flourished (mean density 8.86 Â 10 6 cells/L) resulting intense green coloration of water. The greatest impoverishment of diversity and density of phytoplankton, micro-and mesozooplankton community was observed during the bloom. The phytoplankton community showed an extreme reduction in diversity (12 species to one) and sharp decrease in standing stock (12.84 Â 10 3 to 8.86 Â 10 6 cells/L) during this period. The late bloom condition coincided with sudden and huge arrival of a clupoid fish Hilsa ilisha which forms the most potential fisheries in Sundarban deltaic region. An attempt has been made to correlate the satellite remote sensing-derived information to the bloom conditions. The MODIS-Aqua derived chlorophyll and TMI satellite derived sea surface temperature and wind speed maps have been interpreted.
Bulletin of Environmental Contamination and Toxicology, 2010
Bioaccumulation of trace metals in four softbottom polychaetes along with the host sediments was ... more Bioaccumulation of trace metals in four softbottom polychaetes along with the host sediments was recorded from the intertidal regions of Indian Sundarban mangrove wetland. The enrichment of Mn (maximum 730 mg kg-1) and Zn (maximum 320 mg kg-1) was recorded for all the polychaetes followed by Cr, Cu, As, Co, Ni and Pb, showing sharp variations between the species. However, concentrations of Sn and Hg were very low with small variations between the species. An overall high bioconcentration factor (BCF) was recorded in the capitellid worm Mastobranchus indicus. The results of the investigation indicate the possibility of developing a standard test protocol for bioaccumulation by polychaetous annelids.
The study presents the first preliminary report on the community composition, abundance, biomass ... more The study presents the first preliminary report on the community composition, abundance, biomass and production rate of the ciliated tintinnids in the coastal waters of Sundarban mangrove wetland, formed at the confluence of the Ganges River Estuary, India. Total 32 species under 5 agglomerated (29 species) and 3 non agglomerated (3 species) genera have been identified from six sites of different hydrodynamic conditions. In general, Tintinnopsis (22 species) dominates the community structure followed by Leprotintinnus (2 species), Tintinnidium (2 species), Stenosemella (2 sp), Codonellopsis (1 sp), Amphorellopsis (1 sp), Metacylis (1 sp) and Favella (1 sp). Pronounced seasonal variations were noticed in environmental parameters and abundance, biomass, production rates of tintinnids: Being the highest during pre monsoon followed by post monsoon and monsoon. Water temperature, Chl a and salinity were found to regulate the seasonal tintinnid variations as revealed by stepwise multiple ...
Plankton biology and ecology, 2001
The geographical variations in taxonomic composition, abundance, biomass and tropho dynamic role ... more The geographical variations in taxonomic composition, abundance, biomass and tropho dynamic role of microzooplankton were investigated across a eutrophic and oligotrophic gradient from Hiroshima Bay, the Inland Sea of Japan, to the Pacific Ocean in summer and winter. The overall mean abundance and biomass of total microzooplankton, excluding the 3 most offshore stations in summer, were higher 2.4 and 2.8 times, respectively, in summer than in winter. Both in summer and winter, ciliated protozoans (i.e. naked ciliates and tintinnids) were numerically overwhelming (81 and 83%, respectively), but in terms of biomass, copepod nauplii were comparable (i.e. 47 and 55% in summer and winter, respectively) to ciliated protozoans. The average production rate of microzoo plankton was also higher (3.3 times) in summer than in winter, and the majority (>83%) of the pro duction was attributed to ciliated protozoans. Geographically there were marked declines in their abundance, biomass and prod...
Ciencias Marinas, 1994
Proyecto académico sin fines de lucro, desarrollado bajo la iniciativa de acceso abierto
Marine Pollution Bulletin
Environmental Monitoring and Assessment, 2014
The study is the first documentation of seasonal variations in species composition, abundance and... more The study is the first documentation of seasonal variations in species composition, abundance and diversity of tintinnid (Ciliata: Protozoa), in relation to water quality parameters along the stretch of the Hooghly (Ganges) River Estuary (HRE), eastern coastal part of India. A total of 26 species (22 agglomerated and 4 non-agglomerated) belonging to 8 genera has been identified from 8 study sites where Tintinnopsis (17 species) represented the most dominant genera, contributing up to 65 % of total tintinnid community followed by Tintinnidium (2 species), Leprotintinnus (2 species) and Dadayiella, Favella, Metacylis, Eutintinnus and Helicostomella (each with solitary species). The maximum (1,666 ind.l −1 ) and minimum (62 ind.l −1 ) abundance of tintinnids was recorded during post-monsoon and monsoon, respectively. A distinct seasonal dynamics in terms of biomass (0.005-2.465 μg C l −1 ) and daily production rate (0.04-3.13 μg C l −1 day −1 ) was also noticed, accounting highest value during pre-monsoon. Chlorophyll a and nitrate were found to be potential causative factors for the seasonal variations of tintinnids as revealed by a stepwise multiple regression model. The result of ANOVA showed a significant variation between species abundance and months (F=2.36, P ≤0.05). k-dominance curves were plotted to determine the comparison of tintinnid dominance between the investigated stations. Based on a principal component analysis (PCA), three main groups were delineated with tintinnid ciliates and environmental parameters. The changes in lorica morphology in terms of temperature and salinity, recorded for three dominant species, provided information on the ecological characteristics of the species assemblage in this estuarine system.
Marine Pollution Bulletin, 2012
This study reports the first evidence of the quantification of two dominant perfluorinated compou... more This study reports the first evidence of the quantification of two dominant perfluorinated compounds (PFCs), namely perfluorooctanesulfate (PFOS) and perfluorooctannoate (PFOA), in surface sediment samples (0-5 cm; n = 13) from the Ganges (Hugli) River including Sundarban wetland, India using HPLC-MS/ MS. The concentrations of PFOA exhibited a wide range of concentrations from <0.5 to 14.09 ng/g dry wt, whereas the concentration of PFOS was always below the detection limit of <0.5 ng/g dry wt. A consistent enrichment of PFOA was recorded in all the five sites of Sundarban (mean value 11.61 ± 1.86) whereas it was of moderate concentration or below the detection level in the seven sites along with the lower stretch of the Ganges (Hugli) River estuary (mean value 5.96 ng/g dry wt ± 5.36). Wastewater and untreated effluents are likely the major causes of accumulation of PFCs in sediments. The present paper could be used as baseline study to assess future monitoring programs of the ecosystem.
IOP Conference Series: Earth and Environmental Science, 2009
Journal of Marine Systems, 2002
Seasonal varaitions in species composition, abundance, biomass and production rates of tintinnids... more Seasonal varaitions in species composition, abundance, biomass and production rates of tintinnids (Protozoa: Ciliata) were investigated in the tropical estuarine and mangrove systems of Parangipettai, South India, monthly from January to December 1994. There were remarkable seasonal variations in environmental parameters, chlorophyll a concentrations and abundance, biomass and production rates of tintinnids: highest in postmosoon/summer and lowest in monsoon. The total abundance and biomass of tintinnids were in the range of 2 -420 indiv. l À 1 and 0.02 3.01 Ag C l À 1 , respectively, with the peak appearing in the estuarine waters. A total of 47 species of tintinnids belonging to 14 genera was identified. Of which, Tintinnopsis was the most abundant genus in terms of number of species (20), followed by Codonellopsis (4), Stenosemella (4), Favella (3), Eutintinnus (3), and the remaining genus, number of species are one or two. Most of the tintinnid species occurred on distinct seasonal pattern and closely associated to species-specific environmental conditions. Due to large thermal gradients (range: 22.5 -33.8 jC), the overall mean biomass was highest (mean: 1.64 Ag C l À 1 ) during summer than the remaining seasons. Estimated production rates of tintinnids ranged from 0.02 to 2.5 Ag C l À 1 day À 1 , with peak in summer. The trophodynamic role of tintinnids was assessed by estimating their grazing impact as expressed by daily removal of phytoplankton biomass. The grazing impact also demonstrated a seasonal pattern and ranged from 0.03% to 1.24% removal day À 1 . The higher grazing impact estimated during summer could be related to high concentrations of food supply. Due to significant positive relationship between the total biomass of tintinnids and chlorophyll a concentrations, food supply is not a problem for tintinnids harboring in this estuarine and mangrove systems. Hence, predation loss by meso-and macrozooplankton might be the possible reasons for the estimated low biomass of tintinnids in the present study. Therefore, the results demonstrate that tintinnids play an important role to transfer the production of pico-and nanoplankton to meso-and macrometazoan predators. Thus, the seasonal environmental factors exert major influence on the species composition, abundance, biomass and production rates of tintinnids. D Estuarine and mangrove waters 0924-7963/02/$ -see front matter D 2002 Elsevier Science B.V. All rights reserved. PII: S 0 9 2 4 -7 9 6 3 ( 0 2 ) 0 0 1 8 5 -9
Indian Journal of Geo-Marine Sciences
ABSTRACT
Marine pollution bulletin, Jan 15, 2014
The present study provides preliminary in-situ data on genetic integrity of marine zooplankton. P... more The present study provides preliminary in-situ data on genetic integrity of marine zooplankton. Paracalanus parvus, Oithona rigida and Euterpina acutifrons were collected during four different seasons (summer, pre-monsoon, monsoon and post-monsoon) from 2011 to 2012 in Ennore and Kovalum estuaries. DNA damage levels in different zooplankton were analyzed by comet assay and were correlated with different environmental stressors. Spatial and temporal variations in DNA damage was observed in all the species. Zooplankton from Ennore estuary showed significantly lower genetic integrity. Particulate, sediment, and zooplankton fractions of Pb, Ni, Cu, Cr and Co were associated with high DNA damage during the period of lowest pH, salinity and dissolved oxygen. Zn and Cd showed lower genotoxic impact than the other metals. Feeding modes strongly influenced the genetic integrity in the zooplankton species studied. These results support the use of comet assay as a tool in effectively monitorin...
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Papers by Nallamuthu Godhantaraman