title: Diversity of retrievable heterotrophic bacteria in Kongsfjorden, an Arctic fjord.
abstract: The diversity and abundance of retrievable pelagic heterotrophic bacteria in Kongsfjorden, an Arctic fjord, was studied during the summer of 2011 (June, August, and September). Retrievable bacterial load ranged from 103to 107CFUL-1in June, while it was 104-106CFUL-1in August and September. Based on 16S rRNA gene sequence similarities, a higher number of phylotypes was observed during August (22 phylotypes) compared to that during June (6 phylotypes) and September (12 phylotypes). The groups were classified into four phyla: Firmicutes, Actinobacteria, Proteobacteria, and Bacteroidetes. Bacteroidetes was represented only by a single member Leewenhoekiella aequorea during the three months and was dominant (40%) in June. However, this dominance changed in August to a well-known phytopathogenic species Rhodococcus fascians (32%), which could be a result of decrease in the phytoplankton biomass following the secondary bloom. It is the first report of Halomonas titanicae isolation from the Arctic waters. It showed an increase in its abundance with the intrusion of Atlantic water into Kongsfjorden. Increased abundance of Psychrobacter species in the late summer months coincided with the presence of cooler waters. Thus, the composition and function of heterotrophic bacterial community was fundamentally different in different months. This could be linked to the changes in the water masses and/or phytoplankton bloom dynamics occurring in Arctic summer.
authors.affiliation: National Centre for Antarctic and Ocean Research, ESSO-NCAOR, Head land Sada, Vasco-da-Gama, Goa, India. Electronic address: kineto.magnetic@gmail.com.
authors.forename: Rupesh Kumar
authors.initials: RK
authors.lastname: Sinha
authors.affiliation: National Centre for Antarctic and Ocean Research, ESSO-NCAOR, Head land Sada, Vasco-da-Gama, Goa, India.
authors.forename: Kottekkatu Padinchati
authors.initials: KP
authors.lastname: Krishnan
authors.affiliation: Cochin University of Science and Technology, Microbiology and Biochemistry, Department of Marine Biology, Cochin, Kerala, India.
authors.forename: Ammanamveetil Abdulla Mohamed
authors.initials: AA
authors.lastname: Hatha
authors.affiliation: Cochin University of Science and Technology, Microbiology and Biochemistry, Department of Marine Biology, Cochin, Kerala, India.
authors.forename: Mujeeb
authors.initials: M
authors.lastname: Rahiman
authors.affiliation: National Centre for Antarctic and Ocean Research, ESSO-NCAOR, Head land Sada, Vasco-da-Gama, Goa, India.
authors.forename: Divya David
authors.initials: DD
authors.lastname: Thresyamma
authors.affiliation: Goa University, Department of Biotechnology, Taleigao Plateau, Goa, India.
authors.forename: Savita
authors.initials: S
authors.lastname: Kerkar
mesh_terms: D001110:Arctic Regions; D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D058491:Bacterial Load; D018407:Bacterial Physiological Phenomena; D044822:Biodiversity; D052836:Heterotrophic Processes; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D012336:RNA, Ribosomal, 16S
keywords: 16S rRNA; Arctic fjord; Kongsfjorden; Retrievable heterotrophic bacteria