title: Salinity and macrophyte drive the biogeography of the sedimentary bacterial communities in a brackish water tropical coastal lagoon.
abstract: Brackish water coastal lagoons are least understood with respect to the seasonal and temporal variability in their sedimentary bacterial communities. These coastal lagoons are characterized by the steep environmental gradient and provide an excellent model system to decipher the biotic and abiotic factors that determine the bacterial community structure over time and space. Using Illumina sequencing of the 16S rRNA genes from a total of 100 bulk surface sediments, we investigated the sedimentary bacterial communities, their spatiotemporal distribution, and compared them with the rhizosphere sediment communities of a common reed; Phragmites karka and a native seagrass species; Halodule uninervis in Chilika Lagoon. Spatiotemporal patterns in bacterial communities were linked to specific biotic factors (e.g., presence and type of macrophyte) and abiotic factors (e.g., salinity) that drove the community composition. Comparative assessment of communities highlighted bacterial lineages that were responsible for segregating the sediment communities over distinct salinity regimes, seasons, locations, and presence and type of macrophytes. Several bacterial taxa were specific to one of these ecological factors suggesting that species-sorting processes drive specific biogeographical patterns in the bacterial populations. Modeling of proteobacterial lineages against salinity gradient revealed that α- and γ-Proteobacteria increased with salinity, whereas β-Proteobacteria displayed the opposite trend. The wide variety of biogeochemical functions performed by the rhizosphere microbiota of P. karka must be taken into consideration while formulating the management and conservation plan for this reed. Overall, this study provides a comprehensive understanding of the spatiotemporal dynamics and functionality of sedimentary bacterial communities and highlighted the role of biotic and abiotic factors in generating the biogeographical patterns in the bacterial communities of a tropical brackish water coastal lagoon.
authors.affiliation: Wetland Research and Training Centre, Chilika Development Authority, Barkul, Balugaon, 752030, Odisha, India.
authors.forename: Pratiksha
authors.initials: P
authors.lastname: Behera
authors.affiliation: Wetland Research and Training Centre, Chilika Development Authority, Barkul, Balugaon, 752030, Odisha, India.
authors.forename: Sofia
authors.initials: S
authors.lastname: Mahapatra
authors.affiliation: Wetland Research and Training Centre, Chilika Development Authority, Barkul, Balugaon, 752030, Odisha, India.
authors.forename: Madhusmita
authors.initials: M
authors.lastname: Mohapatra
authors.affiliation: Department of Integrated Biological Science, Pusan National University, Geumjeong-gu, 46241 Busan, South Korea.
authors.forename: Ji Yoon
authors.initials: JY
authors.lastname: Kim
authors.affiliation: School of Biotechnology, KIIT University, Patia, Bhubaneswar, 751024, Odisha, India.
authors.forename: Tapan K
authors.initials: TK
authors.lastname: Adhya
authors.affiliation: School of Biotechnology, KIIT University, Patia, Bhubaneswar, 751024, Odisha, India.
authors.forename: Vishakha
authors.initials: V
authors.lastname: Raina
authors.affiliation: School of Biotechnology, KIIT University, Patia, Bhubaneswar, 751024, Odisha, India.
authors.forename: Mrutyunjay
authors.initials: M
authors.lastname: Suar
authors.affiliation: Wetland Research and Training Centre, Chilika Development Authority, Barkul, Balugaon, 752030, Odisha, India.
authors.forename: Ajit K
authors.initials: AK
authors.lastname: Pattnaik
authors.affiliation: Wetland Research and Training Centre, Chilika Development Authority, Barkul, Balugaon, 752030, Odisha, India. Electronic address: rastogigurdeep@gmail.com.
authors.forename: Gurdeep
authors.initials: G
authors.lastname: Rastogi
mesh_terms: D001419:Bacteria / Q000145:classification*; D019015:Geologic Sediments / Q000382:microbiology; D007194:India; D010944:Plants; D012336:RNA, Ribosomal, 16S; D058441:Rhizosphere; D000068357:Saline Waters; D054712:Salinity; D062211:Spatio-Temporal Analysis; D014871:Water Microbiology
chemical_list: D012336:RNA, Ribosomal, 16S
keywords: Bulk sediment; Coastal lagoon; Halodule uninervis; Illumina sequencing; Phragmites karka