title: Near-Bottom Hypoxia Impacts Dynamics of Bacterioplankton Assemblage throughout Water Column of the Gulf of Finland (Baltic Sea).
abstract: Over the past century the spread of hypoxia in the Baltic Sea has been drastic, reaching its 'arm' into the easternmost sub-basin, the Gulf of Finland. The hydrographic and climatological properties of the gulf offer a broad suite of discrete niches for microbial communities. The current study explores spatiotemporal dynamics of bacterioplankton community in the Gulf of Finland using massively parallel sequencing of 16S rRNA fragments obtained by amplifying community DNA from spring to autumn period. The presence of redoxcline and drastic seasonal changes make spatiotemporal dynamics of bacterioplankton community composition (BCC) and abundances in such estuary remarkably complex. To the best of our knowledge, this is the first study that analyses spatiotemporal dynamics of BCC in relation to phytoplankton bloom throughout the water column (and redoxcline), not only at the surface layer. We conclude that capability to survive (or benefit from) shifts between oxic and hypoxic conditions is vital adaptation for bacteria to thrive in such environments. Our results contribute to the understanding of emerging patterns in BCCs that occupy hydrographically similar estuaries dispersed all over the world, and we suggest the presence of a global redox- and salinity-driven metacommunity. These results have important implications for understanding long-term ecological and biogeochemical impacts of hypoxia expansion in the Baltic Sea (and similar ecosystems), as well as global biogeography of bacteria specialized inhabiting similar ecosystems.
authors.affiliation: Marine Systems Institute at Tallinn University of Technology, Akadeemia Rd. 15A, 12618, Tallinn, Estonia.
authors.forename: Peeter
authors.initials: P
authors.lastname: Laas
authors.affiliation: Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, 12618, Tallinn, Estonia.
authors.forename: Elina
authors.initials: E
authors.lastname: Šatova
authors.affiliation: Marine Systems Institute at Tallinn University of Technology, Akadeemia Rd. 15A, 12618, Tallinn, Estonia.
authors.forename: Inga
authors.initials: I
authors.lastname: Lips
authors.affiliation: Marine Systems Institute at Tallinn University of Technology, Akadeemia Rd. 15A, 12618, Tallinn, Estonia.
authors.forename: Urmas
authors.initials: U
authors.lastname: Lips
authors.affiliation: Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, 12618, Tallinn, Estonia.
authors.forename: Jaak
authors.initials: J
authors.lastname: Simm
authors.affiliation: Institute of Technology at University of Tartu, Nooruse 1, 50411, Tartu, Estonia.
authors.forename: Veljo
authors.initials: V
authors.lastname: Kisand
authors.affiliation: Institute of Mathematics and Natural Sciences, Tallinn University, Narva Rd. 25, 10120, Tallinn, Estonia.
authors.forename: Madis
authors.initials: M
authors.lastname: Metsis
mesh_terms: D059001:Aquatic Organisms / Q000378:metabolism*; D001419:Bacteria / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D001454:Baltic States; D058448:Biota / Q000235:genetics; D017753:Ecosystem; D063366:Estuaries; D005387:Finland; D006874:Hydrostatic Pressure; D000860:Hypoxia / Q000382:microbiology; D010084:Oxidation-Reduction; D010839:Phytoplankton; D010933:Plankton / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000032:analysis / Q000235:genetics; D012623:Seawater / Q000737:chemistry / Q000382:microbiology*
chemical_list: D012336:RNA, Ribosomal, 16S