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Seasonal growth potential of rare lake water bacteria suggest their disproportional contribution to carbon fluxes
Author(s) -
Neuenschwander Stefan M.,
Pernthaler Jakob,
Posch Thomas,
Salcher Michaela M.
Publication year - 2015
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.12520
Subject(s) - biology , trophic level , phytoplankton , ecology , spring bloom , bloom , nutrient , growth rate , seasonality , bacterioplankton , microbial population biology , bacteria , genetics , geometry , mathematics
Summary We studied the seasonal growth potential of opportunistic bacterial populations in L ake Z urich ( S witzerland) by a series of grazer‐free dilution culture assays. Pronounced shifts in the composition of the bacterial assemblages were observed within one doubling of total cell numbers, from initially abundant A ctinobacteria to other fast‐growing microbial lineages. Small populations with growth potentials far above community average were detected throughout the year with striking seasonal differences in their respective taxonomic affiliations. Members of C ytophaga‐ F lavobacteria ( CF ) were disproportionally proliferating only during phytoplankton blooms in spring and summer, while B eta ‐ and G ammaproteobacteria showed superior growth at all other occasions. Growth rates of A lphaproteobacteria and esp. S phingomonadaceae were significantly correlated to water temperatures and were far above community average in summer. Within the genus F lavobacterium , two species‐like populations showed a tendency for fast growth in most experiments, while four others were exclusively proliferating either during a spring or during a summer phytoplankton bloom. Their high growth potentials but low in situ abundances hint at a tight control by bacterivorous grazers and at a consequently accelerated carbon flux to higher trophic levels.