Prey-specific growth responses of freshwater flagellate communities induced by morphologically distinct bacteria from the genus Limnohabitans

0445920 - BC 2016 RIV US eng J - Journal Article
Grujčič, Vesna - Kasalický, Vojtěch - Šimek, Karel
Prey-specific growth responses of freshwater flagellate communities induced by morphologically distinct bacteria from the genus Limnohabitans.
Applied and Environmental Microbiology. Roč. 81, č. 15 (2015), s. 4993-5002. ISSN 0099-2240. E-ISSN 1098-5336
R&D Projects: GA ČR(CZ) GA13-00243S; GA MŠMT(CZ) EE2.3.30.0032
Institutional support: RVO:60077344
Keywords : freshwater reservoir * heterotrophic flagellate bacterivory * Limnohabitans * bacterial food quality * growth responses of flagellates
Subject RIV: EH - Ecology, Behaviour
Impact factor: 3.823, year: 2015

Because their large growth potential is counterbalanced with grazing by heterotrophic nanoflagellates (HNF), bacteria of the genus Limnohabitans, which are common in many freshwater habitats, represent a valuable model for examining bacterial carbon flow to the grazer food chain. We conducted experiments with natural HNF communities taken from two distinct habitats, the meso-eutrophic Římov Reservoir and the oligo-mesotrophic Lake Cep (South Bohemia). HNF communities from each habitat at distinct seasonal phases, a late April algal bloom and a late May clear water phase, were each fed 3 Limnohabitans strains of differing cell sizes. Water samples were prefiltered (5 μm) to release natural HNF communities from zooplankton control and then amended with the Limnohabitans strains L. planktonicus II-D5 (medium sized, rod shaped), Limnohabitans sp. strain T6-5 (thin, long, curved rod), and Limnohabitans sp. strain 2KL-3 (large solenoid). Using temporal sampling and prey treatment, we determined HNF growth parameters such as doubling time, growth efficiency, and length of lag phase prior starting to exponential growth. All three Limnohabitans strains supported HNF growth but in significant prey-, site-, and season-dependent fashions. For instance, addition of the moderately large T6-5 strain yielded very rapid HNF growth with a short lag phase. In contrast, the curved morphology and larger cell size of strain 2KL-3 made this prey somewhat protected against grazing by smaller HNF, resulting in slower HNF growth and longer lag phases. These trends were particularly pronounced during the late May clear-water phase, which was dominated by smaller HNF cells. This may indicate a longer "adaptation time" for the flagellate communities toward the large prey size offered.
Permanent Link: http://hdl.handle.net/11104/0251537