Document Type

Article

Department/Program

Virginia Institute of Marine Science

Publication Date

2007

Journal

Aquatic Microbial Ecology

Volume

48

Issue

3

First Page

207

Last Page

215

Abstract

Fluxes of particulate matter to depth and dynamics of dissolved organic matter in the water column are influenced by microbial processes associated with organic aggregates like marine snow. These microscale processes include the encounter between bacteria and aggregates, which has been previously modeled and tested with well-fed and actively growing bacteria. In the present study, we investigated the effects of starvation on initial bacterial colonization of aggregates by measuring colonization and detachment of 6 isolates in different physiological states (fed vs. starved) using model aggregates. Because aggregate encounter depends on motility, the motility behaviors of fed and starved bacteria of 3 selected strains were also compared using image analysis. All 6 fed isolates colonized faster and achieved significantly higher steady-state abundances on model aggregates than those that were starved. However, there was no difference in detachment rates between fed and starved bacteria. The 3 selected strains had significantly lower average swimming speeds when starved. Diffusivities calculated from motilities of 2 starved isolates were more than 6 times lower than those of their fed counterparts. Our results show that starvation significantly affects bacterial behavior and bacteria-aggregate interactions, which may lead to differences in particulate and dissolved organic matter fluxes and cycling under different productivity regimes.

DOI

10.3354/ame048207

Keywords

Pacific Subtropical Gyre; Attached Bacteria; Heterotrophic Bacteria; Pseudomonas Sp; Snow; Dynamics; Communities; Assemblages; Recovery; Adhesion

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