Reduced diversity and changed bacterioplankton community composition do not affect utilization of dissolved organic matter in the Adriatic Sea

TY - JOUR

T1 - Reduced diversity and changed bacterioplankton community composition do not affect utilization of dissolved organic matter in the Adriatic Sea

AU - Sjöstedt, Johanna

AU - Pontarp, Mikael

AU - Tinta, Tinkara

AU - Alfredsson, Hanna

AU - Turk, Valentina

AU - Lundberg, Per

AU - Hagström, Åke

AU - Riemann, Lasse

PY - 2013

Y1 - 2013

N2 - To obtain insights into the coupling between community composition, diversity and community function, bacterioplankton assemblages from the Gulf of Trieste (Northern Adriatic Sea) were exposed to increasing environmental stress throughout 2 wk in continuous seawater cultures to construct communities differing in composition and diversity. The assemblages were exposed to (1) decreased temperature, (2) decreased temperature and phosphate addition or (3) decreased temperature, phosphate addition and lowered oxygen level. Bacterial and viral abundances as well as bacterial community composition stabilized during the second week of the experiment. Denaturing gradient gel electrophoresis and pyrosequencing of 16S rRNA genes showed dramatic reductions in bacterial diversity in all treatments and major compositional differences relative to the inoculum. Nevertheless, no differences in the ability to exploit dissolved organic carbon (DOC) were found for the acquired communities relative to the inoculum, indicating that the bacterial communities were functionally redundant. We speculate that oscillations in exploitation of the DOC pool in situ are mainly governed by factors limiting the overall bacterial growth, rather than perturbations affecting only subsets of the microbial biota.

AB - To obtain insights into the coupling between community composition, diversity and community function, bacterioplankton assemblages from the Gulf of Trieste (Northern Adriatic Sea) were exposed to increasing environmental stress throughout 2 wk in continuous seawater cultures to construct communities differing in composition and diversity. The assemblages were exposed to (1) decreased temperature, (2) decreased temperature and phosphate addition or (3) decreased temperature, phosphate addition and lowered oxygen level. Bacterial and viral abundances as well as bacterial community composition stabilized during the second week of the experiment. Denaturing gradient gel electrophoresis and pyrosequencing of 16S rRNA genes showed dramatic reductions in bacterial diversity in all treatments and major compositional differences relative to the inoculum. Nevertheless, no differences in the ability to exploit dissolved organic carbon (DOC) were found for the acquired communities relative to the inoculum, indicating that the bacterial communities were functionally redundant. We speculate that oscillations in exploitation of the DOC pool in situ are mainly governed by factors limiting the overall bacterial growth, rather than perturbations affecting only subsets of the microbial biota.

U2 - 10.3354/ame01660

DO - 10.3354/ame01660

M3 - Journal article

SN - 0948-3055

VL - 71

SP - 15

EP - 24

JO - Aquatic Microbial Ecology

JF - Aquatic Microbial Ecology

ER -