Bacterial uptake of DOM released from P-limited phytoplankton.
The growth and the structure of a coastal bacterioplankton community were monitored in short-term bottle experiments in order to investigate the bacterial uptake of extracellular organic carbon released by the diatom Cylindrotheca closterium grown under P-balanced and P-depleted conditions. Bacterial specific growth rates and carbon demand were significantly lower in the exudates from P-depleted algae (24% and 30% reduction, respectively). The origin of the extracellular carbon appeared also to affect the taxonomic composition of the bacterioplankton assemblage, mainly reducing the development of gamma-Proteobacteria. This pattern of bacterial carbon uptake could contribute to a longer persistence of the exudates released in P-depleted conditions affecting the dynamics of the carbon cycle in marine environments.
Puddu
Alberto
A
Istituto di Ricerca Sulle Acque, CNR, Via Reno 1, 00198 Rome, Italy. puddu@irsa.rm.cnr.it
Zoppini
Annamaria
A
Fazi
Stefano
S
Rosati
Michela
M
Amalfitano
Stefano
S
Magaletti
Erika
E