Publications des scientifiques de l'IRD

Knapp A. N., Dekaezemacker J., Bonnet Sophie, Sohm J. A., Capone D. G. (2012). Sensitivity of Trichodesmium erythraeum and Crocosphaera watsonii abundance and N-2 fixation rates to varying NO3- and PO43- concentrations in batch cultures. Aquatic Microbial Ecology, 66 (3), p. 223-236. ISSN 0948-3055.

Titre du document
Sensitivity of Trichodesmium erythraeum and Crocosphaera watsonii abundance and N-2 fixation rates to varying NO3- and PO43- concentrations in batch cultures
Année de publication
2012
Type de document
Article référencé dans le Web of Science WOS:000306321900002
Auteurs
Knapp A. N., Dekaezemacker J., Bonnet Sophie, Sohm J. A., Capone D. G.
Source
Aquatic Microbial Ecology, 2012, 66 (3), p. 223-236 ISSN 0948-3055
Batch cultures of Trichodesmium erythraeum, strain IMS101, and Crocosphaera watsonii, strain WH8501, were grown under metal- and vitamin-replete conditions to evaluate differences in diazotroph abundance and N-2 fixation rates as well as biomass C:N:P ratios resulting from changes in the concentrations of nitrate (NO3-) and phosphate (PO43-) in culture media. Holding light levels and temperature constant, variations in culture NO3- and PO43- concentrations included (N:P ratios in mu M) 0:0.5, 5:1, 8:0.5, and 16:1. The abundance of both diazotrophs was greatest in the 16:1 and 5:1 N:P ratio treatments (i.e. those grown with 1 mu M PO43-) while the highest N-2 fixation rates for both diazotrophs were observed in the 0:0.5 treatment (i.e. those grown in NO3--free media). Measurable but reduced (similar to 25 to 50% of the rates in cultures grown with no NO3-) N-2 fixation rates were evident in both T. erythraeum and C. watsonii cultures grown with up to 16 mu M NO3-. These results indicate that while diazotrophs grown in the presence of NO3- have significantly lower N-2 fixation rates than those not chronically exposed to NO3-, these lower per cell N-2 fixation rates are compensated for by a greater abundance of diazotrophs in treatments with 1 mu M PO43- and result in comparable volume-integrated rates of N-2 fixation. Additionally, N-2 fixation rates for T. erythraeum and C. watsonii were comparable when normalized to carbon (biomass). Finally, the exponential-phase C:N:P biomass ratios of both diazotrophs were similar to each other as well as to previous studies and varied little among the treatments but increased, often significantly, between exponential and stationary growth phases.
Plan de classement
Micro-organismes [034MIORG] ; Milieu marin [036MILMAR]
Descripteurs
MICROORGANISME ; CULTURE IN VITRO ; FIXATION BIOLOGIQUE DE L'AZOTE ; ABONDANCE ; BIOMASSE ; INHIBITION ; FACTEUR LIMITANT ; NITRATE ; PHOSPHATE ; CYANOBACTERIE ; RATIO CNP
Localisation
Fonds IRD [F B010057037]
Identifiant IRD
fdi:010057037
Contact