Growth efficiency and respiration at different growth rates in glucose-limited chemostats with natural marine bacteria populations

Aquatic Microbial Ecology

Ramón Cajal-Medrano Helmut Maske¹ 

关键词: Bacterial growth efficiency;    Respiration;    Chemostats;    Glucose;   

DOI  :  10.3354/ame038125

学科分类：生物科学（综合）

来源: Inter-Research

【 摘 要 】

ABSTRACT: Chemostats with glucose-enriched seawater and inoculated with natural populations of heterotrophic marine bacteria were run at different dilution rates (0.05 to 1.0 d^-1), at constant temperature (22°C) and with low organicsubstrate medium (20 µM glucose). The following parameters were measured: cell abundance, POC, PON and total CO₂ produced. The results demonstrated an increase in growth efficiency with higher specific growth rates within the growth raterange investigated here that is typical for oceanic samples. The results were parameterized according to the Pirt model, with a maximum efficiency of substrate conversion (ε = 0.57) and a specific rate of maintenance metabolism (a = 0.41d^-1), although the experimental results within the limited growth rate range investigated here are not statistically different from a linear relationship. On first principals it can be argued that the growth efficiency has to pass throughthe origin and have a maximum efficiency below 1.0, thus suggesting an asymptotic relationship like the Pirt model. Applying the iterative method of model parameter adjustment to previously published data, similar growth efficiency versus growth raterelationships were arrived at. Our results confirm that at a particular temperature a proportionately higher fraction of dissolved organic material is remineralized in oligotrophic oceans that support lower growth rates than in waters supporting highergrowth rates. Consequently, in the latter waters, the efficiency of transfer of dissolved organic material into the particulate form is supposed to be higher.

【 授权许可】

Unknown