Heterotrophic prokaryotic growth and loss rates along a latitudinal gradient in the Northeast Atlantic Ocean
Mojica, K.D.A.; Brussaard, C.P.D. (2015). Heterotrophic prokaryotic growth and loss rates along a latitudinal gradient in the Northeast Atlantic Ocean, in: Mojica, K.D.A. Viral lysis of marine microbes in relation to vertical stratification. pp. 173-204 In: Mojica, K.D.A. (2015). Viral lysis of marine microbes in relation to vertical stratification. PhD Thesis. Universiteit van Amsterdam: Amsterdam. ISBN 978-94-91407-20-8. 247 pp. hdl.handle.net/11245/1.487499, more |  |
| Authors | | Top | - Mojica, K.D.A., more
- Brussaard, C.P.D., more
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| Abstract | The production and mortality of prokaryotes were assessed over a latitudinal gradient in the North Atlantic Ocean during summer stratification. Heterotrophic production was uncoupled from phytoplankton biomass and closely tied to nutrient availability suggesting nutrient limitation played an important role in regulating host production dynamics. Viruses were the dominate mortality factor regulating prokaryotic losses in the surface waters of the Northeast Atlantic Ocean. Wherein, lytic viral production was the favored life strategy for prokaryotic viruses in the mixed layer, independent of system trophic status, with rates ranging from 0.9 to 57.0 x109 viruses l-1 d-1. Lytic VP in the surface waters was correlated to heterotrophic production and the nitrogen to phosphorus ratio. Lysogeny was important only within the deep chlorophyll maximum layer of oligotrophic stations wherein prophage induction decreased hyperbolically from 16.0 to 0.2 x109 viruses l-1 d-1 with latitude and Chl a. Our results suggest that inorganic nutrient limitation is an important factor regulating heterotrophic prokaryotic production, viral life strategy selection and lytic viral production in the North Atlantic Ocean. Moreover, the ratio of total mortality to heterotrophic production decreased over the latitudinal gradient signifying a gradual change from a system regulated by high turnover in regions of strong stratification to net heterotrophic production with reduced stratification. |
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