The effect of water depth on bacterial numbers, thymidine incorporation rates and C:N ratios in northeast Atlantic surficial sediments
Dixon, J.L.; Turley, C.M. (2000). The effect of water depth on bacterial numbers, thymidine incorporation rates and C:N ratios in northeast Atlantic surficial sediments, in: Jones, M.B. et al. Island, Ocean and Deep-Sea Biology: Proceedings of the 34th European Marine Biology Symposium, held in Ponta Delgada (Azores), Portugal, 13-17 September 1999. Developments in Hydrobiology, 152: pp. 217-225. https://dx.doi.org/10.1007/978-94-017-1982-7_20 In: Jones, M.B. et al. (2000). Island, ocean and deep-sea biology: Proceedings of the 34th European Marine Biology Symposium, held in Ponta Delgada (Azores), Portugal, 13-17 September 1999. European Marine Biology Symposia, 34. Developments in Hydrobiology, 152. ISBN 978-0-7923-6846-5; e-ISBN 978-94-017-1982-7. XII, 391 pp. https://dx.doi.org/10.1007/978-94-017-1982-7, more In: European Marine Biology Symposia., more Related to:Dixon, J.L.; Turley, C.M. (2000). The effect of water depth on bacterial numbers, thymidine incorporation rates and C:N ratios in northeast Atlantic surficial sediments. Hydrobiologia 440(1-3): 217-225. https://dx.doi.org/10.1023/A:1004127312756, more |
| Abstract | The effect of water depth on bacterial biomass and their ability to synthesise DNA, by measuring their rate of [3H]-thymidine incorporation, was investigated in the northeast Atlantic at three sites of varying water depth (1100-3580 m) and sediment characteristics. Thymidine incorporation rates (y) in surficial sediments varied between 0.028 and 1.44 pmol h-1 g-1 and showed an exponential relationship with depth (x) according to the equation y = 2.05e-0.0011x (r=0.9830 for n=7, P<0.001). However, this relationship failed when a layer of phytodetritus was found overlying the surface sediment and [3H]-thymidine incorporation rates increased by 80-339%. In contrast, bacterial numbers varied between 1.09 and 11.96 × 108 cells g-1 (dry weight) and showed no significant relationships with water depth or sediment POC/TN content. Significant exponential relationships were also found between water depth (x) and the POC (y1) and total nitrogen (TN, y2) content of surficial sediments according to the following equations: where y1 = 719e-0.0003x (r=0.8700 for n=9, P<0.01) and y2 = 76e-0.0002x(r=0.7582 for n=9 P<0.02). These relationships were irrespective of the presence or absence of an overlying layer of phytodetritus. This suggests that the POC and TN content of these surficial deep sea sediments is directly related to the flux of material through the water column, which significantly impacts bacterial production. |
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