2024-03-28T18:58:48Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/254192019-03-07T10:40:26Zcom_10261_47com_10261_8com_10261_123col_10261_300col_10261_376
Gasol, Josep M.
Doval, M. Dolores
Pinhassi, Jarone
Calderón-Paz, Juan I.
Guixa-Boixareu, Núria
Vaqué, Dolors
Pedrós-Alió, Carlos
2010-06-18T10:19:53Z
2010-06-18T10:19:53Z
1998-04-09
Marine Ecology Progress Series 164: 107-124 (1998)
0171-8630
http://hdl.handle.net/10261/25419
10.3354/meps164107
Primary producers must respond to the diel changes in light availability. Therefore, detection of diel cycles in bacterial activity would imply tight coupling between the production of photosynthetic dissolved organic carbon (DOC) and its consumption by bacteria. Absence of diel cycles, on the contrary, would indicate that bacteria depend largely upon allochthonous organic carbon and that bacteria are not tightly dependent on photosynthetically produced autochthonous carbon. In 1993 and 1994 we sampled 3 sites in the NW Mediterranean Sea several times a day, and measured several microbial parameters as well as the vertical profiles of DOC along the diel cycle. The sites were selected so that one was on the continental shelf and, thus, was more influenced by coastal runoff; a second one was over the shelf slope and a third, oceanic one was located further offshore over a depth of 2000 m. We found clear diel cycles in bacterial total and specific activity always in the oceanic stations and sometimes in the shelf slope stations. Diel changes were detected as changes in both DNA and protein synthesis rates. These diel cycles were accompanied by diel changes in the distribution of total DOC, and by diel changes in the proportion of bacteria containing visible nucleoids. Noon estimates of bacterial activity were more than twice the daily average in the oceanic site, but they were less different in the other 2 sites. DOC changed daily by 15 µM (5 to 15% of the total stock). For bacterial activity to explain the diel changes in DOC concentration, bacteria should have growth efficiencies lower than 10% in general, and lower than 2% in the oceanic station.
eng
openAccess
Bacterial production
Mediterranean
Diel cycles
DOC diel changes
Nucleoid-containing bacteria
Bacterial carbon conversion efficiencies
Diel variations in bacterial heterotrophic activity and growth in the northwestern Mediterranean Sea
artículo