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Please use this identifier to cite or link to this item: http://hdl.handle.net/10261/15729
Title: Bacterial activity and diffusive nutrient supply in the oligotrophic Central Atlantic Ocean
Authors: Gasol, Josep M.; Vázquez-Domínguez, Evaristo; Vaqué, Dolors; Agustí, Susana ; Duarte, Carlos M.
Keywords: Bacterial activity
Bacterial production
Central Atlantic
Nutrient supply
Primary production
Water column stability
Mediterranean mesocosms
Issue Date: 9-Jul-2009
Publisher: Inter Research
Citation: Aquatic Microbial Ecology 56(1): 1-12 (2009)
Abstract: Growing evidence of inorganic nutrient limitation on oceanic bacteria suggests a global dependence of bacterial activity and production on rates of nutrient supply. The present study examined whether surface bacterial abundance is significantly related to water column stability, and whether bacterial activity and growth rate are related to the rate of diffusive supply of inorganic nutrients to the mixed layer in the Central Atlantic during 2 meridional cruises. The 2 cruises were run under very different oceanic conditions, with relatively low values of bacterial activity in spring 1995 and relatively higher values in fall 1995. We obtained depth-resolved data in the second cruise and found that the integrated value of bacterial production was also related to the rate of nutrient supply, while integrated particulate primary production and chlorophyll concentration were not. There was also no relationship between particulate primary production and bacterial production. The relationship between nutrient supply and integrated bacterial production was tested with data from a mesocosm experiment showing a good fit to the pattern obtained in the Atlantic. Average bacterial production was ~21% of primary production in the Central Atlantic, with values ranging between 5 and 100%, and higher values in the tropical areas. The demonstration of a direct relationship between nutrient supply and bacterial activity helps to explain a relatively large bacterial biomass as compared to phytoplankton biomass, a low bacterial growth efficiency, and a high bacterial carbon demand relative to contemporaneous primary production often measured in the open ocean, as well as the accumulation of dissolved organic carbon (DOC) observed in nutrient-limited oligotrophic seas.
Description: 12 pages, 4 figures, 2 tables.-- Full-text version available Open Access at: http://www.icm.csic.es/bio/projects/icmicrobis/pdf/Gasola056p001.pdf
Publisher version (URL): http://dx.doi.org/10.3354/ame01310
URI: http://hdl.handle.net/10261/15729
DOI: 10.3354/ame01310
ISSN: 0948-3055 (Print)
1616-1564 (Online)
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