Data/hora: 01/06/2024 04:31:46

Provedor de dados: | 5
País: | France
Título: | The effects of nutrient additions on particulate and dissolved primary production and metabolic state in surface waters of three Mediterranean eddies
Autores: | Lagaria, A.; Psarra, S.; Lefevre, D.; Van Wambeke, France; Courties, C.; Pujo-pay, M.; Oriol, L.; Tanaka, T.; Christaki, U.
Data: | 2011
Ano: | 2011
Resumo: | We examined the effects of nutrient additions on rates of (14)C-based particulate and dissolved primary production as well as O(2)-based metabolic rates in surface waters (8 m) of three anticyclonic eddies, located in the Western, Central and Eastern Mediterranean. Ship-board microcosm experiments employing additions of inorganic nitrogen (+N) and phosphorus (+P), alone and in combination (+NP), were conducted in June/July 2008 during the BOUM (Biogeochemistry from the Oligotrophic to the Ultra-oligotrophic Mediterranean) cruise. In all three experiments, particulate primary production was significantly stimulated by the additions of nitrogen (+N, +NP) while no effect was observed with the addition of phosphorus alone (+P). Percent extracellular release of photosynthate (PER) displayed the lowest values (4-8%) in the +NP treatment. Among the three treatments (+N, +P, +NP), the +NP had the strongest effect on oxygen metabolic rates, leading to positive values of net community production (NCP&gt;0). These changes of NCP were mainly due to enhanced gross primary production (GPP) rather than reduced dark community respiration rates (DCR). In all three sites, in +NP treatment autotrophic production (whether expressed as GPP or PP(total)) was sufficient to fulfil the estimated carbon requirements of heterotrophic prokaryotes, while addition of nitrogen alone (+N) had a weaker effect on GPP, resulting in metabolically balanced systems. At the three sites, in treatments with N (+N, +NP), phytoplankton and heterotrophic prokaryote production were positively correlated. Heterotrophic conditions were observed in the Control and +P treatment at the central and eastern sites, and autotrophic production was not sufficient to supply estimated bacterial carbon demand, evidence of a decoupling of phytoplankton production and consumption by heterotrophic prokaryotes.
Tipo: | Text
Idioma: | Inglês

Identificador:

http://archimer.ifremer.fr/doc/00133/24401/22418.pdf

DOI:10.5194/bg-8-2595-2011

Editor: | Copernicus Gesellschaft Mbh
Relação: | http://archimer.ifremer.fr/doc/00133/24401/
Formato: | application/pdf
Fonte: | Biogeosciences (1726-4170) (Copernicus Gesellschaft Mbh), 2011 , Vol. 8 , N. 9 , P. 2595-2607
Fonte: | Author(s) 2011. CC Attribution 3.0 License.