Data/hora: 01/06/2024 12:35:40

Provedor de dados: | 5
País: | France
Título: | Phytoplankton and bacterial alkaline phosphatase activities in relation to phosphate and DOP availability within the Gironde plume waters (Bay of Biscay)
Autores: | Labry, Claire; Delmas, Daniel; Herbland, Alain.
Data: | 2005-05
Ano: | 2005
Palavras-chave: | Phytoplankton; Phosphate; Gironde; DOP; Bacteria; Alkaline phosphatases.
Resumo: | Previous studies conducted on the continental shelf in the Southeast Bay of Biscay influenced by Gironde waters (one of the two largest rivers on the French Atlantic coast) showed the occurrence of late winter phytoplankton blooms and phosphorus limitation of algal growth thereafter. In this context, the importance of dissolved organic phosphorus (DOP) for both algae and bacteria was investigated in 1998 and 1999 in terms of stocks and fluxes. Within the mixed layer, although phosphate decreased until exhaustion from winter to spring, DOP remained high and phosphate monoesters made up between I I to 65% of this pool. Total alkaline phosphatase activity (APA, V-max) rose gradually from winter (2-8 nM h(-1)) to late spring (100-400 nM h-1), which was mainly due to an increase in specific phytoplankton (from 0.02 to 3.0 nmol mu gC(-1) h(-1)) and bacterial APA (from 0.04 to 4.0 nmol mu gC(-1) h(-1)), a strategy to compensate for the lack of phosphate. At each season, both communities had equal competitive abilities to exploit DOP but, taking into account biomass, the phytoplankton community activity always dominated (57-63% of total APA) that of bacterial community (9-11%). The dissolved APA represented a significant contribution. In situ regulation of phytoplanktonic APA by phosphate (induction or inversely repression of enzyme synthesis) was confirmed by simultaneously conducted phosphate-enrichment bioassays. Such changes recorded at a time scale of a few days could partly explain the seasonal response of phytoplankton communities to phosphate depletion.
Tipo: | Text
Idioma: | Inglês

Identificador:

http://archimer.ifremer.fr/doc/2005/publication-608.pdf

DOI:10.1016/j.jembe.2004.12.017

Editor: | Elsevier
Relação: | http://archimer.ifremer.fr/doc/00000/608/
Formato: | application/pdf
Fonte: | Journal of Experimental Marine Biology and Ecology (0022-0981) (Elsevier), 2005-05 , Vol. 318 , N. 2 , P. 213-225
Fonte: | 2005 Elsevier B.V. All rights reserved