Data/hora: 05/06/2024 02:16:09

Provedor de dados: 	5	
País: 	France	
Título: 	The significance of organic nutrients in the nutrition of Pseudo-nitzschia delicatissima (Bacillariophyceae)	
Autores: 	Loureiro, Sofia; Jauzein, Cecile; Garces, Esther; Collos, Yves; Camp, Jordi; Vaque, Dolors.	
Data: 	2009-04	
Ano: 	2009	
Palavras-chave: 	Harmful Algal Blooms (HABs); Nitrogen Uptake; Urea; Dissolved Organic Matter (DOM).	
Resumo: 	The influence of organic nutrients on the evolution of Pseudo-nitzschia delicatissima cultures was investigated in an enrichment experiment with high-molecular-weight dissolved organic matter (HMWDOM) and in an uptake assay with N-15-ammonium and N-15-urea. HMWDOM was extracted from seawater collected at a nearby shore station during the decline of a diatom bloom. Four incubations were prepared: L1/5+DOM (P. delicatissima grown in L1 growth medium with 1/5 of the nitrate concentration of standard L1), (L1-N)+DOM (L1 without nitrate, i.e. nitrogen-deficient treatment), L1-DOM (control culture without added DOM) and BV+DOM (bacterial and viral control, free of microalgae). Incubations were carried out for 10 days. Chlorophyll a concentrations differed after day 4 and reached higher levels in the L1-DOM incubation by the end of the experiment; however, similar growth rates were observed in all incubations (1.64 +/- 0.05 divisions day(-1)). The persistently lower cellular chlorophyll content in (L1-N)+DOM during the experiment was consistent with N limitation conditions. The data suggested that the nitrogen needed for the growth of (L1-N)+DOM cells might have originated from the DOM. Based on the results of N-15 uptake assays, it was concluded that P. delicatissima more readily acquires ammonium than urea. Nevertheless, under low N conditions, P. delicatissima may use urea as an alternative N source, and comparable photosynthetic rates are attained on either substrate. Taken together, our results suggest a positive effect of organic nutrients on the growth of P. delicatissima.	
Tipo: 	Text	
Idioma: 	Inglês	
Identificador: 	http://archimer.ifremer.fr/doc/2009/publication-6438.pdf

DOI:10.1093/plankt/fbn122	
Editor: 	Oxford university press	
Relação: 	http://archimer.ifremer.fr/doc/00000/6438/	
Formato: 	application/pdf	
Fonte: 	Journal of plankton research (0142-7873) (Oxford university press), 2009-04 , Vol. 31 , N. 4 , P. 399-410	
Fonte: 	2009 Oxford university press