La Tour du Valat

Institut de recherche pour la conservation des zones humides méditerranéennes

Titre :	Variations in Apparent Oxygen Utilization and Effects of P Addition on Bacterial Respiration in Subtropical Hong Kong Waters
Auteurs :	Xiangcheng Yuan, Auteur ; Kedong Yin, Auteur ; Paul J. Harrison, Auteur ; Lei He, Auteur ; Jie Xu, Auteur
Type de document :	Article
Dans :	Estuaries and Coasts (34(3) MAY 2011)
Article en page(s) :	536-543
Résumé :	Seven cruises during June 2005-November 2006 were conducted to study the variations in apparent oxygen utilization in Hong Kong coastal waters, and PO(4) addition experiments were conducted in the summer to study bacterial responses to PO(4) additions. Apparent oxygen utilization (AOU) was significantly correlated with PO(4) concentrations. AOU was more responsive to PO(4) when DIN/PO(4) ratio was 50:1 in the summer wet season, and PO(4) was more responsive to AOU in the dry season when N/P ratio was close to or less than 16:1, which suggested less regenerated PO(4) during oxygen consumption in the former case than in the latter case. The PO(4) addition experiment showed that 0.1 mu M PO(4) addition increased bacterial respiration (BR) by 20 +/- 4%, but a 0.2-mu M PO(4) addition saturated BR even when DIN/PO(4) was 80:1, suggesting that there was a limit for PO(4) stimulation of bacterial respiration. This finding of a 0.2-A mu M PO(4) saturation concentration for stimulating bacterial respiration is significant, and it also indicates that the release of PO(4) during regeneration might be reduced by the same concentration.

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