La Tour du Valat

Institut de recherche pour la conservation des zones humides méditerranéennes

Titre :	Effects of Seagrass Rhizospheres on Sediment Redox Conditions in SE Asian Coastal Ecosystems
Auteurs :	Nuria Marba, Auteur ; Carlos M. Duarte, Auteur ; Jorge Terrados, Auteur ; Zayda Halun, Auteur ; Esperança Gacia, Auteur ; Miguel D. Fortes, Auteur
Type de document :	Article
Dans :	Estuaries and Coasts (33(1) JAN 2010)
Article en page(s) :	107-117
Résumé :	We examined the rhizosphere structure of 14 seagrass meadows (seven mixed, three Enhalus acoroides, two Zostera japonica, one Thalassia hemprichii, and one Halophila ovalis) in the Philippines and Vietnam and tested their effect on sediment redox potential by comparing the redox potential in vegetated vs unvegetated sediments. The effect of seagrass photosynthesis on sediment redox potential was tested in an E. acoroides meadow during a short-term (2-day) clipping experiment. In all the meadows, the centroidal depth (i.e., depth comprising 50%) of seagrass belowground biomass was within the top 15 cm sediment layer. Redox potentials in vegetated sediments tended to be higher than those in adjacent unvegetated ones; sediment redox potential anomaly ranged from -61 to 133 mV across the meadows. The centroidal depths of positive redox potential anomaly and seagrass root biomass were significantly correlated across the meadows investigated (type II regression analysis, slope=0.90, lower confidence limit [CL]=0.42 upper CL=1.82, R(2)=0.59, p

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