La Tour du Valat

Institut de recherche pour la conservation des zones humides méditerranéennes

Titre :	Seasonal Composition of Benthic Macroinfauna Exposed to Hypoxia in the Northern Gulf of Mexico
Auteurs :	Melissa M. Baustian, Auteur ; Nancy N. Rabalais, Auteur
Type de document :	Article
Dans :	Estuaries and Coasts (32(5) SEP 2009)
Article en page(s) :	975-983
Résumé :	Bottom-water hypoxia in the northern Gulf of Mexico has increased in severity (duration, frequency, and intensity) since the 1970s and has impacted the less-mobile benthos ever since. From September 2003 to October 2004, the macrobenthic density, species richness, community composition, and vertical distribution were studied at a frequently hypoxic station, C6B (28A degrees 52.10' N and 90A degrees 28.00' W). The polychaete-dominated community was approximately three times less dense and diverse in post-hypoxic months compared to pre-hypoxic months. The lowest oxygen concentrations in July 2004 did not significantly affect the infaunal community as predicted; rather, the response was observed 1 month later after a longer, low-oxygen exposure. The opportunistic, hypoxia-tolerant polychaete, Paraprionospio pinnata, population increased in July 2004 when other common species decreased, thereby maintaining pre-hypoxic densities. Determining the duration and severity of hypoxia prior to sampling rather than at the time of sampling helps to better understand benthic community responses to hypoxia.

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