Effects of hypoxia on benthic macrofauna and bioturbation in the Estuary and Gulf of St. Lawrence,Canada |
| |
| Authors: | Rénald Belley Philippe Archambault Bjorn Sundby Franck Gilbert Jean-Marc Gagnon |
| |
| Institution: | 1. Institut des sciences de la mer de Rimouski, 310 allée des Ursulines, C. P. 3300, Rimouski, QC G5L 3A1, Canada;2. Earth & Planetary Sciences, McGill University, 3450 University, Montreal QC H3A 2A7, Canada;3. Université de Toulouse, UPS, INP, EcoLab (Laboratoire d’écologie fonctionnelle), 29 rue Jeanne Marvig, F-31055 Toulouse, France;4. CNRS, EcoLab, F-31055 Toulouse, France;5. Canadian Museum of Nature, P.O. Box 3443, Station D, Ottawa, ON K1P 6P4, Canada |
| |
| Abstract: | The bottom water in the >300 m deep Lower St. Lawrence Estuary (LSLE) is persistently hypoxic in contrast to the normoxic bottom waters in the Gulf of St. Lawrence (GSL). We photographed the seabed at 11 stations in the Estuary and Gulf of St. Lawrence (EGSL) during the summers 2006 and 2007 and analysed the images to identify bioturbation traces (lebensspuren) and benthic macrofauna. The objective was to identify the environmental variables that influence the density and diversity of benthic macrofauna and bioturbation traces, and the differences that exist among regions with high, medium and low oxygen levels in the bottom water. The bottom water oxygen concentration is the variable that best explains the densities of total-traces as well as surface-traces. However, the density of these traces was higher in hypoxic regions than in well-oxygenated regions. The higher density of traces in the hypoxic region of the LSLE is mainly due to the activities of the surface deposit feeder Ophiura sp., which occurs in large numbers in this region. Possible explanations explored are stress behaviour of the organisms in response to hypoxia and different benthic macrofauna community structures between the hypoxic regions of the LSLE and the normoxic regions of the GSL. In the former, surface deposit feeders and low-oxygen tolerant species dominate over suspension feeders and low-oxygen intolerant species. |
| |
| Keywords: | Biodiversity Bioturbation traces Gulf of St Lawrence Hypoxia Macrofauna Photography |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
