Organisms in intertidal zones experience fluctuations in environmental stressors such as hypoxia and temperature. These stressors and their fluctuations often appear in combination. Combination of stressors can have different effects compared to single stressors. In this study, we investigate the physiological effects of intermittent hypoxia in combination with different temperature regimes on the Pacific Oyster Crassostrea (Magallana) gigas. The oysters were exposed to hypoxic cycles (12h hypoxia by emersion/12h submersion) at normal (15°C), elevated (30°C) or fluctuating (15°C submersion/30°C emersion) temperature for 10 days. After the last submersion phase, the gills and digestive gland were sampled. We measured markers for bioenergetics and redox-balance in the gills and digestive gland using colorimetric methods as well as a set of metabolites (predominantly amino acids, osmolytes, anaerobic end products and energetic metabolites) in the gills using LC-MS/MS. Oysters kept submerged for up to 10 days were used as controls.
The dataset comprises abundances and lengths of the Pacific oyster Magellana gigas (formerly Crassostrea gigas). The data were collected at 14 sites along the pier system around the island of Helgoland in the German Bight, North Sea (54°11' N, 7°53' E). Ten replicate quadrats (0.25 m²) were placed at the vertical pier walls at each site by SCUBA divers. In each replicate quadrat, all oysters were counted and measured in 2005, 2006 and 2012.