Metabolic rate and activity of blue mussel Mytilus edulis trossulus under short-term exposure to carbon dioxide-induced water acidification and oxygen deficiency

Abstract

This work investigated the effect of carbon dioxide-induced decreased water pH (8.1 – control, 7.5 and 7.0), oxygen saturation (~100% and ~20%) and the combination of both factors on the behaviour (gaping activity) and the total metabolic rate of blue mussel Mytilus edulis trossulus from the southern Baltic Sea. Heat dissipation measurements were carried out in a Calvet-type isothermal twin calorimeter equipped with a flow-through system. The resting metabolic rate was not significantly (p > 0.05) affected by pH or oxygen saturation. Neither was there significant (p > 0.05) effect of the interaction of both factors on this process. The high inter-individual variability in behaviour affected the value of maximal recorded activity and duration of activity peaks connected with shell gaping behaviour. In some mussels, they were short and appeared periodically, and other individuals were inactive or exhibited temporal activity terms of different duration. The lowered oxygen saturation significantly (p < 0.05) affected the time spent on activity. However, there was no effect (p > 0.05) of lowered pH on this parameter, which indicates that oxygen deficiency may affect the Baltic population of M. edulis trossulus more seriously than acidification.

Keywords:

• acidification
• direct calorimetry
• heat production
• hypoxia
• mussel
• Mytilus edulis trossulus

Acknowledgements

We wish to thank Mr Jerzy Drzazgowski from the University of Gdańsk for technical assistance during performance of the calorimetric measurements and Mr Timothy Alexander for help in linguistic improvement of the manuscript.

Additional information

Funding

This work was supported by the University of Gdańsk [grant number 538-G220-B261-13.]; the experimental set-up was built from the state funds for science in years 2010–2013 [grant number KBN/3613/PO1/2010/39].