Recoverable impacts of ocean acidification on the tubeworm, Hydroides elegans: implication for biofouling in future coastal oceans

Abstract

Ocean uptake of anthropogenic CO₂ causes ocean acidification (OA), which not only decreases the calcification rate, but also impairs the formation of calcareous shells or tubes in marine invertebrates such as the dominant biofouling tubeworm species, Hydroides elegans. This study examined the ability of tubeworms to resume normal tube calcification when returned to ambient pH 8.1 from a projected near-future OA level of pH 7.8. Tubeworms produced structurally impaired and mechanically weaker calcareous tubes at pH 7.8 compared to at pH 8.1, but were able to recover when the pH was restored to ambient levels. This suggests that tubeworms can physiologically recover from the impacts of OA on tube calcification, composition, density, hardness and stiffness when returned to optimal conditions. These results help understanding of the progression of biofouling communities dominated by tubeworms in future oceans with low pH induced by OA.

Keywords:

• Biofouling
• biomineralization
• calcification
• ocean acidification
• Hydroides elegans

Acknowledgements

The authors would like to thank Kelvin W. K. Yeung and Tony Liu of the Department of Orthopaedics and Traumatology, Li Ka Shing School of Medicine, University of Hong Kong for their help with the micro-CT work.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was supported by GRF grants from the HKSAR-RGC (Grant Numbers: 17304914 and 17303517) and PolyU 152193/14E.