Mechanical robustness of the calcareous tubeworm Hydroides elegans: warming mitigates the adverse effects of ocean acidification

Abstract

Development of antifouling strategies requires knowledge of how fouling organisms would respond to climate change associated environmental stressors. Here, a calcareous tube built by the tubeworm, Hydroides elegans, was used as an example to evaluate the individual and interactive effects of ocean acidification (OA), warming and reduced salinity on the mechanical properties of a tube. Tubeworms produce a mechanically weaker tube with less resistance to simulated predator attack under OA (pH 7.8). Warming (29°C) increased tube volume, tube mineral density and the tube’s resistance to a simulated predatory attack. A weakening effect by OA did not make the removal of tubeworms easier except for the earliest stage, in which warming had the least effect. Reduced salinity (27 psu) did not affect tubes. This study showed that both mechanical analysis and computational modeling can be integrated with biofouling research to provide insights into how fouling communities might develop in future ocean conditions.

Keywords:

• Biofouling
• climate change
• ocean acidification
• global warming
• calcification
• micro-CT scanning
• finite element analysis
• Hydroides elegans

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Addendum

Acknowledgements

The authors would like to thank YY Chui (University of Hong Kong, HKU) for sectioning, Kelvin Yeung and Tony Liu of HKU for their help with micro-CT work and HKU-EMU for the SEM analysis.