Ocean Acidification & Mussel Byssus Attachment

To date, most research on the possible impacts of ocean acidification on marine organisms has focused on potential adverse impacts on secretion of calcium carbonate in species e.g. corals and echinoderms. However, a study published in the latest issue of the  journal Nature Climate Change demonstrates potential impacts on other biomaterials critical for bivalve molluscs, a group of species that provide for than $1.5 billion in revenue to the global aquaculture industry.

Mytilid mussels are competitive dominant species in many rocky shore ecosystems throughout the world. This is largely attributable to their ability to attach themselves to bare rocks with byssal threads, which are formed from collagen-like liquid precursors that polymerizes into a stiff and extensible thread. Byssal threads contain high concentrations o f a modified amino acid and histidine-metal crosslinkages that appear critical to facilitating surface adhesion and self-healing following deformation.

In the study, carbon dioxide was increased from 300 to 1,500 μatm (a pH decline from 8.0 to 7.5). Under high carbon dioxide concentrations (1,200 μatm), the study found substantial diminution of the performance of bysall performance, including a 35-10% decline in tenacity. The authors concluded that this could adversely affect community and ecosystem dynamics given the importance of mussels’ ability to securely attach themselves to rocks.

Of course, ocean acidification is not a manifestation of climate change, but rather a parallel impact of rising levels of carbon dioxide concentrations. The potential impacts of carbon dioxide emissions on an array of bio-structures may provide an additional rationale for focusing climate policymaking on reducing this discrete greenhouse source. It thus provides a good gateway for discussing the interface of efforts to reduce greenhouse gas emissions and to confront ocean acidification, as well as the appropriate regimes to address these issues, including coordination of initiatives.

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