The impact of ocean acidification on the byssal threads of the blue mussel (Mytilus edulis)

Grant Dickey,Brian M Preziosi,Charles T Clark,Timothy J Bowden,Erik V Thuesen

doi:10.1371/journal.pone.0205908

Abstract

Blue mussel (Mytilus edulis) produce byssal threads to anchor themselves to the substrate. These threads are always exposed to the surrounding environmental conditions. Understanding how environmental pH affects these threads is crucial in understanding how climate change can affect mussels. This work examines three factors (load at failure, thread extensibility, and total thread counts) that indicate the performance of byssal threads as well as condition index to assess impacts on the physiological condition of mussels held in artificial seawater acidified by the addition of CO2. There was no significant variation between the control (~786 μatm CO2 / ~7.98 pH/ ~2805 μmol kg-1 total alkalinity) and acidified (~2555 μatm CO2 / ~7.47 pH/ ~2650 μmol kg-1 total alkalinity) treatment groups in any of these factors. The results of this study suggest that ocean acidification by CO2 addition has no significant effect on the quality and performance of threads produced by M. edulis.

Highlights

Mytilus edulis, is a sessile, intertidal species that is both economically and ecologically important to the coastline of the Gulf of Maine
There was no significant difference in condition index, load at break, thread counts, and extensibility between the mussels kept at a pH of 8 and those kept at a pH of 7.5
These results indicate that byssal threads in M. edulis are not significantly impacted by an increase in ocean acidification

Summary

Introduction

Mytilus edulis, is a sessile, intertidal species that is both economically and ecologically important to the coastline of the Gulf of Maine. The 2013–2017 commercial Maine landings for M. edulis were worth well over $2,000,000 [1] yet aquaculture accounts for less than 20% of U.S mussel supply. In Maine, aquaculture accounts for an estimated 9% of total mussel supply [2]. Mussels can be grown from spat to market size using a range of methods including; suspended culture on hanging ropes and bottom culture in large beds. Successful cultivation of this species is dependent on the strength of the byssal threads M. edulis produces to anchor itself to hard substrates in the face of intense wave action present in the natural environment [3]. The production of a single thread can take anywhere between 30 seconds

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