Abstract Title

Session S-05A: Frontiers of Ocean Acidification Research in the Salish Sea

Proposed Abstract Title

The effects of elevated temperature and pCO2 on mussel attachment strength in a field and laboratory setting

Keywords

Ocean Acidification

Location

Room 615-616-617

Start Date

1-5-2014 10:30 AM

End Date

1-5-2014 12:00 PM

Description

Mussels form strong byssal threads to attach themselves to substrate in order to survive in their hydrodynamic environment. In an aquaculture setting, weak attachment leads to mussel fall-off, where lines once dense with mussels become bare, reducing farm yields. Recent reports of increased fall-off events leads us to question how physical stressors of ocean temperatures and pCO2, associated with ocean warming and acidification, may affect attachment strength. Byssal threads are composed of three functionally distinct regions connected in series, therefore the ability of multiple stressors to work synergistically is dependent upon the region they affect. Our previous work demonstrated elevated temperature weakens all thread regions, while elevated pCO2 affects only the adhesive plaques. In both the lab and field, we tested the hypothesis that at warmer temperatures, temperature is responsible for thread weakening with minimal effects of pCO2, and at cooler temperatures, high pCO2 conditions will weaken threads. The field portion of this study was conducted at Penn Cove Shellfish Farm at Penn Cove on Whidbey Island, WA. Here mussels (Mytilus trossulus) are farmed on vertical lines reaching 7.3 m in depth. During certain parts of the year, water stratification leads to a natural temperature and CO2 gradient with cooler, high CO2 water at depth and warmer, low CO2 water at the surface. Monthly measurements of mussel tenacity were taken to understand the relative effects of warming and CO2. In the lab, mussels produced threads in temperature and pCO2 controlled aquaria for three days, after which, we measured thread strength. Both studies show high temperature reduces byssal thread strength and tenacity, masking the effects of pCO2. Future increases in ocean temperature and pCO2 could prove challenging to mussel aquaculture.

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May 1st, 10:30 AM May 1st, 12:00 PM

The effects of elevated temperature and pCO2 on mussel attachment strength in a field and laboratory setting

Room 615-616-617

Mussels form strong byssal threads to attach themselves to substrate in order to survive in their hydrodynamic environment. In an aquaculture setting, weak attachment leads to mussel fall-off, where lines once dense with mussels become bare, reducing farm yields. Recent reports of increased fall-off events leads us to question how physical stressors of ocean temperatures and pCO2, associated with ocean warming and acidification, may affect attachment strength. Byssal threads are composed of three functionally distinct regions connected in series, therefore the ability of multiple stressors to work synergistically is dependent upon the region they affect. Our previous work demonstrated elevated temperature weakens all thread regions, while elevated pCO2 affects only the adhesive plaques. In both the lab and field, we tested the hypothesis that at warmer temperatures, temperature is responsible for thread weakening with minimal effects of pCO2, and at cooler temperatures, high pCO2 conditions will weaken threads. The field portion of this study was conducted at Penn Cove Shellfish Farm at Penn Cove on Whidbey Island, WA. Here mussels (Mytilus trossulus) are farmed on vertical lines reaching 7.3 m in depth. During certain parts of the year, water stratification leads to a natural temperature and CO2 gradient with cooler, high CO2 water at depth and warmer, low CO2 water at the surface. Monthly measurements of mussel tenacity were taken to understand the relative effects of warming and CO2. In the lab, mussels produced threads in temperature and pCO2 controlled aquaria for three days, after which, we measured thread strength. Both studies show high temperature reduces byssal thread strength and tenacity, masking the effects of pCO2. Future increases in ocean temperature and pCO2 could prove challenging to mussel aquaculture.