Climate change alters shellfish reef communities: A temperate mesocosm experiment.

Area of Science:

• Marine Ecology
• Climate Change Biology
• Invertebrate Zoology

Background:

• Rocky shore ecosystems face significant alterations due to climate change.
• Mussel species and their associated infaunal communities are vulnerable to environmental shifts.

Purpose of the Study:

• To investigate the effects of warming and ocean acidification on native Trichomya hirsuta and introduced Mytilus galloprovincialis mussels.
• To assess the impact of these climate change factors on the infaunal communities associated with these mussel species.

Main Methods:

• Outdoor mesocosm experiments with controlled temperature (22°C vs. 25°C) and pCO2 (400 μatm vs. 1000 μatm).
• Orthogonal combinations of mussel species (T. hirsuta, M. galloprovincialis, or both) and mussel configuration.
• Replicated experiments (n=3) to analyze mussel growth and infaunal colonization.

Main Results:

• Elevated pCO2 significantly reduced T. hirsuta growth but did not affect M. galloprovincialis growth.
• Warming and elevated pCO2 altered infaunal communities, decreasing molluscs and increasing polychaetes.
• No significant effect on crustacean abundance was observed.

Conclusions:

• Climate change stressors differentially impact mussel species' growth.
• Shifts in dominant mussel species due to climate change can profoundly influence associated infaunal community structure.
• Ocean acidification and warming pose a threat to rocky shore biodiversity.