Acclimation in intertidal animals reduces potential pathogen load and increases survival following a heatwave

Area of Science:

• Marine Biology
• Ecology
• Environmental Science

Background:

• Intertidal animals face extreme heat during marine heatwaves, often leading to mass mortality.
• Previous research attributed heatwave deaths to physiological failure, but disease is implicated in other animal groups.

Purpose of the Study:

• To investigate the role of bacterial infection in intertidal oyster mortality following heatwave events.
• To determine if acclimation and antibiotic treatments can mitigate heatwave-induced mortality in oysters.

Main Methods:

• Oysters were acclimated under four conditions, including antibiotic treatment.
• All oysters were exposed to a simulated 50°C heatwave for 2 hours.
• Microbiome analysis was performed to assess bacterial pathogen abundance.

Main Results:

• Acclimation and antibiotic treatments significantly increased oyster survival rates.
• Both treatments reduced the prevalence of potential bacterial pathogens.
• Non-acclimated oysters exhibited a significant shift in their microbiome, with increased Vibrio genus bacteria.

Conclusions:

• Bacterial infection plays a critical role in post-heatwave mortality of intertidal oysters.
• Management strategies for aquaculture and intertidal habitats should consider disease dynamics in the context of climate change.
• Findings suggest that enhancing oyster resilience to heat stress may involve managing microbial communities.