Warming and temperature variability determine the performance of two invertebrate predators

Area of Science:

• Marine biology
• Oceanography
• Climate change ecology

Background:

• Rising ocean temperatures and increased temperature variability present significant challenges for marine ectotherms.
• Experimental data on the effects of short-term temperature variability on marine invertebrates are scarce.
• Understanding species-specific responses to thermal stress is crucial for predicting ecosystem changes.

Purpose of the Study:

• To investigate the impact of simulated warming and sinusoidal temperature variability on two key marine invertebrate predators.
• To assess the effects of different temperature variability scales on feeding, growth, and survival.
• To determine species-specific thermal tolerance and adaptive capacity under future ocean conditions.

Main Methods:

• Simulated sinusoidal temperature variability (±3°C) around current and future warming scenarios (+4°C) over two months.
• Utilized high-resolution historical temperature data for realistic seasonal shifts.
• Monitored feeding rates (Mytilus edulis consumption) and growth in sea stars (Asterias rubens) and shore crabs (Hemigrapsus takanoi).

Main Results:

• Warming reduced energy uptake and growth in sea stars (Asterias rubens).
• Temperature variability under future warming scenarios induced additional stress in sea stars, leading to earlier feeding cessation.
• Increased temperatures enhanced feeding in shore crabs (Hemigrapsus takanoi) but did not affect their growth rates, irrespective of variability.

Conclusions:

• Marine invertebrate responses to ocean warming are species-specific.
• Temperature variability, especially under future warming scenarios, acts as an additional stressor, potentially exceeding thermal limits.
• Short-term (days to months) temperature variability is a critical factor influencing marine ectotherm responses to climate change.