Spatio-temporal environmental variation mediates geographical differences in phenotypic responses to ocean...

Area of Science:

• Marine Biology
• Ecology
• Climate Change Science

Background:

• Phenotypic plasticity is crucial for species adaptation to environmental changes like ocean acidification (OA).
• Population-specific tolerances to OA can arise from local environmental contexts and genetic diversity.
• The climatic variability hypothesis (CVH) suggests that environments with greater variability promote greater adaptive plasticity.

Purpose of the Study:

• To investigate the role of phenotypic plasticity in the adaptive response of sea urchin populations to ocean acidification (OA).
• To test the predictions of the climatic variability hypothesis (CVH) in natural populations of *Loxechinus albus* exposed to fluctuating *p*CO2/pH conditions.

Main Methods:

• Studied populations of the sea urchin *Loxechinus albus* across natural gradients of seawater *p*CO2 and pH.
• Assessed the effects of elevated *p*CO2 on sea urchin larval morphology, physiology, development, and survival.
• Compared the magnitude of OA effects among different populations to evaluate population-specific tolerances.

Main Results:

• Elevated *p*CO2 significantly impacted sea urchin larval morphology, physiology, development, and survival.
• The magnitude of these impacts varied significantly among different populations.
• Populations experiencing greater natural fluctuations in *p*CO2/pH exhibited higher tolerance to OA, aligning with CVH predictions.

Conclusions:

• Geographical variation in phenotypic plasticity and tolerance influences species' responses to ocean acidification.
• The climatic variability hypothesis provides a useful framework for predicting species' adaptive capacities to OA.
• Accurate predictions of species' responses to future OA require consideration of population-specific differences in plasticity and tolerance.