Physiological performance of intertidal coralline algae during a simulated tidal cycle

Area of Science:

• Marine Biology
• Ecology
• Physiology

Background:

• Intertidal macroalgae experience daily fluctuations in light, temperature, and desiccation.
• Physiological differences in stress tolerance influence species' spatial zonation along shorelines.
• Species with higher stress tolerance inhabit higher shores, while those with lower tolerance occupy lower shores or tidepools.

Purpose of the Study:

• To investigate physiological differences between tidepool (Calliarthron tuberculosum) and non-tidepool (Corallina vancouveriensis) coralline algae.
• To understand how these physiological differences contribute to habitat partitioning in intertidal zones.

Main Methods:

• Simulated tidal conditions were used to monitor physiological responses of both species.
• Photosynthetic activity, pigment composition, desiccation resistance, and recovery from stress were assessed.

Main Results:

• Corallina vancouveriensis showed higher photosynthetic activity than Calliarthron tuberculosum during high tide and in warming tidepools.
• Both species ceased photosynthesis when emerged in air, but Corallina demonstrated greater water retention and desiccation resistance.
• Only Corallina vancouveriensis recovered from combined temperature and desiccation stress upon re-immersion.

Conclusions:

• Physiological and morphological differences, particularly in desiccation tolerance and recovery, underpin the habitat partitioning observed between Calliarthron tuberculosum and Corallina vancouveriensis.
• Corallina's superior stress tolerance allows it to inhabit more exposed intertidal areas compared to Calliarthron.