Warm-Loving Species Perform Well Under Limiting Resources: Trait Combinations for Future Climate

Area of Science:

• Aquatic ecology
• Phytoplankton physiology
• Climate change impacts

Background:

• Ecosystems face simultaneous warming and altered resource availability.
• Understanding interactive effects on populations is crucial.
• Pelagic ecosystems experience thermal stratification impacting light and nutrient dynamics.

Purpose of the Study:

• Investigate combined effects of temperature and resources on freshwater phytoplankton growth.
• Examine how temperature affects minimum resource needs (light, N, P).
• Evaluate resource limitation impacts on phytoplankton thermal performance curves (TPCs).

Main Methods:

• Studied 19 freshwater phytoplankton populations (17 species).
• Assessed growth rates under varying temperature and resource conditions.
• Analyzed Monod parameters for light, N, and P, and TPC parameters.

Main Results:

• Resource requirements for light and phosphorus showed U-shaped relationships with temperature.
• Population-specific responses to temperature varied, altering competitive hierarchies for N and P.
• Resource limitation often decreased thermal optima/maxima but increased thermal breadths of phytoplankton TPCs.
• High thermal optima correlated with low minimum resource requirements.

Conclusions:

• Phytoplankton exhibit diverse responses to combined temperature and resource changes.
• Trait associations suggest some taxa are pre-adapted for future warm, resource-limited conditions.
• Competitive advantage shifts with temperature and resource availability, impacting community structure.