A method to transform a variable thermal regime to a physiologically equivalent effective temperature.

Area of Science:

• Physiology
• Ecology
• Biophysics

Background:

• Biological processes are temperature-dependent, but variable thermal regimes complicate accurate assessment.
• Traditional methods like mean temperature or thermal sums can be inaccurate, especially near zero or with non-linear responses.

Purpose of the Study:

• To introduce a novel method for characterizing variable thermal regimes using an effective temperature.
• To provide a metric that accurately reflects thermal conditions for biological responses that scale exponentially with temperature.

Main Methods:

• A first-order exponential transformation of temperature time series data.
• Calculation of an exponentially-weighted mean temperature (T_e¯).

Main Results:

• The effective temperature (T_e¯) provides a species-independent descriptor of thermal regimes.
• This metric allows prediction of growth under variable temperatures using constant temperature models.
• The method is mathematically simple, adaptable to different Q10 values, and accounts for Jensen's inequality.

Conclusions:

• The exponential mean (T_e¯) is a superior metric for summarizing variable thermal regimes compared to traditional mean temperature.
• This approach improves the accuracy of predicting biological responses, particularly where responses are temperature-sensitive.
• The method offers a robust and broadly applicable tool for ecological and physiological studies.