Thermal Limits Determination for Zooplankton Using a Heat Block.

Area of Science:

• Marine Biology
• Ecology
• Physiology

Background:

• Species distribution is often predicted using thermal limits and breadth.
• Rising global temperatures necessitate understanding species' vulnerability to warming, especially concerning thermal limits across life stages and populations.
• Marine organisms often have complex life cycles with vulnerable early planktonic stages.

Purpose of the Study:

• To present a novel, cost-effective setup for measuring thermal limits in small marine organisms (mL to tens of mL volumes).
• To address challenges in quantifying thermal limits of small early developmental stages, crucial for identifying developmental bottlenecks.
• To provide a method for assessing species' vulnerability to climate change.

Main Methods:

• Development of a setup using commercially available components to create a stable, linear thermal gradient.
• Adaptation of methods for small-volume experiments (mL to tens of mL).
• Procedures for introducing, enumerating live/dead individuals, and calculating lethal temperatures.

Main Results:

• A functional setup for generating precise thermal gradients in small volumes was successfully developed.
• The presented methodology allows for accurate quantification of thermal limits in small, early-stage marine organisms.
• The setup is cost-effective and requires less bench space compared to traditional methods.

Conclusions:

• The developed setup offers a practical solution for studying thermal tolerance in small marine life stages.
• Accurate thermal limit data for early life stages are essential for predicting species' responses to climate change.
• This research facilitates vulnerability assessments for marine species facing rising ocean temperatures.