Temperature Controls eDNA Persistence across Physicochemical Conditions in Seawater

Area of Science:

• Marine Biology
• Environmental Science
• Molecular Ecology

Background:

• Environmental DNA (eDNA) is a powerful tool for marine biodiversity assessment.
• eDNA transport by currents necessitates understanding its persistence for spatial interpretation.
• Physicochemical factors influence eDNA degradation rates in marine environments.

Purpose of the Study:

• To investigate the impact of temperature, pH, and oxygen on marine eDNA persistence.
• To model the degradation kinetics of eDNA in oceanic conditions.
• To predict the maximum detectable eDNA persistence time for biodiversity monitoring.

Main Methods:

• Controlled laboratory degradation experiments simulating open ocean and deep-sea conditions.
• Analysis of eDNA decay rates under varying temperature, pH, and dissolved oxygen levels.
• Development of a two-phase degradation model incorporating physicochemical factors.

Main Results:

• eDNA degradation occurs in two phases: rapid initial degradation followed by slower degradation.
• Temperature significantly controls the slow degradation phase, with higher temperatures reducing persistence.
• pH showed a weak influence, while dissolved oxygen had no significant effect on eDNA persistence.
• Marine eDNA can persist over two weeks at ≤10 °C but less than a week at ≥20 °C.

Conclusions:

• Marine eDNA persistence is primarily temperature-dependent, especially at lower temperatures.
• A generalizable, temperature-dependent model can predict eDNA persistence for single-species quantification.
• These findings are crucial for refining spatial scales in eDNA-based marine biodiversity monitoring.