DNA metabarcoding and microscopic analyses of sea turtles biofilms: Complementary to understand turtle behavior

Area of Science:

• Marine biology
• Ecology
• Microbial ecology

Background:

• Sea turtles are vital marine ecosystem indicators.
• Epibiotic diatoms on turtle shells can reveal insights into turtle behavior.
• Traditional diatom identification is challenging due to time, expertise, and novel taxa.

Purpose of the Study:

• To compare the effectiveness of morphological (microscopy) and molecular (DNA metabarcoding) approaches for analyzing epibiotic diatom communities on sea turtles.
• To determine which method better discriminates between individual turtles based on their associated diatoms.
• To assess the complementary information provided by each method for studying sea turtle ecology and behavior.

Main Methods:

• Sampling of epibiotic diatom assemblages from seven juvenile green turtles (Chelonia mydas).
• Analysis using both traditional microscopy and DNA metabarcoding (high throughput sequencing).
• Comparison of diatom community structures and resulting turtle clustering between methods.

Main Results:

• Significant differences in epibiotic diatom assemblage structures were observed between microscopy and metabarcoding.
• Metabarcoding provided superior discrimination between individual turtles based on their diatom communities.
• Metabarcoding revealed cryptic diatom diversity previously undetected.
• Microscopy offered valuable ecological data through historical context and diatom ecological guilds.

Conclusions:

• Both microscopy and DNA metabarcoding are valuable tools for studying epibiotic diatoms on sea turtles.
• Metabarcoding excels at species-level identification and revealing hidden diversity.
• Microscopy provides crucial ecological context and abundance data.
• The complementary nature of these methods offers a more comprehensive understanding of sea turtle ecology and behavior.