Rubble fields shape planktonic protist communities in Indonesia at a local scale

Area of Science:

• Marine biology
• Microbial ecology
• Coral reef ecosystems

Background:

• The Coral Triangle, a global epicenter of marine biodiversity, faces significant reef degradation due to destructive fishing and natural disturbances.
• Reef damage results in extensive coral rubble fields, impacting ecosystem structure and function.
• While metazoan responses to disturbances are known, the effects on foundational microbial communities remain poorly understood.

Purpose of the Study:

• To characterize protist community composition in tropical marine rubble fields.
• To investigate the influence of fisheries management and benthic profiles on protist communities.
• To identify key environmental drivers of protist community shifts in degraded reef areas.

Main Methods:

• Utilized metabarcoding to analyze protist community composition.
• Sampled sites across Lombok, Indonesia, with varying fisheries management and benthic characteristics.
• Correlated protist community data with environmental variables like rubble coverage and net primary productivity.

Main Results:

• Rubble coverage and net primary productivity were the primary factors explaining protist community variation.
• Rubble fields showed increased abundance of small heterotrophic protists, including ciliates and cercozoans.
• Diatom relative abundance increased in rubble fields, correlating with higher net primary productivity.

Conclusions:

• This study provides the first characterization of protist communities in tropical marine rubble fields.
• Rubble fields support distinct microbial communities dominated by heterotrophic protists and diatoms.
• Environmental factors like rubble extent and productivity play a crucial role in shaping local protist communities in degraded reefs.