Unseen players shape benthic competition on coral reefs

Area of Science:

• Marine biology
• Ecology
• Coral reef science

Background:

• Algae produce organic matter (OM) that impacts coral health.
• Hydrophilic and hydrophobic OM from algae can disrupt the coral holobiont.
• Algal OM can promote opportunistic pathogen invasion, leading to coral disease.

Purpose of the Study:

• To introduce and explain the (3)DAM model (dissolved organic matter, direct contact, disease, algae, and microbes).
• To explore the complex interactions between corals and different types of algae.
• To highlight the role of microbes, viruses, and OM in coral reef health and response to disturbances.

Main Methods:

• Review of recent scientific literature on coral-algae interactions and OM.
• Analysis of the mechanisms by which algal OM affects coral holobionts.
• Examination of factors influencing pathogen invasion and coral disease.

Main Results:

• Turf and macroalgae promote microbial overgrowth and harm corals via hydrophobic OM.
• Crustose coralline algae generally support benign microbial communities.
• Flow patterns and direct contact facilitate OM and pathogen transport to corals.

Conclusions:

• Algal OM and associated microbes are critical drivers of coral reef health.
• These "invisible players" exhibit non-linear responses to disturbances.
• Monitoring these components provides real-time indicators for coral reef conservation and restoration efforts.