Molecular Cartography of a Hawaiian Coral Assemblage

Coral reefs are declining due to multiple factors including overfishing, anthropogenic pollution, and ocean acidification. Diseases affecting corals have increased in recent decades, yet the etiology of nearly all diseases remains poorly understood. Here, we investigated three-dimensionally mapped molecules and microbes from healthy and diseased coral tissue sampled across the landscape of a coral assemblage at the Wai'opae tide pools, Southeast Hawai'i Island. A 3D molecular cartographic platform was used in combination with molecular networking tools to characterize healthy coral tissue and tissue affected by the disease growth anomaly (GA). Tissues of healthy Montipora flabellata and Montipora capitata exhibited higher microbial diversity compared to Porites lobata and GA-affected M. capitata corals. Increases in relative abundance of Ulvophyceae and sterols were observed in GA lesions, while chlorophyll decreased. Conversely, healthy coral tissues were characterized by the presence of cyanobacteria in the order of Stramenopiles, in addition to higher relative chlorophyll levels. Leveraging innovative molecular cartography provides new insight into molecular characteristics of coral colonies, and helps to better understand how diseases affect the molecular landscape of corals.