Metabolic fingerprinting to track coral health

The marine environments in which corals reside are rapidly changing, and stressors such as climate change and ocean acidification are associated with global declines in coral reefs. Current methods used to assess coral health are borrowed from medicine including cytology (i.e., identifying abnormal cells). However, these markers typically diagnose coral at advanced stages of disease. To prevent or mitigate disease outbreak and death of corals, new markers and scientific tools are needed to assess coral health before significant disease progression. What if you could tell a coral was stressed based on the metabolism of a tiny piece of coral?

An animal’s metabolism responds rapidly to environmental stressors and our research team at the North Carolina State University Environmental Medicine Consortium is developing ways to measure the metabolic state of corals. Using aquarium corals, we took tissue samples weighing less than 1 g and analyzed metabolites such as amino acids and lactate using nuclear magnetic resonance (NMR) spectroscopy. When there was an unexpected decline in the aquarium water quality (moderately increased ammonia and phosphorus and decreased calcium concentrations), we observed corals showing signs of stress including bleaching; the corals expelled symbiotic algae living in their tissues and turned white in colour.

We opportunistically took samples of deteriorating coral to monitor the coral’s metabolism. Using NMR-based metabolomic analyses, we found marked accumulations of acrylic acid in tissues of hard (Acropora sp.) and soft (Lobophytum sp.) corals; concentrations of acrylic acid increased nearly 200% only 11 days after the decline in water quality. We also detected acrylic acid in isolated coral tissues without the algal symbionts supporting the hypothesis that acrylic acid was being produced by the coral itself. Hard and soft corals are distantly related but had a similar physiological response to the environmental stressor. This conserved response suggests acrylic acid is possibly a useful marker for early detection of coral stress.

Read the full paper — Altered acrylic acid concentrations in hard and soft corals exposed to deteriorating water conditions by Lori S.H. Westmoreland, Jennifer N. Niemuth, Hanna S. Gracz and Michael K. Stoskopfon on the FACETS website.