Bacterial decomposition of coral mucus as evaluated by long-term and quantitative observation
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- Tanaka, Y., Ogawa, H. & Miyajima, T. Coral Reefs (2011) 30: 443. doi:10.1007/s00338-011-0729-3
Coral mucus released from Acropora formosa and Montipora digitata was incubated with bacteria under dark conditions for 1 year to evaluate the quantitative degradability. All the mucus samples showed a similar decomposition pattern: about 80% of total organic carbon (TOC) in the mucus was mineralized within 1 month, while some mucus was slowly decomposed over the 1 year. Regression analysis using an exponential curve considering three degradability pools (labile, semilabile, and refractory) fitted the changes of the TOC concentrations very well (r2 > 0.99). Compiling the data on the two coral species, the labile organic C in the coral mucus had mineralization rates of 10–18% d−1 and accounted for 79–87% of the initial TOC in the mucus. Semilabile organic C had mineralization rates of 0.3−1.6% d−1 and accounted for 11−18% of the initial TOC. Refractory organic C accounted for 6% at most. These results suggest that not all coral mucus is rapidly decomposed by bacteria but some mucus remains as semilabile and refractory organic matter for several months.