Global microbialization of coral reefs

Haas, Andreas F., Fairoz, Mohamed F. M., Kelly, Linda W., Nelson, Craig E., Dinsdale, Elizabeth A., Edwards, Robert A., Giles, Steve, Hatay, Mark, Hisakawa, Nao, Knowles, Ben, Lim, Yan Wei, Maughan, Heather, Pantos, Olga, Roach, Ty N. F., Sanchez, Savannah E., Silveira, Cynthia B., Sandin, Stuart, Smith, Jennifer E. and Rohwer, Forest (2016) Global microbialization of coral reefs. Nature Microbiology, 1 6: 16042. doi:10.1038/nmicrobiol.2016.42


Author Haas, Andreas F.
Fairoz, Mohamed F. M.
Kelly, Linda W.
Nelson, Craig E.
Dinsdale, Elizabeth A.
Edwards, Robert A.
Giles, Steve
Hatay, Mark
Hisakawa, Nao
Knowles, Ben
Lim, Yan Wei
Maughan, Heather
Pantos, Olga
Roach, Ty N. F.
Sanchez, Savannah E.
Silveira, Cynthia B.
Sandin, Stuart
Smith, Jennifer E.
Rohwer, Forest
Title Global microbialization of coral reefs
Journal name Nature Microbiology   Check publisher's open access policy
ISSN 2058-5276
Publication date 2016-04-25
Sub-type Article (original research)
DOI 10.1038/nmicrobiol.2016.42
Open Access Status Not yet assessed
Volume 1
Issue 6
Start page 16042
Total pages 7
Place of publication London, United Kingdom
Publisher Nature Publishing Group
Language eng
Abstract Microbialization refers to the observed shift in ecosystem trophic structure towards higher microbial biomass and energy use. On coral reefs, the proximal causes of microbialization are overfishing and eutrophication, both of which facilitate enhanced growth of fleshy algae, conferring a competitive advantage over calcifying corals and coralline algae. The proposed mechanism for this competitive advantage is the DDAM positive feedback loop (dissolved organic carbon (DOC), disease, algae, microorganism), where DOC released by ungrazed fleshy algae supports copiotrophic, potentially pathogenic bacterial communities, ultimately harming corals and maintaining algal competitive dominance. Using an unprecedented data set of >400 samples from 60 coral reef sites, we show that the central DDAM predictions are consistent across three ocean basins. Reef algal cover is positively correlated with lower concentrations of DOC and higher microbial abundances. On turf and fleshy macroalgal-rich reefs, higher relative abundances of copiotrophic microbial taxa were identified. These microbial communities shift their metabolic potential for carbohydrate degradation from the more energy efficient Embden-Meyerhof-Parnas pathway on coral-dominated reefs to the less efficient Entner-Doudoroff and pentose phosphate pathways on algal-dominated reefs. This 'yield-to-power' switch by microorganism directly threatens reefs via increased hypoxia and greater CO2 release from the microbial respiration of DOC.
Formatted abstract
Microbialization refers to the observed shift in ecosystem trophic structure towards higher microbial biomass and energy use. On coral reefs, the proximal causes of microbialization are overfishing and eutrophication, both of which facilitate enhanced growth of fleshy algae, conferring a competitive advantage over calcifying corals and coralline algae. The proposed mechanism for this competitive advantage is the DDAM positive feedback loop (dissolved organic carbon (DOC), disease, algae, microorganism), where DOC released by ungrazed fleshy algae supports copiotrophic, potentially pathogenic bacterial communities, ultimately harming corals and maintaining algal competitive dominance. Using an unprecedented data set of >400 samples from 60 coral reef sites, we show that the central DDAM predictions are consistent across three ocean basins. Reef algal cover is positively correlated with lower concentrations of DOC and higher microbial abundances. On turf and fleshy macroalgal-rich reefs, higher relative abundances of copiotrophic microbial taxa were identified. These microbial communities shift their metabolic potential for carbohydrate degradation from the more energy efficient Embden–Meyerhof–Parnas pathway on coral-dominated reefs to the less efficient Entner–Doudoroff and pentose phosphate pathways on algal-dominated reefs. This ‘yield-to-power’ switch by microorganism directly threatens reefs via increased hypoxia and greater CO2 release from the microbial respiration of DOC.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Global Change Institute Publications
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