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Abstract Work on marine biofilms has primarily focused on host-associated habitats for their roles in larval recruitment and disease dynamics; little is known about the factors regulating the composition of reef environmental biofilms. To contrast the roles of succession, benthic communities and nutrients in structuring marine biofilms, we surveyed bacteria communities in biofilms through a six-week succession in aquaria containing macroalgae, coral, or reef sand factorially crossed with three levels of continuous nutrient enrichment. Our findings demonstrate how biofilm successional trajectories diverge from temporal dynamics of the bacterioplankton and how biofilms are structured by the surrounding benthic organisms and nutrient enrichment. We identify a suite of biofilm-associated bacteria linked with the orthogonal influences of corals, algae and nutrients and distinct from the overlying water. Our results provide a comprehensive characterization of marine biofilm successional dynamics and contextualize the impact of widespread changes in reef community composition and nutrient pollution on biofilm community structure.
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Light‐use efficiency for coral reef communities and benthic functional types
Abstract Coral reef metabolism is dominated by benthic photoautotrophic communities that comprise varying combinations of algae, coral, and sand. Rates of daily gross primary production (GPP) for these benthic functional types (BFTs) are remarkably consistent across biogeographical regions, supporting the idea that reefs exhibit modal metabolism. Most variability in reported rates likely arises from differences in light availability. In fact, GPP is a linear function of incident photosynthetically active radiation (PAR), the fraction of PAR absorbed (fAPAR) by photoautotrophic organisms or communities, and light‐use efficiency (ε), which parameterizes photosynthesizers' biochemical capacity for CO2fixation: GPP = ε × fAPAR × PAR. On time scales of days to weeks, fAPAR andεare far more stable than PAR.εis a critical parameter, because it represents productive response integrated across all environmental conditions, other than light. If BFTs exhibit consistent GPP across wide geographic ranges, then theirεs must also be consistent. The aim of this study was to estimateεfor algae, coral, and sand. Using data collected during NASA's CORAL mission in 2016–2017,εwas calculated for 32 mixed communities at Lizard Island, Australia (10); Kāne'ohe Bay, Hawai'i (8); Guam (6); and Palau (8). Nonnegative least squares was used to solve forεof each BFT, producing values of 0.038, 0.060, and 0.016 C photon−1for algae, coral, and sand, respectively. These values can be used in light‐driven models of reef metabolism. Further work is necessary to refine these estimates and, importantly, to explore howεis affected by environmental conditions.
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- Award ID(s):
- 2224354
- PAR ID:
- 10515864
- Publisher / Repository:
- https://mcr.lternet.edu/bibliography
- Date Published:
- Journal Name:
- Limnology and Oceanography
- Volume:
- 69
- Issue:
- 3
- ISSN:
- 0024-3590
- Page Range / eLocation ID:
- 712 to 722
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1002/lno.12535
