Year-long effects of high pCO2 on the community structure of a tropical fore reef assembled in outdoor flumes

2020 ◽  
Vol 77 (3) ◽  
pp. 1055-1065 ◽  
Author(s):  
Peter J Edmunds ◽  
Steve S Doo ◽  
Robert C Carpenter
Keyword(s):  
Community Structure ◽  
Reef Coral ◽  
French Polynesia ◽  
Coral Community ◽  
High Pco2 ◽  
Fore Reef ◽  
Planar Area ◽  
Massive Porites ◽  
Low Sensitivity ◽  
Planar Growth

Abstract In this study, fore reef coral communities were exposed to high pCO2 for a year to explore the relationship between net accretion (Gnet) and community structure (planar area growth). Coral reef communities simulating the fore reef at 17-m depth on Mo’orea, French Polynesia, were assembled in three outdoor flumes (each 500 l) that were maintained at ambient (396 µatm), 782 µatm, and 1434 µatm pCO2, supplied with seawater at 300 l h−1, and exposed to light simulating 17-m depth. The communities were constructed using corals from the fore reef, and the responses of massive Porites spp., Acropora spp., and Pocillopora verrucosa were assessed through monthly measurements of Gnet and planar area. High pCO2 depressed Gnet but did not affect colony area by taxon, although the areas of Acropora spp. and P. verrucosa summed to cause multivariate community structure to differ among treatments. These results suggest that skeletal plasticity modulates the effects of reduced Gnet at high pCO2 on planar growth, at least over a year. The low sensitivity of the planar growth of fore reef corals to the effects of ocean acidification (OA) on net calcification supports the counterintuitive conclusion that coral community structure may not be strongly affected by OA.

Reefs at the edge: coral community structure around Rapa, southernmost French Polynesia

2016 ◽  
Vol 37 (3) ◽  
pp. 565-575 ◽  
Author(s):  
Mehdi Adjeroud ◽  
Carden C. Wallace ◽  
Pauline Bosserelle ◽  
Claude Payri ◽  
Jean-Louis Menou ◽  
...  
Keyword(s):  
Community Structure ◽  
French Polynesia ◽  
Coral Community

scholarly journals Transects, quadrats, or points? What is the best combination to get a precise estimation of a coral community?

2019 ◽  
Author(s):  
Luis M. Montilla ◽  
Emy Miyazawa ◽  
Alfredo Ascanio ◽  
María López-Hernández ◽  
Gloria Mariño-Briceño ◽  
...  
Keyword(s):  
Community Structure ◽  
Coral Reef ◽  
Effect Size ◽  
Standard Error ◽  
Scleractinian Coral ◽  
Statistical Power ◽  
Coral Community ◽  
Sampling Effort ◽  
Precise Estimation

ABSTRACTThe characteristics of coral reef sampling and monitoring are highly variable, with numbers of units and sampling effort varying from one study to another. Numerous works have been carried out to determine an appropriate effect size through statistical power, however, always from a univariate perspective. In this work, we used the pseudo multivariate dissimilarity-based standard error (MultSE) approach to assess the precision of sampling scleractinian coral assemblages in reefs of Venezuela between 2017 and 2018 when using different combinations of number of transects, quadrats and points. For this, the MultSE of 36 sites previously sampled was estimated, using four 30m-transects with 15 photo-quadrats each and 25 random points per quadrat. We obtained that the MultSE was highly variable between sites and is not correlated with the univariate standard error nor with the richness of species. Then, a subset of sites was re-annotated using 100 uniformly distributed points, which allowed the simulation of different numbers of transects per site, quadrats per transect and points per quadrat using resampling techniques. The magnitude of the MultSE stabilized by adding more transects, however, adding more quadrats or points does not improve the estimate. For this case study, the error was reduced by half when using 10 transects, 10 quadrats per transect and 25 points per quadrat. We recommend the use of MultSE in reef monitoring programs, in particular when conducting pilot surveys to optimize the estimation of the community structure.

scholarly journals Ocean acidification accelerates dissolution of experimental coral reef communities

2015 ◽  
Vol 12 (2) ◽  
pp. 365-372 ◽  
Author(s):  
S. Comeau ◽  
R. C. Carpenter ◽  
C. A. Lantz ◽  
P. J. Edmunds
Keyword(s):  
Coral Reef ◽  
Ocean Acidification ◽  
Benthic Communities ◽  
French Polynesia ◽  
High Pco2 ◽  
Back Reef ◽  
Percentage Cover ◽  
Tropical Coral ◽  
Reef Communities ◽  
Coral Reef Communities

Abstract. Ocean acidification (OA) poses a severe threat to tropical coral reefs, yet much of what is know about these effects comes from individual corals and algae incubated in isolation under high pCO2. Studies of similar effects on coral reef communities are scarce. To investigate the response of coral reef communities to OA, we used large outdoor flumes in which communities composed of calcified algae, corals, and sediment were combined to match the percentage cover of benthic communities in the shallow back reef of Moorea, French Polynesia. Reef communities in the flumes were exposed to ambient (~ 400 μatm) and high pCO2 (~ 1300 μatm) for 8 weeks, and calcification rates measured for the constructed communities including the sediments. Community calcification was reduced by 59% under high pCO2, with sediment dissolution explaining ~ 50% of this decrease; net calcification of corals and calcified algae remained positive but was reduced by 29% under elevated pCO2. These results show that, despite the capacity of coral reef calcifiers to maintain positive net accretion of calcium carbonate under OA conditions, reef communities might transition to net dissolution as pCO2 increases, particularly at night, due to enhanced sediment dissolution.

Community structure of Quaternary coral reefs compared with Recent life and death assemblages

Paleobiology ◽  
2001 ◽  
Vol 27 (4) ◽  
pp. 669-694 ◽  
Author(s):  
Evan N. Edinger ◽  
John M. Pandolfi ◽  
Russell A. Kelley
Keyword(s):  
Community Structure ◽  
Coral Reef ◽  
Reef Coral ◽  
Historical Record ◽  
Taxonomic Composition ◽  
Time Averaging ◽  
Rare Taxa ◽  
Life And Death ◽  
Death Assemblages

This paper assesses the reliability with which fossil reefs record the diversity and community structure of adjacent Recent reefs. The diversity and taxonomic composition of Holocene raised fossil reefs was compared with those of modern reef coral life and death assemblages in adjacent moderate and low-energy shallow reef habitats of Madang Lagoon, Papua New Guinea. Species richness per sample area and Shannon-Wiener diversity (H′) were highest in the fossil reefs, intermediate in the life assemblages, and lowest in the death assemblages. The taxonomic composition of the fossil reefs was most similar to the combination of the life and death assemblages from the modern reefs adjacent to the two fossil reefs. Depth zonation was recorded accurately in the fossil reefs. The Madang fossil reefs represent time-averaged composites of the combined life and death assemblages as they existed at the time the reef was uplifted.Because fossil reefs include overlapping cohorts from the life and death assemblages, lagoonal facies of fossil reefs are dominated by the dominant sediment-producing taxa, which are not necessarily the most abundant in the life assemblage. Rare or slow-growing taxa accumulate more slowly than the encasing sediments and are underrepresented in fossil reef lagoons. Time-averaging dilutes the contribution of rare taxa, rather than concentrating their contribution. Consequently, fidelity indices developed for mollusks in sediments yield low values in coral reef death and fossil assemblages. Branching corals dominate lagoonal facies of fossil reefs because they are abundant, they grow and produce sediment rapidly, and most of the sediment they produce is not exported.Fossil reefs distinguished kilometer-scale variations in community structure more clearly than did the modern life assemblages. This difference implies that fossil reefs may provide a better long-term record of community structure than modern reefs. This difference also suggests that modern kilometer-scale variation in coral reef community structure may have been reduced by anthropogenic degradation, even in the relatively unimpacted reefs of Madang Lagoon. Holocene and Pleistocene fossil reefs provide a time-integrated historical record of community composition and may be used as long-term benchmarks for comparison with modern, degraded, nearshore reefs. Comparisons between fossil reefs and degraded modern reefs display gross changes in community structure more effectively than they demonstrate local extinction of rare taxa.

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