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1. 2D and 3D coral models imaged in Curaçao: George, Mullinix, et al PeerJ 2021

   https://doi.org/10.5061/dryad.5x69p8d2x  

   George, Emma E.; Mullinix, James A.; Meng, Fanwei; Bailey, Barbara A.; Edwards, Clinton; Felts, Ben; Haas, Andreas F.; Hartmann, Aaron; Mueller, Benjamin; Roach, Ty F.; et al (January 2021, Dryad)

   Abstract from the article associated with the dataset: George, Mullinix, et al PeerJ 2021. Reef-building corals are ecosystem engineers that compete with other benthic or- ganisms for space and resources. Corals harvest energy through their surface by photosynthesis and heterotrophic feeding, and they divert part of this energy to defend their outer colony perimeter against competitors. Here, we hypothesized that corals with a larger space-filling surface and smaller perimeters increase energy gain while reducing the exposure to competitors. This predicted an association between these two geometric properties of corals and the competitive outcome against other benthic organisms. To test the prediction, fifty coral colonies from the Caribbean island of Curac ̧ao were rendered using digital 3D and 2D reconstructions. The surface areas, perimeters, box-counting dimensions (as a proxy of space-filling property), and other geometric properties were extracted and analyzed with respect to the percentage of the perimeter losing or winning against competitors based on the coral tissue apparent growth or damage. The increase in surface space-filling dimension was the only significant single indicator of coral winning outcomes, but the combination of surface space-filling dimension with perimeter length increased the statistical prediction of coral competition outcomes. Corals with larger surface space-filling dimensions (Ds > 2) and smaller perimeters displayed more winning outcomes, confirming the initial hypothesis. We propose that the space-filling property of coral surfaces complemented with other proxies of coral competitiveness, such as life history traits, will provide a more accurate quantitative characterization of coral competition outcomes on coral reefs. This framework also applies to other organisms or ecological systems that rely on complex surfaces to obtain energy for competition. For the compressed files: - Reconstruction of the split file can be accomplished by issuing the command cat *.tar.bz2*part-a* > 3D_model_stl_data.tar.bz2 - Unzipping the compressed files can be accomplished by issuing the command tar -jxvf *.tar.bz2 

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2. Three competitors in three dimensions: photogrammetry reveals rapid overgrowth of coral during multispecies competition with sponges and algae

   https://doi.org/10.3354/meps13579  

   Olinger, LK; Chaves-Fonnegra, A; Enochs, IC; Brandt, ME (January 2021, Marine Ecology Progress Series)

   null (Ed.)

   Competition for limited space is an important driver of benthic community structure on coral reefs. Studies of coral-algae and coral-sponge interactions often show competitive dominance of algae and sponges over corals, but little is known about the outcomes when these groups compete in a multispecies context. Multispecies competition is increasingly common on Caribbean coral reefs as environmental degradation drives loss of reef-building corals and proliferation of alternative organisms such as algae and sponges. New methods are needed to understand multispecies competition, whose outcomes can differ widely from pairwise competition and range from coexistence to exclusion. In this study, we used 3D photogrammetry and image analyses to compare pairwise and multispecies competition on reefs in the US Virgin Islands. Sponges ( Desmapsamma anchorata, Aplysina cauliformis ) and macroalgae ( Lobophora variegata ) were attached to coral ( Porites astreoides ) and arranged to simulate multispecies (coral-sponge-algae) and pairwise (coral-sponge, coral-algae) competition. Photogrammetric 3D models were produced to measure surface area change of coral and sponges, and photographs were analyzed to measure sponge-coral, algae-coral, and algae-sponge overgrowth. Coral lost more surface area and was overgrown more rapidly by the sponge D. anchorata in multispecies treatments, when the sponge was also in contact with algae. Algae contact may confer a competitive advantage to the sponge D. anchorata, but not to A. cauliformis , underscoring the species-specificity of these interactions. This first application of photogrammetry to study competition showed meaningful losses of living coral that, combined with significant overgrowths by competitors detected from image analyses, exposed a novel outcome of multispecies competition. 

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3. Three-dimensional printing can provide opportunities to promote coral recruitment on disturbed reefs

   https://doi.org/10.5343/bms.2023.0131  

   Muñoz-Maravilla, J David; Edmunds, Peter J (January 2025, Bulletin of Marine Science)

   Tropical corals are undergoing population declines due to disturbances. The implications of these trends are modulated by the ability of corals to support population recovery through recruitment. Current research underscores the importance of physical features of benthic surfaces in promoting coral recruitment, which creates opportunities to enhance recruitment by engineering surfaces to replicate these features with the goal of enhancing coral settlement. This study examined the interaction between the settlement of coral larvae and three-dimensional (3D) surfaces and employed 3D printing to enhance recruitment. We tested the effects of the features of microhabitats on the settlement preference, gregariousness, and survival of the brooding coral Pocillopora acuta. Grooved microhabitats that are common in the shallow (<7 m depth) backreef of Moorea, French Polynesia, were printed onto tiles made of polylactic acid, and were favored for settlement by freshly released larvae fromP.acuta. The percent survivorship over 20 d of coral recruits that settled in grooved microhabitats was 16.4% vs none on open flat surfaces. These results underscore the importance of naturally forming benthic features in promoting coral recruitment, and they highlight the potential for duplication of these features through 3D printing to enhance coral recruitment and accelerate reef restoration following damage. 

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4. Scaling the effects of ocean acidification on coral growth and coral–coral competition on coral community recovery

   https://doi.org/10.7717/peerj.11608  

   Evensen, Nicolas R.; Bozec, Yves-Marie; Edmunds, Peter J.; Mumby, Peter J. (January 2021, PeerJ)

   Ocean acidification (OA) is negatively affecting calcification in a wide variety of marine organisms. These effects are acute for many tropical scleractinian corals under short-term experimental conditions, but it is unclear how these effects interact with ecological processes, such as competition for space, to impact coral communities over multiple years. This study sought to test the use of individual-based models (IBMs) as a tool to scale up the effects of OA recorded in short-term studies to community-scale impacts, combining data from field surveys and mesocosm experiments to parameterize an IBM of coral community recovery on the fore reef of Moorea, French Polynesia. Focusing on the dominant coral genera from the fore reef, Pocillopora , Acropora , Montipora and Porites , model efficacy first was evaluated through the comparison of simulated and empirical dynamics from 2010–2016, when the reef was recovering from sequential acute disturbances (a crown-of-thorns seastar outbreak followed by a cyclone) that reduced coral cover to ~0% by 2010. The model then was used to evaluate how the effects of OA (1,100–1,200 µatm pCO 2 ) on coral growth and competition among corals affected recovery rates (as assessed by changes in % cover y −1 ) of each coral population between 2010–2016. The model indicated that recovery rates for the fore reef community was halved by OA over 7 years, with cover increasing at 11% y −1 under ambient conditions and 4.8% y −1 under OA conditions. However, when OA was implemented to affect coral growth and not competition among corals, coral community recovery increased to 7.2% y −1 , highlighting mechanisms other than growth suppression (i.e., competition), through which OA can impact recovery. Our study reveals the potential for IBMs to assess the impacts of OA on coral communities at temporal and spatial scales beyond the capabilities of experimental studies, but this potential will not be realized unless empirical analyses address a wider variety of response variables representing ecological, physiological and functional domains. 

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5. Climatologically invariant scale invariance seen in distributions of cloud horizontal sizes

   https://doi.org/10.5194/acp-24-109-2024  

   DeWitt, Thomas D.; Garrett, Timothy J.; Rees, Karlie N.; Bois, Corey; Krueger, Steven K.; Ferlay, Nicolas (January 2024, Atmospheric Chemistry and Physics)

   Abstract. Cloud area distributions are a defining feature of Earth's radiative exchanges with outer space. Cloud perimeter distributions n(p) are also interesting because the shared interface between clouds and clear sky determines exchanges of buoyant energy and air. Here, we test using detailed model output and a wide range of satellite datasets a first-principles prediction that perimeter distributions follow a scale-invariant power law n(p) ∝ p-(1+β), where the exponent β = 1 is evaluated for perimeters within moist isentropic atmospheric layers. In model analyses, the value of β is closely reproduced. In satellite data, β is remarkably robust to latitude, season, and land–ocean contrasts, which suggests that, at least statistically speaking, cloud perimeter distributions are determined more by atmospheric stability than Coriolis forces, surface temperature, or contrasts in aerosol loading between continental and marine environments. However, the satellite-measured value of β is found to be 1.26 ± 0.06 rather than β = 1. The reason for the discrepancy is unclear, but comparison with a model reproduction of the satellite perspective suggests that it may owe to cloud overlap. Satellite observations also show that scale invariance governs cloud areas for a range at least as large as ∼ 3 to ∼ 3 × 105 km2, and notably with a corresponding power law exponent close to unity. Many prior studies observed a much smaller range for power law behavior, and we argue this difference is due to inappropriate treatments of the statistics of clouds that are truncated by the edge of the measurement domain. 

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