July 17, 2018
Broadcast live from the Great Barrier Reef Restoration Symposium in Cairns, Australia, experts from around the globe share lessons learned from years working on coral restoration. From offshore coral nurseries, to restoration mitigation techniques, to climate change adaptation, this presentation session seeks to foster knowledge sharing and exchange between managers and practitioners across the globe.
Abstract: Active restoration initiatives are increasingly considered in natural resource management. Laboratory‐reared coral larvae and recruits have been proposed for stock production but it is unknown if their use impacts subsequent symbiosis once transplanted to the reef. We exposed laboratory and field settled aposymbiotic recruits (recently settled <1 month) to Symbiodinium in the wild, then analyzed the acquired communities using ITS‐2 sequencing. There was no significant difference between treatments based on overall community and diversity metrics, or differential abundance of individual taxa. These results suggest that early acquisition is analogous and thus supports the use of either life‐stage as an option for reef restoration.
Authors: K. M. Quigley, G. Torda, L. K. Bay
Restoration Ecology 26: doi.org/10.1111/rec.12695
Abstract: Applications for electrolysis of seawater include preventing fouling in piping systems, conditioning water for aquaculture and reef restoration. Electrolysis creates a variety of chlorine-produced oxidants that attack essential proteins of living tissues and react with metals, other compounds (e.g., ammonia, nitrites) and organic materials (e.g., amines). The Biorock® process developed by Dr. T.J. Goreau and Dr. W. Hilbertz uses electrolysis for restoring reefs and enhancing growth and survival of corals. It is believed to act by elevating pH and alkalinity at the cathode and/or by reducing enzymatic costs for pumping cations and anions across cell membranes by providing an appropriate electrical gradient (Goreau, 2013). I hypothesize that a third mechanism for enhancing organisms may also be involved: inhibition of microorganisms by significant amounts of chlorine-produced oxidants arising from the anode. Applying Faraday’s laws of electrolysis for a system at 8.0 amperes and 90% efficiency gives an estimated evolution of ~230 grams of chlorine per day (equivalent to ~70 liters of gas at STP). In nature (i.e., an open system), diffuse follow-on reaction products (including hypochlorous acid, hypochlorite, hypobromous acid and hypobromite ion) may benefit macrobiota via inactivation of microbial pathogens and competitors, or by other improvements to water quality, as long as concentrations are too low to harm larger, ecotoxicologically less vulnerable organisms.
Authors: J. Koster
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ResearchGate (Masters Thesis, UC Santa Cruz) 5: doi.org/10.13140/RG.2.2.11469.74725
Abstract: Coral reefs are among the most biodiverse and productive ecosystems on Earth, and provide critical ecosystem services such as protein provisioning, coastal protection, and tourism revenue. Despite these benefits, coral reefs have been declining precipitously across the globe due to human impacts and climate change. Recent efforts to combat these declines are increasingly turning to restoration to help reseed corals and speed-up recovery processes. Coastal restoration theory and practice has historically favored transplanting designs that reduce potentially harmful negative species interactions, such as competition between transplants. However, recent research in salt marsh ecosystems has shown that shifting this theory to strategically incorporate positive interactions significantly enhances restoration yield with little additional cost or investment. Although some coral restoration efforts plant corals in protected areas in order to benefit from the facilitative effects of herbivores that reduce competitive macroalgae, little systematic effort has been made in coral restoration to identify the entire suite of positive interactions that could promote population enhancement efforts. Here, we highlight key positive species interactions that managers and restoration practitioners should utilize to facilitate the restoration of corals, including (i) trophic facilitation, (ii) mutualisms, (iii) long-distance facilitation, (iv) positive density-dependence, (v) positive legacy effects, and (vi) synergisms between biodiversity and ecosystem function. As live coral cover continues to decline and resources are limited to restore coral populations, innovative solutions that increase efficiency of restoration efforts will be critical to conserving and maintaining healthy coral reef ecosystems and the human communities that rely on them.
Authors: Shaver, E. C., and B. R. Silliman
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PeerJ 5: doi.org/10.7717/peerj.3499
Abstract: Climate change and other anthropogenic disturbances have created an era characterized by the inability of most ecosystems to maintain their original, pristine states, the Anthropocene. Investigating new and innovative strategies that may facilitate ecosystem restoration is thus becoming increasingly important, particularly for coral reefs around the globe which are deteriorating at an alarming rate. The Great Barrier Reef (GBR) lost half its coral cover between 1985 and 2012, and experienced back-to-back heat-induced mass bleaching events and high coral mortality in 2016 and 2017. Here we investigate the efficacy of interspecific hybridization as a tool to develop coral stock with enhanced climate resilience. We crossed two Acropora species pairs from the GBR and examined several phenotypic traits over 28 weeks of exposure to ambient and elevated temperature and pCO2. While elevated temperature and pCO2 conditions negatively affected size and survival of both purebreds and hybrids, higher survival and larger recruit size were observed in some of the hybrid offspring groups under both ambient and elevated conditions. Further, interspecific hybrids had high fertilization rates, normal embryonic development, and similar Symbiodinium uptake and photochemical efficiency as purebred offspring. While the fitness of these hybrids in the field and their reproductive and backcrossing potential remain to be investigated, current findings provide proof-of-concept that interspecific hybridization may produce genotypes with enhanced climate resilience, and has the potential to increase the success of coral reef restoration initiatives.
Authors: Chan, W. Y., L. M. Peplow, P. Menéndez, A. A. Hoffmann, and M. J. H. van Oppen
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Frontiers in Marine Science 5: doi.org/10.3389/fmars.2018.00160
Abstract: Sexual reproduction in scleractinian corals is a critical component of species recovery, fostering population connectivity and enhancing genetic diveristy. The relative contribution of sexual reproduction to both connectivity and diversity in Acropora cervicornis may be variable due to this species’ capacity to reproduce effectively by fragmentation. Using a biophysical model and genomic data in this threatened species, we construct potential connectivity pathways on the Florida Reef Tract (FRT) and compare them to inferred migration rates derived from next-generation sequencing, using a link and node-based approach. Larval connectivity on the FRT can be divided into two zones: the northern region, where most transport is unidirectional to the north with the Florida Current, and the southern region that is more dynamic and exhibits complex spatial patterns. These bihysical linkages are poorly correlated with genetic connectivity patterns, which resolve many reciprocal connections and suggest a less sparse network. These results are difficult to reconcile with genetic data which indicate that individual reefs are diverse, suggesting important contributions of sexual reproduction and recruitment. Larval connectivity models highlight potential resources for recovery, such as areas with high larval export like the Lower Keys, or areas that are well connected to most other regions on the FRT, such as the Dry Tortugas.
Authors: Drury, C., C. B. Paris, V. H. Kourafalou, and D. Lirman
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Coral Reefs 37: doi.org/10.1007/s00338-018-1683-0
Abstract: Currently, information on nearshore reef-associated fisheries is frequently disparate or incomplete, creating a challenge for effective management. This study utilized an existing non-commercial fishery dataset from Hawaiʻi, covering the period 2004-13, to estimate a variety of fundamental fishery parameters, including participation, effort, gear use, and catch per unit effort. We then used those data to reconstruct total catches per island. Non-commercial fisheries in this case comprise recreational, subsistence, and cultural harvest, which may be exchanged, but are not sold. By combining those data with reported commercial catch data, we estimated annual catch of nearshore reef-associated fisheries in the main Hawaiian Islands over the study period to be 1,167,758 ± 43,059 kg year-1 (mean ± standard error). Average annual commercial reef fish catch over the same time period – 184,911 kg year-1 – was 16% of the total catch, but that proportion varied greatly among islands, ranging from 23% on Oʻahu to 5% on Molokaʻi. These results emphasize the importance of reef fishing in Hawaiʻi for reasons beyond commerce, such as food security and cultural practice, and highlight the large differences in fishing practices across the Hawaiian Islands
Authors: Mccoy, K. S., I.D. Williams, A.M. Friedlander, H. Ma, L. Teneva, and J.N. Kittinger
PLoS ONE 13(4): e0195840. https://doi.org/10.1371/journal.pone.0195840
Abstract: Incorporating ecological processes into restoration planning is increasingly recognized as a fundamental component of successful restoration strategies. We outline a scientific framework to advance the emerging field of coral restoration. We advocate for harnessing ecological processes that drive community dynamics on coral reefs in a way that facilitates the establishment and growth of restored corals. Drawing on decades of coral reef ecology research and lessons learned from the restoration of other ecosystems, we posit that restoration practitioners can control factors such as the density, diversity, and identity of transplanted corals; site selection; and transplant design to restore positive feedback processes – or to disrupt negative feedback processes – in order to improve restoration success. Ultimately, we argue that coral restoration should explicitly incorporate key natural processes to exploit dynamic ecological forces and drive recovery of coral reef ecosystems.
Ecological Society of America 16(4): doi:10.1002/fee.1792
Abstract: Active coral restoration through coral ‘gardening’ aims to remediate some of the drastic coral cover lost on Caribbean reefs, with increasing attention to the imperiled, iconic foundation species elkhorn coral Acropora palmata. We documented 2 experiments quantifying effects of A. palmata outplant characteristics and habitat on outplant success. Two thermal stress events (summer 2014 and 2015) occurred while the experiments were underway and thus lend insight into environmental interactions and coral restoration outcomes under projected thermal regimes. In the first experiment comparing 2 size classes of a single genotype, smaller fragments produced significantly more live tissue area, experienced less bleaching, and demonstrated equal survivorship compared to larger fragments. The second experiment compared 4 genotypes outplanted to both fore reef and mid-channel patch reef habitats. Genotypes varied significantly in survivorship, bleaching severity, and net change in size, with one (CN2g) performing well in all 3 metrics, and another (SLg) exhibiting poor survivorship, the most bleaching, and smaller changes in size. Overall, bleaching was less severe and survivorship less varied between genotypes in fore reef versus patch reef habitats. Fragments returned to the site of genotype origin did not consistently outperform ‘foreign’ genotypes from a different habitat type. Recognizing unique attributes associated with size and specific genotypes may improve the efficacy of active coral restoration in the face of future climate scenarios.
Author: Pausch, R. E., D.E. Williams, M.W. Miller
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Marine Ecology. doi:10.3354/meps12488
Abstract: Acropora cervicornis and Acropora palmata have declined dramatically in the Caribbean since the early 80’s, and are classified as Critically Endangered Species. To promote their recovery, restoration programs focusing on introducing fragmented specimens have been intensified. The current study was conducted in the south-eastern part of the Dominican Republic in September 2015 and August 2016. During these two periods, gametes from six mature colonies were collected from a five-year-old nursery with an area of 150 m2 at a depth of 12.5 m. 80% of the studied colonies spawned both years. Fertilization was assisted between 21:50 and 00:00 h, immediately after spawning. Fertilization and settlement rates were 90% and 50%, respectively. To our knowledge, this is the first scientific report on nursery propagated A. cervicornis spawning, assisted fertilization, larvae rearing and breeding.
Author: Calle-Trivino, J., C. Cortes-Useche, R.I. Sellares-Blasco, J.E. Arias-Gonzalez
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Regional Studies in Marine Science. doi:10.1016/j.rsma.2018.02.002