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Local Management Actions Can Increase Coral Resilience to Thermally-Induced Bleaching

Abstract: Recent large-scale analyses suggest that local management actions may not protect coral reefs from climate change, yet most local threat-reduction strategies have not been tested experimentally. We show that removing coral predators is a common local action used by managers across the world, and that removing the corallivorous snail Coralliophila abbreviata from Caribbean brain corals (Pseudodiploria and Diploriaspecies) before a major warming event increased coral resilience by reducing bleaching severity (resistance) and post-bleaching tissue mortality (recovery). Our results highlight the need for increased evaluation and identification of local interventions that improve coral reef resilience.

Authors: E. C. Shaver, D. E. Burkepile, B. R. Silliman

Year: 2018

View the article here, or request a copy from lizcshaver@gmail.com

Nature Ecology & Evolution 2: doi.org/10.1038/s41559-018-0589-0

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Host and Symbionts in Pocillopora damicornis Larvae Display Different Transcriptomic Responses to Ocean Acidification and Warming

Abstract: As global ocean change progresses, reef-building corals and their early life history stages will rely on physiological plasticity to tolerate new environmental conditions. Larvae from brooding coral species contain algal symbionts upon release, which assist with the energy requirements of dispersal and metamorphosis. Global ocean change threatens the success of larval dispersal and settlement by challenging the performance of the larvae and of the symbiosis. In this study, larvae of the reef-building coral Pocillopora damicornis were exposed to elevated pCO2 and temperature to examine the performance of the coral and its symbionts in situ and better understand the mechanisms of physiological plasticity and stress tolerance in response to multiple stressors. We generated a de novo holobiont transcriptome containing coral host and algal symbiont transcripts and bioinformatically filtered the assembly into host and symbiont components for downstream analyses. Seventeen coral genes were differentially expressed in response to the combined effects of pCO2 and temperature. In the symbiont, 89 genes were differentially expressed in response to pCO2. Our results indicate that many of the whole-organism (holobiont) responses previously observed for P. damicornis larvae in scenarios of ocean acidification and warming may reflect the physiological capacity of larvae to cope with the environmental changes without expressing additional protective mechanisms. At the holobiont level, the results suggest that the responses of symbionts to future ocean conditions could play a large role in shaping success of coral larval stages.

Authors: E. B. Rivest, M. W. Kelly, M. B. DeBiasse, G. E. Hofmann

 

Year: 2018

View the full article here

Frontiers in Marine Science 5: doi.org/10.3389/fmars.2018.00186

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The Use of Larvae or Recruits in Coral Restoration Initiatives: Symbiodinium Acquisition Does Not Differ Between Coral Life Stages in the Wild

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

Year: 2018

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Restoration Ecology 26: doi.org/10.1111/rec.12695

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A Framework for Identifying and Characterising Coral Reef “Oases” Against a Backdrop of Degradation

Abstract:

  1. Human activities have led to widespread ecological decline; however, the severity of degradation is spatially heterogeneous due to some locations resisting, escaping, or rebounding from disturbances.
  2. We developed a framework for identifying oases within coral reef regions using long‐term monitoring data. We calculated standardised estimates of coral cover (z‐scores) to distinguish sites that deviated positively from regional means. We also used the coefficient of variation (CV) of coral cover to quantify how oases varied temporally, and to distinguish among types of oases. We estimated “coral calcification capacity” (CCC), a measure of the coral community’s ability to produce calcium carbonate structures and tested for an association between this metric and z‐scores of coral cover.
  3. We illustrated our z‐score approach within a modelling framework by extracting z‐scores and CVs from simulated data based on four generalized trajectories of coral cover. We then applied the approach to time‐series data from long‐term reef monitoring programmes in four focal regions in the Pacific (the main Hawaiian Islands and Mo’orea, French Polynesia) and western Atlantic (the Florida Keys and St. John, US Virgin Islands). Among the 123 sites analysed, 38 had positive z‐scores for median coral cover and were categorised as oases.
  4. Synthesis and applications. Our framework provides ecosystem managers with a valuable tool for conservation by identifying “oases” within degraded areas. By evaluating trajectories of change in state (e.g., coral cover) among oases, our approach may help in identifying the mechanisms responsible for spatial variability in ecosystem condition. Increased mechanistic understanding can guide whether management of a particular location should emphasise protection, mitigation or restoration. Analysis of the empirical data suggest that the majority of our coral reef oases originated by either escaping or resisting disturbances, although some sites showed a high capacity for recovery, while others were candidates for restoration. Finally, our measure of reef condition (i.e., median z‐scores of coral cover) correlated positively with coral calcification capacity suggesting that our approach identified oases that are also exceptional for one critical component of ecological function.

Authors: J. R. Guest, P. J. Edmunds, R. D. Gates, I. D. Kuffner, A. J. Andersson, B. B. Barnes, I. Chollett, T. A. Courtney, R. Elahi, E. A. Lenz, S. Mitarai, P. J. Mumby, H. R. Nelson, B. A. Parker, H. M. Putnam, C. S. Rogers, L. T. Toth

Year: 2018
Download the open access article here

Journal of Applied Ecology pg. 1-11: doi.org/10.1111/1365-2664.13179 

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Spatial and Temporal Patterns of Mass Bleaching of Corals in the Anthropocene

Abstract: Tropical reef systems are transitioning to a new era in which the interval between recurrent bouts of coral bleaching is too short for a full recovery of mature assemblages. We analyzed bleaching records at 100 globally distributed reef locations from 1980 to 2016. The median return time between pairs of severe bleaching events has diminished steadily since 1980 and is now only 6 years. As global warming has progressed, tropical sea surface temperatures are warmer now during current La Niña conditions than they were during El Niño events three decades ago. Consequently, as we transition to the Anthropocene, coral bleaching is occurring more frequently in all El Niño–Southern Oscillation phases, increasing the likelihood of annual bleaching in the coming decades.

Authors: Hughes, T. P. , K. D. Anderson, S. R. Connolly, S. F. Heron, J. T. Kerry, J. M. Lough, A. H. Baird, J. K. Baum, M. L. Berumen, T. C., Bridge, D. C. Claar, C. M. Eakin, J. P. Gilmour, N. A. J. Graham, H. Harrison, J. A. Hobbs, A. S. Hoey, M. Hoogenboom, R. J. Lowe, M. T. McCulloch, J. M. Pandolfi, M. Pratchett, V. Schoepf, G. Torda, S. K. Wilson

Year: 2018
View the article here

Science 359: doi.org/10.1126/science.aan8048

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Electrolysis, Halogen Oxidizing Agents and Reef Restoration

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
Year: 2018
View the thesis here

ResearchGate (Masters Thesis, UC Santa Cruz) 5: doi.org/10.13140/RG.2.2.11469.74725

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Time to Cash in on Positive Interactions for Coral Restoration

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
Year: 2017
View the article here

PeerJ 5: doi.org/10.7717/peerj.3499

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Response of a Fringing Reef Coastline to the Direct Impact of a Tropical Cyclone

Abstract: Tropical cyclones generate extreme hazards along coastlines, often leading to losses of life and property. Although coral reefs exist in cyclone-prone regions globally, few studies have measured the hydrodynamic conditions and morphological responses of reef-fringed coastlines to tropical cyclones. Here, we examine the impact of Tropical Cyclone Olwyn on a section of Australia’s largest fringing reef (Ningaloo Reef) using in situ wave and water level observations, topographic surveys, and numerical modeling. Despite forereef significant wave heights reaching 6 m and local winds of 140 km h-1, average beach volume change was only -3 mm-1. The results indicate that this erosion was due to locally generated wind waves within the lagoon rather than the offshore waves that were dissipated on the reef crest. A comparison of these volume changes to observations of tropical cyclone impacts along exposed sandy beaches quantitatively demonstrates the substantial coastal protection reefs can provide against extreme storms.

Authors: Cuttler, M. V., J.E. Hansen, R.J. Lowe, and E.J. Drost
Year: 2018
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Limnology and Oceanography Letters 3(2). https://doi.org/10.1002/lol2.10067

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Nudging Pro-Environmental Behavior: Evidence and Opportunities

Abstract: Human behavior is responsible for many of our greatest environmental challenges. The accumulated effects of many individual and household decisions have major negative impacts on biodiversity and ecosystem health. Human behavioral science blends psychology and economics to understand how people respond to the context in which they make decisions (e.g., who presents the information and how it is framed). Behavioral insights have informed new strategies to improve personal health and financial choices. However, less is known about whether and how these insights can encourage choices that are better for the environment. We review 160 experimental interventions that attempt to alter behavior in six domains in which decisions have major environmental impacts: family planning, land management, meat consumption, transportation choices, waste production, and water use. The evidence suggests that social influence and simple adjustments to decision settings can influence pro- environmental decisions. We identify four important gaps in the evidence that provide opportunities for future research. To address these gaps, we encourage collaborations between researchers and practitioners that look at the effects of embedding tests of behavior-change interventions within environmental programs.

Authors: Byerly, H., A. Blamford, P.J. Ferraro, C.H. Wagner, E. Palchak, S. Polansky, et. al
Year: 2018
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Frontiers in Ecology and the Environment 16(3): 159-168, doi: 10.1002/fee.1777

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Harnessing Ecological Processes to Facilitate Coral Restoration

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.

Authors: Ladd, M. C., M.W. Miller, J.H. Hunt, W.C. Sharp, and D.E. Burkepile
Year: 2018
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Email for the full article: resilience@tnc.org

Ecological Society of America 16(4): doi:10.1002/fee.1792

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