Archives

Assisted Fertilization of Threatened Staghorn Coral to Complement the Restoration of Nurseries in Southeastern Dominican Republic

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
Year: 2018
View More
Email for the full article: resilience@tnc.org
Regional Studies in Marine Science. doi:10.1016/j.rsma.2018.02.002

Share on FacebookTweet about this on TwitterEmail this to someone

Timing of Mass Spawning in Corals: Potential Influence of the Coincidence of Lunar Factors and Associated Changes in Atmospheric Pressure From Northern and Southern Hemisphere Case Studies

Abstract: Synchronised multispecies mass spawning events are striking features of reproduction in corals. This synchronous gamete release of thousands of animals over vast stretches of reef is thought to be cued by rhythms of the Moon. However, the mechanisms are not fully understood. We propose an explanation that may contribute to understanding this mechanism, that spawning is triggered by the coincidence of two factors, each in different lunar rhythms. We investigate this proposal in case studies using seven years of coral spawning data from two locations: Kochi, Japan and Lizard Island, Australia. Our calculations show that a feature in a lunar synodic rhythm (the third quarter) will synchronise with a feature in a lunar non-synodic rhythm (the zero declination) usually once, although occasionally twice in a year. Supported by data on the date of spawning from the two locations, we suggest that this coincidence of lunar factors exerts an important influence on the timing of annual mass spawning in corals. This coincidence may be associated with low atmospheric pressure. Spawning at the time of the third lunar quarter may favour fertilisation success due to the reduced currents during neap tides associated with the lower gravitational pressure of the lunar quarters.

Author: Wolstenholme, J., Y. Nozawa, M. Byrne, and W. Burke
Year: 2018
View More
Email for the full article: resilience@tnc.org
Invertebrate Reproduction & Development. doi:10.1080/07924259.2018.1434245

Share on FacebookTweet about this on TwitterEmail this to someone

Coral Reefs for Coastal Protection: A New Methodological Approach and Engineering Case Study in Grenada

Abstract: Coastal communities in tropical environments are at increasing risk from both environmental degradation and climate change and require urgent local adaptation action. Evidences show coral reefs play a critical role in wave attenuation but relatively little direct connection has been drawn between these effects and impacts on shorelines. Reefs are rarely assessed for their coastal protection service and thus not managed for their infrastructure benefits, while widespread damage and degradation continues. This paper presents a systematic approach to assess the protective role of coral reefs and to examine solutions based on the reef’s influence on wave propagation patterns. Portions of the shoreline of Grenville Bay, Grenada, have seen acute shoreline erosion and coastal flooding. This paper (i) analyzes the historical changes in the shoreline and the local marine, (ii) assess the role of coral reefs in shoreline positioning through a shoreline equilibrium model first applied to coral reef environments, and (iii) design and begin implementation of a reef-based solution to reduce erosion and flooding. Coastline changes in the bay over the past 6 decades are analyzed from bathymetry and benthic surveys, historical imagery, historical wave and sea level data and modeling of wave dynamics. The analysis shows that, at present, the healthy and well-developed coral reefs system in the southern bay keeps the shoreline in equilibrium and stable, whereas reef degradation in the northern bay is linked with severe coastal erosion. A comparison of wave energy modeling for past bathymetry indicates that degradation of the coral reefs better explains erosion than changes in climate and historical sea level rise. Using this knowledge on how reefs affect the hydrodynamics, a reef restoration solution is designed and studied to ameliorate the coastal erosion and flooding. A characteristic design provides a modular design that can meet specific engineering, ecological and implementation criteria. Four pilot units were implemented in 2015 and are currently being field-tested. This paper presents one of the few existing examples available to date of a reef restoration project designed and engineered to deliver risk reduction benefits. The case study shows how engineering and ecology can work together in community-based adaptation. Our findings are particularly important for Small Island States on the front lines of climate change, who have the most to gain from protecting and managing coral reefs as coastal infrastructure.

Author: Reguero, B. G., M.W. Beck, V.N. Agostini, P. Kramer, B. Hancock
Year: 2018
View More
Email for the full article: resilience@tnc.org
Journal of Environmental Management.

Share on FacebookTweet about this on TwitterEmail this to someone

A Potential Method for Improving Coral Self-Attachment

Abstract: Coral restoration is becoming increasingly important to sustain declining reefs. The survival rate of translocated corals in restoration projects is around 65%. This rate is, however, highly variable among projects, with success ranging from 0 to 90% and with detachment being a significant cause of mortality. Improving the speed and strength of coral self-attachment would increase survivorship in translocated corals. To address this need, we tested whether fragments of the scleractinian coral, Hydnophora rigida, artificially attached upside-down would self-attach more rapidly to the substratum than those artificially attached the right way up, which is the normal practice. We also tested the effect of three different diets (unfed, normal Artemia, and lipid-enriched Artemia) on coral growth and other biological responses. After 100 days, our results demonstrated that corals fixed upside-down grew significantly wider and faster over the substratum than corals fixed the right way up. A significantly higher number of fragments fixed upside-down were also able to self-attach and grow over the substratum (87%) compared with fragments fixed the right way up (58%). Neither the buoyant weight, height increment, symbiont density, chlorophyll, maximum quantum yield nor colour of corals fixed upside-down differed significantly from corals fixed the right way up. Our data shows that simply inverting the orientation of coral fragments may substantially accelerate the time for self-attachment and increase the survival rate of translocated corals in restoration projects.

Author: Tagliafico, A., S. Rangel, L. Christidis, B.P. Kelaher
Year: 2018
View More
Email for the full article: resilience@tnc.org
Restoration Ecology. doi:10.1111/rec.12698

Share on FacebookTweet about this on TwitterEmail this to someone

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 analysed 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.

Author: Quigley, K. M., G. Torda, L.K Bay
Year: 2018
View More
Email for the full article: resilience@tnc.org
Restoration Ecology. doi:10.1111/rec.12695

Share on FacebookTweet about this on TwitterEmail this to someone

Climate Change Promotes Parasitism In a Coral Symbiosis

Abstract: Coastal oceans are increasingly eutrophic, warm and acidic through the addition of anthropogenic nitrogen and carbon, respectively. Among the most sensitive taxa to these changes are scleractinian corals, which engineer the most biodiverse ecosystems on Earth. Corals’ sensitivity is a consequence of their evolutionary investment in symbiosis with the dinoflagellate alga, Symbiodinium. Together, the coral holobiont has dominated oligotrophic tropical marine habitats. However, warming destabilizes this association and reduces coral fitness. It has been theorized that, when reefs become warm and eutrophic, mutualistic Symbiodinium sequester more resources for their own growth, thus parasitizing their hosts of nutrition. Here, we tested the hypothesis that sub-bleaching temperature and excess nitrogen promotes symbiont parasitism by measuring respiration (costs) and the assimilation and translocation of both carbon (energy) and nitrogen (growth; both benefits) within Orbicella faveolata hosting one of two Symbiodiniumphylotypes using a dual stable isotope tracer incubation at ambient (26 °C) and sub-bleaching (31 °C) temperatures under elevated nitrate. Warming to 31 °C reduced holobiont net primary productivity (NPP) by 60% due to increased respiration which decreased host %carbon by 15% with no apparent cost to the symbiont. Concurrently, Symbiodinium carbon and nitrogen assimilation increased by 14 and 32%, respectively while increasing their mitotic index by 15%, whereas hosts did not gain a proportional increase in translocated photosynthates. We conclude that the disparity in benefits and costs to both partners is evidence of symbiont parasitism in the coral symbiosis and has major implications for the resilience of coral reefs under threat of global change.

Author: Baker, D. M., C.J. Freeman, J.C. Wong, M.L. Fogel, N. Knowlton
Year: 2018
View More
Email for the full article: resilience@tnc.org
The ISME Journal. doi:10.1038/s41396-018-0046-8

Share on FacebookTweet about this on TwitterEmail this to someone

Molecular Characterization of Larval Development from Fertilization to Metamorphosis In a Reef-building Coral.

Abstract: Background- Molecular mechanisms underlying coral larval competence, the ability of larvae to respond to settlement cues, determine their dispersal potential and are potential targets of natural selection. Here, we profiled competence, fluorescence and genome-wide gene expression in embryos and larvae of the reef-building coral Acropora millepora daily throughout 12 days post-fertilization. Results- Gene expression associated with competence was positively correlated with transcriptomic response to the natural settlement cue, confirming that mature coral larvae are “primed” for settlement. Rise of competence through development was accompanied by up-regulation of sensory and signal transduction genes such as ion channels, genes involved in neuropeptide signaling, and G-protein coupled receptor (GPCRs). A drug screen targeting components of GPCR signaling pathways confirmed a role in larval settlement behavior and metamorphosis. Conclusions- These results gives insight into the molecular complexity underlying these transitions and reveals receptors and pathways that, if altered by changing environments, could affect dispersal capabilities of reef-building corals. In addition, this dataset provides a toolkit for asking broad questions about sensory capacity in multicellular animals and the evolution of development.

Author: Strader, M.E., G.V. Aglyamova, M.V Matz
Year: 2018
View More
Email for the full article: resilience@tnc.org
BMC Genomics 19(1). doi:10.1186/s12864-017-4392-0

Share on FacebookTweet about this on TwitterEmail this to someone

Corals in Healthy Populations Produce More Larvae Per Unit Cover

Abstract: In coral reef conservation and management, the prevailing metric of reef health is percent coral cover, a measurement commonly used with the assumption that each
unit of live coral tissue has equivalent ecological value. Here we show that the
reproductive output of a coral population is not proportional to the cover of coral present.
Instead, when compared to declining populations nearby, high cover coral populations
produced up to four times more larvae per square centimeter of tissue, resulting in up to
200 times higher larval production per square meter of reef. Importantly, corals that
produced more larvae did not produce smaller larvae, as predicted by resource allocation
theory. Instead, higher fecundity corresponded to higher energetic lipid reserves in higher
cover coral populations. In the wake of unprecedented global coral bleaching, our
findings suggest that the largest reductions in coral reproduction may occur when corals
are lost from previously healthy populations.

Author: Hartmann, A.C., K.L Marhaver, M.J Vermeij
Year: 2017
View Abstract
http://onlinelibrary.wiley.com/doi/10.1111/conl.12410/full
Email for the full article: resilience@tnc.org

Conservation Letters. doi:10.1111/conl.12410

Share on FacebookTweet about this on TwitterEmail this to someone

Year in Review – 2017

Reflecting on the past year, there has never been a more critical time for effective coral reef management. In June of 2017, the world’s longest and most widespread bleaching event on record ended, with many reefs experiencing significant mortality. To address these – and other – challenges, the Reef Resilience Network continues to empower a global network of marine managers and scientists to improve coral reef management by sharing and implementing cutting-edge resilience science, inspiring greater collaboration, and working with global and regional reef initiatives to roll out guidance and best practices. Based on feedback from our managers, we have led in-person and online trainings, and have added new webinars, case studies, journal summaries, guidebooks, and modules on key topics to our website, reefresilience.org, which had over 150,000 visitors this year alone!

We are inspired by the thousands of reef managers, practitioners, and scientists in our Network and beyond, who spend their days working to reduce the threats facing reefs and supporting the necessary policies and programs to help our reefs to recover and thrive. We thank you and look forward and ahead to 2018 – the International Year of the Reef – and are grateful for the renewed attention to one of our world’s most precious resources, our coral reefs. See how we, as a Network, have improved reef management around the world.

RR Year in Review 2017_final

Share on FacebookTweet about this on TwitterEmail this to someone

Assisted Evolution: A Novel Tool to Overcome the Conservation Crisis?

Assisted Evolution Announcement PhotoThis symposium was live streamed as part of the Coral Restoration Consortium webinar series in conjunction with The Geomar Helmholtz Centre for Ocean Research Kiel and “The Future Ocean” cluster in Kiel. Speakers shared information on new approaches for the conservation of coral reefs such as assisted colonization and assisted evolution and synthetic biology. View the presentation recordings below.

Presentations:

Welcome and introduction – Marlene Wall, Geomar, Germany

Session 1: Shifting paradigms in conservation: social, public and scientific landscape of conservation genetics
Objective: The aim of session 1 is to (i) discuss new approaches for the conservation of natural environments, such as assisted colonization, assisted evolution and synthetic biology and (ii) introduce the current legal, public and scientific framework of novel methods in conservation.

Session 2: Assisted evolution in corals: Opportunities, applications, challenges, and limitations
Objective: The aim is to introduce how assisted evolution might change our way of restoring natural marine environments. What new tools are available that can improve the selection of environmental stress resistance and be implemented in conservation? What are the promises and perils of such approaches?

Share on FacebookTweet about this on TwitterEmail this to someone