Project: Killer Seaweeds: Allelopathy against Fijian Corals

Acronym/Short Name:Killer Seaweeds
Project Duration:2009-09 - 2014-08
Geolocation:Viti Levu, Fiji (18º13.049’S, 177º42.968’E)

Description

Extracted from the NSF award abstract:

Coral reefs are in dramatic global decline, with reefs commonly converting from species-rich and topographically-complex communities dominated by corals to species- poor and topographically-simplified communities dominated by seaweeds. These phase-shifts result in fundamental loss of ecosystem function. Despite debate about whether coral-to-algal transitions are commonly a primary cause, or simply a consequence, of coral mortality, rigorous field investigation of seaweed-coral competition has received limited attention. There is limited information on how the outcome of seaweed-coral competition varies among species or the relative importance of different competitive mechanisms in facilitating seaweed dominance. In an effort to address this topic, the PI will conduct field experiments in the tropical South Pacific (Fiji) to determine the effects of seaweeds on corals when in direct contact, which seaweeds are most damaging to corals, the role allelopathic lipids that are transferred via contact in producing these effects, the identity and surface concentrations of these metabolites, and the dynamic nature of seaweed metabolite production and coral response following contact. The herbivorous fishes most responsible for controlling allelopathic seaweeds will be identified, the roles of seaweed metabolites in allelopathy vs herbivore deterrence will be studied, and the potential for better managing and conserving critical reef herbivores so as to slow or reverse conversion of coral reef to seaweed meadows will be examined.

Preliminary results indicate that seaweeds may commonly damage corals via lipid- soluble allelochemicals. Such chemically-mediated interactions could kill or damage adult corals and produce the suppression of coral fecundity and recruitment noted by previous investigators and could precipitate positive feedback mechanisms making reef recovery increasingly unlikely as seaweed abundance increases. Chemically-mediated seaweed-coral competition may play a critical role in the degradation of present-day coral reefs. Increasing information on which seaweeds are most aggressive to corals and which herbivores best limit these seaweeds may prove useful in better managing reefs to facilitate resilience and possible recovery despite threats of global-scale stresses. Fiji is well positioned to rapidly use findings from this project for better management of reef resources because it has already erected >260 MPAs, Fijian villagers have already bought-in to the value of MPAs, and the Fiji Locally-Managed Marine Area (FLMMA) Network is well organized to get information to villagers in a culturally sensitive and useful manner.

The broader impacts of this project are far reaching. The project provides training opportunities for 2-2.5 Ph.D students and 1 undergraduate student each year in the interdisciplinary areas of marine ecology, marine conservation, and marine chemical ecology. Findings from this project will be immediately integrated into classes at Ga Tech and made available throughout Fiji via a foundation and web site that have already set-up to support marine conservation efforts in Fiji and marine education efforts both within Fiji and internationally. Business and community leaders from Atlanta (via Rotary International Service efforts) have been recruited to help organize and fund community service and outreach projects in Fiji -- several of which are likely to involve marine conservation and education based in part on these efforts there. Media outlets (National Geographic, NPR, Animal Planet, Audubon Magazine, etc.) and local Rotary clubs will be used to better disseminate these discoveries to the public.

PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH

Rasher DB, Stout EP, Engel S, Kubanek J, and ME Hay. "Macroalgal terpenes function as allelopathic agents against reef corals", Proceedings of the National Academy of Sciences, v. 108, 2011, p. 17726.

Beattie AJ, ME Hay, B Magnusson, R de Nys, J Smeathers, JFV Vincent. "Ecology and bioprospecting," Austral Ecology, v.36, 2011, p. 341.

Rasher DB and ME Hay. "Seaweed allelopathy degrades the resilience and function of coral reefs," Communicative and Integrative Biology, v.3, 2010.

Hay ME, Rasher DB. "Corals in crisis," The Scientist, v.24, 2010, p. 42.

Hay ME and DB Rasher. "Coral reefs in crisis: reversing the biotic death spiral," Faculty 1000 Biology Reports 2010, v.2, 2010.

Rasher DB and ME Hay. "Chemically rich seaweeds poison corals when not controlled by herbivores", Proceedings of the National Academy of Sciences, v.107, 2010, p. 9683.


DatasetLatest Version DateCurrent State
Coral metagenome accessions archived at NCBI from a coral-seaweed competition experiment in the Fiji Islands, Dec. 20142020-07-15Preliminary and in progress
Microbial alpha diversity of Acropora millepora samples from a coral-seaweed competition experiment in the Fiji Islands, Dec. 20142020-07-15Preliminary and in progress
Microbial ESV counts for Acropora millepora corals exposed to Sargassum seaweed2020-07-13Preliminary and in progress
Initial mass and growth data, as change in mass over 33 days, for Acropora millepora corals exposed to one of nine experimental treatments of killer seaweeds, Fiji, 20142020-07-13Preliminary and in progress
Coral photosynthetic efficiency (Pulse-Amplitude-Modulation, PAM) fluorometry from Acropora millepora corals exposed to seaweeds 2020-07-13Preliminary and in progress
Microbial ESV counts for Acropora millepora corals exposed to Galaxaura seaweed2020-07-09Preliminary and in progress
Macroalgal biomass at month 16 in experimental plots on a fringing reef in Fiji.2019-02-25Preliminary and in progress
Macroalgal cover at month 4 in experimental plots on a fringing reef in Fiji.2019-02-25Data not available
Percent tissue mortality of corals in experimental plots at month 4 and 16 on a fringing reef in Fiji.2019-02-25Data not available
Densities of corallivorous gastropods in 36 cm × 36 cm plots on a fringing reef in Fiji2019-02-22Data not available
Percent growth of corals in experimental plots for month 4 and month 162019-02-21Data not available
Frequency of coral species richness in 36 cm × 36 cm quadrats from field surveys on a fringing reef in Fiji2019-02-21Data not available
GPS location coordinates of Acanthaster individuals used in a tagging study in Viti Levu, Fiji from 2010-20122017-06-23Final no updates expected
Movement distance and direction data of tagged Acanthaster in Viti Levu, Fiji from 2010-2012.2017-06-23Final no updates expected
Behavioral observation data of tagged and untagged Acanthaster in Viti Levu, Fiji from 2010-20122017-06-23Final no updates expected
Acanthaster count data collected in protected and fished areas from Viti Levu, Fiji from 2010-2012.2017-06-23Final no updates expected
Biodiversity of fish feeding groups in Viti Levu, Fiji from 2010-2012 (Killer Seaweeds project)2017-01-06Final no updates expected
Rates of grazing by parrotfishes and macroalgal browsing in Fiji during 2010-2012 (Killer Seaweeds project)2017-01-06Final no updates expected
Herbivore grazing rates in Viti Levu, Fiji from 2010-2012 (Killer Seaweeds project)2017-01-06Final no updates expected
Density of coral recruits in and out of MPAs in Viti Levu, Fiji from 2010 to 2012 (Killer Seaweeds project)2017-01-06Final no updates expected
Species richness in and out of MPAs in Viti Levu, Fiji from 2010-2012 (Killer Seaweeds project)2017-01-06Final no updates expected
Benthic cover data from six sites in Viti Levu, Fiji from 2010-2012 (Killer Seaweeds project)2017-01-06Final no updates expected
Biomass of fish feeding groups on reefs in Viti Levu, Fiji from 2010-2012 (Killer Seaweeds project)2017-01-06Final no updates expected
Biomass and density data from in and outside of an MPA in Viti Levu, Fiji from 2010-2012 (Killer Seaweeds project)2017-01-06Final no updates expected
Benthic data collected in and out of MPA borders in Viti Levu, Fiji from 2010-20122016-06-23Final no updates expected
Growth and survival of mature Sargassum polycystum fronds in crowded and isolated habitats2016-05-02Final no updates expected
Survival and growth of recruit-sized ramets growing inside or outside Sargassum beds (crowded and isolated conditions, respectively) in the MPA and non-MPA of two villages in Fiji2016-05-02Final no updates expected
Effect of habitat, origin, and herbivory on the survival and growth of recruit-sized S. polycystum fronds from MPAs and non-MPAs when reciprocally transplanted2016-05-02Final no updates expected
Growth of mature caged Sargassum polycystum fronds from MPAs and non-MPAs when reciprocally transplanted2016-04-29Final no updates expected
Stoney coral survival experiments on replacement tiles collected from the Coral Coast of Viti Levu, Fiji in 2013 (Killer Seaweeds project)2015-08-14Final no updates expected
Data from the stoney coral fragment survival experiment on the Coral Coast of Viti Levu, Fiji in 2013 (Killer Seaweeds project)2015-08-14Final no updates expected
Tile array metadata and fish identified from photos taken on the Coral Coast of Viti Levu, Fiji in 2013 (Killer Seaweeds project)2015-08-13Final no updates expected
Spatial distribution of P. damicornis and S. hystrix on the Coral Coast of Viti Levu, Fiji in 2013 (Killer Seaweeds project)2015-08-12Final no updates expected
Coral colony sizes and distribution on the Coral Coast of Viti Levu, Fiji in 2013 (Killer Seaweeds project)2015-08-12Final no updates expected
Palatability of Galaxaura & Sargassum to herbivores in the Viti Levu, Fiji from 2011 (Killer Seaweeds project)2014-01-22Final no updates expected
Seaweed growth, palatability, and chemical defense (anti-coral and anti-herbivore) following 8 days of contact with a coral competitor in the Viti Levu, Fiji from May 2011 (Killer Seaweeds project)2014-01-22Final no updates expected
Palatability of Galaxaura extract on Padina to herbivores from in the Viti Levu, Fiji from 2011 (Killer Seaweeds project)2014-01-22Final no updates expected
Porites PSII quantum yield after exposure to seaweed extracts in the Viti Levu, Fiji from May 2011 (Killer Seaweeds project)2014-01-22Final no updates expected
Palatability of Galaxaura extract on Amphiroa to herbivores in the Viti Levu, Fiji from 2011 (Killer Seaweeds project)2014-01-22Final no updates expected
Porites PSII quantum yield after exposure to Galaxaura thalli in the Viti Levu, Fiji from May 2011 (Killer Seaweeds project)2014-01-22Final no updates expected

People

Principal Investigator: Mark E. Hay
Georgia Institute of Technology (GA Tech)


Data Management Plan

DMP_Hay_OCE-0929119.pdf (185.83 KB)
02/09/2025