The impact of bleaching on disease susceptibility and defence in reef building corals
Lead Research Organisation:
Newcastle University
Department Name: Sch of Biology
Abstract
Most scientists agree that sea temperature increases due to global climate change have already caused mass mortality of corals throughout the tropics over the last 5-10 years. Given the current climate change predictions from organisations like the Hadley Centre in the UK, it appears likely that increases in sea temperatures will cause the complete collapse of these ecosystems within only a few decades. These estimates may be too pessimistic, because corals are able to adapt to rising temperatures using a variety of mechanisms. However, at the same time coral diseases have become increasingly common, as they have in many other systems and groups of organisms. Several scientists have proposed that these increases in disease are linked to climate change and we aim here to test whether temperature stress increases a corals' susceptibility to disease by monitoring indicators of health, antimicrobial defences and bacterial community structure and function. There are other possible causes of the recorded increase in diseases, however, such as increased transport and transfer of micro-organisms via tourists or ships' ballast water, for example. It is therfore vital that we understand the disease process so that appropriate and effective measures can be used to improve the health of coral reefs.
Publications
Alastair Lindop (Author)
(2008)
The unknowns in coral disease identification: An experiment to assess consensus of opinion amongst experts
Fitt W
(2009)
Response of two species of Indo-Pacific corals, Porites cylindrica and Stylophora pistillata, to short-term thermal stress: The host does matter in determining the tolerance of corals to bleaching
in Journal of Experimental Marine Biology and Ecology
Guppy R
(2019)
Preserving the viscous coral surface mucus layer using low-acid glycol methacrylate (GMA) resin
in Coral Reefs
Hoegh-Guldberg O
(2009)
Bleaching and Related Ecological Factors: CRTR Working Group Findings 2004-2009
Leggat W
(2007)
The hologenome theory disregards the coral holobiont
in Nature Reviews Microbiology
Lesser M
(2007)
Are infectious diseases really killing corals? Alternative interpretations of the experimental and ecological data
in Journal of Experimental Marine Biology and Ecology
Palmer C
(2008)
Evidence of an inflammatory-like response in non-normally pigmented tissues of two scleractinian corals
in Proceedings of the Royal Society B: Biological Sciences
Palmer CV
(2011)
Corals use similar immune cells and wound-healing processes as those of higher organisms.
in PloS one
Palmer CV
(2011)
A comparative study of phenoloxidase activity in diseased and bleached colonies of the coral Acropora millepora.
in Developmental and comparative immunology
Palmer CV
(2010)
Levels of immunity parameters underpin bleaching and disease susceptibility of reef corals.
in FASEB journal : official publication of the Federation of American Societies for Experimental Biology
Description | The study used an holistic approach to investigate both the host defenses and microbial pathogens associated with reef coral diseases, a major cause of coral reef decline globally. We were able to show that: 1) Coral immunity, measured via a suite of indicator variables, is strongly correlated to coral disease and bleaching susceptibility. 2) Pathogen community shifts occur rapidly (within min.) of a threshold being reached following exposure to stress, during which little change to associated communities occurs. Disease is neither a result of 'imbalance' in associated microbial communities, nor delivery of novel pathogens, but a loss of host defenses allowing invasion of microbes to the normally virtually sterile tissues. 3) Ciliates (single-celled eukaryotes) are involved in several of the common coral diseases and may allow invasion of bacterial pathogens that further weaken host defenses. |
Exploitation Route | Our work has been disseminated and exploited at two levels: 1) a policy approach facilitated through international research networks and applied policy forums at international level (supported by the GEF/World Bank) and 2) an industrial approach within the UK and overseas aquarium trade, including both public aquaria and the commercial aquarium trade. These initiatives are aimed at reducing wild harvest and improving husbandry of captive corals. This work has been facilitated through a NERC Knowledge Exchange programme (Coral Aquarist Research Network) and collaborations with a number of public aquaria. Future work will investigate the potential for genetic selection and husbandry as a a viable means of combatting climate change impacts in coral reef environments. Our further studies have since shown that antibiotic treatment is an effective control for coral diseases, although unfortunately this is not a feasible (or ethical) treatment on regional/global scales. Our immunity studies suggest that both different host species and genetic variants have strikingly different levels of investment in immune defenses and different susceptibilities to temperature stress (which is increasing due to climate change and correlated to increased bleaching and disease). Thus, artificial selection for heat-tolerant corals may be a pragmatic solution to climate change impacts in tropical reef systems. |
Sectors | Environment |
URL | http://www.ncl.ac.uk/biology/staff/profile/john.bythell#tab_profile |
Description | Outcomes of the research contributed to policy development and further research in a major international collaboration funded by GEF/World Bank. The 10-year findings of this group were published in 2010(http://www.gefcoral.org/LinkClick.aspx?fileticket=zv3UV2E9Dzg%3d&tabid=3260?uage=en-US). |
First Year Of Impact | 2000 |
Sector | Education,Environment |
Impact Types | Societal Economic Policy & public services |
Description | Coral Reef Targeted Research |
Amount | £45,193 (GBP) |
Funding ID | CRTR-BWG |
Organisation | World Bank Group |
Department | Global Environment Facility |
Sector | Public |
Country | United States |
Start | 01/2007 |
End | 12/2007 |
Description | Coral Reef Targeted Research |
Amount | £45,193 (GBP) |
Funding ID | CRTR-BWG |
Organisation | World Bank Group |
Department | Global Environment Facility |
Sector | Public |
Country | United States |
Start | 01/2007 |
End | 12/2007 |
Description | Re-evaluation of the importance of ciliates in coral disease |
Amount | £323,988 (GBP) |
Funding ID | NE/H020616/1 |
Organisation | Natural Environment Research Council |
Sector | Public |
Country | United Kingdom |
Start | 03/2011 |
End | 07/2013 |
Description | Coral Aquarist Researcher Network (CARN) |
Organisation | University of Essex |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Engaged in collaboration with CARN led by NERC KE Fellow Philippa Mansell (Essex Univ), including major representatives of UK aquarium trade and public aquarium operators with coral reef experts. |
Start Year | 2009 |
Description | Coral Reef Targeted Research |
Organisation | World Bank Group |
Department | Global Environment Facility |
Country | United States |
Sector | Public |
PI Contribution | 12-member international research network collaboration, funded by GEF/World Bank |
Start Year | 2007 |
Description | Coral Reef Targeted Research |
Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
Part Of Official Scheme? | Yes |
Geographic Reach | International |
Primary Audience | Policymakers/politicians |
Results and Impact | Web site for dissemination to policy makers, decision makers and practitioners at local/regional, national and international levels - see http://www.gefcoral.org/Howwework/gefcoralv3/Meetourpeople/WorkingGroups/tabid/3290/Default.aspx. Various types of outputs and activities e.g http://www.gefcoral.org/VideoGallery/VideoPlayer/TabId/3700/VideoId/131/CRTR-Bleaching-Working-Group-Heron-Island-2009.aspx |
Year(s) Of Engagement Activity | Pre-2006,2006,2007,2008,2009,2010 |
URL | http://www.gefcoral.org/ |