School of Natural and Environmental Sciences

Staff Profile

Professor John Bythell

Prof of Coral Reef Biology



Coral reef ecology is at the forefront of national and international media attention because of the serious threats to these ecosystems from global climate change, disease and over-exploitation. As long ago as 1998, a global sea surface temperature event is estimated to have killed 17% of the corals of the world. Regional mass bleaching events are now common occurrences, often followed by disease outbreaks. My recent research has addressed two main foci in the study of coral health and disease: 1) the development of a culture-independent molecular microbial ecology approach to the study of emergent diseases in reef corals, and 2) The cellular and molecular responses of reef corals to infection and environmental stress, most recently in relation to cell death pathways and mucus secretion dynamics. The next phase of this research is to combine the molecular and cellular host coral stress responses with experimental manipulation of microbial exposure and environmental stress. As genomic information becomes available for corals and related lower invertebrates, post-genomic and proteomic approaches to stress and disease analysis have also become possible.

From 2012-2015 I held the position of Deputy Vice-Chancellor (Research & International) at the University of the South Pacific, based in Fiji. The small island states of the south Pacific are at the forefront of global climate change impacts. Prior to that, I was a member of an international ‘Coral Reef Targeted Research’ programme investigating coral bleaching ( and more recently acted on the Western Indian Ocean Marine Science Association programme committee ( I am particularly concerned about raising awareness of the dramatic impacts of climate change in tropical coastal ecosystems (see video article at:

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Research Interests

Large-scale coral bleaching episodes were unknown prior to 1979 but have become more frequent with repeated mass coral bleaching events on the Great Barrier Reef in 2016 and 2017. These events are linked to environmental stress, particularly temperature increases, and in addition to the local and regional loss of biodiversity, may represent the first case of the functional collapse of an ecosystem due to global climate change. Concurrent with these mass bleaching events, there has been widespread concern over the emergence of coral diseases over the past three decades. Reef core data from Belize indicates that the mass mortality of two of the dominant coral species in the Caribbean is unprecedented in at least the last 3-4000 years, which suggests a link to anthropogenic activities. Unfortunately, identification and characterisation of the causal agents of most coral diseases remains unresolved or poorly characterised, with traditional microbiological approaches to determining disease causation being misleading in these typically polymicrobial diseases. My research group addresses these areas by applying molecular approaches to understanding microbial ecology of corals and coral reefs. Other research interests focus on the host responses to environmental stress and host-microbe interactions.


Degree Programme Director: MSc Ecological Consultancy

Module Leader:

SPG8013 Environmental Impact Assessment (Flexible Learning)

BIO3041 Molecular Evolution & Systematics


MST8011 Critical Appraisal of Coastal Production Systems 

BIO3022 Residential Fieldcourse                   

BIO1010 Biology in Action

BIO2017 Microbiology 2

BIO3037 Current Zoology