Analysis of 50 years of coral disease research visualized through the scope of network theory (original) (raw)

Field manual for investigating coral disease outbreaks

2008

Coral reefs throughout their circumtropical range are declining at an accelerating rate. Recent predictions indicate that 20% of the world’s reefs have been degraded, another 24% are under imminent risk of collapse, and if current estimates hold, by 2030, 26% of the world’s reefs will be lost (Wilkinson 2004). Recent changes to these ecosystems have included losses of apex predators, reductions of important herbivorous fishes and invertebrates, and precipitous declines in living coral cover, with many reefs now dominated by macroalgae. Causes have been described in broad sweeping terms: global climate change, over-fishing and destructive fishing, land-based sources of pollution, sedimentation, hurricanes, mass bleaching events and disease. Recognition that corals can succumb to disease was first reported in the early 1970’s. Then it was a unique observation, with relatively few isolated reports until the mid 1990’s. Today disease has spread to over 150 species of coral, reported fro...

Deciphering Coral Disease Dynamics: Integrating Host, Microbiome, and the Changing Environment

Frontiers in Ecology and Evolution, 2020

Diseases of tropical reef organisms is an intensive area of study, but despite significant advances in methodology and the global knowledge base, identifying the proximate causes of disease outbreaks remains difficult. The dynamics of infectious wildlife diseases are known to be influenced by shifting interactions among the host, pathogen, and other members of the microbiome, and a collective body of work clearly demonstrates that this is also the case for the main foundation species on reefs, corals. Yet, among wildlife, outbreaks of coral diseases stand out as being driven largely by a changing environment. These outbreaks contributed not only to significant losses of coral species but also to whole ecosystem regime shifts. Here we suggest that to better decipher the disease dynamics of corals, we must integrate more holistic and modern paradigms that consider multiple and variable interactions among the three major players in epizootics: the host, its associated microbiome, and t...

Vectors and environmental drivers of coral disease dynamics on the Great Barrier Reef

2017

Coral diseases are causing significant levels of coral mortality at a global scale, based on the frequency of reports of disease and the rates of disease-related coral tissue loss worldwide. Of further concern is that the recent increase in the prevalence of coral diseases has been linked to environmental changes that can alter the outcome of host/pathogen interactions. Thus, coral diseases are expected to have increasing impacts on the structure and dynamics of coral populations and communities as the environment continues to change in the future. Despite the growing body of literature on the various diseases and pathogens that affect corals, the aetiology (i.e., causes of disease) and ecology (i.e., how the environment affects interactions between hosts and pathogens) and transmission of most coral diseases remain poorly understood. Understanding disease transmission mechanisms is critical to evaluate the potential impact of diseases on their host population. Diseases where pathog...

Education and Research: A Symbiosis to Better Understand a Novel Coral Disease

Frontiers in Marine Science, 2021

Ongoing ecological events, such as new and emerging diseases, provide an important platform for education and research. Field courses and undergraduate research projects can be critical to assisting students with learning scientific skills and career discernment as these experiences provide more one-on-one instruction and an immersive learning environment. A novel coral disease called “Stony Coral Tissue Loss Disease” (SCTLD) provided one such opportunity. SCTLD is characterized by rapid progression with entire coral heads dying within 2–3 weeks after initial observation of the onset of symptoms. At a wider geographic scale, the disease has migrated with extreme velocity and has now been documented across the Caribbean from as far North as the Southeast Florida Reef Tract, as far South as St. Lucia, and as far West as Honduras and Belize. Here, I summarize what is currently known about SCTLD and document an educational field course that involved eight undergraduate students with vis...

On the Importance of the Microbiome and Pathobiome in Coral Health and Disease

The term " microbiome " was first coined in 1988 and given the definition of a characteristic microbial community occupying a reasonably well defined habitat which has distinct physio-chemical properties. A more recent term has also emerged, taking this one step further and focusing on diseases in host organisms. The " pathobiome " breaks down the concept of " one pathogen = one disease " and highlights the role of the microbiome, more specifically certain members within the microbiome, in causing pathogenesis. The development of next generation sequencing has allowed large data sets to be amassed describing the microbial communities of many organisms and the field of coral biology is no exception. However, the choices made in the analytical process and the interpretation of these data can significantly affect the outcome and the overall conclusions drawn. In this review we explore the implications of these difficulties, as well as highlighting analytical tools developed in other research fields (such as network analysis) which hold substantial potential in helping to develop a deeper understanding of the role of the microbiome in disease in corals. We also make the case that standardization of methods will substantially improve the collective gain in knowledge across research groups.