Composition of Microbial Communities in Waters Around the Florida Reef Tract and Their Potential Significance for Stony Coral Tissue Loss Disease

The Florida Keys, a delicate archipelago of sub-tropical islands extending from the south-eastern tip of Florida, host the vast majority of the only coral barrier reef in the continental United States. Stony Coral Tissue Loss Disease (SCTLD), which was first detected near Virginia Key in 2014, has spread throughout the Florida Reef Tract and to reefs throughout the Caribbean, af-fecting nearly all reef-building corals. Molecular studies of SCTLD have identified opportunistic pathogens associated with the disease, but so far no single pathogen can be clearly pinpointed as its cause. One focus of recent research has been the surrounding environment of the corals, coined the 'coral ecosphere'. Abiotic and microbial components of the coral ecosphere are pivot-al for understanding the health of a reef, and could play an important role in SCTLD in Florida. In this study, we analyzed microbial community structure and abiotic factors that can impact coral (and human) health. Both, bacterial and eukaryotic community structure were significantly linked with variations in temperature, dissolved oxygen and total organic carbon values. High abundances of copiotrophic bacteria as well as several potentially harmful microbes, including coral pathogens, fish parasites, and taxa that have been previously associated with Red Tide and shellfish poisoning, were present in our datasets and can have a pivotal impact on coral health in this ecosystem.

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Composition of Prokaryotic and Eukaryotic Microbial Communities in Waters around the Florida Reef Tract

Microorganisms ◽

10.3390/microorganisms9061120 ◽

2021 ◽

Vol 9 (6) ◽

pp. 1120

Author(s):

Peeter Laas ◽

Kelly Ugarelli ◽

Michael Absten ◽

Breege Boyer ◽

Henry Briceño ◽

...

Keyword(s):

Community Structure ◽

Red Tide ◽

Abiotic Factors ◽

Florida Keys ◽

Fish Parasites ◽

Shellfish Poisoning ◽

Coral Diseases ◽

Florida Reef Tract ◽

Reef Health ◽

Reef Tract

The Florida Keys, a delicate archipelago of sub-tropical islands extending from the south-eastern tip of Florida, host the vast majority of the only coral barrier reef in the continental United States. Abiotic as well as microbial components of the surrounding waters are pivotal for the health of reef habitats, and thus could play an important role in understanding the development and transmission of coral diseases in Florida. In this study, we analyzed microbial community structure and abiotic factors in waters around the Florida Reef Tract. Both bacterial and eukaryotic community structure were significantly linked with variations in temperature, dissolved oxygen, and total organic carbon values. High abundances of copiotrophic bacteria as well as several potentially harmful microbes, including coral pathogens, fish parasites and taxa that have been previously associated with Red Tide and shellfish poisoning were present in our datasets and may have a pivotal impact on reef health in this ecosystem.

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Impacts of Stony Coral Tissue Loss Disease (SCTLD) on Coral Community Structure at an Inshore Patch Reef of the Upper Florida Keys Using Photomosaics

Frontiers in Marine Science ◽

10.3389/fmars.2021.682163 ◽

2021 ◽

Vol 8 ◽

Author(s):

Graham Kolodziej ◽

Michael S. Studivan ◽

Arthur C. R. Gleason ◽

Chris Langdon ◽

Ian C. Enochs ◽

...

Keyword(s):

Community Structure ◽

Coral Reef ◽

Coral Cover ◽

Florida Keys ◽

Coral Community ◽

Tissue Loss ◽

Coral Tissue ◽

Coral Mortality ◽

Stony Coral ◽

Reef Tract

Since the appearance of stony coral tissue loss disease (SCTLD) on reefs off Miami in 2014, this unprecedented outbreak has spread across the entirety of Florida’s coral reef tract, as well as to many territories throughout the Caribbean. The endemic zone reached the upper Florida Keys by 2016, resulting in partial or complete mortality of coral colonies across numerous species. Disease was first observed at Cheeca Rocks (Islamorada, Florida) in the beginning of 2018, with reports of coral mortality peaking mid-year. The disease was still present at Cheeca Rocks as of March 2020, however, to a lesser degree compared to the initial outbreak. Annual monitoring efforts have been ongoing at Cheeca Rocks since 2012, including repeated benthic photomosaics of a 330 m2 survey zone, spanning six replicate sites. As such, a repository of coral community composition data exists for before and after the disease outbreak that was analyzed to assess the impacts of SCTLD on reef communities at an upper Florida Keys inshore reef. Cheeca Rocks is hypothesized to be a resilient reef due to its persistent high coral cover despite its inshore location, which subjects corals to fluctuating water quality and marginal environmental conditions. Coral populations here have been shown to recover from bleaching events and heat stress with minimal coral mortality. Though colonies of coral species characterized as highly and moderately susceptible to SCTLD (e.g., Colpophyllia natans, Diploria labyrinthiformis, Pseudodiploria strigosa, Orbicella annularis, and O. faveolata) suffered mortality as a result of the outbreak with an average loss of 16.42% relative cover by species, the overall impacts on coral cover and community structure were relatively low, contributing to a loss of total coral cover of only 1.65%. Comparison of photomosaic data to other studies indicate Cheeca Rocks may not have been affected as severely as other sites on Florida’s coral reef tract, underlying this site’s potential role in coral resilience to stressors including bleaching events, land-based pollution, and disease epizootics.

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Microbial community shifts associated with the ongoing stony coral tissue loss disease outbreak on the Florida Reef Tract

10.1101/626408 ◽

2019 ◽

Cited By ~ 3

Author(s):

Julie L. Meyer ◽

Jessy Castellanos-Gell ◽

Greta S. Aeby ◽

Claudia Häse ◽

Blake Ushijima ◽

...

Keyword(s):

Coral Species ◽

Initial Step ◽

Disease Outbreak ◽

Healthy Tissue ◽

Tissue Loss ◽

Coral Tissue ◽

Florida Reef Tract ◽

Stony Coral ◽

Reef Tract ◽

Apparently Healthy

ABSTRACTAs many as 22 of the 45 coral species on the Florida Reef Tract are currently affected by stony coral tissue loss disease (SCTLD). The ongoing disease outbreak was first observed in 2014 in Southeast Florida near Miami and as of early 2019 has been documented from the northernmost reaches of the reef tract in Martin County down to Key West. We examined the microbiota associated with disease lesions and apparently healthy tissue on diseased colonies of Montastraea cavernosa, Orbicella faveolata, Diploria labyrinthiformis, and Dichocoenia stokesii. Analysis of differentially abundant taxa between disease lesions and apparently healthy tissue identified five unique amplicon sequence variants enriched in the diseased tissue in three of the coral species, namely an unclassified genus of Flavobacteriales and sequences identified as Fusibacter (Clostridiales), Planktotalea (Rhodobacterales), Algicola (Alteromonadales), and Vibrio (Vibrionales). In addition, several groups of likely opportunistic or saprophytic colonizers such as Epsilonbacteraeota, Patescibacteria, Clostridiales, Bacteroidetes, and Rhodobacterales were also enriched in SCTLD disease lesions. This work represents the first microbiological characterization of SCTLD, as an initial step toward identifying the potential pathogen(s) responsible for SCTLD.

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Rapid Population Decline of the Pillar Coral Dendrogyra cylindrus Along the Florida Reef Tract

10.1101/2020.05.09.085886 ◽

2020 ◽

Cited By ~ 1

Author(s):

Karen L. Neely ◽

Cynthia L. Lewis

Keyword(s):

Population Decline ◽

Tissue Loss ◽

Coral Tissue ◽

Florida Reef Tract ◽

Stony Coral ◽

Chronic Stressors ◽

The Status ◽

Reef Tract ◽

Functional Extinction ◽

Dendrogyra Cylindrus

AbstractCoral reefs worldwide are in a state of decline, but the status of populations and stressors for rare species are generally not well documented using broad-scale monitoring protocol. We fate-tracked all known colonies of the pillar coral Dendrogyra cylindrus on the Florida Reef Tract from 2013 – 2020 to assess the population and document the impacts of chronic and acute stressors. Large average colony size, an absence of juveniles, and large geographic distances between genotypes suggest that the Florida D. cylindrus population has been reproductively extinct for decades. During the study period, low-intensity chronic stressors were balanced by regrowth, while back-to-back years of coral bleaching and thermally-exacerbated disease led to declines that the subsequent years of recovery suggest would take 11 uninterrupted years to overcome. The most recent stressor on Florida’s D. cylindrus population is “stony coral tissue loss disease.” Following the appearance of the disease in Florida in 2015, it resulted in unrecoverable losses to the D. cylindrus population as tissue, colonies, and whole genotypes were driven to extinction. Losses of 91% of coral tissue, 88% of colonies, and 73% of genotypes between 2014 and early 2020 have led to functional extinction of D. cylindrus on the Florida Reef Tract.

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Microbial Community Shifts Associated With the Ongoing Stony Coral Tissue Loss Disease Outbreak on the Florida Reef Tract

Frontiers in Microbiology ◽

10.3389/fmicb.2019.02244 ◽

2019 ◽

Vol 10 ◽

Cited By ~ 23

Author(s):

Julie L. Meyer ◽

Jessy Castellanos-Gell ◽

Greta S. Aeby ◽

Claudia C. Häse ◽

Blake Ushijima ◽

...

Keyword(s):

Microbial Community ◽

Disease Outbreak ◽

Tissue Loss ◽

Coral Tissue ◽

Florida Reef Tract ◽

Stony Coral ◽

Reef Tract ◽

Community Shifts

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Stony Coral Tissue Loss Disease biomarker bacteria identified in corals and overlying waters using a rapid field-based sequencing approach

10.1101/2021.02.17.431614 ◽

2021 ◽

Author(s):

Cynthia C. Becker ◽

Marilyn Brandt ◽

Carolyn A. Miller ◽

Amy Apprill

Keyword(s):

Coral Disease ◽

The United States ◽

Virgin Islands ◽

Tissue Loss ◽

Coral Tissue ◽

Rna Sequences ◽

Disease Biomarker ◽

Stony Coral ◽

Ribosomal Rna Sequences ◽

Reef Tract

AbstractStony Coral Tissue Loss Disease (SCTLD) is a devastating disease. Since 2014, it has spread along the entire Florida Reef Tract, presumably via a water-borne vector, and into the greater Caribbean. It was first detected in the United States Virgin Islands (USVI) in January 2019. To more quickly identify disease biomarker microbes, we developed a rapid pipeline for microbiome sequencing. Over a span of 10 days we collected, processed, and sequenced coral tissue and near-coral seawater microbiomes from diseased and apparently healthy Colpophyllia natans, Montastraea cavernosa, Meandrina meandrites and Orbicella franksi. Analysis of the resulting bacterial and archaeal 16S ribosomal RNA sequences revealed 25 biomarker amplicon sequence variants (ASVs) enriched in diseased tissue. These biomarker ASVs were additionally recovered in near-coral seawater (within 5 cm of coral surface), a potential recruitment zone for pathogens. Phylogenetic analysis of the biomarker ASVs belonging to Vibrio, Arcobacter, Rhizobiaceae, and Rhodobacteraceae revealed relatedness to other coral disease-associated bacteria and lineages novel to corals. Additionally, four ASVs (Algicola, Cohaesibacter, Thalassobius and Vibrio) were exact sequence matches to microbes previously associated with SCTLD. This work represents the first rapid coral disease sequencing effort and identifies biomarkers of SCTLD that could be targets for future SCTLD research.

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Association of butterflyfishes and stony coral tissue loss disease in the Florida Keys

Coral Reefs ◽

10.1007/s00338-020-01986-8 ◽

2020 ◽

Vol 39 (6) ◽

pp. 1581-1590

Author(s):

Kara R. Noonan ◽

Michael J. Childress

Keyword(s):

Coral Disease ◽

Florida Keys ◽

Time Lapse ◽

Reef Fishes ◽

Disease Prevalence ◽

Tissue Loss ◽

Coral Tissue ◽

Individual Species ◽

Stony Coral ◽

Surface Areas

AbstractSince 2014, stony coral tissue loss disease (SCTLD) has rapidly spread throughout the Florida reef tract infecting and killing dozens of coral species. Previous studies have found that corallivorous fishes, such as butterflyfishes, are positively correlated with coral disease prevalence at both local and regional scales. This study investigates the association of SCTLD infection and butterflyfish abundance and behaviors on ten reefs in the middle Florida Keys. Divers conducted video surveys of reef fish abundance and disease prevalence in June 2017, 2018, and 2019; before, during, and after the outbreak of SCTLD infections. SCTLD prevalence increased from 3.2% in 2017 to 36.9% in 2018 and back to 2.7% in 2019. Butterflyfish abundances also showed a similar pattern with a twofold increase in abundance in 2018 over abundances in 2017 and 2019. To better understand the association of individual species of butterflyfishes and diseased corals, 60 coral colonies (20 healthy, 20 diseased, 20 recently dead) were tagged and monitored for butterflyfish activity using both diver-based AGGRA fish counts and 1-h time-lapse videophotography collected in the summers of 2018 and 2019. All reef fishes were more abundant on corals with larger surface areas of live tissue, but only the foureye butterflyfish preferred corals with larger surface areas of diseased tissues. Estimates of association indicate that foureye butterflyfish were found significantly more on diseased corals than either healthy or recently dead corals when compared with the other species of butterflyfishes. Foureye butterflyfish were observed to feed directly on the SCTLD line of infection, while other butterflyfish were not. Furthermore, association of foureye butterflyfish with particular diseased corals decreased from 2018 to 2019 as the SCTLD infections disappeared. Our findings suggest that foureye butterflyfish recruit to and feed on SCTLD-infected corals which may influence the progression and/or transmission of this insidious coral disease.

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Effectiveness of topical antibiotics in treating corals affected by Stony Coral Tissue Loss Disease

PeerJ ◽

10.7717/peerj.9289 ◽

2020 ◽

Vol 8 ◽

pp. e9289 ◽

Cited By ~ 3

Author(s):

Karen L. Neely ◽

Kevin A. Macaulay ◽

Emily K. Hower ◽

Michelle A. Dobler

Keyword(s):

Coral Species ◽

Tissue Loss ◽

Coral Tissue ◽

Success Rates ◽

Hard Coral ◽

Topical Antibiotic ◽

Topical Antibiotics ◽

Stony Coral ◽

Orbicella Faveolata ◽

Reef Tract

Since 2014, Stony Coral Tissue Loss Disease (SCTLD) has led to mass mortality of the majority of hard coral species on the Florida Reef Tract. Following the successful treatment of SCTLD lesions on laboratory corals using water dosed with antibiotics, two topical pastes were developed as vehicles to directly apply antibiotic treatments to wild corals. These pastes were tested as placebos and with additions of amoxicillin on active SCTLD lesions on multiple coral species. The effectiveness of the pastes without antibiotics (placebo treatments) was 4% and 9%, no different from untreated controls. Adding amoxicillin to both pastes significantly increased effectiveness to 70% and 84%. Effectiveness with this method was seen across five different coral species, with success rates of the more effective paste ranging from 67% (Colpophyllia natans) to 90% (Orbicella faveolata and Montastraea cavernosa). Topical antibiotic application is a viable and effective tool for halting disease lesions on corals affected by SCTLD.

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Fine Scale Temporal and Spatial Dynamics of the Stony Coral Tissue Loss Disease Outbreak Within the Lower Florida Keys

Frontiers in Marine Science ◽

10.3389/fmars.2021.631776 ◽

2021 ◽

Vol 8 ◽

Author(s):

Sara D. Williams ◽

Cory S. Walter ◽

Erinn M. Muller

Keyword(s):

Spatial Clustering ◽

Coral Cover ◽

Spatial Scales ◽

Florida Keys ◽

Incidence Rates ◽

Tissue Loss ◽

Coral Tissue ◽

Maximum Temperature ◽

Small Scale ◽

Stony Coral

One of the latest threats to Florida’s Coral Reef is the stony coral tissue loss disease (SCTLD) outbreak which affects all but a few Caribbean scleractinian species and has spread throughout the Caribbean since 2014. Without a known pathogen, ecological studies of disease dynamics are essential for understanding SCTLD susceptibility at the individual colony and reef level. We investigated the epizootiology of the SCTLD outbreak in the lower Florida Keys at two spatial scales (among reefs ∼1 km and within reefs <10 m) over a 19 month period. In May 2018, three sites absent of SCTLD were established to characterize coral demographics (i.e., live tissue cover and colony diameter) along an offshore to nearshore gradient, and were subsequently surveyed for disease every 2–3 weeks until December 2019. SCTLD was first noted within the offshore and mid-channel reef sites in early October 2018 and later appeared at the nearshore site in early February 2019. SCTLD was negatively correlated with thermal stress, showing reduced progression and incidence rates after 2–3 weeks of water temperatures above the mean monthly maximum temperature for the region (i.e., 2–3 degree heating weeks). Although Pseudodiploria strigosa, Dichocoenia stokesii, Colpophyllia natans, and Diploria labyrinthiformis were the most susceptible species at our sites, areas with more Montastraea cavernosa and Orbicella faveolata colonies had higher prevalence and greater tissue loss associated with disease. The disease was more severe within quadrats with high species diversity, high coral cover, and disproportionately affected larger colonies. Our spatial analyses suggest that (1) SCTLD followed a contagious disease model within small (<10 m) spatial scales, (2) colonies within 1.5–3 m of a diseased coral were at higher risk for subsequently showing disease signs compared with those farther away, and (3) high incidence rates coincided with the loss of small scale (<10 m radius) spatial clustering, suggesting pulses of contagious spread on large spatial scales.

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Evaluating the small-scale epidemiology of the stony-coral -tissue-loss-disease in the middle Florida Keys

PLoS ONE ◽

10.1371/journal.pone.0241871 ◽

2020 ◽

Vol 15 (11) ◽

pp. e0241871

Author(s):

William C. Sharp ◽

Colin P. Shea ◽

Kerry E. Maxwell ◽

Erinn M. Muller ◽

John H. Hunt

Keyword(s):

Disease Transmission ◽

Positive Association ◽

Florida Keys ◽

Mitigation Strategies ◽

Tissue Loss ◽

Coral Tissue ◽

Small Scale ◽

Stony Coral ◽

Frequency Monitoring ◽

Coral Communities

Along the Florida reef tract, stony-coral-tissue-loss disease (SCTLD) has caused extensive mortality of more than 20 scleractinian coral species. The pathogen is unknown, but its epizoology indicates that the disease, facilitated by water currents, has progressed linearly along the tract, affecting reefs at the scale of hundreds of kilometers. To inform ongoing disease mitigation efforts, we examined the small-scale spatial and temporal epidemiology of SCTLD. We established a series of sites in the middle Florida Keys at offshore and inshore locations that had not yet shown signs of SCTLD. We then conducted high-frequency monitoring from February 2018 through September 2019 and documented the onset of SCTLD and its progression through the sites. SCTLD was first observed at one site during early February 2018 and by early March 2018 all sites showed signs of the disease. A dynamic multistate model suggested that disease transmission was independent of coral density and found little evidence of a positive association between a colony showing signs of SCTLD and the condition or distance to its neighboring colonies. The model did, however, indicate that the probability of a colony showing signs of SCTLD increased with increasing colony surface area. These results are consistent with the water-borne transmission of a pathogen that progressed rapidly through the survey area. However, by the end of our survey the progression of SCTLD had slowed, particularly at inshore sites. Many affected colonies no longer exhibited progressive tissue mortality typical of the disease, suggesting the existence of differentially resilient colonies or coral communities, meriting their use for future coral rescue and propagation and disease research. These results are useful for refining ongoing SCTLD mitigation strategies, particularly by determining when disease rates are sufficiently low for direct intervention efforts designed to arrest disease progression on individual coral colonies will be most effective.

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