scholarly journals Effect of species, size, and chimerism on the susceptibility of Caribbean brain coral recruits to stony coral tissue loss disease (SCTLD)

2021 ◽  
Author(s):  
Olivia Mavahlia Williamson ◽  
Caroline E Dennison ◽  
Keri L O'Neil ◽  
Andrew Charles Baker
Keyword(s):  
Life History ◽  
Tissue Loss ◽  
Coral Tissue ◽  
Life History Stage ◽  
Relative Resistance ◽  
Reef Restoration ◽  
Stony Coral ◽  
Algal Symbionts ◽  
Potential Sources ◽  
Caribbean Coral

Stony coral tissue loss disease (SCTLD) has devastated coral populations along Florida′s Coral Reef and beyond. Although widespread infection and mortality of adult colonies have been documented, no studies have yet investigated the susceptibility of recruits to this disease. Here, we exposed eight-month-old Diploria labyrinthiformis recruits and four-month-old Colpophyllia natans recruits to two sequential doses of SCTLD in the laboratory to track infection and assess potential resilience. Both species began to develop lesions as early as 48 h after exposure began. During the first dose, 59.0% of C. natans recruits lost all tissue (died) within two to eight days of developing lesions, whereas D. labyrinthiformis recruits experienced significantly slower rates of tissue loss and minimal eventual mortality. In C. natans, larger recruits and those fused into groups of multiple genets (chimeras) exhibited the highest survivorship. In contrast, smaller and/or single (ungrouped) recruits had the lowest survivorship (9.9 - 26.5%). After 20 days, a second SCTLD dose was delivered to further test resistance in remaining recruits, and all recruits of both species succumbed within 6 days. Although no recruits showed absolute resistance to SCTLD following repeated exposures, our results provide evidence that interactions between species, size, and chimerism can impact relative resistance. This study represents the first report of SCTLD in Caribbean coral recruits and carries implications for natural species recovery and reef restoration efforts. Additional research on the susceptibility of coral juveniles to SCTLD is urgently needed, to include different species, locations, parents, and algal symbionts, with the goal of assessing relative susceptibility and identifying potential sources of resilience for this critical life history stage.

scholarly journals Changing Stony Coral Tissue Loss Disease Dynamics Through Time in Montastraea cavernosa

2021 ◽  
Vol 8 ◽  
Author(s):  
Greta Aeby ◽  
Blake Ushijima ◽  
Erich Bartels ◽  
Cory Walter ◽  
Joseph Kuehl ◽  
...  
Keyword(s):  
Common Species ◽  
Disease Prevalence ◽  
Tissue Loss ◽  
Coral Tissue ◽  
Disease Dynamics ◽  
Western Atlantic ◽  
Fort Lauderdale ◽  
Stony Coral ◽  
Montastraea Cavernosa ◽  
Lesion Morphology

Stony coral tissue loss disease (SCTLD) is affecting corals across the Western Atlantic and displays species-specific and regional differences in prevalence, incidence, degree of mortality, and lesion morphology. We examined two Florida sites with different temporal histories of disease emergence; Fort Lauderdale where SCTLD is endemic and the Lower Florida Keys where SCTLD has recently emerged. Our objectives were to (1) assess the potential impact of SCTLD on overall reef condition by surveying reefs in each region, (2) in a single common species, Montastraea cavernosa, examine differences in SCTLD prevalence, colony mortality, and lesion morphology in each region, and (3) look for differences in contagion by conducting transmission experiments using lesions from each region. Reef surveys found sites in both regions had low coral cover, high algae cover, and similar coral species composition. SCTLD prevalence was higher in the Lower Keys than at Fort Lauderdale and two of the common species, M. cavernosa and S. siderea at Fort Lauderdale were dominated by smaller colonies (<5 cm) whereas larger colonies occurred in the Lower Keys. Tagged M. cavernosa SCTLD-affected colonies were followed for 2 years at one site in each region. In both years, Fort Lauderdale colonies showed declining disease prevalence, low colony mortality, and disease lesions were mainly bleached spots lacking tissue loss. In contrast, Lower Keys colonies tagged in the first year maintained 100% disease prevalence with high mortality, and disease lesions were predominantly tissue loss with no bleached edges. However, SCTLD dynamics changed, with year two tagged colonies showing declining disease prevalence, low mortality, and lesion morphology switched to a mixture of bleached polyps and tissue loss with or without bleached edges. Lesion morphology on colonies was a significant predictor of amount of tissue loss. Aquaria studies found the rate of SCTLD transmission using lesions from the different zones (emergent and endemic) were similar. Our study highlights that differences in coral mortality from SCTLD are not necessarily linked to host species, lesion morphology is reflective of subsequent rate of mortality, and disease dynamics change through time on reefs where the disease has newly emerged.

Reef-scale impacts of the stony coral tissue loss disease outbreak

Coral Reefs ◽  
2020 ◽  
Vol 39 (4) ◽  
pp. 861-866 ◽  
Author(s):  
Nuria Estrada-Saldívar ◽  
Ana Molina-Hernández ◽  
Esmeralda Pérez-Cervantes ◽  
Francisco Medellín-Maldonado ◽  
F. Javier González-Barrios ◽  
...  
Keyword(s):  
Disease Outbreak ◽  
Tissue Loss ◽  
Coral Tissue ◽  
Stony Coral

scholarly journals Stony Coral Tissue Loss Disease in Florida Is Associated With Disruption of Host–Zooxanthellae Physiology

2020 ◽  
Vol 7 ◽  
Author(s):  
Jan H. Landsberg ◽  
Yasunari Kiryu ◽  
Esther C. Peters ◽  
Patrick W. Wilson ◽  
Noretta Perry ◽  
...  
Keyword(s):  
Body Wall ◽  
Chromatin Condensation ◽  
Periodic Acid ◽  
Clinical Signs ◽  
Host Cells ◽  
Tissue Loss ◽  
Coral Tissue ◽  
Crystalline Inclusion ◽  
Periodic Acid Schiff ◽  
Stony Coral

Samples from eight species of corals (Colpophyllia natans, Dendrogyra cylindrus, Diploria labyrinthiformis, Meandrina meandrites, Montastraea cavernosa, Orbicella faveolata, Pseudodiploria strigosa, and Siderastrea siderea) that exhibited gross clinical signs of acute, subacute, or chronic tissue loss attributed to stony coral tissue loss disease (SCTLD) were collected from the Florida Reef Tract during 2016–2018 and examined histopathologically. The hallmark microscopic lesion seen in all eight species was focal to multifocal lytic necrosis (LN) originating in the gastrodermis of the basal body wall (BBW) and extending to the calicodermis, with more advanced lesions involving the surface body wall. This was accompanied by other degenerative changes in host cells such as mucocyte hypertrophy, degradation and fragmentation of gastrodermal architecture, and disintegration of the mesoglea. Zooxanthellae manifested various changes including necrosis (cytoplasmic hypereosinophilia, pyknosis); peripheral nuclear chromatin condensation; cytoplasmic vacuolation accompanied by deformation, swelling, or atrophy; swollen accumulation bodies; prominent pyrenoids; and degraded chloroplasts. Polyhedral intracytoplasmic eosinophilic periodic acid–Schiff-positive crystalline inclusion bodies (∼1–10 μm in length) were seen only in M. cavernosa and P. strigosa BBW gastrodermis in or adjacent to active lesions and some unaffected areas (without surface lesions) of diseased colonies. Coccoidlike or coccobacilloidlike structures (Gram-neutral) reminiscent of microorganisms were occasionally associated with LN lesions or seen in apparently healthy tissue of diseased colonies along with various parasites and other bacteria all considered likely secondary colonizers. Of the 82 samples showing gross lesions of SCTLD, 71 (87%) were confirmed histologically to have LN. Collectively, pathology indicates that SCTLD is the result of a disruption of host–symbiont physiology with lesions originating in the BBW leading to detachment and sloughing of tissues from the skeleton. Future investigations could focus on identifying the cause and pathogenesis of this process.

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

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.

scholarly journals Considering Commercial Vessels as Potential Vectors of Stony Coral Tissue Loss Disease

2021 ◽  
Vol 8 ◽  
Author(s):  
Nicholas A. Rosenau ◽  
Sarah Gignoux-Wolfsohn ◽  
Richard A. Everett ◽  
A. Whitman Miller ◽  
Mark S. Minton ◽  
...  
Keyword(s):  
Ballast Water ◽  
Management Strategies ◽  
Tissue Loss ◽  
Coral Tissue ◽  
Caribbean Region ◽  
Future Research ◽  
Ship Traffic ◽  
Marine Invasion ◽  
Stony Coral ◽  
Resource Managers

Stony coral tissue loss disease (SCTLD) is a troubling new disease that is spreading rapidly across the greater Caribbean region, but the etiological agent(s) and the mechanisms(s) of spread are both unknown. First detected off the coast of Miami, Florida, major ocean currents alone do not explain the pattern of spread, with outbreaks occurring across geographically disjunct and distant locations. This has raised concerns by researchers and resource managers that commercial vessels may contribute as vectors to spread of the disease. Despite existing regulatory and management strategies intended to limit coastal marine invasion risks, the efficacy of these measures is still unresolved for ship-borne microorganisms, and disease transport via ballast water and hull biofouling are under examination given the high ship traffic in the region. Here, to help inform the discussion of ships as possible vectors of SCTLD, we provide an overview of the current state of knowledge about ships and their potential to transfer organisms in the greater Caribbean, focusing in particular on ballast water, and outline a set of recommendations for future research.

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

2021 ◽  
Author(s):  
Peeter Laas ◽  
Kelly Ugarelli ◽  
Breege Boyer ◽  
Michael J. Absten ◽  
Henry O. Briceño ◽  
...  
Keyword(s):  
Community Structure ◽  
Abiotic Factors ◽  
Florida Keys ◽  
Fish Parasites ◽  
Tissue Loss ◽  
Coral Tissue ◽  
Shellfish Poisoning ◽  
Florida Reef Tract ◽  
Stony Coral ◽  
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. 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.

scholarly journals 3D Photogrammetry Reveals Dynamics of Stony Coral Tissue Loss Disease (SCTLD) Lesion Progression Across a Thermal Stress Event

2020 ◽  
Vol 7 ◽  
Author(s):  
Sonora Meiling ◽  
Erinn M. Muller ◽  
Tyler B. Smith ◽  
Marilyn E. Brandt
Keyword(s):  
Thermal Stress ◽  
Disease Ecology ◽  
The United States ◽  
Tissue Loss ◽  
Coral Tissue ◽  
Critical Parameters ◽  
Bleaching Event ◽  
Stony Coral ◽  
Wide Range ◽  
Loss Rates

Stony coral tissue loss disease (SCTLD) was first observed in the United States Virgin Islands in January 2019 on a reef at Flat Cay off the island of St. Thomas. A year after its emergence, the disease had spread to several reefs around St. Thomas causing significant declines in overall coral cover. Rates of tissue loss are an important metric in the study of coral disease ecology, as they can inform many aspects of etiology such as disease susceptibility and resistance among species, and provide critical parameters for modeling the effects of disease among heterogenous reef communities. The present study quantified tissue loss rates attributed to SCTLD among six abundant reef building species (Colpophyllia natans, Montastraea cavernosa, Diploria labyrinthiformis, Pseudodiploria strigosa, Orbicella annularis, and Porites astreoides). Field-based 3D models of diseased corals, taken approximately weekly, indicated that the absolute rates of tissue loss from SCTLD slowed through time, corresponding with the accumulation of thermal stress that led to mass bleaching. Absolute tissue loss rates were comparable among species prior to the bleaching event but diverged during and remained different after the bleaching event. Proportional tissue loss rates did not vary among species or through time, but there was considerable variability among M. cavernosa colonies. SCTLD poses a significant threat to reefs across the Caribbean due to its persistence through time, wide range of susceptible coral species, and unprecedented tissue loss rates. Intervention and management efforts should be increased during and immediately following thermal stress events in order maximize resource distribution when disease prevalence is decreased.

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

Coral Reefs ◽  
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.

scholarly journals Bacterial Metabolic Potential and Micro-Eukaryotes Enriched in Stony Coral Tissue Loss Disease Lesions

2022 ◽  
Vol 8 ◽  
Author(s):  
Stephanie M. Rosales ◽  
Lindsay K. Huebner ◽  
Abigail S. Clark ◽  
Ryan McMinds ◽  
Rob R. Ruzicka ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Energy Efficient ◽  
South Florida ◽  
Tissue Loss ◽  
Coral Tissue ◽  
Rrna Gene ◽  
Nucleotide Biosynthesis ◽  
Stony Coral ◽  
Eukaryotic Community

The epizootic disease outbreak known as stony coral tissue loss disease (SCTLD) is arguably the most devastating coral disease in recorded history. SCTLD emerged off the coast of South Florida in 2014 and has since moved into the Caribbean, resulting in coral mortality rates that have changed reef structure and function. Currently, the cause of SCTLD is unknown, but there is evidence from 16S rRNA gene sequencing and bacterial culture studies that the microbial community plays a role in the progression of SCTLD lesions. In this study, we applied shotgun metagenomics to characterize the potential function of bacteria, as well as the composition of the micro-eukaryotic community, associated with SCTLD lesions. We re-examined samples that were previously analyzed using 16S rRNA gene high-throughput sequencing from four coral species: Stephanocoenia intersepta, Diploria labyrinthiformis, Dichocoenia stokesii, and Meandrina meandrites. For each species, tissue from apparently healthy (AH) corals, and unaffected tissue (DU) and lesion tissue (DL) on diseased corals, were collected from sites within the epidemic zone of SCTLD in the Florida Keys. Within the micro-eukaryotic community, the taxa most prominently enriched in DL compared to AH and DU tissue were members of Ciliophora. We also found that DL samples were relatively more abundant in less energy-efficient pathways like the pentose phosphate pathways. While less energy-efficient processes were identified, there were also relatively higher abundances of nucleotide biosynthesis and peptidoglycan maturation pathways in diseased corals compared to AH, which suggests there was more bacteria growth in diseased colonies. In addition, we generated 16 metagenome-assembled genomes (MAGs) belonging to the orders Pseudomonadales, Beggiatoales, Rhodobacterales, Rhizobiales, Rs-D84, Flavobacteriales, and Campylobacterales, and all MAGs were enriched in DL samples compared to AH samples. Across all MAGs there were antibiotic resistance genes that may have implications for the treatment of SCTLD with antibiotics. We also identified genes and pathways linked to virulence, such as nucleotide biosynthesis, succinate dehydrogenase, ureases, nickel/iron transporters, Type-1 secretion system, and metalloproteases. Some of these enzymes/pathways have been previously targeted in the treatment of other bacterial diseases and they may be of interest to mitigate SCTLD lesion progression.

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