Quantifying impacts of stony coral tissue loss disease on corals in Southeast Florida through surveys and 3D photogrammetry

Abstract

Since 2014, stony coral tissue loss disease (SCTLD) has contributed to substantial declines of reef-building corals in Florida. The emergence of this disease, which impacts over 20 scleractinian coral species, has generated a need for widespread reef monitoring and the implementation of novel survey and disease mitigation strategies. This study paired SCTLD prevalence assessments with colony-level monitoring to help improve understanding of disease dynamics on both individual coral colonies and at reef-wide scales. Benthic surveys were conducted throughout the northern Florida Reef Tract to monitor the presence/absence of disease, disease prevalence, and coral species affected by SCTLD. Observed SCTLD prevalence was lower in Jupiter and Palm Beach than in Lauderdale-by-the-Sea or St. Lucie Reef, but there were no significant changes in prevalence over time. To assess colony-level impacts of the disease, we optimized a low-cost, rapid 3D photogrammetry technique to fate-track infected Montastraea cavernosa coral colonies over four time points spanning nearly four months. Total colony area and healthy tissue area on fate-tracked colonies decreased significantly over time. However disease lesion area did not decrease over time and was not correlated with total colony area. Taken together these results suggest that targeted intervention efforts on larger colonies may maximize preservation of coral cover. Traditional coral surveys combined with 3D photogrammetry can provide greater insights into the spatiotemporal dynamics and impacts of coral diseases on individual colonies and coral communities than surveys or visual estimates of disease progression alone.

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

“…SCTLD is known to have a rapid progression rate within colonies (Cunning et al, 2019;Gintert et al, 2019), suggesting that more frequent monitoring efforts are warranted for finescale assessment of disease impacts at the individual level. Photogrammetric methods have been successfully applied to SCTLD fate-tracking studies on weekly or monthly scales (Meiling et al, 2020;Combs et al, 2021;Shilling et al, 2021), yet similar techniques remain equally informative over larger areas and annual temporal scales, capturing community-level impacts of SCTLD and other disturbance events as presented here.…”

“…Photomosaics have been gaining traction in ecological studies over the past decade (Van Rein et al, 2011;Casella et al, 2016;Wood et al, 2016;Gintert et al, 2018;Carter et al, 2019), including with fate-tracking of SCTLD-infected colonies (Meiling et al, 2020;Combs et al, 2021;Shilling et al, 2021). In approximately 30 min of diving, and subsequent processing time that is dependent on computer resources, an area of roughly 10 m by 10 m (100 m 2 ) can be surveyed, resulting in a permanent record in the form of a snapshot of any reef area, often with resolution high enough to identify individual polyps of certain species.…”

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

“…Of our study coral species, all are categorized as highly susceptible to SCTLD except SINT. SINT is considered moderately susceptible, and the prevalence of lesions and mortality in SINT colonies are usually lower than the other three study species (Case Definition: Stony Coral Tissue Loss Disease (SCTLD), 2018; Sharp et al, 2020;Combs et al, 2021). We know from our previous study (Rosales et al, 2020) that there were more bacterial taxa enriched in DL tissue of SINT compared to the other corals.…”

Differences in the progression rate of SCTLD in Pseudodiploria strigosa are related to colony size and morphology

“…Disease progression differs between species, or colonies of the same species, due to various factors such as morphology, colony condition, duration of infection or geographic location (Walton et al, 2018;Aeby et al, 2019;Landsberg et al, 2020;Combs et al, 2021;Eaton et al, 2021). For example, foliose and massive species can easily accumulate sediment and thus a greater load of pathogens (Jones et al, 2019).…”

“…This approach, however, does not consider the three-dimensional structure of corals. Photogrammetry and 3D modeling have greater accuracy when measuring approximately semi-spherical objects with an irregular surface as previous works have shown (Meiling et al, 2020;Combs et al, 2021). To gain insight into the colony-level dynamics of SCTLD, we used a simplified photogrammetry approach to quantify SCTLD-related tissue loss rates for 20 colonies of P. strigosa over a period of six months on Limones reef, in the northern Mexican Caribbean.…”