ABSTRACT Marine disturbance events are often influenced by the environment, making it difficult to parse abiotic and biotic drivers. This is particularly true of disease infection and spread in coral reef environments, where pathogens are challenging to isolate and transmission may occur through the movement of water masses. Here we assess mesoscale conditions related to coral community disturbance from 2001 to 2023 on isolated reefs, using the Flower Garden Banks (FGB) as a case study. During the study period, relative to other western Atlantic reefs, this high latitude coral reef system experienced relatively few disturbance events (2 disease events, 1 hypoxia event, and 6 thermal stress events) and lower coral mortality, allowing it to maintain remarkably high coral cover. We explore mesoscale oceanographic features during the study period, predominantly the northwest extension of the Loop Current (LC), to understand its connection to disturbance events at FGB. LC position was linked to disease and hypoxia events, but not consistently to thermal stress events. Low LC extension, as seen in 2016, may have facilitated the transport of freshwater river output across the GoM resulting in a hypoxia event at FGB. To examine the influence of circulation and upstream connectivity to disease at FGB, we used a biophysical Lagrangian particle tracking model to backtrack virtual disease agents from FGB over 23 years of hydrodynamic forcing. Our results highlight a link between observed coral disease incidence at FGB, seasonality, and a 30‐day connectivity window to reefs of the Mesoamerican Reef. Operational biophysical and oceanographic models can provide a valuable tool for reef disturbance prediction and monitoring. These models are likely to become increasingly relevant as climate change alters the behavior of ocean circulation, with implications for reef connectivity, disease dispersal, freshwater inputs, and the management of these and other isolated coral reefs.
Carpenter et al. (Fri,) studied this question.