Port of Miami Corals Remarkably Persistent

The Port of Miami is a bustling waterway with large cruise and cargo ships, ferries, fishing vessels, and recreational boats. As it turns out, this waterway is also home to a resilient coral community.

According to a new study in Nature’s Scientific Reports by researchers with NOAA’s Atlantic Oceanographic and Meteorological Laboratory (AOML), the University of Miami Cooperative Institute of Marine and Atmospheric Studies (CIMAS) and other partners, the corals within this urbanized environment have demonstrated great resilience against unfavorable conditions, such as poor water quality, excess nutrients, high temperatures, high salinity, and low pH levels. These corals have built strong and diverse communities on man-made substrates, such as seawalls and discarded objects.

Square color image of a yellow brain coral (Diploria labyrinthiformis) beneath the surface of the water centered and viewed from above. — A brain coral (Diploria labyrinthiformis) living on an extremely shallow (~1 ft) shoreline in the Port of Miami.
_{Photo Credit: Colin Foord/Coral Morphologic}

“The Port of Miami is quite different from the places where we normally work. Everything is artificial, engineered, and constructed,” said Ian Enochs, Research Ecologist at AOML and lead author of the new study. “Somehow, nature has found a way to persist even in the most unnatural of environments”.

Scientists visited the Port of Miami over a three-year period beginning in 2018 to monitor environmental conditions and measure coral community dynamics. The research team used a suite of state-of-the-art instruments that included sub-surface autonomous samplers designed at CIMAS/AOML and coral photomosaics.

The samplers monitored the temperature, pH, oxygen, carbonate chemistry, light, and tidal flow at three reef sites. Photomosaics consisting of thousands of high resolution underwater photos stitched together created detailed maps of these habitats to characterize their coral cover, spread, and species diversity.

Through a collaboration with Coral Morphologic’s Coral City Camera, live underwater cameras were placed at an urban coral nursery site, which helped scientists to identify unique fish species visiting the site, including the endangered smalltooth sawfish.

Square color image of a purple fan coral (Gorgonia ventalina) partially submerged in seawater as a small wave breaks over it. In the background is the Miami skyline with white moderate cloud cover over blue sky. A small wave is breaking through the fan coral and rocky substrate with algae is visible in the bottom third of the frame. Image used to highlight the resilience of these species in an urban and largely disrupted ecosystem. — A purple fan coral (Gorgonia ventalina) partially submerged in seawater with the Miami skyline in the background.
_{Photo Credit: Colin Foord/Coral Morphologic}

Enochs added: “Studying these ‘urban’ corals is important because they are rare and threatened, and also because they demonstrate surprising resilience that can teach us about the future of coral reef ecosystems today. The fact that these rare, valuable species have the ability to persist in the waterways of Miami offers us a glimpse into a tenuous coexistence and provides a ray of hope that some of these species may be able to survive in a landscape increasingly defined by human influence.”

A knobby brain coral species demonstrating resilience attached at the waterline to a man-made substrate in the Port of Miami — Knobby brain coral (*Pseudodiplora clivosa*) colony in the intertidal zone of a man-made shoreline in the Port of Miami.
_{Photo Credit: Colin Foord/Coral Morphologic}

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This research was funded by NOAA OAR’s ‘Omics Initiative. Additional support was provided by NOAA’s Ocean Acidification Program and Coral Reef Conservation Program. The results of this study were only possible through a close collaboration among NOAA AOML, UM CIMAS, and Coral Morphologic, especially the dedicated field efforts of numerous scuba divers and laboratory technicians.

All images produced by Colin Foord of Coral Morphologic

Citation:

Ian C. Enochs, Michael S. Studivan, Graham Kolodziej, Colin Foord , Isabelle Basden, Albert Boyd, Nathan Formel, Amanda Kirkland, Ewelina Rubin, Mike Jankulak, Ian Smith, Christopher R. Kelble & Derek P. Manzello. Coral persistence despite marginal conditions in the Port of Miami. Sci Rep 13, 6759 (2023). https://doi.org/10.1038/s41598-023-33467-7

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