Unveiling the underwater impact: Miami’s coral reefs destroyed

A graphic showing fish swimming in a coral reef. Photo credit: Roberta Macedo

As researchers and scientists rush to salvage what is left of the world’s coral reefs, a recent study by the National Oceanic and Atmospheric Administration (NOAA) revealed the drastic consequences of a dredging project right here in Miami.

The project, conducted by the Port of Miami from 2013-2015, has severely impacted over 278 acres of coral reef along the Port of Miami Entrance Channel.

The NOAA report, released on Aug. 29, revealed that moderate to severe coral impacts extended approximately 3,600 meters north of the channel and 2000 feet south of the channel.

Dial, Cordy and Associates Inc., an environmental consulting firm, was tasked with monitoring the coral reefs adjacent to the Port of Miami before and during the project. University of Miami Senior Research Associate II, Martine D’Alessandro was involved in this monitoring effort.

“[Dredging] is essentially just removing the sediment and digging deeper. And what that does is it creates this plume,” D’Alessandro said. “[Dredging] could cause them to be buried under the sediment, which is damaging and stressful to the coral and, if it’s covered with sediment long enough, it could kill them,” said D’Alessandro.

According to the study, sedimentation covered an average of 42% at assessment locations, compared to 7% at reference sites.

The dredging project aimed to deepen the port channel for larger ships to pass through the Panama Canal.

The study by NOAA was prompted by concerns raised by various partner, regulatory and action agencies after satellite images depicted sediment plumes over areas of coral reef during the dredging.

D’Alessandro, who participated in coral tagging and monitoring, described the process of documenting its effects on the coral reefs.

“We would get a baseline so before the dredging even started, we could know how these ecosystems, how the seagrass and how the corals look to then know the impact of dredging on these animals and on the seagrass,” D’Alessandro said.

The report’s findings underscore the urgency of addressing the significant consequences of the Port Miami dredging project on Miami’s coral reef habitat and the necessity of establishing an environmental baseline for future projects in the area.

At the University of Miami, D’Alessandro works at The Lirman lab which focuses on coral propagation and reef restoration in Florida and the Caribbean through in-water and offshore nurseries.

“We can continuously go to these nurseries, collect corals, and then we plant them onto reefs with the hope that adding more coral to that site will attract more fish and jump-start the ecosystem that has been steadily declining over the last several decades,” Alessandro said about the Lirman lab.

Healthy reefs are not only critical to maintaining biodiversity, they also provide ecosystem services including as a recreational attraction and for coastal protection.

“When waves are crashing over the coral, it reduces the impact of waves against the shoreline. So that protects our coastline and reduces the amount of erosion,” D’Alessandro said.

D’Alessandro explained that dredging is not the only threat to healthy reefs.

“Climate change is a huge stressor for corals. It’s causing oceans to warm and become more acidic, and it’s changing the actual water chemistry.”

As the topic of coral reef preservation grows among students, they are increasingly eager to contribute to safeguarding these ecosystems.

“My goal, along with many of my professors and fellow classmates, is to make sure that we don’t lose these ecosystems and their tremendous amount of biodiversity,” sophomore and marine biology major John Yudt said.

The NOAA report has prompted a reevaluation of current and upcoming dredging projects, including the next expansion of the Port of Miami, which is currently in the planning stage.

Officials have not yet estimated the potential impact on corals for this project, which will have a significantly larger footprint than the dredging that occurred from 2013-2015.

Meanwhile, the Port Everglades’ dredging project, further along in its progress, anticipates a direct impact on approximately 449,000 corals, with extensive coral replanting planned along South Florida’s coast.

The NOAA report concluded with a stark warning: “Future port expansions cannot further contribute to the downward trajectory of the condition of Florida’s Coral Reef and must be in the public interest.” It called for a thorough examination of lessons learned to prevent similar damage in the future.