By Kailey Aiken, FloridaBulldog.org
Coral reefs across the east coast of Florida, once teeming with sea life and bursts of color, have become a shadow of what they once were, deteriorated into barren, monochrome plains.
The causes are many, scientists say. Extreme heat waves, disease, bleaching, and coastal overdevelopment have taken a huge toll on the Florida Coral Reef Tract, which stretches from the St. Lucie inlet in Martin County to beyond the Dry Tortugas. In 1975, live coral coverage was 40-60% of reefs. Now, it is about 3-7%.
The tract is the only near-shore reef in the continental U.S., home to 6,000 marine species, including a variety of fish, green sea turtles, sharks, and barracuda. It attracts six million residents and more than 38 million tourists annually, according to the Treasure Coast Regional Planning Council and contributes more than $6 billion in tourism dollars to Florida’s economy, according to the Florida Department of Environmental Protection (DEP).
Despite massive die-offs over the past 50 years, a stretch of reef off Broward County, including areas surrounding Port Everglades, remains one of the last living sections of Florida’s Coral Reef.
For a couple of decades the U.S. Army Corps of Engineers (USACE) has been developing a project to deepen and widen Port Everglades to accommodate today’s larger container ships and tankers. It’s South Florida’s latest high-stakes contest in the struggle between the forces of commerce and the needs of the natural environment.
Today, a smaller sand bypass project which began last October is ongoing. Full-on dredging is expected to start in 2028.
The biggest concern is to avoid a repeat, or worse, of what happened a decade ago when the Army Corps dredged PortMiami to deepen its channel.
“They didn’t plan for impacts to the area’s reefs from the sediment plumes that were kicked up and ended up falling on and smothering the reef for what we now know is over 270 acres around the port,” said Miami Waterkeeper CEO Rachel Silverstein.
NOAA Researchers concluded that sediment accumulation from the project smothered millions of corals, with impacts likely exceeding initial estimates and extending 1,100 meters north and 600 meters south.
If the corps goes through with its Port Everglades Harbor Navigation Improvements Project it could push an already fragile reef system past its limits, environmentalists warn. As it stands, the USACE plans to deepen and widen the Outer Entrance Channel of the port from the existing 42-foot depth and 500-foot channel width to a 55-foot depth and 800-foot width.
Coral v Cargo
A 2025 study published in Science found that two of Florida’s most ecologically important reef-building coral species, Staghorn coral (Acropora cervicornis) and Elkhorn coral (Acropora palmata), are now functionally extinct following the record-setting marine heat wave of 2023. In some regions, temperatures over 100℉ caused 98-100% coral mortality rates. Researchers say the reefs have already lost their ability to recover naturally, and scientists warn that additional stressors, like a dredging project of this scale, could further destabilize one of the last remaining coral systems along Florida’s coast.
According to a statement from Port Everglades, the project is necessary because today’s larger cargo and petroleum ships are unable to enter the port fully loaded due to restricted water depth. Cargo ships get stuck waiting for hours for cruise ships to leave the port and larger oil tankers can only enter the port at high tide, creating inefficient processes that increase the carbon footprint of the ships.
The estimated cost of the project shot up to $1.35 billion in August 2023, with $614 million planned to be spent on environmental mitigation activities. USACE states the funds for the project will come from Port Everglades revenue generated through port user fees, federal appropriations, and state grants. No local property taxes will be used, because Port Everglades is a self-funded enterprise of Broward County government.
The USACE Chief of Engineers Report in 2015 includes mitigation measures, such as transplanting nursery-propagated corals over existing reef areas and new artificial reefs and relocating existing corals that may be affected within the project’s footprint. The report also calls for building environmentally friendly bulkheads throughout the channels to reduce impacts. Recently, the port completed part of its mitigation plan to restore seagrasses and mangroves in West Lake Park, located south of Port Everglades.
In the past few years, the project’s environmental considerations have expanded in response to failures from projects like PortMiami’s dredging in 2013-2015. Additional environmental studies have expanded the project’s area of coral reef and direct impact from 14.62 acres to 26.43 acres, and after reviewing PortMiami’s sedimentation analysis, 123.72 acres were added to the project’s protected area.
Citing ongoing litigation, public affairs officers for USACE and the Department of Justice declined to comment on behalf of the Jacksonville District regarding the Port Everglades project’s goals and environmental safeguards.
“We have one shot to get this right, and we agree that the added science-based environmental considerations and mitigation activities will ensure that our unique natural environment and wildlife are protected during construction so they can continue to thrive,” the statement from Port Everglades reads.
But is this enough? Miami Waterkeeper’s Silverstein doesn’t think so.
REEF LESSONS FROM PORTMIAMI
“I think it all goes back to the PortMiami dredging and learning lessons from what is at stake if these projects aren’t handled properly, and how much damage they can do.”
Following the 2013-2015 PortMiami dredging project, Miami Waterkeeper and three government agencies provided evidence from direct underwater surveys, measured sediment depth on the reef, and satellite imagery that damage from the dredging was widespread and severe, yet the final report on the project from the environmental monitoring company claimed that only six corals were killed during dredging.
Miami Waterkeeper and co-plaintiffs took legal action against USACE, and in 2023, the National Oceanic and Atmospheric Administration (NOAA) published an assessment that found clear evidence linking dredging-related sediment to widespread reef damage. The study documented significantly elevated sediment levels near the channel (dredging site), well above thresholds known to cause coral mortality, and found that at least 278 acres of reef were impacted, compared to the Environmental Impact Statement (EIS) prediction of about 3.3 acres of reef damage.
But the environmental damage was not the only issue to emerge from the project. Questions about project oversight and transparency followed as well
Tracey Jordan Sellers, an Army Corps biologist pleaded guilty in July 2019 to making a false official statement about “engaging in outside employment with a consulting company despite being part of a team that oversaw that company’s work for the Army Corps in relation to large dredging projects in South Florida.” She was sentenced to time served and placed on supervised release for two years following her arrest two months earlier.
In addition to providing internal government documents about a USACE dredging project to the unnamed consulting company as early as November 2014, court records say she was paid $9,000 by the company for consulting work over a six-month period in 2018. “At no time did Sellers seek or obtain authorization from USACE,” says a joint factual statement she signed.
Sellers also provided a photo to the Department of Justice that it later used in court. The photo allegedly showed healthy threatened staghorn corals near the PortMiami dredging site, post-dredging. Miami Waterkeeper, however, discovered the photo was actually taken in 1992 in the Virgin Islands. Sellers claimed the photo mishap was an inadvertent mistake.
Two weeks after the alleged mistake, Sellers produced another false photo at a public meeting regarding plans to dredge Port Everglades. The photo showed a staghorn coral, labeled as taken post-dredging at PortMiami. Yet, Miami Waterkeeper found that it was captured prior to dredging. The Corps later retracted the photo, according to Miami Waterkeeper.
As the Port Everglades dredging project advances, environmental advocates worry USACE will not be fully transparent about ecological effects and mitigation measures. USACE has still yet to finalize new environmental reviews for the Port Everglades dredging project, according to Silverstein.
“From what we’ve seen so far, [USACE] is being more honest, although we still don’t think that they’ve done all of the modeling and scientific actions correctly,” Silverstein said.
Already, millions of corals are expected to be impacted by the Port Everglades dredge project, a level of damage that Silverstein says cannot be adequately mitigated.
“We can (move and replant) tens of thousands of corals a year, but not millions,” she said. According to Silverstein, the state has said that even with full capacity field teams operating 24/7, it would still take 10 years just to move the corals out of the way that USACE is proposing to move.
THE GREATEST THREAT TO CORAL
The most damaging impact on corals is not the dredging itself, but the sediment it releases. These plumes of sediment can travel up to about 10 km before settling, meaning its impacts are not confined to the channel.
“Corals need clear water and low levels of nutrients and sediment to survive,” said Kevin Beach, a marine botanist and ecophysiologist at the University of Tampa.
Even in low capacities, sediment can block sunlight from reaching corals, which they need to photosynthesize to convert light energy into food. When higher concentrations of sediment settle, it can smother the corals, killing them. This disrupts the entire reef ecosystem, and in turn, the food web breaks down, Beach said.
Reefs support nursery habitats for a variety of fish and invertebrates, which cannot gain the ecological benefits a reef provides if it is unable to function properly. A new food web and ecosystem will replace the reef, most likely seaweed, but it is unlikely the new system would be as ecologically advantageous as a coral reef.
The sediment that would be dispersed from dredging at Port Everglades isn’t just made up of rocks and shells. A 2023 study assessing the ecological risk of heavy metal sediment contamination from Port Everglades found 14 different heavy metals in Port Everglades sediment including arsenic (As), lead (Pb), mercury (Hg), copper (Cu), and zinc (Zn). Results of the study indicate a moderate to high overall ecological risk from remobilized sediment due to metal contamination.
Contamination makes sediment even more deadly to corals, said Beach, even if corals are only exposed to it for a short amount of time. In addition to corals, the contaminated sediment can be absorbed by other small organisms, accumulate, and cause toxic effects that would enter the food chain and impact entire ecosystems.
There is no way to dredge without producing sediment spillage, according to a model from the Army Corps‘ most recent Biological Assessment for the Port Everglades Expansion Dredging. The model estimates 15% of fine sediment resulting from dredging will enter the water column and eventually settle. Silt and clay (fine sediment) which is the most harmful to coral systems, will be dispersed according to the study, further perpetuating ecological risk.
“There are still millions of corals and 278 acres of reef that were never fixed in Miami,” Silverstein said. “It’s really hard to trust that they’re going to do things well the next time, because they have still not kept their promises to the people of Florida.”
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