Miami Boomed
Are Bay Fish Doomed?
Biscayne Bay and the surrounding waters border not some remote, pristine land, but one of the fastest growing urban areas in the United States.
Miami-Dade County is ranked sixth of the 20 most populous metropolitan areas located within Atlantic or Gulf coastal areas. Given recent statistics, this ranking is likely to increase. From 2000 to 2006, the population of Miami-Dade County rose by approximately 2 million residents.
In areas such as downtown Miami, where cranes and high-rise condos line the coast, the number of residents is projected to increase by 70,000 in 2030, as compared to only 20,000 in 2000, according to the Downtown Development Authority.
While expansion will undoubtedly have an economic impact, the environmental impact is undeniable and particularly dangerous for wildlife, especially fish in the bay.
"The more we build out, the more space we are losing and the more strain we are putting on Biscayne and Florida Bays," said Sara Fain, Everglades restoration program manager for the National Parks Conservation Association. "We are losing more permeable space, meaning we are losing ground that can allow water to soak into it."
RUNOFF EVERYWHERE
Paved parking lots, streets and building foundations prevent the land from absorbing residential and agricultural runoff, allowing polluted rainwater to drain directly into inland and coastal canal systems. The freshwater content and high nutrient levels generated by pollution in canals are separated from Biscayne Bay only by a series of canal locks, which are released into the bay several times a year.
"It is very important that we try to fix the problem that is going on right now, which is dirty water coming into the bay and not enough water coming into the bay," Fain said. The Miami-Dade County canal system is a 1,400-mile network used in flood prevention and freshwater flow modulation.
"What this has done is allow people to live comfortably without getting flooded out," Fain said. "The unintended consequence is that it has disrupted the sheet flows to our natural areas."
During the rainy season, South Florida waters in the past would flow naturally from Lake Okeechobee south, through the Everglades, out into Florida Bay and then into Biscayne Bay. The canal system has diverted the natural flow east, starving these water bodies of the gradual influx of fresh water that was typical of the past.
During the dry season, fresh water from the canals is withheld. When the rains return, canal water is dumped into the sea, shocking the naturally estuarine systems of Biscayne and Florida Bays.
"When we are dumping these large pulses of freshwater, we instantly turn these ecosystems into a freshwater system and the wildlife and the vegetation cannot adapt to that very well," Fain said.
DELICATE ECOSYSTEM AS CONVEYOR BELT
Jerald S. Ault, a professor of marine science and fisheries at the University of Miami's Rosenstiel School of Marine and Atmospheric Science, compares the delicate ecosystem to a conveyor belt.
"Open-water fish come in to the shallow waters to spawn, then return back out," he said. "When we have this massive influx of freshwater, the younger species are in danger."
Also in danger is the third-longest coral reef in the world, which begins in southern Biscayne Bay. These ecosystems require a delicate balance of fresh and saltwater to sustain life. A recent U.S. Geological Survey report indicated that the bay's ecosystem "shows increasing signs of distress: declines in fisheries, increased pollution and dramatic changes in near-shore vegetation."
DESTRUCTIVE FORCES
The survey cites the alteration and control of freshwater flow into the bay as one of two destructive forces.
"When you open up these canals and blow out all the water, animals become negatively adapted. Even fish cannot swim away, it is too disorienting for them," said Sarah Bellmund, an ecologist for the National Parks Service.
"For a person, it would be like taking you from Alaska at negative 60 degrees to Florida at 80 degrees," Bellmund added. "It would be a complete shock, you can become hypothermic because your body is adapted to being at a lower temperature [and] the same thing happens with the fish."
The survey also cites the urbanization of Miami-Dade County, which has led to increased storm runoff and pollutants in Biscayne Bay. The Miami River is an example a canal that filters into the bay.
Originally a natural river, it has since been dredged and polluted by the ports that line it. Formerly a dumping ground for 29 sewers in the county, the Miami River represents the highest annual freshwater input into Biscayne Bay.
Southern Biscayne Bay receives water from the Black Creek canal, which drains the South Dade Landfill, the Old South Dade Dump and the Miami-Dade Sewage Treatment Facility. Military and Mowry canals, which feed into the same region, drain the former Homestead Air Force Base and agricultural lands in South Dade.
Florida Bay, just south of Biscayne Bay, is another estuarine water body hit hard by the natural hydrocycle alteration and polluted waters. The building of Henry Flagler's railway into the Florida Keys, coupled with the extension of U.S. 1, blocked the fresh and salt water exchange between Florida Bay and the Atlantic Ocean.
With salinity levels increasing in the bay each year, the C-111 drainage canal has even further reduced the amount of fresh water reaching Florida Bay. In the 1980s, an algae bloom threatened to make the bay waters forever uninhabitable for marine life.
"People refer to that as the time when Florida Bay died," Fain said. "When you have this green substance over the top of Florida Bay, you are preventing photosynthesis."
"We all know that our vegetation needs light from the sun in order to survive," she continued. "When you have this algae covering the surface and not allowing the light to penetrate to the base of the bay floor, you are going to have this ecosystem suffer and that is exactly what is happening."
ANOTHER POSSIBLE DEAD ZONE
In 2005, another algae bloom surfaced in the waters of northern Florida Bay, threatening to turn 100 square miles of it into a dead zone. Though scientists are still studying who or what may have been responsible, there are three possible culprits.
The first is the C-111 canal, which services most of the agricultural community in the Homestead/Redland area and empties into Florida Bay.
"It appears that the C-111 canal, when it dumps fresh water out is also carrying nitrogen and phosphorous, and these are two nutrients that do not exist naturally in Florida Bay," Fain said. "When you have these nutrients, it causes an algae to build up over the surface."
When the canal is emptied, it releases runoff from farms that use nutrient-rich pesticides. The pesticides provide phytoplankton, which rests on the surface of the bay waters, with too much food. In turn, the phytoplankton respond by creating more waste, cutting off oxygen flow to bottom dwellers and essentially suffocating them.
The canal would have been emptied in preparation for the active hurricane season in 2005, which is another possible cause for the algae bloom.
"That was the year that we had three hurricanes come through that area," said Peter Frezza, a biologist with Audubon of Florida's Tavernier Science Center. "The storm surge associated with those hurricanes certainly played a role in exacerbating the bloom's size and intensity. We had redistribution of sediment, seagrass die off and more nutrients releasing into the water column."
Though Frezza acknowledges that the hurricanes may have added to the bloom, he places the primary blame elsewhere.
Road Construction and Destruction
The 18-mile stretch is a project of the Florida Department of Transportation (FDOT) that will expand the stretch of U.S. 1 between Key Largo and Florida City. The expansion will include the replacement of the C-111 canal bridge, the replacement of the Jewfish Creek Bridge, the removal of the Lake Surprise Causeway and the expansion of the highway into a two-lane safety project with one southbound lane, one northbound lane and a divided median and outside shoulders.
While the 140-foot C-111 spreader canal bridge is designed to help restore original tidal flows from the Everglades into the Florida Keys, the rest of the project is under intense scrutiny by environmental organizations.
"Most likely, it was a combination of factors that kicked off the bloom in the vicinity of the 18-mile stretch in 2005," Frezza said. "However, we are almost three years away from that hurricane season and we still have a phytoplankton bloom in that area. If we would not have had this road construction in place and [still] had these hurricanes, I do not think we would have had these blooms."
The estimated area of permanent impact that the project will have is 85.6 acres. Though the FDOT is required to replace any land that it destroys while building the road, including acres of mangroves, there may be an underlying and irreversible impact.
"The problem with the project is when you cut down 100 acres of mangroves, chop it up, grind it up and essentially put it into the water that is just like giving fertilizer to an algal bloom; and that is exactly what we saw," Frezza said.
Though the FDOT said that the construction materials could not have produced enough excess nitrogen and phosphorous to account for the bloom, the mangroves that were mulched may have done it for them.
In an effort to stabilize the soil, the FDOT combined the mulched mangrove material with concrete and injected it into bore holes to prevent it from spreading to surrounding waters. The effort, Frezza said, is not enough.
"What they did was drill a hole into the limestone bedrock. Now, they did not drill holes everywhere," he said. "As far as I can see they only injected this slag material into certain holes and pumped that full of cement."
"That is only a tiny portion of the entire bedrock system, and it is a very porous limestone," he continued. "On a daily basis, water is going to get moved through that system and flush all of those nutrients into the water. By no means was it an end-all solution to the problem. It probably did not do anything to help, to tell you the truth."
The bloom in northern Florida Bay is still present and shows no sign of dissipating. In fact, the bloom has migrated even further into southern Biscayne Bay.
"The bloom seems like a permanent presence in this area," Frezza said. "It is just not going away. In terms of how it has impacted wildlife, we spoke with many fishing guides that used to use this area pretty heavily, and essentially the fish are just gone."
Though construction associated with the 18-mile stretch is not slated for completion until 2009, efforts are being made to restore the natural freshwater flow into the Everglades, and Florida and Biscayne Bays in turn. The Comprehensive Everglades Restoration Project (CERP), a 30-year plan passed in 2000, attempts to address the quality, quantity, timing and distribution of water into Miami-Dade County.
"The CERP is the largest ecological restoration plan that we have ever taken on in the world," Fain said. "All eyes are on us and we need to make sure that we do this in the right way."
