Join as we follow the Nitrogen Trail...

How to Navigate the
Nitrogen Trail

By clicking on the dots, you can review the issues facing Florida’s clean water future in that location. Each dot contains a description of an issue and the science-based solutions that COAST is recommending to save Florida's clean water future.

Pensacola Bay: Aerial photography shows that 95% of seagrass has been lost in in Pensacola Bay since 1950. Thousands of nearby homes are on septic tanks whose discharge contributes to algae and phytoplankton blooms shading out and eventually killing the seagrasses.

Florida’s Springs: Intensive studies of springsheds such as Wakulla Springs have shown that septic systems have become a major, and in many cases the major, source of nitrogen pollution. For Example, a recent study by FDEP showed that 51% of the nitrogen loading causing algae blooms in Wakulla Springs is from septic systems. Similar studies in Silver Springs have shown that Septic systems are contributing 40% of the nitrogen loads.

For More Information: Please see the link for the following video sponsored by the Chamber of Commerce Foundation on the health of the springs.

Tampa & Sarasota: Dr. Lapointe’s mentor John Ryther’s research in the 1950’s and 1960’s led officials in Tampa & Sarasota to pass the Grizzle Figg Act requiring Advanced Wastewater Treatment (AWT) that has dramatically reduced the negative impacts associated with excess sewage nitrogen. Seagrasses have grown back and are now at the same level as they were during the 1950’s.

For More Information: Coast’s Advisory Board member Dr. David Tomasko’s research paper has shown that the areas affected by the Grizzle Figg Act are now in recovery. Read more here:

Lee County: Low nitrogen to phosphorus ratios in Lee County result in the growth of harmful algae blooms commonly referred to as “red tide”. Dr. Lapointe’s recent research has linked these red tide events with heavy runoff and excessive nitrogen loading from sewage and fertilizers.

Solution: Replicate the policy changes implemented in Sarasota Bay and Tampa Bay to remove nitrogen from wastewater to reduce the severity of harmful algal blooms.

Kissimmee Basin: From 2013 to 2017, the Kissimmee Basin watersheds north of Lake Okeechobee contributed 89% of the total nitrogen loading into the Lake. Dumping nitrogen- laden water from booming population centers in central Florida into Lake Okeechobee has contributed substantially to toxic algae blooms in Lake Okeechobee and the Caloosahatchee and St. Lucie estuaries. Attempting to restore these interconnected ecosystems by simply sending this nitrogen-laden water to a reservoir south of the Lake only delays critically needed restoration - and at a tremendous cost to taxpayers.

Solution: Restore state and federal funding for water quality monitoring (followed by COAST's compilation and analysis of the resulting data) so that our state can make future decisions based on sound science. Fund septic-to-sewer conversions to remove sewage nitrogen at its source.Change the law to require that all agricultural operations utilize Best Management Practices to reduce nitrogen loading into the Kissimmee watershed that ends up in Lake Okeechobee.

Caloosahatchee: Nutrient enriched water from Lake Okeechobee flows down the Caloosahatchee, Peace, and Shark Rivers during each rainy season. Combining high water temperatures with nutrient rich water is a recipe for the harmful algae blooms that harm seagrasses, coral reef, and the marine wildlife that depend on them.

Florida Bay: The Pew Institute has identified Florida Bay as a “dead zone”, the result of too much nitrogen pollution. The National Academy of Sciences has confirmed that there is very little peer-reviewed science to support the “hypersalinity” hypothesis which asserts that decreased flow of freshwater has been the root cause of seagrass loss in Florida Bay. Although high levels of salinity and increased temperatures are secondary factors that lead to seagrass stress, there is a substantial body of data showing that reduced light and low oxygen levels (caused by increased growth of harmful algae blooms as a result of nitrogen rich waters) are the primary causes of seagrass loss.

Solution: Direct all available resources towards the improved treatment and storage of polluted water at the source and moderate the flow of nitrogen-rich freshwater into Florida Bay.

Everglades: Freshwater once flowed south from Lake Okeechobee through the Everglades, naturally filtering and cleaning the water. Rapid development in South Florida has forever altered these historic flow patterns. In order to manage this crisis, the State of Florida is considering the implementation of ineffective and financially irresponsible plans to store polluted freshwater south of Lake Okeechobee and then dump it into Florida Bay. This approach will only lead to the same outcome as it did during previous periods of heavy freshwater discharge - blue-green algae blooms, a dead zone in Florida Bay, and a die-off of downstream coral reefs.

Everglades Solution: Direct the federal, state, and local financial resources necessary to store and treat water north of the Lake (e.g. deep wells). Implement existing plans to provide additional storage at C-44 and C-43 reservoirs.

Additional Information: Please see the following video about Algae Blooms in Florida:

Florida Keys: Dr. Lapointe recently completed a 30-year study that shows how increased coral bleaching and diseases at Looe Key is directly correlated with increased freshwater flows and nitrogen loading coming from the Everglades. High nitrogen levels combined with relatively low phosphorus in the water at Looe Key leads to phosphorus starvation in the corals and metabolic stress.

Solution: Reduce the flow of nitrogen-rich freshwater into Florida Bay and the Florida Keys by enhancing the storage and treatment of the water at its source. It is imperative that historical data linking freshwater discharges to coral reef collapse be used to dismantle the flawed “hypersalinity” hypothesis.

For More Information: Please see the following video about what is being done to protect water quality in the Florida Keys:

Coral Reef in the Florida Keys: COAST’s Executive Director Dr. Brian Lapointe’s paper “Nitrogen enrichment, altered stoichiometry, and coral reef decline at Looe Key, Florida Keys, USA: A three-decade study” was recently published in the journal Marine Biology. The results provide compelling evidence that the nitrogen pollution from the Florida Keys and the greater Everglades ecosystem caused by humans is the primary driver of the alarming coral reef death at Looe Key. These findings refute the false belief that warming temperatures or elevated salinity are the primary causes of recent coral reef death. Between 1991 and 1995 increased freshwater deliveries aimed to reduce salinity in Florida Bay resulted in expansive harmful cyanobacterial blooms and significant coral reef death in the Florida Keys National Marine Sanctuary. Stormwater discharges from urbanized areas of the Florida Keys and the Everglades basin (which extends north to Orlando) have very high Nitrogen to Phosphorus ratios (up to 260:1). This paper correlates the decades-long practice of sending this deadly nitrogen-laden water south with the collapse of our phosphorus starved coral reefs. There are interest groups that want to continue sending this pollution south to Florida Bay- one of COAST’s top priorities is is to use Dr. Lapointe’s science to end this devastating practice.

Solution: Policymakers and resource managers must reduce the amount of nitrogen-laden freshwater that is being sent south through the Everglades and on to Florida’s coral reefs. Fortunately, local land-based contributions of nitrogen are being mitigated through the completion of centralized advanced wastewater treatment throughout the Florida Keys. This includes the deep well injection of treated wastewater at Cudjoe Regional which has been constructed partially as a result of COAST’s science. The future success of the Comprehensive Everglades Restoration Plan will require action based on Dr. Lapointe’s findings related to the hydrological and nutrient linkages between the Everglades, Florida Bay and the Florida Keys.

For More Information: Please read the Full Study Here: include the link to full paper and have the box read “Dr. Lapointe’s 30 Year Looe Key Study”

Indian River Lagoon (IRL): Dr. Lapointe’s state-of-the-art research methods have proven that human wastewater has become the major source of nitrogen pollution supporting harmful algae blooms in the IRL. Nitrogen pollution and bacteria from septic systems can cause algal blooms to double in size in just one day throughout the IRL (as well as other urban settings in Florida.)

Solution: Build upon initiatives like Brevard County’s collection of a half-cent in sales tax to clean up the IRL. This initiative is projected to raise $486 million over the next ten years. COAST also recommends the development of a wastewater master plan for the IRL containing similar initiatives aimed at lowering levels of total nitrogen from sewage.

For more information: Read Dr. Lapointe’s 2015 Research Study on the sources of pollution in the Indian River Lagoon:

Please also see the following video about the IRL:

Lake Okeechobee Discharges: The rolling averages from the SFWMD indicate that 50% of nitrogen pollution loads from Lake Okeechobee head down the Caloosahatchee River, 30% is sent down the St. Lucie River, and 20% of the load is sent south into the waterbodies south of the Lake(SFWMD), primarily to the Shark Slough/River. Increasing water temperatures and rising nitrogen levels in Florida's waters is a recipe for the harmful algae blooms that increasingly devastate seagrasses, coral reefs, and the wildlife that depend on them.

Solution: The State of Florida must designate Lake Okeechobee as legally “impaired” for nitrogen as it has already has been designated as impaired for phosphorus. Future management can then focus on the reduction of nitrogen entering Lake Okeechobee from the north. This management approach, in turn, will reduce the amount of blue-green algae that flows from the Lake (merging with local sewage-laden waters) creating toxic conditions in urban settings.

For Additional Information: Please see Dr. Lapointe’s following video about the polluted water entering Lake Okeechobee:

Miami: Dr. Lapointe’s research on invasive green tides on coral reefs in SE Florida led to legislation to phase out six sewage outfalls between Miami Dade County and Palm Beach County.

Solution: Accelerate the phase-out on ocean outfalls. Promote the use of advanced waste treatment, reuse, and deep-well injection.

Additional Information: Please see a link to the following paper that led to the Florida Legislature phasing out ocean outfalls:

St Lucie Estuary: Dr. Lapointe’s research on septic system pollution in the St. Lucie estuary in 2017 provided compelling evidence that traced the nitrogen trail from septic drain fields through shallow groundwaters and into the blue-green algae blooms in the estuary. The study used state-of-the art source tracking methods involving stable nitrogen isotopes and sucralose (artificial sweetener) to identify that it was indeed human waste from septic systems causing the nitrogen enrichment in the estuary. Unfortunately, environmental advocacy groups have oversimplified this problem as being caused solely by Lake Okeechobee discharges. In reality, from 2013-2017 71% of total nitrogen loading was coming from local basin sources including septic systems. The overwhelming importance of the local basin inputs was clearly evident in late May 2018 following an extreme rainfall event when the salinity in the St. Lucie estuary fell to 0 and fecal coliform contamination caused health advisories to be posted throughout the estuary prior to any Lake Okeechobee discharges (that began on June 1 of 2018.)

Solution: It is paramount that local communities take steps to convert problematic septic systems to advanced sewer systems that provide nutrient removal. For example, following Dr. Lapointe’s paper in 2017, Martin County has begun the process of converting septic to sewer in the study areas including Old Palm City and Golden Gate Estates.

For More Information: The following press release has received the most public interest ever in the history of press releases from Florida Atlantic University:

Please also see Dr. Lapointe’s paper on nutrient sources:

Please also see the following video about the St. Lucie Estuary:

Sanibel Island: Low nitrogen to phosphorus ratios in Lee County result in the growth of harmful algae blooms that include both toxic red tides and red drift algae blooms (seaweeds). Dr. Lapointe’s recent research has linked these harmful algal blooms with heavy runoff and excessive nitrogen loading from sewage, fertilizers, and other sources.

Solution: Begin septic to sewer conversion programs and begin the removal of the over 60,000 septic systems located in Lee County. Replicate the policy changes implemented in Sarasota Bay and Tampa Bay to remove nitrogen from treated wastewater that will reduce the severity of harmful algal blooms.

Additional Information: Please see the following video:

Also read Dr. Lapointe’s papers on red tides and red drift algae blooms:

Ft Myers: Runoff from Hurricane Irma in September 2017, followed by extreme rainfall in May of 2018, caused excessive water and nutrient inputs into Lake Okeechobee. On June 1st 2018 water released from Lake Okeechobee seeded the Caloosahatchee Estuary with blue-green algae that formed massive, thick algal blooms in the sewage-polluted waters of Cape Coral and Ft Myers. These thick “guacamole-like” blooms of toxic blue-green algae caused serious human health issues causing many people living on canals to have to evacuate their homes.

Solution: Accelerate septic to sewer conversion in Lee County. Upgrade aging municipal sewer systems that are leaking raw sewage feeding the algae blooms. Phase out sewage outfalls in the Caloosahatchee and upgrade to advanced wastewater treatment, reuse, and deep-well injection.

Additional Information: Please see attached video sponsored by the Chamber of Commerce about the Caloosahatchee