The Primary Cause of Florida's Toxic Algal Blooms Completely Ignored

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Politicians, the tourism and real estate industries, and even environmental groups are loathe to admit it, but near shore Algal Blooms and Red Tide are the result of land-based, man made pollution.

To combat the algal blooms near shore in Florida we must first admit the scientifically validated fact that algal blooms are the result of land based activities (man made pollution of organic nitrogen) from sewage spills, septic tanks leaks, and and overuse of organic nitrogen from manure on lawns. All of this we can abate if we have the will.

The reality is that those of us and authorities who deny the involvement of land-based activities as cause of algae blooms are conveniently ignoring the science, which is peer reviewed and published, that instructs us on what is feeding green algal Synechococcus blooms and as well harmful red tide Karenia Brevis algal bloom near shore.

[To learn more about the real causes of Red Tide read: "The Truth About Red Tide's Manmade Causes and Health Effects"]

With evidence that blooms of Synechococcus (a green slime algae) can be enhanced due to anthropogenic nutrients, the poten­tial importance of this particulate nutrient (urea nitrogen) source for sustaining red tide blooms is large and may help to resolve the current uncertainty as to how algal blooms and red tide K. brevis blooms are maintained.

According to the peer reviewed science, urea nitrogen run off appears to be the cause of exacerbation of Red Tide near shore. The Red Tide organisms feed on the green slime algae as a source of energy. Peruse the following study to better understand how this happens:

Grazing by Karenia brevis on Synechococcus enhances its growth rate and may help to sustain blooms Patricia M. Glibert1,*, JoAnn M. Burkholder2 University of Maryland Center for Environmental Science, Horn Point Laboratory, PO Box 775, Cambridge, Maryland 21613, USA2Center for Applied Aquatic Ecology, North Carolina State University, Raleigh, North Carolina 27695, USA)

Based on this research and its conclusions if we reduce urea nitrogen pollution from all sources, including stopping septic tank leaks, prevent and stop sewage spills, and reduce inappropriate organic manure lawn applications on lawns, we should be able to significantly reduce the duration of green slime algal blooms and Red Tide blooms near shore.

What the published research essentially proves is that the runoff from land-based applications of urea nitrogen fertilizers such as commonly used as stated in lawn care, as well as additional sources of nitrogen urea from septic tanks, sewage spills and close-to-water sewage treatment effluent, result in Synachoccus green algal blooms, which is a harmless, green slime algae. According to the science cited here Karenia brevis (red tide) uses the green slime as an energy source. The more Synechoccus the more red tide; it's simple cause and effect.

So, What Is The Real Cause of Prolonged, Near-To-Shore Algal Outbreaks?

We can learn much from history in Japan where Eutrophication and occurrences of harmful algal blooms in the Seto Inland Sea, Japan. What was proven is that reducing urea nutrient pollution is one solution: "Eutrophication and occurrences of harmful algal blooms in the Seto Inland Sea, Japan."

The Seto Inland Sea is the largest enclosed coastal sea in Japan and is also a major fishing ground including aquacultures of fish, bivalves and seaweeds. The incidents of red tides dramatically increased in frequency and scale in the Seto Inland Sea along with serious eutrophication in the 1960s and 1970s. In Japan The “Law Concerning Special Measures for Conservation of the Environment of the Seto Inland Sea” was legislated in 1973 and industrial loading was decreased to half the level of 1972.

The enactment of this law was triggered by a red tide of Chattonella antiqua (Hada) Ono, which caused the largest economic loss by the mass mortality of cultured yellowtails (7.1 billion yen) in the summer of 1972. As a result of this law, the quantity of COD dumped in the Seto Inland Sea, which was 1700 tons per day in 1972, had been reduced to 717 tons per day by 1999 (Ministry of the Environment Government of Japan & the Association for the Environ- mental Conservation of the Seto Inland Sea 2001)

To learn more about the link between urea fertilizers and global increases in eutrophication and harmful algal blooms read: "Escalating worldwide use of urea – a global change contributing to coastal eutrophication." 

So, back to the question: are these outbreaks entirely natural phenomena, as many health authorities, and certainly folks within the mainstream media, tourist and real estate industry, often maintain?

The answer is a resolute and resounding NO.  In April, 2009, the journal Aquatic Microbial Ecology published a groundbreaking study titled, “Grazing by Karenia brevis on Synechococcus enhances its growth rate and may help to sustain blooms,” which provided the missing link in how Red Tide is directly fed by human, land-based activities.  Here is the study abstract:

Ironically, plants need primarily magnesium (for chlorophyll) and potassium, and not nearly as much nitrogen, which is presently being used at up to 5 times higher levels than required. In fact, excess nitrogen leads to plasmolysis in plants, causing excess water to leave the plant entering the soil, resulting in wilting. The excess nitrogen, of course, leaches into the soil and eventually a portion of its causes water pollution.

The obvious solution to the accelerating red tide problem is to reduce land-based applications of urea nitrogen, especially in the summer months. As the green slime is reduced, the red tide will have no additional energy source and will die out.

The reality is that authorities who deny the involvement of land-based activities and algae blooms are conveniently ignoring the science, which is peer reviewed and published, that instructs us on what is feeding red tide near shore. The tourism and real estate industries also have a vested interest in minimizing and/or denying the extent of the problem, at least in the short term. The long term outlook, however, is dismal for these industries, who failing to act, would see the primary attractor for tourists or potential buyers of real estate — watch their ocean and beach deteriorate.

How We Can Contribute To A Long-Term Solution 

The long-term solution is to reduce the use of nitrogen organic manure based urea fertilizers in both lawn and agricultural applications. There is no question that nitrogen urea rich agricultural runoff, are sizable contributors to the overall nitrogen burden in the bays in Florida. Much of agricultural runoff ends up in Lake Okeechobee, which eventually empties into the bays in Florida

A 2006 study published in the journal Biogeochemistry titled, “Escalating worldwide use of urea – a global change contributing to coastal eutrophication,” indicates worldwide use of urea as a nitrogen fertilizer and feed additive has increased more than 100-fold in the past 4 decades. The study pointed out:

Long thought to be retained in soils, new data are suggestive of significant overland transport of urea to sensitive coastal waters. Urea concentrations in coastal and estuarine waters can be substantially elevated and can represent a large fraction of the total dissolved organic nitrogen pool. Urea is used as a nitrogen substrate by many coastal phytoplankton and is increasingly found to be important in the nitrogenous nutrition of some harmful algal bloom (HAB) species."

They also noted that “the global increase from 1970 to 2000 in documented incidences of paralytic shellfish poisoning, caused by several HAB species, is similar to the global increase in urea use over the same 3 decades.”

The reality is that these agricultural practices have been a long time in the making, and will take considerable time, energy and political clout to change. The good news is that you can make changes at the local level, from the bottom up, as it were, by starting with your own lawn. 


Key Source : Grazing by Karenia brevis on Synechococcus enhances its growth rate and may help to sustain blooms

Patricia M. Glibert1,*, JoAnn M. Burkholder2, 1University of Maryland Center for Environmental Science, Horn Point Laboratory, PO Box 775, Cambridge, Maryland 21613, USA2Center for Applied Aquatic Ecology, North Carolina State University, Raleigh, North Carolina 27695, USA

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