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Cyanobacteria in Lake Okeechobee--What should we do, and how serious is it? 

E. Allen Stewart III P.E.

September 16, 2018

PASOP Apopka 3.jpg
PASOP Dead Fish.jpg

The 33,000-acre Lake Apopka in Central Florida is testimony to what can happen with loss of biodiversity. Because of poor management and excessive nutrient pollution Lake Apopka was changed from a crystal clear, biodiverse lake with very high recreational and economic value, to a pea-green low biodiversity lake which is in a continual fish kill and promotes the production of toxic blue-green algae (Cyanobacteria). Its economic and recreational value is de minimis, even though it is located only 15 miles from Disney World. (From Google Earth) Could this be the fate of Lake Okeechobee?

As I read the editorials, blogs and social media comments about our red tide/cyanobacteria blooms in South Florida, I have noticed several reactions. The first is surprise that this could happen so fast and so dramatically; the second is the search for someone to blame; and the third is what “quick fixes” can be done to alleviate the impact. Recognize there may not be quick fixes, only Band-Aids to protect, to some degree, what we can as we develop meaningful, long term programs.


Blaming is easy but does little to resolve the issue. The fact is scientists have seen this problem coming for decades, and yet few political and business leaders have paid any attention to their warnings. Note for example the excerpt in the following paragraph from a letter I wrote to the Lake Okeechobee Technical Advisory Committee (LOTAC) in 1987. This was following a Cyanobacteria bloom in parts of Lake Okeechobee, which created fear that Lake Okeechobee would become overwhelmed by a “permanent” bloom of Cyanobacteria and continual fish kill as experienced at Lake Apopka (See picture at the front of this text and note how green Lake Apopka is compared to the surrounding lakes).  Of course, the first reaction to the 1987 bloom was to assign blame—the people in the north of the lake blamed back-pumping from sugar cane farms. The sugar cane farmers blamed the dairies to the north. In retrospect both were right—it was a manifestation of a systemic issue related to excessive nutrients contributed by a diversity of sources exacerbated by disruptive water management practices.


“In the early days of the Lake Okeechobee Technical Advisory Committee (LOTAC) it was clearly expressed that there was a desire to take action to protect “the lake’s water supply, water quality and recreational functions” by reducing the rate of eutrophication[1]. However, the assessment of the extent and rate of eutrophication became, and has remained, an issue of disagreement among the various individuals and groups involved with the Committee. For many, the Lake Apopka experience stands as a reminder of the impacts of complacency and poor lake management. And while limnologists[2] may argue that there are few parallels between the two lakes, it should be recognized that agricultural back-pumping, aquatic plant spraying, artificial manipulation of lake levels, extensive diking and canalization, and notable point source discharges are shared, potentially deleterious components of both Lake Apopka and Lake Okeechobee. Any concern for a repeat performance therefore must be considered legitimate, and scientific rhetoric regarding the relationship between various nutrient and hydraulic loading parameters and short term responses of in-lake concentrations and phytoplankton[3] production provides little assurance that continuation of present practices (e.g. back-pumping, heavy phosphorus loading from Taylor Creek, extensive aquatic plant spraying) is going to ensure preservation of the desired water quality and sport’s fisheries.”--Allen Stewart 1987


Of course, well before 1987, scientists and activists had expressed concern over nutrient loading to Lake Okeechobee. Most notable was Art Marshall, a marine biologist and Kissimmee River-Lake Okeechobee-Everglades advocate (for more on Marshall        go to                       ); Ernest Coe; Nat Reed; Paul Parks; Paul Gray; and of course Marjorie Stoneman Douglas. Despite these concerns and warnings very little has been done. What in 1987 was a serious but manageable situation has morphed into today’s problem of serious urgency. The possibility of Lake Okeechobee becoming another Lake Apopka creeps closer to reality, and this summer we documented what I believe is the most expansive Cyanobacteria bloom experienced in the lake. And of course, this bled over into the Caloosahatchee and St. Lucie. Can you imagine 450,000 acres of year-round pea green water, with continual fish kills—loss of a healthy “speck” and bass fishery and wildlife resources; imposition on human health and water utilities; no apple snails for the kites; and serious economic impact to the region?

Ok, you are probably thinking I am being an alarmist. But do not take my word for it. In their 2015 report on this issue, the University of Florida Water Institute                      noted that:

“Increased and sustained State and Federal funding is critical to provide additional water storage and treatment before the system becomes so degraded that major attributes reach tipping points that cannot be reversed.” 


For scientists this is bold language! Reading between the lines I interpret this that Lake Okeechobee as we know it and enjoy it could be lost forever, as could many of our estuaries, as well as what remains of the Everglades and Florida Bay, if we do not take serious action. And what would that serious action be? Well, one critical action relates to management of excessive phosphorus, both incoming and that stored within the watershed—what they call legacy phosphorus, and what I call rogue phosphorus. From the UF report:


“Beyond existing and planned approaches, the substantial reservoir of legacy phosphorus in the Northern Everglades watersheds will necessitate new and more aggressive strategies to combat the mobility of phosphorus.”


Note that the Northern Everglades refers to the Kissimmee River, Lake Okeechobee, Caloosahatchee, and St. Lucie River watersheds


In my last two Blogs I presented one possible long-term strategy for managing phosphorus. Central to this proposed strategy are;


1) Phosphorus must be removed, recovered, and either recycled within the watershed or exported from the watershed such that exports exceed imports.

2) Recovering phosphorus can result in products of considerable value, such a livestock feed, soil amendments, fiber products, biogas etc.

3) To entice involvement of the private sector, a long-term Pay-for-Performance commitment should be adopted by the regulating agencies/governments to pay for each pound of phosphorus (and possibly nitrogen) which is ultimately removed from the watershed, with the price paid for each pound to be less than the price presently being assumed by the agencies for phosphorus (and nitrogen) reduction through technologies which simply store phosphorus within the watershed such as Stormwater Treatment Areas (STA).

4) Refine the technologies which could cost-effectively provide these removals through public-private partnerships.

5) Develop an implementation plan that facilitates effective transition which would strengthen the regional economy and ease the impact of any necessary replacement of previous agricultural practices such that job availability and quality are at the least unchanged, and at best, enhanced.   

6) Commensurate with this nutrient removal and recovery strategy, an additional 1,600,000 acre-ft of water storage needs to be expeditiously developed, as recommended within the UF report.


  • 400,000 acre-feet of water storage within the Caloosahatchee River watershed,

  •  200,000 acre-feet of water storage within the St. Lucie River watershed, and

  • approximately 1,000,000 acre-ft of water storage distributed north and south of Lake Okeechobee.


I encourage each of you to seriously consider the issues presented herein, share your thoughts with others, and ask our candidates serious questions about how they would approach these problems.  Thanks


[1] Eutrophication which literally means “high growth or production” is a when a body of water becomes overly enriched with minerals and nutrients that induce excessive growth of plants and algae.

[2] Limnology is the study of the biological, chemical, and physical features of lakes and other bodies of fresh water.

[3] Phytoplankton refers to algae and photosynthetic bacteria suspended in the water column, including several Cyanobacteria species.



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