First and Last name
4202 E Fowler Ave
Tampa, FL 33620
November 21, 2021
Robert A. Spottswood,
Florida Fish and Wildlife Conservation Commission,
3900 Drane Field Road
Lakeland, FL 33811-1206
Dear Dr. Robert Spottswood,
In this report, we are sending you a research project entitled “Red Tide in Tampa Bay,” which is a research study of algae blooms in Tampa Bay. The marine environment situation, though brief, is hazardous to aquatic life and people that leisure in the Bay as well as those that may consume seafood that is contaminated. There are numerous ripple effects well beyond the immediate ecosystem.
The report contains courses on algae bloom and the different dimensions of their hazardous effects. There are also various recommendations in the research report to combating algae bloom, including using phosphatic clay in clay flocculation. This method is understood to be the most cost-effective, easy to implement, and sustainable for the environment.
The reason for sending you this report is because of the need to amplify the urgency needed to act now. As one of the Seven Commissioners of the Florida Fish and Wildlife Conservation Commission, your office is positioned to reach stakeholders and secure the implementation of the recommendations contained in the attached report.
Thank you, Dr. Robert Spottswood! I am hopeful you will identify with the report and the benefits of the recommendations.
Respectfully,
First and Last name
Tampa Bay’s Red Tide Solution Proposal
Authors: First and last name
Table of Contents
Executive Summary 1
Introduction 1
Problem 1
Explanation of red tide 1
Cause of red tide in Tampa Bay 4
Solution 4
Clay flocculation 5
Modifying clay 6
Benefits of using clay flocculation 7
Implementation 9
Budget 9
Schedule 10
Conclusion 10
Works Cited 11
Executive Summary
A high concentration of red tide has been identified as dangerous to both humans and sea animals. Red tide is hazardous to human health for the fact that it affects anyone who swims in the water and consumes contaminated seafood (Stoller-Conrad, 2021). It produces a harmful toxin-like chemical that endangers the life of the living organism. The red tide blooms are present in the Tampa Bay regions including Anna Maria, Bradenton Beach, Lido Key, Coquina Beach Park, Fort De Soto Park, and Longboat key. This report investigates the cause of the red tide, possible solutions, and what people can do to avoid this disaster in the future. It also highlights the negative side effects of red tide on human beings and sea life. There are also various recommendations in the research report to combating algae bloom, including using phosphatic clay in clay flocculation. This method is understood to be the most cost-effective, easy to implement, and sustainable for the environment.
Introduction
A red tide refers to an event in which algae undergoes an enormous growth period known as an algae bloom. It is a marine environment situation that can last 2 to 3 weeks and is marked by a growth of algae cells that produces millions of cells. The rapid growth of algae leads to the change of watercolor which scientists call a Red Tide. The protists are what produce the toxin once algae bloom has developed, and it causes the death of sea animals and damage to humans (Skripnikov, 2021). Also, algae bloom causes discoloration, but the only visible color pigment is red. However, red tides are popular in oceans, and they are associated with negative effects on natural resources as well as humans. At Tampa Bay beaches, red tide emerged recently after a detected high concentration of organisms which causes algae bloom. Some of these organisms were spotted near Clearwater Beach and around Anna Maria Island. The paper seeks to highlight the causes of red tide at Tampa Bay and provide the potential solutions that can be implemented to save marine species and humans.
Problem
Explanation of red tide
As stated previously, red tide is a name given to describe the event of a harmful algae bloom (HAB). An algae bloom occurs when algae, a microorganism whose cellular makeup is similar to that of a plant, begins to reproduce in a single area at an such a rate it causes an overabundance of the algae (Mote, n.d.).
While these blooms typically consist of several species of algae, one of the most common and hazardous algae found within these HAB’s is known as Karenia brevis, typically abbreviated as K. brevis. When this species of algae rises to the surface of the water in large masses it causes the water to appear to have a reddish hue, earning this bloom the title of red tide. Additionally, K. brevis naturally produces a neurotoxin brevetoxin that can contaminate the body of water that the algae reside in. The neurotoxin can also travel as an airborne contaminant. Exposure to brevetoxin can cause serious illness and often death in marine life. For example, a common life-threatening symptom found in marine life that have been exposed to this neurotoxin is the disruption of the firing of neurons or nerve cells (Hall, 2020).
Neurons are some of the most vital cells found within the nervous system. These cells are the main way that the body receives inputs from the external world. They are also responsible for sending electric signals from the brain that commands the body’s muscles. When a neuron fails to fire, the signal that the brain was attempting to send is unable to be delivered, and as a result there is no muscle movement (Woodruff, 2019).
This inability to receive external inputs or send internal outputs will leave the fish unable to move or accurately understand what is happening around it. As a result, the infected specimens are either easy prey to other aquatic life that is high on the food chain or are washed up onto nearby shores due to the tide carrying their carcasses inland. Both case scenarios have their own negative side effects. For example, let’s assume that a predator decides to take advantage of the easy catch of some prey that was infected by the brevetoxin. This will simply end in the predator now being exposed to the neurotoxin and succumbing to the same fate as its prey. Moreover, there are even more issues if the infected specimen were to be washed up on land. For instance, the smell of their decomposing bodies would be most undesirable. Additionally, there is the possibility that other non-aquatic predators such as birds may consume the remains of the beach, which will end up leading to them being exposed to the neurotoxin as well (Hall, 2020).
Furthermore, another issue arises when the algae that make up a red tide bloom reaches the end of its life cycle. Because algae reproduce so rapidly during a bloom, a large majority of the algae will experience similar life cycle durations. When the algae die it is quickly devoured by other microbes such as bacteria. With the overabundance of dying algae this will likewise result in an overabundance of microbes in one area. These microbes, like most other organisms in the ocean, require the intake of oxygen to survive. So, with the overabundance of microbes in a singular area, will reduce the amount of oxygen in the water will reduce to next to nothing, and with the lack of oxygen the fish that haven’t been exposed to the neurotoxins emitted by the K. brevis, will then either suffocate, or be forced to migrate to another location. Often there will be large groups of floating deceased fish that were unable to escape to a new location where oxygen is more readily available. These areas are referred to as dead zones (Hall, 2020).
With this in mind, red tide is a concern for humans as well. An online poll conducted on the social media website Reddit under the subreddit r/tampa (R/tampa, 2021). This said poll questioned residents of the Tampa Bay area whether they were concerned about red tide blooms, and if they had been directly impacted by one of these blooms.
Figure 1:Percentage of people concerned about red tide Figure 2:Percentage of people impacted by red tide
As shown in Figure 1 an overwhelming 85% of the users that casted a vote on the poll were indeed concerned about red tide and the possible effects that it could have on their lives. Moreover, out of the 85% percent of people concerned about red tide, 42% of users have already been directly impacted by red tide as visualized in Figure 2. Those who were impacted by the red tide also responded with comments explaining how the red tide had impacted their lives. Some of the frequently mentioned issues red tide has caused consisted of the inability to enjoy several popular beaches, a significant decrease in the quality of water in infected areas, and most notably, a putrid smell coming from the coastline. The inability to properly enjoy Florida’s natural attractions could significantly impede tourism in Florida.
By the same token, the seafood industry has suffered due to the impact red tide has had on the environment. Retailers must take extra precautions to ensure that the inventory that they are purchasing from their suppliers have not been sourcing their inventory from areas that were experiencing a harmful algae bloom. Mainly shellfish like oysters, mussels, clams, conch, and other filter-feeding mollusks have been reported to contain trace amounts of the neurotoxin brevetoxin. These creatures are typically classified as bottom feeders, and are a natural predator of algae, and typically will consume algae as part of their regular diet. This however becomes an issue when these bottom feeders are sourced from places that are currently or have recently experienced a harmful algae bloom. There is a high probability that they have been exposed and or have ingested the toxin-emitting algae K. brevis. It is impossible to determine if the shellfish have contained trace amounts of brevetoxin just by relying on taste or smell alone, and typically shellfish do not exhibit the same symptoms other species of marine life may experience. Additionally, the toxin cannot be removed from infected organisms through freezing, cleaning, rinsing, or cooking. Ingestion of contaminated shellfish by humans can lead to them feeling ill, but life-threatening symptoms have not been seen in humans (Watkins, 2021).
Cause of red tide in Tampa Bay
Red tide as well as all other harmful algae blooms, are naturally occurring phenomena. Algae blooms are seasonal, and most blooms will typically occur towards the later months of summer. During this time, conditions in the water are ideal for the growth of algae. Although HABs do occur naturally, research suggests that the frequency and duration of the blooms can be influenced by factors such as nutrient pollution and climate change (Hall, 2020).
Nutrient pollution occurs when an excess of chemicals, namely nitrogen and phosphorus, enter the air or water. Nitrogen and phosphorus are two nutrients that can significantly encourage the growth of algae which can result in a bloom (https://www.epa.gov/nutrientpollution/issue). Some of the primary sources of these nutrients are animal manure and fertilizers used for agriculture, stormwater that flows down streets and sidewalks, and wastewater that can be discharged from sewer and septic systems (Environmental, 2021). Water that is polluted by these nutrients is referred to as runoff. The nutrients contained within runoff eventually flow into the ocean and be exposed to the algae.
Climate change can have a direct effect on the weather of a particular area which in turn can influence the properties of a body of water in such a way that it will increase the chance of an HAB occurrence. For instance, if a freshwater ecosystem is experiencing more droughts because of climate change, then the saline levels of the water have the potential to increase, which as a result can attract marine algae to invade the freshwater ecosystem. Likewise, the sea level is predicted to rise as a result of global warming. If the sea level rises it can lead to more shallow and stable coastal water which are excellent conditions for algae to grow (Environmental, 2020).
Solution
The most promising method of mitigating harmful algal blooms (HABs) in Tampa Bay is by using a method called clay flocculation or clay suspension. It is the most efficient based on three decisional criteria: ease of implementation, cost, and sustainability. The method considers its cheap cost when compared to other solutions and its low impact on the surrounding environment.
Clay flocculation
The process of clay flocculation uses clay as a primary component of reducing algal blooms. The clay can either be applied as a slurry of water through suspension spraying or by powder, the most popular being through suspension spraying. Although powder spraying can be more effective, in the field excess clay powder can fly through the air and affect the surrounding environment that isn’t the water affected by HABs (Zhiming, 2017). Therefore, the solution presented in this report will be based on suspension spraying. To the right is figure 3 depicting how clay flocculation works. A slurry of clay and water is sprayed on the surface water containing HABs. At the surface, the clay flocculates or congregates, with clay and algae becoming a heavier mass. This mass of clay and algae sinks further into the water continuing to pull more algae cells with it. Eventually, the mass of clay and algae hits the sediment and becomes covered with more clay burying the algae. The algae then either dies or ceases growth, mitigating the effects of red tide.
Several factors affect the efficiency of clay flocculation, including the type of algae and the clay structure and type. For clay flocculation to work, the clay must be able to latch onto the algae cell and pull it down. This depends on a combination of clay and algae size and structure. It isn’t as simple as having the clay smaller or larger than the cell because if the clay is larger than the flocculation removal efficiency will be almost zero (Moon-hee, 2014). The U.S. has found several clays with high removal abilities above 80% removal efficiency against Karenia brevis, Aureococcus anophagefferens, Pfiesteria piscicida and Heterosigma akashiwo (SENGCO, 2004). Karenia brevis is the primary culprit of algae blooms in Tampa Bay waters, so this report primarily focuses on countering this type of algae. Studies have found that clays containing montmorillonite minerals have greater removal abilities than kaolinites and zeolites. Several types of pure clays and clay sediments known as phosphatic clays have shown removal abilities above 80% for Karenia Brevis and they contain these montmorillonite minerals (SENGCO, 2004). In conjunction with the above information, the study found that phosphatic clay was the most promising type to deal with algal blooms along the Florida coastline (Sengco, 2001). The clay is a freshwater suspension, 30 to 50% composed of salt and sand as well as a clay-sized fraction less than 2 µm (Sengco, 2001). The clay particles are just smaller than Karenia Brevis, 20 µm in diameter, and have a structure effective in capturing the algae. Fortunately, Florida has a major industry in phosphate mining, and phosphatic clays are a byproduct of this industry, meaning obtaining the clay will be relatively easy to obtain and cheap compared to other clays. Not only will the costs be lower, but the clay is also already part of the existing environment so there shouldn’t be concerns about endangering the ecology.
Figure SEQ Figure \* ARABIC 3:How clay flocculation works
Modifying clay
Before implementing phosphatic clay, its alternative as a modified clay should be considered. Using clay surface modifiers is a key factor in influencing clay surface properties and removal efficiencies of HAB cells (Zhiming, 2017). Clay surface modification theory states that surface potential and effective interaction radius of clay particles are the main factors that influence the HAB organism removal efficiency of clay (Zhiming, 2017). Clays can be modified by both physical and chemical methods, improving the clay’s positive charge, and increasing the chance of a stronger chain between the clay and algae. These modifiers can either be inorganic or organic, the most common are inorganic modifiers like PAC, aluminum sulfate, aluminum chloride, and metal hydroxide. When considering adding modifiers the effect on the environment must also be considered, but the concentration of the modifier is usually at levels too low to make any negative impact on the environment. Although modifiers can improve efficiency, this part of the solution requires more research and laboratory tests to find which one pair successfully with phosphatic-type clay.
Figure SEQ Figure \* ARABIC 4:Process of how clay flocculation mitigates algae growth (Moon-hee, 2014)
Above you’ll see figure 4 from a study in China depicting the process of HAB mitigation using modified clay. The clay uses the same process described earlier in the report by suspension spraying directly onto harmful algae. What was described as the process of direct action in which the algae flocculate with the clay and falls to the floor and eventually dies. Clays also have the natural property of absorbing materials, but modifiers enhance this. The indirect action in this figure describes this process. The use of clays and modified clays reduces the nutrient levels in the water through absorption (Zhiming, 2017). The absorption of nutrients like nitrates and phosphates greatly affect the growth of these HABs and further reduces algal spread because of the lack of nutrients to perform photosynthesis. The removal of these nutrients has been found to improve water quality and prevent remineralization during HAB disintegration, which is the release of nutrients during algal death.
Benefits of using clay flocculation
Figure SEQ Figure \* ARABIC 5:Current and past phosphate mines in Florida.
Clay flocculation using phosphatic clay as a base is a very convenient solution for Tampa Bay’s algal problem. As stated earlier, Central and Southwest Florida has a large industry of phosphate mines and phosphatic clay comes readily as a byproduct of these mines. Florida currently has 27 phosphate mines covering 450,000 acres, 9 of which are currently active (Florida’s, 2021). Above is figure 5, depicting locations of phosphate mining in central Florida, including several locations in Hillsborough County. Due to the clay being readily available, it is also cheap and easily accessible. As the clay is already part of the environment there is no need for concern about introducing foreign minerals into the environment and messing with the ecosystem.
Implementation of clay flocculation is also relatively easy when compared to other possible solutions. All that is required is clay, a boat, and a hose. There are several variations of how to apply the clay, dependent on the size of the boat and the amount of clay needed to be spread. However, all methods require creating a slurry of clay and water and spraying said water through a hose onto the surface water. Figure 6 shows several ways clay dispersal has been done with variations on boat size and type of sprays. “A” shows a South Korean ship spraying clay, “B” shows a dispersal of clay on the rear of the ship, and “C” shows a smaller Chinese vessel spraying clay. “D” depicts a dedicated vessel for clay flocculation, while “E” and “F” show a larger dedicated machine to mix and spray clay. Each system is dependent on the amount of area needed to cover and has variations in costs, but all of which are cheap and quick compared to other solutions relying on wastewater treatment technology.
This solution is based on the criteria of ease of implementation, cost, and sustainability for the environment. As discussed earlier, using phosphatic clay as a base material is very cheap and cost-effective. Implementation of clay flocculation is also easy and adjustable depending on the area needed to cover by clay. We can use larger boats to go over the more open waters of the Bay while still being able to downsize to smaller boats to fit in smaller regions like canals or small estuaries. The most important criteria are clay flocculation’s sustainability on the environment and how it could affect the ecosystem. The main concern is for filter feeders like bivalves and krill. Although the clay is native to the region, there are concerns over the impact on these creatures in excess amounts of clay. The concern for these benthic species is that the juveniles will suffer from burial and have delays in growth, resulting in becoming prey before they reach a safe size. However, several studies indicated that there were no noticeable effects of clay concentration on the clearance rates of these species, meaning there shouldn’t be concern about burying immobile bivalves (SEO, 2008). The study found that there is an excess accumulation of clay in the bivalves’ respiration, but eventually, this is all discharged with little lasting effects on these species. The study found that other species like fish and shellfishes also did not suffer from acute or chronic exposure to clay dispersion (SEO, 2008). The concern for the overall toxicity of the sediment mixture after clay settling was not significantly different from current conditions of red tide, meaning there is little change in initial toxicity of the current toxic waters (SEO, 2008). Therefore, there should be no concerns about having concentrated levels of toxins in the sediment due to clay flocculation.
Figure SEQ Figure \* ARABIC 6:Different dispersal methods of clay flocculation
Using phosphatic clay in clay flocculation covers the criteria of being cost-effective, easy to implement, and sustainable for the environment. This is based on the reasoning that phosphatic clay is effective in fighting Karenia brevis while being easily accessible in Florida due to nearby phosphate mining. Clay is also low in costs and already part of the existing environment, having little effect on the current ecology. The adjustability of sizes of boats makes it easily implementable and only requires a mixture of clay, a boat, and a hose to spray over the bloom.
Implementation
The implementation of the chosen solution will be carried out primarily by The Florida Fish and Wildlife Conservation Commission with support from volunteers and other laboratories that are in the area. To begin there will be a proposal given to The Florida Fish and Wildlife Conservation Commission with a plan laid out for implementation to be approved. Once it is approved research will be conducted to determine where the main contributing waterways leading to the red tide are located so clay can be used to lower the number of harmful algae in the water. Once this step has been completed the water will be retested to see how much algae has been removed and how much is left. Then the process will be repeated until an acceptable level of algae is achieved.
Budget
Figure 7:Proposed budget plan for clay flocculation solution
Schedule
Figure 8:Proposed schedule for implementing clay flocculation solution
Conclusion
Algae bloom is mostly a natural occurrence however certain human actions can be triggers or energizers. It can be very harmful if ignored like Karenia brevis which can contaminate both the water and air. Another dimension of inaction and letting the algae live out it period is a ripple effect syndrome that would lead to shortage of oxygen for marine life in the areas affected. There is also the economic implication to algae bloom as the seafood value chain will be disrupted. phosphatic clay in clay flocculation should be adopted as an effective, environmentally friendly, and cost-efficient measure. The impact of algae bloom, especially K. brevis type goes beyond marine life and the aquatic medium, hence the need to take immediate action to comeback the Red Tide in Tampa Bay. The recommended solution to the Red Tide is effective in that it addresses the problem by outlining the most appropriate measures to deal with this catastrophe in Tampa Bay.
Works Cited
Environmental Protection Agency. (2020, November 27). Climate Change and Harmful Algal Blooms. EPA. Retrieved November 21, 2021, from https://www.epa.gov/nutrientpollution/climate-change-and-harmful-algal-blooms.
Environmental Protection Agency. (2021, August 31). Nutrient Pollution. EPA. Retrieved November 21, 2021, from https://www.epa.gov/nutrientpollution/sources-and-solutions.
Florida’s Phosphate Mines. Florida Department of Environmental Protection. (2021, September 15). Retrieved November 21, 2021, from https://floridadep.gov/water/mining-mitigation/content/phosphate.
Hall, D. (2020, February 19). What exactly is a red tide? Red Tide: What is the algae species Karenia brevis? Retrieved November 21, 2021, from https://ocean.si.edu/ocean-life/plants-algae/what-exactly-red-tide.
Moon-Hee, C., Soon Chang, L., You-Kwan, O., & Hyun Uk, L. (2014). Clay-based Management for Removal of Harmful Red Tide s in Korea: A Multi-perspective Approach. KoreaScience. Retrieved November 21, 2021, from http://koreascience.or.kr/article/JAKO201423366169244.page.
Mote Marine Laboratory & Aquarium. (n.d.). Retrieved November 21, 2021, from https://mote.org/news/florida-red-tide#Areredtidesnewtoflorida?
R/tampa – are you concerned about red tide and has it impacted your life? reddit. (2021). Retrieved November 21, 2021, from https://www.reddit.com/r/tampa/comments/q7nsnd/are_you_concerned_about_red_tide_and_has_it/.
SENGCO, M. A. R. I. O. R., & ANDERSON, D. O. N. A. L. D. M. (2004). Controlling harmful algal blooms through clay flocculation1. The Journal of Eukaryotic Microbiology, 51(2), 169–172. https://doi.org/10.1111/j.1550-7408.2004.tb00541.x
Sengco, M., Li, A., Tugend, K., Kulis, D., & Anderson, D. (2001, January 26). Removal of red- and brown-tide cells using clay flocculation. I. Laboratory culture experiments with Gymnodinium breve and Aureococcus anophagefferens. Marine Ecology Progress Series. Retrieved November 21, 2021, from https://www.int-res.com/articles/meps/210/m210p041.pdf.
SEO, K. S., LEE, C. K., PARK, Y. T., & LEE, Y. (2008). Effect of yellow clay on respiration and phytoplankton uptake of bivalves. Fisheries Science, 74(1), 120–127. https://doi.org/10.1111/j.1444-2906.2007.01476.x
Skripnikov, A., Wagner, N., Shafer, J., Beck, M., Sherwood, E., & Burke, M. (2021, July 6). Using localized twitter activity for Red Tide Impact Assessment. arXiv.org. Retrieved November 21, 2021, from https://arxiv.org/abs/2107.02677.
Stoller-Conrad, J. (2021, November 1). What is a red tide? NOAA SciJinks – All About Weather. Retrieved November 21, 2021, from https://scijinks.gov/red-tide/.
Watkins, S. M., Reich, A., Fleming, L. E., & Hammond, R. (2008). Neurotoxic shellfish poisoning. Marine drugs. Retrieved November 21, 2021, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2579735/.
Woodruff, A. (2019, August 13). What is a neuron? Queensland Brain Institute. Retrieved November 21, 2021, from https://qbi.uq.edu.au/brain/brain-anatomy/what-neuron#:~:text=Neurons(alsocalledneuronesor,ateverystepinbetween.
Zhiming, Y., Xiuxian, S., Xihua, C., & Yang, L. (2017). Mitigation of harmful algal blooms using modified clays: Theory, mechanisms, and applications. Harmful Algae. Retrieved November 21, 2021, from https://www2.whoi.edu/site/andersonlab/wp-content/uploads/sites/20/2018/10/Yu-et-al-Review-Mitigation-of-harmful-algal-blooms-using-modified-clays_2017.pdf.