Karenia Brevis: Adverse Impacts on Human Health and Larger Marine Related Animal Mortality from Red Tides

Home , Dinophyceae, Gymnodinium, Karenia (dinoflagellate), Karenia brevis

Karenia brevis: Adverse Impacts on Human Health and Larger Marine Related Animal Mortality from Red Tides

Vickie Vang Environmental Studies 190 12/14/2018

TABLE OF CONTENTS

ABSTRACT ...... 2

INTRODUCTION ...... 3

BIOLOGY ...... 4 Genus Karenia ...... 4

Vertical Migratory ...... 5

Temperature and Salinity ...... 6

Nourishment ...... 7

Brevotoxin ...... 8

ENVIRONMENTAL IMPACTS ...... 8

HEALTH RISKS FOR HUMANS ...... 9

Respiratory Irritation ...... 10 Neurotic Shellfish Poisoning ...... 11

ECOSYSTEM IMPACTS ...... 13

Sharks ...... 13 Birds ...... 14 Dolphins and Manatees ...... 15 Sea Turtles ...... 15

POSSIBLE MITIGATIONS...... 16

Flow Cytometry ...... 16

Warning Signs ...... 17

CONCLUSION ...... 18

FIGURES ...... 21

TABLES ...... 24

REFERENCE PAGE ...... 25

Abstract

Karenia brevis is a common harmful algal involved in red tides at Florida southwest coast.

K. brevis is one of the most harmful algal that have been studied found to tolerate in high salinity and warm temperatures. The brevotoxins produced by K. brevis is harmful to humans and marine related animals. Inhaled aerosolized brevotoxins will be deposited into the upper and lower airways. NSP is a disease, a result of consuming filter feeders that are contaminated with brevotoxins. There are evidence that animal mortality rates still occurs after a red tide is over. Birds, manatees, bottlenose dolphins and sharks populations are affected by their diet. Flow Cytometry should be used to monitor and detect if K. brevis cell count ahead of time. To prevent NSP incidents, noticeable warning signs of prohibited shellfish bed harvesting should be provided in areas attracted to tourists.

Introduction This paper will focus on a harmful alga, known as K. brevis that is found in the southwest coast of Florida. This paper will investigate the coast of Florida where - there is a history of red tides, also known as harmful algal blooms involving K. brevis, a synthesis of peer review and scientific literature. There was a high number of people reported to hospitals due to respiratory issues after occurrences of the blooms indicating K. brevis exposure. Also, the pathway of exposure for marine related animals are from consuming bivalves with accumulated K. brevis toxins, which is a threat because mortality rates increase.

Karenia brevis (known as the red tides and formally called Gymnodinium breve), are toxic dinoflagellates algae (Gravinese 2018; Evens et., al 2001). Annual red tide blooms involving K. brevis at the southwest of Florida, USA, can last from a few weeks to a year (See

Figure 1. Map of Florida and its Coast). These microorganisms produce a powerful ichthyotoxin that increases fish and aquatic mammal mortality rates and threatens human health (Evens et al., 2001). The proliferation of K. brevis is harmful and should be monitored to predict future outbreaks in order to promote safety for public health and wildlife.

Specifically, this research paper will focus on larger marine animals that are on the higher tier of the food chain. I will study the adverse impacts of human health issues related

Neurotoxic shellfish poisoning (NSP) and respiratory illnesses using the number of visits the

Sarasota Memorial Hospital having during red tides events. Then, I will study how populations are affected in larger fishes, marine mammals, and other marine-related

3 creatures by comparing mortality rates during red tide events. Along with impact analysis on public health and ecosystem, I will investigate possible mitigations for them. My research will answer: 1) What are the public health risks to exposures of K. brevis toxins? 2) How are animals living in and around the marine environment affected by K. brevis? 3) What are the best mitigation practices to reduce K. brevis cell density?

Biology Genus Karenia is a dinoflagellate belonging to the Kareniaceae family and has 12 species (Brand et al., 2012). Kareniaceae is different from the rest of the dinoflagellates because they carry pigments such as fucoxanthin, 19’-butanoyloxyfucoxanthin, 19’- hexanoyloxyfucoxanthin, and 19’-hexanoyloxyparacentrone 3-acetate while other dinoflagellates carry peridinin (Brand et al., 2012). There are no cell wall plates that are known as armors in dinoflagellates for Kareniaceae making them susceptible to rupture by clashing waves (Persson et al., 2013). These dinoflagellates are pleomorphic, meaning - there are variations in shapes and sizes of individual cells. Also, they are polymorphic, meaning there are more than one form (Persson et al., 2013). Ultimately, this shows that these species are highly variable shape and size.

Stage initiation is where K. brevis begins, which is at least two to four kilometers offshore from Gulf of Mexico (Sinclair 2009). When offshore, K. brevis rapidly increase in numbers. Eventually, the K. brevis population moves into other bodies of water by wind or waves. (Redalje et al., 2008; Brand et al., 2012). When K. brevis is nearby shore, nutrients from land runoff stimulates growth (Brand et al., 2012).

Genus Karenia

From the 12 species in genus Karenia, Karenia brevis is one of the most harmful algal that have been studied (Brand et al., 2012). These species are microalgal cells, algal that are too small for the naked eye to see and will need an aid of a microscope (Hauter & Hauter,

2018). K. brevis ranges in size from 20 to 40 µm but can reach 90 µm in rare cases (Figure

2) (Brand et al., 2012). K. brevis is a mixotroph because they have multiple ways of obtaining nutrients for growth. The dinoflagellates are photosynthetic and can use organic compounds for growth (Gallardo-Rodríguez, 2012). Depending on the environmental changes, K. brevis swim speed ranges from 50 to 550 µm s-1 (Mckay et al., 2006).

Dinoflagellates are known to reproduce asexually, K. brevis can reproduce both asexually and sexually. Only at night, binary fission occurs where K. brevis creates a clone of itself (Brand et al., 2012). Division cell rates are recorded to be .3 division 푑푎푦−1 (Persson et al., 2013). There is evidence of sexual reproduction because of planozygotes in a K. brevis lab culture study. When there are signs of an environmental stress such as low temperatures, or nutrient limitation, different clones of K. brevis mixed together, there will be an increase number of gametes observed (Brand et al., 2012). When there are no nutrients, at least 50% of K. brevis would swim to water surface for photosynthesis at the same time and go through cell division (Van Dolah et al., 2009). K. brevis can reproduce at a fast rate determined from life threatening events and by having both asexual and sexual reproduction processes to gain higher chances of survival.

Vertical Migratory

While most algal are nonmotile K. brevis can migrate in one direction with a long flagellum that whips back and forth (Voiland, 2018). Swimming vertically is a behavior of a

K. brevis where resources for growth is to be maximized (Kamykowski, 1999). When the sun is present the dinoflagellates would be found near the surface. There is a pattern of how K. brevis migrate up and down the water column daily, which is thought to have multiple functions to maximize nutrient resources for growth, hide from predators, and protect from sun damage (Heil et al., 2014). When K. brevis swims towards the waters surface, they are swimming to where most sunlight shines for carbon fixation from photosynthesis (Van Dolah et al., 2009). When the sun goes down, K. brevis will swim downwards to dissolve nutrients. By doing so, they are maximizing resources that enables them to live and reproduce for a long period of time, driven by positive phototaxis and negative geotaxis (Heil et al., 2014).

Temperature and Salinity

K. brevis blooms are usually found in areas where they are tolerant in high salinity and warm temperatures (Brown et al., 2006). In places where this microorganism has been found at West of Florida and Gulf of Mexico, the Atlantic Ocean, east coast of the United

States, North Carolina, and even Texas. The conditions where K. brevis grows best is between 24 to 40 psu, the population declines rapidly when salinity is more than 40 psu and less than 24 psu (Magana & Villareal, 2005). As for temperature conditions, K. brevis is best found to grow at 15 to 30 C. Anything over 30 C will have a decline growth. There are rare cases where K. brevis starts to grow in areas where it would usually not be found,

6 estuaries, and in water with 5 psu (Brand, 2012). For example, K. brevis were found near the Mississippi River, where salinity was at 5 psu, and at Texas lagoons during droughts

(Magana, 2015; Brown et al., 2006). Warm temperatures and high salinity are environmental conditions that K. brevis favors for growth and reproduction.

Nutrients

There are uncertainties to where K. brevis receives enough nutrients to flourished.

Some studies believe that nutrient influx is coming from the Mississippi River. During fall seasons when wind patterns influence movements of nutrients from the Mississippi River traveling eastward, blooms would occur at the Texas coast (Vargo, 2009). Vargo (2009) also noticed that “severe” harmful bloom events at Texas occurs shortly after Mississippi

River discharges. Blooms are mostly likely to happen during fall when pollution runoffs are at its peak (Brand, 2012). Other speculations are the increase of human activities that resulted in higher nutrients in groundwater, which helps flourish K. brevis (Brand, 2012).

When nutrients are sparse, K. brevis is resourceful and can find ways to maintain growth by uptaking nutrients in multiple of ways.

K. brevis is both autotrophic and mixotrophic, using photosynthesis to create its own food and having the ability to convert organic compounds to food (Gallardo-Rodríguez,

2012; Persson et al., 2013). There are also studies that show these autotrophic microorganisms consume other microorganisms and can use organic and inorganic nitrogen for growth (Persson et al., 2013). A few kilometers away from shore is where K. brevis begins to “initiate” (Sinclair, 2009). Nutrients are not as available offshore where initiation began so the possible nutrient resource is from aerial deposition, nitrogen

7 fixation, and waste products from Trichodesium species (Sinclair, 2009). Nutrients from sediments can even be derived where the sediment water interface is. K. brevis can also utilize ammonia, nitrate, urea, glycine, aspartic acid and glutamate (Brand, 2012; Vargo,

2009).

Brevotoxin

Neurotoxins produced by K. brevis are called brevotoxins. Brevotoxin’s two main parent compounds are PbTx-1 and PbTx-2 with 10 congeners (Brand, 2012). The 10 congener changes the parent compounds under different environmental conditions such as the metabolism of mammals (Brand, 2012). Brevotoxins are lipid soluble enabling them to pass through membranes of mammal cells and are easily absorbed. The toxin connects with sodium channels to open continuously causing muscles to clench when membrane depolarizes from sodium influx (Watkins et al., 2008). The acute affects in mammals start almost immediately and is removed by the body via urine and bile in about 48 hours.

Brevotoxins are found stored in fish muscles and organs (Watkins et al., 2008). For filter feeders, a huge amount of brevotoxin concentration can be found without affecting the animals’ health (Brand 2012). These accumulated brevotoxins become fatal and can be passed on to the next tier of the food chain.

Environmental Impacts

K. brevis is a harmful algal that can become harmful to the environment or other organisms once there is an abundance in population of K. brevis. Harmful algal blooms (HAB)

8 are the results of rapid flourished algal and becomes a threat to surrounding environment

(Gannon, 2008). One aquatic animal threat that links HAB to fish kills are dissolved oxygen depletion that leads to hypoxia and anoxia (Gannon, 2008). Also, high turbidity in water blocks sunlight that aquatic plants could use for photosynthesis causing less oxygen production (Gravinese, 2018). HAB is an environmental stress for fishes because oxygen depletes leading to kill fishes.

Each of these microorganisms contain a small amount of the neurotoxins, called brevotoxins inside of them. The toxins could be released into the water after death or damage since K. brevis is fragile (Steidinger, 2008a). Algal is a staple food that crustaceans, small mammals and small fish eat (McKinney, 2018). Then, larger aquatic animals eat these smaller fishes that feeds on algal. This shows that algal plays an important role in the food chain as a food source. The only difference between K. brevis and other algal are the brevotoxins that it produces. Once ingested, the toxins impair the nervous system by inhibiting the sodium channels from closing resulting in muscles to clench, “fire”, repeatedly and uncontrollably

(Flewelling, 2010). Ingesting brevotoxin does not always lead to death as toxins can be absorbed into fatty tissues and biomagnifies (Brand, 2012).

Health Risks for Humans

The brevotoxins produced by K. brevis are harmful to humans. Humans can be exposed to the toxins by ingestion and inhalation. When brevotoxin-contaminated shellfish are consumed, a disease called the Neurological Shellfish Poisoning (NSP) is developed onto the consumer. In addition, brevotoxin can aerosolize and travel to humans’ respiratory

9 system causing respiratory irritation (Hoagland et al., 2014). There are no direct links to prove that brevotoxins are causes of these symptoms, but there are strong associations between the number of emergency visits to the hospital during red tide events (Reich, 2015).

Respiratory Irritation

K. brevis can be found at the Gulf of Mexico, south west of Florida’s coast, Texas, and the Atlantic coast, but blooms are more likely to happen at southwest of Florida’s coast

(Watkins, 2016). Since 1844, the common visits to hospitals in Florida were reports of symptoms related to respiratory irritation (Abraham, 2006). Many people make up Florida as there are 23 counties, a hot spot for tourists, and residential increase that are at risk of respiratory irritation through inhalation (Haogland et al., 2014). As stated before, K. brevis are unarmored making them susceptible to break releasing brevotoxins. Sometimes brevotoxins are released into the atmosphere after the cells breaks from the surface water or near the shoreline (Stiedinger, 2008a). Once brevotoxin is incorporated into the atmosphere, it becomes an aerosol that people breathe. Aerosol brevotoxin travels up to six miles inland with the help of wind, 3% to 6% of those can lodge at the lower airway

(Hoagland, 2009; Abraham, 2006; Soto et al., 2018). Aerosolized brevotoxins affect the upper and lower airway following multiple acute symptoms that can last for a month (Kirkpatrick et al., 2010). This shows that humans can be harmed by K. brevis toxin miles away from shore.

Inhaling aerosolized brevotoxins will be deposited into the upper and lower airways.

Symptoms from the upper airways are coughing, sneezing, rhinorrhea, burning sensations of nose and throat, and itchy and water eyes. (Abraham, 2006; Watkins et al., 2008).

Symptoms from the lower airways are related to the difficulty of breathing – tightness in the

10 chest, wheezing, and shortness of breath (Abraham, 2006). People with asthma are most susceptible to these symptoms and symptoms would be harsher (Abraham, 2006; Watkins et al., 2008).

There was a study to show how strong of an association there was between the number of hospital visits for respiratory-related illnesses during red tide events. Barbara

Kirkpatrick (2010) analyzed 2001 and 2002 data from Sarasota Memorial Hospital (SMH) from Sarasota county, which aids more than half of the county’s population and is near by the coastline. There were red tide events containing K. brevis in 2001, while there was none in 2002. The data shows that 2001 had higher gastrointestinal disease visits in SMH during red tide events compared to year 2002 when there were no red tide events (Kirkpatrick et al. 2010). If there were one unit increase of cell density (107 cells / L), there would be five additional emergency visits to the hospital per month (Hoagland et al. 2014). This shows that there is an association between the number of hospital visits and red tides events but does not necessarily mean an individual can get ill directly from brevotoxins.

Another study shows that 28% of people who had visited recreational beaches would have high levels of exposures at their upper and lower respiratory airways (Abraham, 2006).

Even healthy people such as beach life guards would face upper respiratory health issues.

Neurological Shellfish Poisoning (NSP)

NSP is a disease as a result of consuming filter feeders that are contaminated with brevotoxins (Reich, 2015). Outbreaks of NSP have been reported since 1999 but are now rare because of mitigation efforts of monitoring and educating others of NSP. During the

11 same time of red tides, the number of hospital visits for NSP symptoms increases showing an association. Florida’s hospitals show that “pneumonia, bronchitis, asthma and respiratory” problems significantly increase by 31% to 64% during red tide events (Brand,

2012). Brevotoxins does not have any effects on filter feeders, so they keep filtering the algal producing brevotoxin (Steidinger, 2008a). Public health is affected when people eat filter feeders such as clams, oysters, mussels, conch and whelks that have been contaminated with brevotoxin (Watkins, 2008). To reduce the number of NSP incidence, commercial shellfish harvests near the coast beds, keeping a close eye on the status of water quality before they open.

NSP symptoms are acute, involving the gastrointestinal and neurological systems

(Kirkpatrick et al., 2010). The symptoms do not last long, the average recovery time is two to three days. The symptoms are vomiting, nausea, liquid discharge, numbness, tingling in face, partial paralysis of limbs, and loss of coordination. A person with NSP will also experience hot and cold sensations, unclear speech, pupal dilation, tightness of chest and throat, and fatigue (Watkins, 2008; Kirkpatrick et al., 2010; Reich, 2015). NSP is a disease to worry about because of the discomfort with the multiple symptoms that are associated with it.

There are not a lot of records of NSP because this disease is often under reported. NSP is often mistaken as Paralytic Shellfish Poisoning (PSP) because NSP symptoms are comparable to PSP (Watkins, 2008). NSP is also misdiagnosed for food poisoning or an allergic reaction (Reich, 2015). Other times, the individual with NSP choose not to get treated medically because of no health coverage (Brand, 2012). Due to the under reports for NSP,

12 there is not a lot of knowledge to understand fully what the impacts to humans are, except that there is an association of hospital visits for gastrointestinal related illness during red tide events in Florida (Brand, 2012).

Even commercial shellfish harvest closed due to high counts of K. brevis there are still people who may suffer from NSP from obtaining shellfish from other sources. According to

Florida’s Biotoxin Control Plan, shellfish beds must close when there are at least 5,000 cell counts or more per liter sampled (Watkins, 2008). Other sources of shellfishes are from recreational purposes from people who were unaware of red tide outbreaks.

From 2004 to 2009, 78% of the people who were reported to have NSP were either tourists or other non-residents (Reich, 2015). On July 2005, a Vietnamese family of three were hospitalized after consuming boiled clams. Two were children and the other adult that were clamming in the Boca Grande area. At another incident, a 64-year-old Vietnamese man were sent to the hospital on March 2006 shortly after he harvested and cooked his own shellfish (Reich, 2015). These were just a few incidents; the majority of these incidents are from tourists and non-English speakers. Tourists are less aware of what NSP is and there are a language barrier between non-English speakers. The challenges to lower NSP events are to educate ongoing Florida visitors and minorities.

Ecosystem Impacts

Sharks

There is evidence that animal mortality rates still occur even after a red tide is over.

Birds, manatees, bottlenose dolphins and sharks populations are affected due to their diet

(Brand, 2012; Steidinger, 2008a). Fishes, crustaceans and bivalves that are contaminated with brevotoxins had biomagnified the toxin concentration and will transfer over to the next food web once consumed (Steidinger, 2008a). Bivalves are not affected by the neurotoxins, there are high chances that high concentration accumulates in bivalves as they continue to filter feed, known as biomagnifies, and will harm those who consume it (Brand et al., 2012).

For example, in Florida at the St. Andrews bay, dead sharks washed ashore on October 2000

(Flewelling, 2010). There were about 300 sharks ranging from .2 to 2 meters long washed up with no signs of death from fishing (Flewelling, 2010). Two months before the washed up to shore, were red tides blooms in August nearby the area, the sharks’ tissues were positive when tested for brevotoxins in tissue (Flewelling, 2010). This example shows that animals can still be affected when red tides are not active from ingesting brevotoxin-contaminated preys.

Florida’s most common sharks are Atlantic sharpnose, blacktip, bonnethead, and lemon. Flewelling (2010) sampled tissues of listed sharks during a red tide event and a no red tide event. Results (Fig. 3. Comparing brevotoxin mean in tissues of shark that was present and not present in red tides southwest Florida and Florida Keys.) shows that there are higher concentrations of brevotoxins in sharks during red tides. Collections were from the Atlantic Coast of Florida and southwest of Florida. 19% of sharks had brevotoxins detected from samples that were collected with no blooms while 54% of the sharks sampled from red tides were detected with the toxin.

Birds

Seabirds are another affected animal when exposed to K. brevis. Their diet contains mostly shellfish, which is a bivalve that have high accumulation of K. brevis. In October 1973 in Florida, many seabirds such as red breast mergansers (Mergus merganser), lesser scaup

(Aythya affinis) and double crested cormrants (Phalacrocorax auratus) were found dead

(Landsberg et al., 2009) From 2005 to 2006 at a rehabilitation center near West central

Florida, 69% of seabirds were detected for brevotoxins (Fauquier, 2013).

Dolphins and Manatees

The two common marine mammals that had had their population affected by K. brevis are bottleneck dolphins (Tursiops truncates) and manatees (Trichechus senegalensis). One factor that all 740 bottleneck dolphins (Tursiops truncates) that had died from 1987 to 1988 had in common were the high concentrations of brevetoxins found in their system

(Landsberg et al., 2009). The dolphin “die-off” occurred in North Carolina, which was about the same time after the red tide in Florida occurred. The red tide must have traveled up to

North Carolina (Tester et al., 1991). Then, in years 1996, 2002, 2003, and 2005 there were manatees (Trichechus senegalensis) that faced large mortality events (Landsberg et al.,

2009). As the same with the bottleneck dolphins, manatees (Trichechus senegalensis) were found to have the highest detection in stomach, more than likely through ingesting seagrass that has tunicates, filter feeders that are contaminated by brevotoxins (Landsberg et al.,

2009; Brand et al., 2012). Seagrasses had shown to have brevotoxin in some of their components (Landsberg et al., 2009).

Sea Turtles

Florida’s common sea turtles are Loggerheads (Correta caretta), green turtles

(Chebnia mydas), and Kemp’s ridley (Lepidochelys kempii) are common sea turtles that are affected by brevotoxins. Sea turtles are reptiles and would have slower metabolisms. This means the contaminated sea turtles are going to take longer to recover compared to the other animals that were talked about. Also, there should be more of a concern about the high loss of these creatures because they are listed on the Endangered Species list (Fauquier et al., 2013). There is an outstanding number of sea turtle mortality in 2005 in Florida. The number of sea turtle that died due to the red tide was two to three times higher than the average of dead sea turtle loss in the last decade (Landsberg et al., 2009).

During the same year, Fauquier et al. (2013) documented sea turtle mortalities for a year (2015 – 2016). Their experiment was to monitor how much brevotoxins were present in sea turtles, either alive or dead, and documented how much presented in each body part

(Fauquier et. al 2013). As a result, they detected that 95% of their sampled stranded sea turtles contained brevotoxins (Table 1. In percentage, live and dead stranded sea turtles that were positive for brevotoxins). From Table 1, notice that those who died had the highest concentration in stomach (more neurotoxins in small and large intestines), indicating some sort of ingestion of a lower tier prey that was contaminated by brevotoxin.

Possible Mitigation

Flow Cytometry – Monitor and Early Detection System

Flow Cytometry should become an everyday tool to detect and monitor for K. brevis cell count levels ahead of time. To detect K. brevis early is important to lessen human health

16 risks. The current monitoring method for K. brevis is counting cell density using light microscopes. If cell density reaches 5,000 cells per liter of sampled marine water, all shellfish harvest areas are notified to close and the Florida Department of Agriculture and Consumer

(FDAC) website will be updated. Shellfish harvesters should check FDAC every morning as protocol (Reich, 2015). Currently, the light microscope is the common tool used to count K. brevis cell density when monitoring (Buskey, 2006). This method takes five to ten times longer, tedious, and expensive.

A Flow Cytometry used to count cell density will be more effective at detecting high levels of K. brevis at a faster rate. An example of a Flow Cytometry is a Fluid Imaging

Technology (FlowCAM) that can characterize phytoplankton particles continuously (Buskey,

2006). The water samples go through a slim glass chamber where each particle is captured.

After, there is a result list providing extra information a light microscope would not be able to compute. For example, captured images show particle dimension and can magnify. The results also provide the maximum and minimum dimensions (among samples) and algal fluorescence information (Buskey, 2006). To accurately count specific cells by genus and have 200 captured images takes approximately 15 minutes, which is 10 times faster compared to light microscopes (Buskey, 2006; Brand et al., 2012).

Warning Signs

To prevent NSP incidents, noticeable warning signs of prohibited shellfish bed harvesting should be provided in common areas to tourists (Watkins, 2008). Noticeable warning signs are most useful in recreational areas for tourists of Florida. Most NSP incidents

17 happens to Florida non-residents who are most likely less aware. FDAC website updates K. brevis level counts daily where commercial recreational shellfish harvesting areas should check before opening (Reich, 2015). Most recreational shellfish harvesting areas do not know about the website. The website will also have a map that shows which areas are prohibited from harvesting. This can be confusing for a Florida visitor to use; the map is too complex (Reich, 2015). The map should be simpler to use by visitors to reduce NSP outbreaks.

There is a strong idea that pollution or access nutrients is how K. brevis begins, but I do not believe that is true. K. brevis begins offshore of where there are little to no nutrients

(Sinclair, 2009). No one knows for sure how K. brevis blooms starts but when the blooms disperse towards shores the nutrient runoff from lands helps the blooms grow (Brand et al.,

2012). Less pesticide such as fertilizers should be used because fertilizers provide any algal an abundance of nutrients, nitrogen and phosphorus.

Conclusion

The abundance of K. brevis in marine environment is a health risk to the public and large marine-related animals. Frequency of Florida’s red tides involving K. brevis used to be sporadic but increased since 1844 (Abraham, 2006). Currently, red tides occur annually and last longer than usual. The public’s safety is a concern because aerosolized toxins produced by K. brevis, called brevotoxins, can cause respiratory irritation when inhaled. Another concern for public safety is the disease NSP that humans develop after eating contaminated filter feeders. K. brevis is a threat to animal’s mortality. Flow Cytometry to detect lethal levels

18 of harmful algal faster and noticeable warning signs for shellfish-prohibited harvest areas will be useful mitigation efforts.

Considered to be at the top of the food chain, humans are facing sickness and disease that have transported over from a lower tier of the food chain. The consumption of contaminated filter feeders results in NSP, which mostly happens to Florida’s non-residents.

Brevotoxins can aerosolize and travel inland causing respiratory irritation. The symptoms of K. brevis are related to gastrointestinal and respiratory system that have recorded to increase during the red tide events.

Animals living in and around the marine environment are in danger by K. brevis.

Mortality rates of sharks, birds, dolphins, manatees, and sea turtles would increase during and after red tide events. The studies and experiments talked about in this paper show that dead and sick animal during red tides were detected for high concentrations of brevotoxin levels. Levels of toxins were found to be highest at the intestines indicating ingestion of brevotoxin-contaminated prey.

Some solutions to prevent K. brevis from flourishing will include behavioral changes and adjusting monitoring methods. When lethal levels of K. brevis are detected ahead of time, people can better prepare at avoiding seafood consumption. In addition, people can avoid swimming in water. Also, shellfish harvesting areas can close ahead of time. To detect if cell counts of K. brevis is above lethal levels of 5,000 cell counts of K. brevis per liter of sampled water sooner, a Cytometry should be used in the monitoring process. Tourists in Florida are less aware of NSP, having noticeable signs at recreational harvesting area will help tourist determine if the shellfish bed from that area can be harvested.

Although, there are research studies that shows an association between the number of hospital visits during red tide occurrences, there are no direct connections to prove that

K. brevis cause respiratory irritations and NSP. Cases for individuals should be studied before and after Florida red tide events. Another possible study is to interview individuals who visited Sarasota Memorial Hospital (SMH) for gastrointestinal and respiratory related illness; asking what the person did before symptoms occurred. Therefore, there are not enough evidence and more studies are needed.

Figures

Figure 1. Map of Florida and its coast (NOAA).

Figure 2. Microscopic view of Karenia brevis (Persson 2013).

Tables

Figure 3. Comparing brevetoxin mean in tissues of shark that was present and not present in red tides southwest Florida and Florida Keys. Four shark tissues sampled: Atlantic sharpnose, blacktip, bonnethead, and lemon sharks (Flewelling 2010).

Table 1. In percentage, live and dead stranded sea turtles that were positive for brevotoxins. (Fauquier et. al 2013)

Reference

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