Harmful Algal Blooms
Over the last few decades, Harmful Algal Blooms (HABs) have become more prevalent worldwide. Today, the geographic range of HABs has expanded and the number of species responsible for blooms has increased. In addition, blooms have been occurring more frequently, lasting longer and are more severe. These events have a wide range of negative impacts on the environment, wildlife, people and the economy.
|
Environmental Impacts: HABs are characterized by the rapid, uncontrolled growth of an algae population. During a phytoplankton bloom, the water column typically becomes cloudy, or turbid, and the depth that sunlight can penetrate is greatly reduced. This poses a serious threat to submerged vegetation, like seagrasses, which require sunlight to survive. Long lasting blooms can permanently damage seagrass beds and diminish their chance of recovery. In addition, these blooms can also have a variety of impacts on the animals living in an affected area. Excess phytoplankton can clog many filter feeding organisms like clams, oysters and sponges, causing them to starve. Some species of algae are even equipped with sharp spines that can injure the delicate gills of fish and shellfish. Large, dense blooms can also deplete the amount of oxygen in the water column and cause mass die-offs of animals in an area (like fish-kills). Unfortunately, during these events, decaying algae and animals release nutrients back into the water, which continue to fuel the bloom. |
|
Human Health Impacts: Many of the species that cause HABs can also produce harmful toxins. In humans, these toxins cause a wide array of illnesses, ranging from mild respiratory distress to permanent brain damage or, in some cases, death. People typically encounter HAB toxins through direct contact with water during recreational activities or by breathing contaminated air near bloom locations. Illness can also occur as a result of eating contaminated seafood, like fish or shellfish.听 听provides additional information on Harmful Algal Blooms and associated health hazards. |
|
Economic Impacts: HABs can have significant impacts on Florida鈥檚 economy. Treating contaminated water and cleaning up beaches or waterways can be costly, especially during massive or long-lasting bloom events. Tourism and property values can suffer as a result of unsightly shorelines, odors from decaying material and inherent health hazards, making areas less popular to both visitors and residents. Recreational industries also incur losses due to a decline in popular activities like swimming, boating, fishing and sight-seeing. In addition, commercial fisheries are negatively affected due to shellfish closures, mortalities of wild fish stocks and a loss of sales due to declining consumer interests. Together, these factors pose a severe threat to Florida鈥檚 economy and will likely become worse with the increasing prevalence of HABs. |
|
This research is funded by proceeds from Florida's Save Our Seas specialty license plate. |
|
Principal Investigator
Brian E. Lapointe, Ph.D.
Research Professor 772.242.2276 blapoin1@fau.edu
|
Dr. Lapointe鈥檚 research interests include algal physiology and biochemistry, seagrass and coral reef ecology, eutrophication, marine bioinvasions and marine conservation.
He has extensive experience in water quality research in South Florida and the Caribbean region. As Chief Scientist on numerous Caribbean and western North Atlantic Ocean research expeditions, he has amassed valuable field experience in assessing relations between water quality and the health of tropical seagrasses and coral reefs. Dr. Lapointe鈥檚 long-term water quality monitoring at Looe Key reef in the Florida Keys represents the longest low-level nutrient record for a coral reef anywhere in the world. His work in the Keys led to a strong phosphate ban and new state regulations for Monroe County requiring greater nutrient removal from sewage effluents.
Dr. Lapointe鈥檚 work in Florida Bay and the Florida Keys National Marine Sanctuary in the 1990s, which utilized stable nitrogen isotopes to 鈥渇ingerprint鈥� nitrogen sources, was the first to demonstrate the importance of agricultural nitrogen from mainland sources to development of algal blooms in the Keys. He developed the first 鈥渞idge-to-reef鈥� water quality monitoring program for the European Union in Negril, Jamaica, a model that has been adopted by Marine Protected Areas around the Caribbean region. Dr. Lapointe has advised the U.S. Environmental Protection Agency, National Oceanic and Atmospheric Administration, State of Florida and the governments of Monroe County (Florida Keys), Palm Beach County, Lee County, Bahamas, Tobago, Turks & Caicos, Jamaica, Bonaire, Curacao, Martinique and St. Lucia on development of water quality monitoring programs for assessing the impacts of land-based pollution.
Dr. Lapointe鈥檚听 Sargassum 听research has yielded novel insights into the ecology of this macroalgae, the Sargasso Sea and associated communities, including symbiosis with juvenile fish marked by exchange of habitat and nutrients.
What are Algae?
|
Algae are a diverse group of plant-like organisms, with over 70,000 different species that can be found around the globe. These aquatic organisms use photosynthesis to create food from sunlight, like plants on land. However, algae lack roots, stems and leaves which is what separates them from true plants. Instead, some types of algae possess rudimentary structures called holdfasts, stipes and blades which help them carry out similar functions. Algae can be divided into two main groups, microalgae and macroalgae, based on size and further divided based on the color of their pigments, red, green or brown. |
|
Microalgae, also known as phytoplankton, cannot be seen with the naked eye. These microscopic organisms come in a variety of different shapes, sizes and colors. Some phytoplankton can move on their own, with whip-like tails, while others must rely on buoyancy and water movement to transport or distribute them. Phytoplankton are important because they serve as the foundation of many webs and produce about 70% of the oxygen we breathe! |
|
Macroalgae, on the other hand, are large and can easily be seen with the naked eye. These organisms can range from single clumps to massive underwater forests that reach heights of 150 ft. In addition to serving as an important food source, macroalgae also provide critical habitat for animals from microscopic crustaceans to large whales! Macroalgae also have many commercial applications including cosmetics, biofuels and medicines. |
|
Microcystis aeruginosa This cyanobacterium, or 鈥淏lue-green algae鈥�, is a freshwater species that typically blooms during warm, rainy months. These blooms originate in Lake Okeechobee and enter the St. Lucie Estuary and the Caloosahatchee River during seasonal freshwater releases. These cyanobacterium produce toxins called microcystins. While consuming contaminated water is known to cause damage to the liver or digestive system, the effects of inhaling the toxin or its bioaccumulation in seafood are not well documented. |
|
Aureoumbra lagunensis Known as 鈥渂rown-tide鈥�, this alga grows in marine environments and has been documented in the Northern Indian River Lagoon, Mosquito Lagoon and the Banana River. Since 2015, a vast and persistent听 Aureoumbra lagunensis 听bloom in this region has caused major ecological shifts as well as some of the largest fish kills on the east coast of Florida. This species has no known negative impacts on human health. 听 |
|
Karenia brevis Also known as 鈥渞ed-tide鈥�, this dinoflagellate blooms annually in the Gulf of Mexico, usually during late summer or early fall, and widely impacts the west coast of Florida. Under rare circumstances, currents can transport these blooms south, and around the tip of Florida where they can then impact the east coast.听 Karenia brevis 听produces brevetoxin, a neurotoxin that can cause neurologic shellfish poisoning if consumed, or more commonly, asthma-like symptoms if inhaled. 听 |
|
Pseudonitzchia sp. This diatom occurs throughout coastal Florida, specifically the Indian River Lagoon, and generally blooms during the spring and fall. Even in high abundances, this species cannot be seen with the naked eye. It produces a toxin known as domoic acid, a neurotoxin that can cause amnesic shellfish poisoning if consumed. High doses of domoic acid can be fatal, but lower doses can still cause brain damage in the form of short-term memory loss. To date, no clinical cases have been documented in Florida. 听 |
|
Pyrodinium bahamense This dinoflagellate typically blooms in water bodies that have brackish salinities, shallow depths and low flushing rates. Annual blooms occur in Tampa bay and the northern Indian River Lagoon between April and October.听 Pyrodinium bahamense 听produces saxitoxin, a neurotoxin that, when consumed, can cause both paralytic shellfish poisoning and saxitoxin pufferfish poisoning. 听 |
|
Synechococcus sp. This cyanobacterium, or 鈥渂lue-green algae鈥� has only been known to bloom in Florida Bay. The most recent bloom started in late 2016 and subsided in early 2017. There have been no human health implications documented. 听 |
|
Gambierdiscus toxicus This dinoflagellate grows attached to macroalgae, dead coral and sand and occurs regularly during the summer months throughout the Florida Keys. Blooms are invisible to the naked eye but can produce ciguatoxin, a neurotoxin that accumulates in reef fish. When consumed by humans, the toxin can cause ciguatera which leads to nausea, rash and sometimes serious cardiac and neurological abnormalities. Ciguatoxin cannot be detected by appearance, taste or smell and is not removed by freezing or cooking the fish. 听 |
|
Macroalgae While most HABs are formed by phytoplankton, some macroalgal species can cause economic and environmental issues when they bloom uncontrollably. One example is Sargassum, a seaweed that forms floating mats on the ocean鈥檚 surface. When this alga has an explosion of growth, these mats can block light from coral reefs and cause tourism declines when they wash up on beaches. Once the algae begins to decay, it can release hydrogen sulfide gas and make coastal areas unpleasant to recreate near. These blooms typically happen every summer in south Florida, although some years are worse than others. 听 |
|
A primary focus of the Florida Center for Coastal and Human Health is on the Indian River Lagoon (IRL), an estuary that covers 40% of Florida鈥檚 east coast. An estuary is a mix of freshwater from inland and saltwater from the ocean, creating a brackish environment. The IRL ecosystem is 156 miles long, contains 6 inlets, and impacts 6 counties, 45 cities and 1.6 million residents. There are over 4,000 plant and animal species that have been documented within the IRL and its watershed, naming it one of the most biologically diverse estuaries in North America. Due to its biological importance, and an estimated $8 billion annual economic value to the state of Florida, Congress designated the IRL as an 鈥淓stuary of National Significance" |
|
Unfortunately, the Indian River Lagoon is also one of the most impacted estuaries in the country. Recent shifts within the Lagoon鈥檚 ecosystem have resulted in extreme and unprecedented Harmful Algal Blooms that are not only more diverse than other areas in the United States, but also persist for longer periods of time and produce a wider range of harmful toxins. Many of these issues are linked to human activities in and around the IRL ecosystem and they indicate that the Lagoon may have reached a critical tipping point. |