Harmful algal blooms

NOAA, https://www.noaa.gov/what-is-harmful-algal-bloom




Part 1: What are Harmful Algal Blooms?





NOAA, https://www.noaa.gov/what-is-harmful-algal-bloom

Have you ever been to the beach during a red tide in the Gulf of Mexico? Did you see reddish water, or did your eyes begin to sting? That is the result of what's known as a harmful algal bloom or, as it is often abbreviated, "HAB". A HAB is the name for a rapid increase of algae in a body of water. Such algal blooms are commonly known as "red tides", but can be orange, yellow, or brown depending on the type of algae that is blooming.

HABs are often seasonal events, and may be caused by many different factors ranging from an excess of nutrients, slow-moving water, or winds and currents causing physical aggregation of cells. Unfortunately, HABs can often cause damage to coastal ecosystems and economies. Bloom-forming algae not only discolor water, they can create dead zones, and in some cases where species are highly toxic, HABs can lead to the deaths of fish and marine mammals. In the Gulf of Mexico, toxic species can also impact human health either by causing respiratory distress when beachgoers inhale airborne toxins or devastating illnesses if contaminated shellfish are eaten. Shellfish poisoning is the most well-known effect of a HAB. As a result, many state departments resource managers are responsible for monitoring programs for these toxic blooms.

Researchers also contribute to this effort. Using specialized instruments, scientists make sure that HABs are well-monitored, and that human populations are protected from toxic shellfish. Also, by addressing questions like "how do algae make toxins?" and "what triggers a bloom?" scientists move closer to understanding marine biological systems. By working together, researchers are able to help keep coastal communities safer and citizens healthier.

This has been On the Ocean, a program made possible by the Department of Oceanography and a production of KAMU-FM on the campus of Texas A&M University in College Station. For more information and links please go to ocean.tamu.edu and click “On the Ocean.”

Contributing Professor: Dr. Lisa Campbell

Script Author: McKensie Daugherty





Part 2: Causes of HABs







NOAA, https://www.noaa.gov/what-is-harmful-algal-bloom

Harmful algal blooms, also known as "HABs", are caused by tiny plants in the ocean, known as phytoplankton. The term "phytoplankton" comes from the word "phyto", meaning "plant", and the word "plankton", meaning "drifter". There are more than 10,000 known species of oceanic phytoplankton, but only about 300 are known to cause blooms. Blooms occur when one species, of the many living in the water together, rapidly increases in number within a small region.

HABs can cause many biological problems. HAB species produce toxins that can harm fish, corals, and other invertebrates, and can cause respiratory distress in mammals. The effects of HABs also cause many economic problems by negatively impacting shellfish harvesting, as well as tourism in the locations where HABs reach the shore. Toxic algal blooms can shut down beaches for discolored water, can result in smelly piles of dead fish, and present an overall danger to human health. This can ruin a tourism-driven economy for weeks to months at a time. The toxins produced by HAB species include brevetoxins which cause neurotoxic shellfish poisoning, saxitoxins which cause paralytic shellfish poisoning, domoic acid which causes amnesiac shellfish poisoning, and ciguatoxins that cause ciguaterra fish poisoning.

Shellfish ingest toxic algae cells by filter feeding and subsequently concentrate the toxin inside their bodies. When humans eat these shellfish, they get a large dose of toxin, making it harmful since cooking shellfish will not eliminate toxins. Symptoms can include nausea, vomiting, paralysis, amnesia, neurological effects, and sometimes death, depending on the toxin. For this reason, early warning of HABs in the Gulf of Mexico is essential to prevent human illness.

This has been On the Ocean, a program made possible by the Department of Oceanography and a production of KAMU FM on the campus of Texas A&M University in College Station. For more information and links, please go to ocean.tamu.edu and click On the Ocean.

Script Authors: McKensie Daugherty

Contributing Professor: Dr. Lisa Campbell



Part 3: Karenia Blooms





NOAA, https://www.noaa.gov/what-is-harmful-algal-bloom

Harmful algal blooms, also known as "red tides", in the Gulf of Mexico are predominantly caused by the algae species Karenia brevis. Blooms of this toxin-producing alga occur almost annually in Florida, but less frequently along the Texas coast. A rapid increase in the number of K. brevis cells in a region can cause discolored water, widespread death of fish, as well as respiratory distress and neurotoxic shellfish poisoning in humans. Therefore it is very important that fisheries and beachgoers are properly warned of these blooms, making their prediction for the Texas coast a critical subject of scientific research.

Using historical data from the past 20 years, researchers found that measurements of the intensity and duration of along-shore winds were correlated with occurrences of Karenia blooms. Specifically, the along-shore winds create what is known as downwelling conditions. Downwelling occurs when surface waters converge. In this case, convergence occurs when surface water is moved towards the coast and this pileup pushes the surface water downwards. The convergence and consequent downwelling at the coast concentrates Karenia cells. The correlation of specific wind conditions and bloom occurrences allow researchers to accurately predict a Karenia bloom.

A Karenia bloom off the coast of Texas, photo credit NOAA

Researchers accurately predicted a bloom would hit the coastal bend of Texas on September 13th, 2015. This bloom caused widespread death of fish and a strong aerosol of brevetoxin, which produced respiratory distress in some areas along the Texas coast. This distress can be alleviated by going indoors and avoiding the areas affected. Texas Parks and Wildlife regularly updates their website on Red Tide Status to inform Texans of the areas affected and location of fish kills. Shellfish in the areas affected by Karenia blooms are monitored by the Department of State Health Services, which issues warnings, if necessary, to prevent neurotoxic shellfish poisoning.

This has been On the Ocean, a program made possible by the Department of Oceanography and a production of KAMU FM on the campus of Texas A&M University in College Station. For more information and links, please go to ocean.tamu.edu and click On the Ocean.

Script Author: McKensie Daugherty

Contributing Professor: Dr. Lisa Campbell




Part 4: Predicting HABs





NOAA, https://www.noaa.gov/what-is-harmful-algal-bloom

We have been discussing harmful algal blooms, or HABs this month. In this final segment we will discuss how scientists study these blooms and how this will help us to understand these natural phenomena. Gathering data on algae, or phytoplankton, is a multifaceted approach for the scientists involved. Data from satellites can measure things like water temperature, wind speed, current speed and direction, and light intensity at the areas where blooms are occurring. Buoys can provide data similar to satellite data, in addition to water salinity. Together, these instruments can provide detailed data for the conditions during a HAB, and using this data over a several year timescale, scientists can begin to hypothesize about the conditions necessary to cause and sustain a bloom for different species.

by taking samples of ocean water at several locations to identify and count phytoplankton, scientists are able to determine how widespread a bloom is in the ocean. A more advanced technique is using the Imaging-Flow Cytobot, an instrument that takes a small sample of water and uses a camera to take pictures of each phytoplankton cell. Computer software then automatically identifies the phytoplankton present in the sample. This technology is not only incredibly fast, but also allows automation of the identification and sampling process, allowing more samples to be examined each day.

An Imaging FlowCytobot produced by McLane Research Laboratories, Inc.

The Imaging FlowCytobot of Texas A&M University currently operates on the pier at the University of Texas Marine Science Institute and at the Coast Guard station in Surfside Beach, Texas. When a sample has enough toxic algae cells to signal a developing bloom, software programs automatically sends an email to researchers at Texas A&M University, the Texas Parks and Wildlife Department, and the Texas Department of State Health Services. This provides an early warning to state managers and they can begin testing shellfish for toxins. Overall, HABs present a real problem on the coasts, but by using continuous monitoring, researchers are able to help keep coastal populations safe and mitigate the impact of HABs.

This has been On the Ocean, a program made possible by the Department of Oceanography and a production of KAMU-FM on the campus of Texas A&M University in College Station. For more information and links, please go to ocean.tamu.edu and click “On the Ocean”.

Script Author: McKensie Daugherty

Contributing Professor: Dr. Lisa Campbell