The Red Tide

1. The Red Tide Background Information: In the Gulf of Mexico, red tides are caused by the rapid growth of Karenia Brevis, a species of algae. The are called red tides because the high concentration of algae cause the water to appear read (see picture below). Scientists are unsure what causes a red tide, but factors like temperature and nutrient and salt concentration are thought to be important. The algae, K. Brevis, produces a collection of toxins known as brevetoxins. During a red tide, the concentration of brevetoxins increases to a level that is harmful. As a result, the cells and tissue of small organisms shellfish become contaminated or polluted with the toxin. They also discovered that when zooplankton or other organisms consumed contaminated organisms, they absorbed the brevetoxins into their cells and tissue. Simply, the toxin was being passed up the food chain. Scientists also discovered that organisms are unable to quickly break down and remove the toxin, and therefore it collects their cells and tissues. The collection of a chemical or substance in the tissue of an organism is known as bioaccumulation. Bioaccumulation leads to biomagnifacation. Biomagnifacation is a process where the the concentration of a chemical in an organism increases as you move up the food chain. This happens because organisms higher in the food chain or energy pyramid must consume more food, and therefor consume more of the ciguatera toxin. Brevetoxins can kill fish if the concentration in the water is high enough or if they consume other organisms containing the toxins. Human who eat shellfish are at risk of neurotoxic shellfish poisoning (NSP), which in rare situations has caused death. States along the gulf coast like Texas post warnings on beaches and online to warn people of a red tide. Zooplankton Dead Fish Dog Snapper K. Brevis Barracuda Gag Fish Sea Grass and Shellfish contaminated with brevetoxins.

2. (Name of Pollutant or Toxin) • Source: • (What is the source of the pollutant or toxin?) • Bioaccumulation: • (What is bioaccumulation?) • (Where does the pollutant or toxin enter the food chain/web) • Biomagnification: • (What is biomagnification) • (Which organism in the food chain/web is most affected by biomagnification?) • Consequences: • (How does the pollutant or toxin affect living things?) • (Are humans at risk?) Copy and paste a picture that is related to the information Lake Trout 4.83 Lake Trout 4.83

3. (Insert Title) Zooplankton Dead Fish Dog Snapper K. Brevis Barracuda Gag Fish Sea Grass and Shellfish contaminated with brevetoxins. Lake Trout 4.83 Lake Trout 4.83