BIOLOGY SEMINAR
Poisonous Algae Outbreaks
Background
Have you ever noticed a green moss-like substance floating on the surfaces of a lake, pond or swamp? This substance is known commonly as algae. Algae are a form of cyanobacteria. Cyanobacteria are water-dwelling and photosynthetic organisms, which means they live in water, or more-so float on the water’s surface and convert the energy from sunlight into glucose. They are unicellular, which makes them very small and hard to see individually. However, as colonies of these algae grow and clump together they become visible. Although these organisms are small, they are the largest and most important kind of bacteria on the planet. They also serve a useful purpose in the growing of food, by providing nitrogen fertilization in the planting and growing of as rice and beans. They are mostly found in freshwater but can also be seen in salt water such as oceans. (Campos & Vasconcelos, 2010).
Cyanobacteria are more commonly found in colonies, which tend to be unicellular. They can also be seen in filamentous forms, which tend to be multicellular in nature. The unicellular version becomes abundant when daughter cells undergo reproduction through the process of binary fission. They colonies are held together by a matrix of slime that is secreted from the organism during the reproduction. All reproduction that is undergone by cyanobacteria is asexual. The multicellular version becomes abundant when multiple cell division occurs in a single organism. Despite having an abnormally thick peptidoglycan layer surrounding the cell, cyanobacteria are considered gram-negative. However, it has recently been seen that they possess traits of both gram-negative and gram-positive organisms (Campos & Vasconcelos, 2010).