Hobbies And Interests
Characteristics
Golden algae are photosynthetic: they derive their energy from carbon dioxide and sunlight. However, they are also facultatively heterotrophic: when light is low they can become predators, feeding on bacteria and diatoms. They have two unequal flagella, which are small whiplike structures, for locomotion. Most are free swimming, but some join together in filamentous chains or colonies. They are found in cold, low-nutrient waters and prefer a slightly acidic pH. Most lack a cell wall.
Chrysomonads
The chrysomonads or chrysophaceae, are mostly found in freshwater. They have a reproductive form that is heterokont; these have two unequally-sized flagella with different functions, that are 45 degrees relative to each other. They have an eyespot located near the base of the flagella, within a chloroplast. Some form cysts made of silica, and others have an amoeboid form, which moves through extensions of its cytoplasm. Most are free swimming, but some form palmate filaments that resemble palm leaves in shape. Many biologists believe they evolved from a symbiotic relationship with cyanobacteria, which is how they developed the ability to perform photosynthesis.
Silicomonads
The marine silicomonads or synurophyceae also have two flagella: a single long flagellum and a shorter whiplash flagellum. They form starlike silica shells that have been well preserved in the fossil record. When conditions are right, they form blooms, where millions of algae can be found together in a single area. Unlike red tide blooms, the toxins created by blooms of silicomonads are not known to be harmful to humans or other mammals, but can be harmful to fish. It is recommended nonetheless not to eat fish or swim in water where a golden algal bloom is occurring.
Representative Species
Dinobryon is a freshwater chrysomonad whose cells are lined with vase-shaped loricae, a protective covering made of chiton and other polysaccharides. Synura are a typical silicomonad, forming elaborate silica shells. The most common golden algae include: ochromonas, dinobryon, chromulina, mallomonas, synura, dictyocha, chrysamoeba, chryshosphera and chrysosaccus.