Description
Haematococcus pluvialis. This freshwater unicellular alga demonstrates a fascinating survival mechanism. When environmental conditions become unfavorable for H. pluvialis, it forms cysts. The cysts quickly accumulate large quantities of astaxanthin, which turns the cells a bright red color. This is thought to play a role in protecting the cysts from sunlight. Astaxanthin has a number of commercial and aquacultural uses and can be extracted from encysted cells. A number of environmental conditions can trigger encystment, including nutrient availability, overcrowding, light levels, and salinity, making this alga perfect for experiments involving response to the environment and the demonstration of survival mechanisms. Each green algae culture contains approximately 20 mL, enough material for a class of 30 students. This culture requires a low light level for vegetative growth—50 to 100 foot-candles of light 18 to 24″ from the culture. Optimal medium: Alga-Gro® Freshwater (item #153752). Optimum growth temperature: 22° C.