Biomass productivity of snow algae and model production algae under low temperature and low light conditions

Abstract

This study was designed to determine biomass productivities of specific algal species under low temperature and low light conditions. The algal species examined in this study included two psychrophilic algal species (Chlamydomonas yellowstonensis and Chlamydomonas augustae). These species are commonly known as “snow algae” due to their ability to grow in low temperature water bodies including ice and snow deposits. Additionally, two model production algal species used in high biomass productivity pilot studies (Scenedesmus bijuga and Chlorella sorokiniana) were evaluated. Currently, temperature dependent growth data within known optimal limits exists for these model production species but there is no detailed information about their biomass productivity under low temperatures. In addition, little information can be found about the potential for productivity of these species under limited light exposure. This study examined biomass productivity of these four species at four relatively low temperatures (5, 10, 15, and 20 °C) with three relatively low light exposures (50, 100, and 300 μmol/m2 s). It was hypothesized that the two psychrophilic algae species would produce more biomass per day than model production algal species under these limiting conditions. This study found that both snow algae species performed better than model production species at the lowest temperature (5 °C) and two lower light intensities (50 and100 μmol/m2/s). C. augustae growth rate was shown to have a positive correlation with temperature and a negative correlation with light intensity for the values observed in this study. This finding has significant implications for the use of C. augustae as a cool-season algal crop and a source of valuable genetic material for future engineering of algae. This could lead to the development of cool-season algal crops for sustainable, year-round, industrial production of algae in temperate climates. Furthermore, both of the snow algae species studied here showed inhibited growth at the highest light intensity studied here.