Nutrient Absorption and Biomass Production by the Marine Diatom Chaetoceros muelleri: Effects of Temperature, Salinity, Photoperiod, and Light Intensity

Abstract

The marine diatom Chaetoceros muelleri is commonly used for aquacultural feed and is well known for its fast growth and easy maintenance. In order to evaluate the potential of C. muelleri to be used for the nutrient removal and biomass production from eutrophicated saline wastewaters, the algae were cultured under a wide range of temperature, salinity, photoperiod, and light intensity. The optimum temperature for the biomass production was observed at 25°C, but the algae could maintain at least 66% of the highest production between 20°C and 35°C. The optimum salinity for the biomass production was 25, but the algae could maintain at least 22% of the highest production between 10 and 30. Both light intensity and photoperiod affected the algal biomass production, and the minimum light requirement was considered 100 μmol m−2 s−1 for 6 hours to maintain the biomass production and nitrogen (N) and phosphorus (P) absorption. Throughout all the experiments, the N and P absorption increased with the biomass production, but the ratio of N and P to the biomass exponentially decreased with the biomass production. These results showed that C. muelleri is tolerant to the wide range of environmental conditions, absorbing nutrients and producing organic matter. C. muelleri has a great potential to be introduced in the water treatment processes, especially where the temperature and salinity fluctuate.

Keywords

• microalgae
• bioremediation
• wastewater
• eutrophication
• estuary
• brackish water
• aquaculture