Lesson Plan: Estimating the biomass of algae in water
Estimating the biomass of algae in water
Become familiar with Beer’s Law (optical density is directly proportional to dissolved/suspended materials). The basis of using a spectrophotometer.
Become familiar with pros and cons of analytical methods that perform similar tasks.
It is somewhat difficult to determine the ‘mass’ of algae in water, because the cells are often very small and difficult to filter. Spirulina is a algae like cyanobacteria that is large enough to be filtered with a simple screen. Its larger size makes it a great candidate for experiments as separation is fast and easy.
3 liters of algae
Weight Boats, Aluminum
Optically estimate biomass
Dilute solutions of spirulina
Estimate biomass using secchi disk
Estimate biomass using spectrophotometer
Filter, Dry, weigh
Plot on paper
Plot on computer
Dilute spirulina into multiple containers volumetrically
mL Algae Culture
mL culture media (clear)
Determine SDD and all other possible biomass estimates
Filter out each one and create plots
We made a video that describes this dilution with the Secchi Disk.