Algae Beads: Project Worksheets

Project Worksheet 1 of 3: Culturing Algae for Algae Beads

Culturing conditions:

What type of light source (LED, CFL):

Light source power (W, μmol photons/cm2, eV):

  • Note: the Google Science Journal app has an easy-to-use light meter

Distance from culture to the light source (cm):

Temperature (℃, including from light source):

Tracking growth:

Growth can be tracked in algal cultures using the depth at which a Secchi Disk occludes (disappears), as a proxy for cellular concentration. Secchi Disk Depth (SDD) tables provide reference cells/mL values; one is provided below. Below is a table that can be used for tracking growth over time. SDD data is to be recorded at reasonable intervals (between 12-24 hrs) and then converted to cells/mL using the provided conversion table. Data can then be plotted on the provided graph paper.

Time to reach SDD of ~20cm:




What is the relationship between the depth the Secchi disk occludes and the biomass of the algae?

According to your data, how does biomass change over time?

What variables could have affected the algal growth rate in your experiment? How did those variables present themselves on your graph?

What variables affect algal growth rates in the wild? How might those variables affect or change the graph of the population growth rate in the wild?

Project Worksheet 2 of 3: Creation of Algae Beads  


What was the consistency of the algae/alginate solution? Was it runny or thick? What made it like that?

What happened when the algae/alginate solution came into contact with the calcium chloride? Why did that happen?

Time how long it did take for the beads to harden. Roughly how long did this take? How do you think that time might change if there was more or less CaCl2 in your solution?

Record where you stored the beads. At what temperature were the beads stored? Are they kept in contact with light? Did you loosen the cap slightly to allow for gas exchange with the atmosphere?

Project Worksheet 3 of 3: Creation and Testing of pH Indicator Solution

How many beads did you put into each snap-cap tube?

Is your indicator solution functioning correctly? What test did you perform to verify that the indicator solution correctly identified acids? What about bases?

If your indicator solution did not function properly, how did you fix it?

Why is it important for future experimentation that the algae beads to start in a CO2 rich environment?

How will you know if photosynthesis is taking place?

How will you know if the solution or algae beads are not working?

**This section is for those who did not purchase the pre-diluted indicator solution**

Record the volume of water:

Record the volume of 10x stock indicator:

Record the final volume of the solution:

Record the final concentration of indicator solution (hint- this should be 1:10) and show any calculations below: