Home >> Science & Nature >> Science

How to Monitor Algae Growth

Algae are tiny, photosynthetic organisms that live almost everywhere on earth. They range from single-cell organisms to intricate, multicellular organisms like giant sea kelp. Algae are important because they provide food and nutrients to many other living organisms and provide oxygen to the underwater world. Some algae even serve as food additives to pudding, cheese, sherbet, milk, rubber and ice cream, others in medicine and still others for use as biofuel. Monitoring the growth of algae is a relatively simply task in a controlled laboratory environment and a spectrophotometer.

Things You'll Need

Sterile glass dish
Algae cells
Spectrophotometer

Instructions

- 1
  Place algae cells or a small sample of an algae strain you want to grow or research into a sterile dish. Place the dish in a controlled environment, such as a laboratory or office, where you can control the temperature and light conditions so that they are optimal for the heat and light needed by the algae strain to thrive.
- 2
  Bring a spectrophotometer next to the dish where the algae is growing. Set the optical lens and light wave generator of the spectrophotometer above the dish so that it is pointed at the algae sample.
- 3
  Set a few wavelengths on the spectrophotometer so that it shines several near-infrared wavelengths, such as 300, 400 and 500 nanometers, into the algae. Record the measurement of absorbance shown on the spectrophotometer for each wavelength. Understand that as the algae grows, it will absorb more of the light directed at it; read increased optical density measurements as algae growth.
- 4
  Take measurements twice a day, at the same times each day. Record the measurements to determine the growth rate of the algae over a few weeks' period. Use the information to better understand how the algae you are observing grows and what it may be used for.

Science