The Difference is Night and Day

Our initial intention for performing these treatments in the dark was that in darkness, the plants under treatment will not respire any O2, further depriving the pests of oxygen, therefore accelerating the expiration of the aerobic entities like pests and eggs. In addition, in darkness, the plant's stomata remain closed, further protecting plants with a mechanism that algae does not enjoy.

However, we did somewhat unexpectedly, did observe that the rate of expiration of the algae accelerated in darkness substantially as well. The algae expired at more than TWICE the rate when treated in the dark. In fact, some 12-hour expiratory events shortened to as little as 30 minutes simply from being performed in the dark.

These charts are derived from a 1977 study done at the Department of Vegetable Crops, UC Davis. The difference between chlorophyll reduction between light and dark treatments in the chart above is the interference of electrons in the algae with external, photonic energy. That energy taken by the CO2 solution takes the form of a photon (light), but in the dark, the energy (electrons) comes from the algae itself.