Thursday, 22 August 2019


Experimenting with a CO2-enriched environment

Mercury Bay Area School science teacher Thomas Everth is spending part of the summer school holidays developing an experiment that will enable school students to investigate questions relating to plant growth in a CO2-enriched environment.

“I’ve created two identical boxes, with one of the boxes connected to a Sodastream CO2 bottle. The bottle releases CO2 into the box to maintain a CO2 level of 2,000 part per million [ppm], which is approximately five times the CO2 level in our atmosphere today. The CO2 level in the other box is similar to the ‘normal’ CO2 level in the atmosphere.”

Radishes are at the moment growing in both boxes. The radishes germinated from seed Thomas planted about two weeks ago. The plants have to be watered by hand.

In order to create the experiment, Thomas had to build a climate control unit and develop software to record the atmospheric data in both boxes. The climate control unit is WIFI enabled and post data every 10 minutes to an online database.

“The experiment isn’t only topical given the current worldwide focus on the level of CO2 in the atmosphere and how it may impact climate change, but can be applied in a variety of subjects at school,” says Thomas. “I can use the experiment in the earth and space science and statistics classes I’m teaching. For example, is there a difference in the average length of the plants growing in the CO2-enriched environment as opposed to the plants growing in the ‘normal’ CO2 environment? The same applies to the root systems of the plants. Another question that may be answered is whether the acidity level of water is different in a high CO2 environment?

“The technology in the experiment is also interesting to learn about, both the electronics and the software that are being used.

“There are possibilities for biology classes as well. Immediately coming to mind are stomata cells [the cells of plants that facilitate gas exchange]. Is the stomatal opening of plants growing in ‘normal’ conditions bigger or smaller than the opening of cells growing in a high CO2 environment?

“What I have already determined is that the radishes I’ve planted haven’t consumed much CO2 in the seed phase, but that changed dramatically once the plants have germinated.

“As far as I know, no other school in New Zealand is conducting an experiment like this at the moment.”

The Informer will from time to time check in with Thomas to see what the results of his experiment with the radishes and other CO2-enriched experiments are.

Picture: Thomas Everth with the CO2-enriched environment experiment he’s developing.



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