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“Can I fumigate an aircraft to remove rats using CO2?” A client who owned an expensive private aircraft needed to know. Here's how he did it.

If you’re looking for something fun to do together with your kids, family or friends this season; why not try these fun and spooky experiments with CO2? 

Guest post by Michael Forster, Edaphic Scientific Pty Ltd

Everyone knows that plants need carbon dioxide to grow. But fewer people know that carbon dioxide can also effect plant transpiration and even the water balance of entire ecosystems and catchments. Even fewer people know that carbon dioxide can affect biodiversity and which plant species are more common than other species.

Let’s just leave aside all of the topics on how increasing carbon dioxide is leading to global warming and how this, in turn, is impacting on plant species. Let’s just focus purely on how increasing atmospheric carbon dioxide changes the fundamental physiology of plants and how this, in turn, can lead to changes in transpiration and which species are more common in a forest.

Firstly, how do we know all of this? Scientists have been conducting experiments for years now where they have artificially increased atmospheric carbon dioxide around plants and forests.

They do this via experiments called FACE – or Free Air Carbon Enrichment – where massive towers gorge out copious amounts of CO2. Image: FACE experiment at Duke University, North Carolina, USA (source: https://www.czen.org/content/duke-forest-face-experiment)

Another approach is to grow a large tree in what is called a Whole Tree Chamber and manipulate carbon dioxide levels in the chamber. Image: Whole Tree Chamber Experiment at University of Western Sydney, Australia (source: http://www.uws.edu.au/hie/facilities/whole_tree_chambers)

What these experiments have generally shown is that plants actually like it when there is more carbon dioxide in the atmosphere. Plants generally grow larger and faster with more CO2. The process is similar to when you add fertilizer to the soil to assist the plant’s growth. Instead, we are adding fertilizer to the atmosphere in the form of more carbon dioxide. As there is more carbon dioxide in the atmosphere, it is generally easier for plants to perform photosynthesis and accumulate biomass.

In terms of transpiration, or plant water use, an increase in atmospheric CO2 means that stomata, or the pores on leaves that exchange gases between the leaf and the atmosphere, do not need to open as much. This means that, at the scale of a leaf, less water is lost and there is lower transpiration. With increased photosynthesis and lower water loss, then the water efficiency of plants is increased.

So it seems that more carbon dioxide in the atmosphere is a good thing for plants – they grow faster and use less water. However, nothing in biology is so simple. Yes the water loss at the scale of a leaf is lower, however, there are more leaves on the plant because it is growing faster and bigger. So, at the scale of the entire plant, water use or transpiration is actually higher.

This may seem trivial but consider this: a 30 metre (100 foot) tall tree transpires about 200 litres (53 gallons) on a good day. A forest of woodland contains many thousands to millions of individual trees all transpiring about 200 litres per day. This can impact on water reserves – particularly around dams for drinking water or irrigation. With increased atmospheric carbon dioxide, all of those trees may potentially transpire more water and having a greater impact on water supplies.

Also, not all species of plants are created equally. Increasing carbon dioxide does improve growth but some species perform better than others. In a woodland or rainforest, some species may grow better and out compete their neighboring plants. That is, some species may become more common and others scarce. This may then impact on the animals that rely on those plants for food and shelter.
Increasing atmospheric carbon dioxide can benefit plants – something greenhouse and glasshouse growers use to their advantage. However, the process and outcomes are complex. In the real world increasing carbon dioxide does not benefit all plants.

Poultry is the most-consumed meat in both the United States and worldwide. Much of this expansion is due to the growth of large-scale production methods capable of delivering birds – especially chicken - to consumers at relatively low prices.

Bulk carbon dioxide has become an integral part of the booming poultry industry. In fact, at virtually every stage of a chicken's life-cycle, CO2 is used to maximize production. CO2Meter has had the opportunity to work with many producers in the industry, and we’ve developed an understanding of how our products are used.

• It starts with egg incubation. Using CO2 as a blanket gas over the eggs helps regulate overall temperature, resulting in fewer "early peeps". Many of our clients use our 1% CO2 Transmitter/Controller to monitor and control the CO2 levels.

• For eggs used in vaccine production, a virus is inserted into an egg, incubated, harvested, then inactivated. This process requires carbon dioxide levels in the 5-11% range, which can be achieved using our 30% CO2 controller in a NEMA4 enclosure. 

• Once the eggs have hatched, thousands of chicks are shipped from hatcheries to growers in trucks. Temperature and CO2 levels inside the trucks are logged for insurance purposes using our Remote CO2 Data Logger with the head unit inside the cab and the transmitter in the truck's trailer. 

• Chicks metabolize their food more slowly under high-CO2 levels. By regulating CO2, growers can shorten the time it takes to transform the chicks into broilers or egg laying hens. Many of our clients use the 1% CO2 IAQ Transmitter/Controller to maximize the balance between production and energy efficiency. 

• Once it is time for slaughter, CO2 is used in controlled atmosphere stunning (CAS) as a humane alternative to electrical stunning. The birds are placed in a portable unit or a sealed building that is flooded with CO2. Unconsciousness occurs at 40% CO2 levels within seconds, and death occurs at 65% CO2 concentration. To monitor high CO2 levels – and to protect farm workers from accidental leaks, our clients use 100% CO2 Sample Draw Meters.

• In poultry waste decomposition, Industrial ammonia fixed detectors play a crucial role in maintaining safety and ensuring optimal conditions in poultry farms. Because Ammonia (NH₃) is a common byproduct of poultry waste, if not properly managed, can reach levels that are harmful to both the poultry and farm workers. For this reason, industrial fixed ammonia gas detectors are critical for any workers near and around high concentrations of ammonia (NH3)

• Packaged poultry maintains its shelf-life longer using CO2 for modified atmosphere processing (MAP). Vacuum-sealed packages of poultry get up to 20% more shelf life by replacing the normal air in packages with CO2. To test the atmosphere inside packages, we offer the iSense CO2 & Oxygen MAP Inspection Station. This unit allows spot-check verification of sealed packaging equipment.