The rising CO2 levels are impacting everything, from humans to insects in the soil!
SHARE:
- The story: Insects are not only the most numerous creatures, but a vital cog in the natural scheme of things. They outnumber humans a billion to one and make up more than 75 per cent of animals on earth. They are the primary providers of essential ecosystem services such as pollination and waste recycling.
- Dying out fast: Various researches show that their numbers are falling fast. Some even call it an “insect apocalypse”. Why is that happening? There are many reasons, including light pollution, insecticide use, habitat loss and changing weather etc. These effects are patchy in terms of their occurrence across the planet.
- CO2 is the culprit: Elevated atmospheric carbon dioxide (eCO₂), is a global problem. It permeates every inch of our biosphere, including the soil. More than half of the known species of insects spend a substantial portion of their life cycle underground. This is where they are potentially under the influence of eCO₂.
- For air breathing animals, increases in atmospheric CO₂ are trivial. The CO₂ levels in human lungs are 100 times greater than those in the air, and can be rapidly returned to atmospheric levels by hyperventilating, with no ill effects.
- But Soil microbes see an increase in biomass under eCO₂. This allows them to consume more organic material in the soil and compete with other organisms for oxygen.
- Latest research used dung beetles as a model “canary in the mine” to test the effect of eCO₂ on soil-dwelling insects. It was found that beetles exposed to eCO₂ emerged later and smaller, and had a reduced chance of making it to adulthood.
- Soil creatures: Dung beetles are creatures of the soil. There, they bury dung and recycle it by feeding on it, both as larvae and as adults. They are an ideal organism on which to test the effects of eCO₂. Some dung dwelling beetles can tolerate extreme levels of CO₂, accompanied by low levels of O₂. These exposures are only for short periods (minutes to hours), such as those experienced when tunnelling through oxygen-depleted dung.
- But immature dung beetles developing inside their brood balls, buried deep in the soil, will be exposed to eCO₂ for weeks or even months.
- Dung beetle larvae develop inside a ball of dung, where they eat the inner walls, digest the dung and defecate the remains back onto the wall, to be eaten again.
- Unlike the adults, they consume all the big bits with the help of strong jaws, which the adults lack. Microbes, both within their gut and on the inner wall of the ball, probably assist in the breakdown of tough plant remains containing what would be otherwise undigestible lignin (the compound that makes plants woody) and cellulose. Microbes may even fix valuable nitrogen from the atmosphere, which would contribute to proteins in the growing larvae.
- Elevated CO₂ could be interfering with this symbiotic relationship in the dung ball, either by promoting the growth of unwanted microorganisms which consume what the dung beetle larva should be eating, or by changing the physical conditions inside the larval ball – or both.
- More and more: Humans add more than 35 billion metric tons of CO₂ to the atmosphere every year. This CO₂ is stimulating microbial activity in the soil, which leads to a contest for food and oxygen with developing insects, while altering their underground habitat.
- When experiments used pre-industrial levels of CO₂ (250 parts per million, or ppm), current levels (400 ppm), and levels predicted by 2050 (600 ppm), and 2070 (800 ppm) in the experiments, even the current eCO₂ reduced beetle size and slowed their development compared to their “pre-industrial” relatives. It appears therefore that the soil insects are already taking strain.
- The balls in which the beetles were growing was changed by the atmosphere in the chambers.
- Summary: The best policy now is for humans to curtail the CO₂ output sooner rather than later. This will safeguard not only humanity, but the little things that run our world, too.
- EXAM QUESTIONS: (1) Explain the manner in which CO2 level in atmosphere impacts the numerous insects of the soil. (2) The soil biome is a whole subset of nature. Comment analytically. (3) Rising CO2 levels will impact not only humanity, but every component of nature. Do you agree? How?
#CO2 #DungBeetle #SoilBiome #Nitrogen #Insects #GlobalWarming #ClimateChange #Environment
* Content sourced from free internet sources (publications, PIB site, international sites, etc.). Take your own subscriptions. Copyrights acknowledged.
COMMENTS