Our final assignment was to use everything we’ve learned this term to design and conduct our own independent project. Other than taking part in my elementary school’s science fairs, I had never directed my own research project. I started by choosing an invertebrate that I wanted learn more about. Easy enough, but there are a lot of interesting (bizarre, adorable, creepy, amazing) invertebrates out there. Eventually, I decided to pick a terrestrial invertebrate. I chose, drum roll please… earthworms!
Earthworms play an important role in soil ecosystems. They’re decomposers, which means that they recycle organic matter (ex. leaves) in the soil. This not only benefits the worms, but also other organisms in the soil and above ground. Next, I thought about what it was that I wanted to learn from my project?
In another one of my classes, I’ve been learning about sources of pollution and their effect(s) on the environment. One source of pollution that we keep returning to is pesticide use. Pesticides contain various chemicals that are used to control pests. These chemicals can be very toxic to organisms. Each year, large quantities of pesticides are sprayed on farmlands in an effort to improve the quality and quantity of crops. Shockingly, it has been estimated that less than 0.1% of sprayed pesticides actually make it to their target pest. All this got me thinking about where pesticides end up and how they could potentially impact ecosystems. Voila! Just like that, I had an idea for my project. I looked at the effects of pesticides on decomposition by earthworms.
More specifically, I looked at how quickly Red Wigglers (Eisenia Fetida) ate pieces of banana when placed in large plastic cups containing either regular garden soil or garden soil treated with a widely used weed killer called RoundUp. Red Wigglers are composting worms. They enjoy eating food scraps and are very fast eaters!
My experiment consisted of two parts. First, I wanted to determine if Red Wigglers preferred regular or treated soil. They had a very strong preference for the regular soil. In fact, when I placed my worms in the plastic cups for the second part of my experiment, instead of quickly burrowing into the soil, some of the worms did the exact opposite and tried to escape! Eventually, all of them burrowed into the soil and for the next 10-days were left to chow down on pieces of banana. Afterwards, I emptied all of the cups, recording the difference in the weight of the worms and pieces of banana.
Originally, I predicted that the worms in the treated soil would eat less banana than the worms in the regular soil. To my surprise, the average difference in weight between the worms and banana pieces in the regular and treated soil were practically the same. In other words, the worms in the treated soil, ate the same amount of banana as the worms in the control soil.
I designed my experiment to mimic how people use RoundUp on their lawns and gardens. Based on the results of my experiment, it’s possible that the domestic use of RoundUp doesn’t negatively effect the health of earthworms. This is good news for the worms and soil ecosystems. Nevertheless, pesticides do contain potentially harmful chemicals, and should always be used with caution. All and all, I ended up having a lot of fun with my project! If you want to learn more about pesticides and/or worm composting, aka. vermicomposting follow the links below.
WormWorx Organic Recycling – http://wormworx.ca/
General info about pesticides – http://www.agf.gov.bc.ca/pesticides/