Tomorrow will be an exiting day in our global decomposition (plant decay) study. After four years of burying tea bags (25 000 bags to be exact) and collecting data (from 2500 locations), our collaborators in Zurich have been putting things together and will show us the first global decomposition maps! The tea bag virus broke out about ten years ago, when I was having a coffee break with my colleagues (well, actually I was having a tea break; Who needs coffee?). All day long, I had been filling so-called ’litter bags’ with plant material (reed). Before that, I had spend hours sowing these bags. So I needed a break.
Litter bags are bags made of plastic with little holes in it. In this way, only the plant material inside the bag will decompose whereas the bags remain a constant weight. So after making, filling and weighing such bags, one has to place them in the field and weight. Micro-organisms and everything else that fits trough the mesh of the bags will than start eating the plant material, and the bag will loose weight. By taking out bags at different time intervals (three or more) one can graph the weight loss over time and calculate decomposition rates. However, depending on the number of treatments, replicates and time intervals, one can end up with scary numbers of bags to prepare.
So did I, and therefore, I complained a lot during this coffee break. Staring at the tea bags in our cups we contemplating about al the sacrifices we made for science. The teabag was one of those fancy triangle ones that were new and fashionable in 2010’s. Suddenly I noticed that the fabric was equivalent to the bags that I had been struggling with in the lab. Plastic, with little holes. Not to let things in, but to let the flavor out. I showed it to my colleague and his replied that I was drinking a litter bag, as tea is also plant material. Instead of complaining, we started joking, and with a refreshed mind I filled my remaining litter bags.
Time went by and the thought of tea bags as equivalents of those laborious litter bags grew. So on a sunny day I was convinced that burying teabags was a better contribution to science than the manuscript I was working on so I shut down my computer, and went go out, into the sun, into the fresh green grass and got my hands dirty. On that memorial day the first triangle tea bags were buried, and the Tea Bag Index project was born. It would take another three year and a course project to develop the method further, and another four years concur the world. Last February researcher from everywhere gathered in Umeå, and tomorrow, we will take an important step towards publishing the results.
How does it work? It’s simple. We bury green tea and rooibos and measure the weight loss of the tea bags after three months. With the weight loss of rooibos we calculate a proxy for initial decomposition rates, whereas green tea tells us how much material will not be decomposed but stabilizes. With this information, we will create a global map of decomposition that can for instance be used as a reference for future decomposition studies or as input for climate models. You can read more about it on our website. During the past years, many people started their own projects, and they tell about their work in a short video made by Umeå University. Our work continues, aiming not only on data collection but also in providing a platform where people get connected and can share ideas, methodological insights and data. There are always opportunities for more research, and you are all welcome to join!