Learning Science during Teatime: Using a Citizen Science Approach to Collect Data on Litter Decomposition in Sweden and Austria

Taru Sandén,Hannah Wenng,Heide Spiegel,Michael Schwarz,Judith M Sarneel

doi:10.3390/su12187745

Abstract

The decay of organic material—litter decomposition—is a critical process for life on Earth and an essential part of the global carbon cycle. Yet, this basic process remains unknown to many citizens. The Tea Bag Index (TBI) measures decomposition in a standardized, measurable, achievable, climate-relevant, and time-relevant way by burying commercial tea bags in soil for three months and calculating proxies to characterize the decomposition process (expressed as decomposition rate (k) and stabilization factor (S)). We measured TBI at 8 cm soil depth with the help of school and farm citizen scientists in 2015 in Sweden and in 2016 in Austria. Questionnaires to the participating schools and farms enabled us to capture lessons learned from this participatory data collection. In total >5500 citizen scientists participated in the mass experiments, and approximately 50% of the tea bags sent out yielded successful results that fell well within previously reported ranges. The average decomposition rates (k) ranged from 0.008 to 0.012 g d−1 in Sweden and from 0.012 to 0.015 g d−1 in Austria. Stabilization factors (S) were up to four times higher in Sweden than Austria. Taking part in a global experiment was a great incentive for participants, and in future experiments the citizen scientists and TBI would benefit from having enhanced communication between the researchers and participants about the results gained.

Highlights

Soil is a key resource that is pivotal for our existence by providing numerous ecosystem services, such as food, fibre and fuel production, water purification, habitat for diverse organisms, nutrient recycling, and carbon sequestration [1,2]
No statistically significant differences were observed in the initial decomposition rates (k) and stabilization factors (S) between warming and control treatments in any of the environmental zones investigated in Sweden (Figure 1)
Our study successfully collected standardized data on litter decomposition in mass experiments in Sweden and in Austria, showing that citizen science can greatly contribute to generating new scientific knowledge on soils and help increase soil awareness among the general public

Summary

Introduction

Soil is a key resource that is pivotal for our existence by providing numerous ecosystem services, such as food, fibre and fuel production, water purification, habitat for diverse organisms, nutrient recycling, and carbon sequestration [1,2]. The interactions between the biotic breakdown of litter (by microbial communities) and the abiotic drivers of decomposition speed (chemical and physical soil parameters) are crucial for SOM accumulation and turnover, but not yet fully understood across large climatic gradients [3,5,6]. The influence of these interactions is of major interest for understanding, predicting, and modeling carbon cycle responses to environmental changes at different scales (local, national, global). These interactions are crucial in maintaining of a balanced carbon cycle and in preserving species and soil functions [3]

Objectives

Methods

Results

Discussion

Conclusion