U of M graduate students test leaf decomposition in CRWD’s Como neighborhood.
Graduate students in the college of Ecology, Evolution and Behavior at the University of Minnesota are at work on an urban biogeochemistry project trying to show how nutrients like phosphorous (P) and nitrogen (N) move through cities.
In winter and spring 2012 they spearheaded a small project to determine what happens to leaves that get ‘stuck’ overwinter either in lawns, curbs/gutters or storm drains: replicate bags of dried leaves were placed in these three potentially important spots in the urban landscape and collected over time to compute a rate of decay. Preliminary results show that leaves decompose faster in catch basins, due possibly to the consistently higher moisture conditions (water pools in the basins) which can be an important control of microbial activity.
In winter and spring 2013, the study is being replicated to see if these patterns are maintained despite the difference in total snowfall. In conjunction with this project, an undergraduate biology student is evaluating the amount of leachable nitrogen and phosphorus remaining in the leaves through time. In total, this project has implications for management of cities, e.g. how often streets are swept, and will help with the understanding of how leaf litter influences fluxes of nutrients that ultimately reach Como Lake and beyond.