Cities host a diverse community of microorganisms, which includes, fungi, bacteria, viruses, and archaea. In fact, microorganisms inhabit everything from the soil and urban plants to buildings. Importantly, city-dwelling microorganisms play essential roles in the structure and functioning of urban spaces and well-being of humans. Urban landscapes often differ in microorganisms they host, e.g. no 2 cities have the same composition of microorganisms. However, we still lack a clear understanding of distribution and functions of microorganisms within cities, e.g. do neighborhoods of different socio-economic status differ in the composition of microorganisms? Answering this question is important to facilitate the design of the cities’ microbes and their importance for city-dwellers.

Project objectives: In this project, we aim to study the distribution and drivers of microbial communities associated with the urban landscapes of two cities in Quebec, i.e., Montreal and Sherbrooke. For this purpose, we plan to sample microorganisms in the air, tree leaves, roots, and soil over two urban gradients: tree diversity and social inequalities. We will also study microorganisms’ variation in time by sampling their communities at different time points during the season. To do that, we established 40 samplers in two cities (25 in Montreal and 15 in Sherbrooke) that collected microorganisms and air contaminants from early May to late September. We also collected leaves, roots, and soil of tree major trees species, such as Norway, Sugar and Silver maples. As the next step, we will use molecular tools (e.g. DNA screening methods) to describe the taxonomy of microorganisms present in the cities as well as their important functions.

Project significance: By providing answers to the heated question of whether neighbourhoods of different socio-economic status differ in the composition and functional roles of microorganisms, we will contribute to understanding how these microbes can be used in modulating the health and social inequalities of our cities. This knowledge is also essential to predict the consequences of urbanization, climate change and their interaction in altering microbial communities.

Figure 1. Figure demonstrates the location of traps in two target cities: Island of Montreal and Sherbrooke.