Galina Churkina
In this chapter, the interactions between urbanization and biogeochemical cycles are eximined, beginning with an analysis of how material flows are connected to these cycles and followed by a discussion of their broader implications. Cycles of carbon and nitrogen are highlighted because their alterations are prominent in urban areas and directly relevant to climate change. Carbon and nitrogen are two essential components of living matter on Earth, and their cycles are tightly linked with each other. The fluxes and reservoirs of those cycles are described and illustrated with multiple examples. The chapter concludes with a discussion of interactions among biogeochemical cycles, emphasizing that while carbon and nitrogen are central to urban biogeochemistry, accointing for other elemental cycles such as phosphorus, sulfur, and trace metals is essential for a more comprehensive understanding of urbanization feedback with biogeochemical cycles.