Biogeochemical Cycling The cycling of nutrients through ecosystems via food chains and food webs,including the exchange of nutrients between the biosphere and the hydrosphere,atmosphere and geosphere (e.g.,soils and sediments) 16 16 Biogeochemical Cycling The cycling of nutrients through ecosystems via food chains and food webs, including the exchange of nutrients between the biosphere and the hydrosphere, atmosphere and geosphere (e.g., soils and sediments)