SEARCH Articles Figures Tables Biogeochemical cycle of nitrogen Biogeochemical cycling of nitrogen Evolution of the Nitrogen Biogeochemical Cycle Nitrogen cycle Nitrogen cycle cycling ( Oceanic Biogeochemistry of Iron and Phosphorus with the Marine Nitrogen Cycle Role of Nitrification in the Marine Nitrogen Cycle The Role of Marine Macroalgae in Nitrogen Retention, Cycling, Turnover, and Loss Tracer Methods for Studies of the Marine Nitrogen Cycle Used for Measurements of Nitrogen Cycle Process Rates