Introduction to Nitrogen Fixation
Biological N2 fixation is an important part of the marine nitrogen cycle as it provides a source of new nitrogen that can support biological carbon export and sequestration. Research in the past decade has focused on determining the patterns of distribution and abundance of diazotrophs, defining the environmental features leading to these patterns and characterizing the factors that constrain marine N2 fixation overall.
The export of organic material from surface into deeper waters is dependent on the amount of CO2 fixation (primary production) that is based on new nitrogen inputs (N2 fixation or nitrate diffusion from deep waters). Alternatively, some primary productivity is based on the regeneration of organic material to ammonia in surface waters. PON, particulate organic nitrogen.