Global Nitrogen Cycle: Critical Enzymes, Organisms, and Processes for Nitrogen Budgets and Dynamics

Abstract

Nitrogen (N) is used in many of life’s fundamental biomolecules, and it is also a participant in environmental redox chemistry. Biogeochemical processes control the amount and form of N available to organisms (“fixed” N). These interacting processes result in N acting as the proximate limiting nutrient in most surface environments. Here, we review the global biogeochemical cycle of N and its anthropogenic perturbation. We introduce important reservoirs and processes affecting N in the environment, focusing on the ocean, in which N cycling is more generalizable than in terrestrial systems, which are more heterogeneous. Particular attention is given to processes that create and destroy fixed N because these comprise the fixed N input/output budget, the most universal control on environmental N availability. We discuss preindustrial N budgets for terrestrial and marine systems and their modern-day alteration by N inputs from human activities. We summarize evidence indicating that the simultaneous roles of N as a required biomass constituent and an environmental redox intermediate lead to stabilizing feedbacks that tend to blunt the impact of N cycle perturbations at larger spatiotemporal scales, particularly in marine systems. As a result of these feedbacks, the anthropogenic “N problem” is distinct from the “carbon dioxide problem” in being more local and less global, more immediate and less persistent.

Elevated Levels of Biogenic Nonmethane Hydrocarbons in the Marine Boundary Layer of the Arabian Sea During the Intermonsoon

“…The widely used acetylene reduction assay technique to estimate nitrogen fixation rates suggests that Trichodesmium produce alkenes (Capone, 1993). Cyanobacteria are abundant primary producers that have a profound effect on the oceanic biogeochemical cycles (Zhang et al, 2020). Some prominent cyanobacterial genera such as Prochlorococcus , Synechococcus , and Trichodesmium can impact the sea‐air exchange of reactive VOCs (Swarthout et al, 2017).…”

High Resistance of a Sludge Enriched with Nitrogen-Fixing Bacteria to Ammonium Salts and Its Potential as a Biofertilizer

“…Possible microbial associations between the most representative genera were identified with the aim of getting an approximation of their role in the community. These genera were compared against the UniProt database (updated 2018) using the enzymes involved in the nitrogen cycle [ 1 , 37 ]. The nitrogenase enzyme was present in the inocula and 54.42% of the genera were reported as NFB.…”

“…Magnetospirillum has been described as oxidase and catalase positive. Oxidases enzymes are important in the nitrification process [ 1 , 37 ]. Magnetospirillum could be involved in the nitrifying process and it uses organic acids as a carbon source; however, it is not common for it to use carbohydrates.…”

Review on Biochemical Detection of Biological, Plant Samples Using Integrative Approach

“…In the recognition of the biological molecule the flurochrome is used which is used to produce the light in the sample. Some of the molecules which does not have the spectral properties in the fluorescence based transducer the dye is used in the sample which attached with the recognize element and when the chemical reaction take place in the sample they emit light which can be measured with the help of the transducer [28,29].…”