Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Microbes and the Nitrogen Cycle01:26

Microbes and the Nitrogen Cycle

The nitrogen cycle is a complex biogeochemical process critical to maintaining the balance of nitrogenous compounds in ecosystems. This cycle involves multiple microbial-mediated transformations through which nitrogen changes oxidation states, supporting essential ecological functions and contributing to plant and microbial growth.Nitrogen Fixation and AmmonificationNitrogen fixation initiates the cycle by converting inert atmospheric nitrogen (N₂) into bioavailable ammonia (NH₃), a process...
Inorganic Nitrogen Assimilation01:22

Inorganic Nitrogen Assimilation

Nitrogen is an essential element in biological systems, forming a crucial component of proteins, nucleic acids, and other cellular constituents. Many bacteria and archaea acquire nitrogen in the form of nitrate (NO₃⁻) or ammonia (NH₃), which are then assimilated into biomolecules through specific enzymatic pathways.Assimilatory Nitrate ReductionWhen nitrate enters the cell, it undergoes a two-step reduction process known as assimilatory nitrate reduction. Initially, the enzyme nitrate reductase...
Overview of Nitrogen Metabolism01:20

Overview of Nitrogen Metabolism

Nitrogen is a very important element for life because it is a major constituent of proteins and nucleic acids. It is a macronutrient, and in nature, it is recycled from organic compounds and stored in the form of  ammonia, ammonium ions, nitrate, nitrite, or  nitrogen gas by many metabolic processes. Many of these metabolic processes are carried out only by prokaryotes.
The largest pool of nitrogen available in the terrestrial ecosystem is gaseous nitrogen (N2) from the air, but this nitrogen...
Carbon-dioxide Fixation01:28

Carbon-dioxide Fixation

Carbon dioxide fixation in prokaryotes enables the assimilation of inorganic carbon into organic molecules, supporting biosynthetic pathways, sustaining ecosystems, and contributing to the global carbon cycle. It also has industrial applications in carbon capture and bioproduct synthesis. Autotrophic organisms rely on this process to utilize CO₂ as a carbon source in diverse environments.The Calvin CycleThe Calvin cycle is the most widespread carbon fixation mechanism, primarily used by...
The Nitrogen Cycle01:49

The Nitrogen Cycle

Nitrogen atoms, present in all proteins and DNA, are recycled between abiotic and biotic components of the ecosystem. However, the primary form of nitrogen on Earth is nitrogen gas, which cannot be used by most animals and plants. Thus, nitrogen gas must first be converted into a usable form by nitrogen-fixing bacteria before it can be cycled through other living organisms. The use of nitrogen-containing fertilizers and animal waste products in human agriculture has greatly influenced the...
Metabolism of Chemolithotrophs01:15

Metabolism of Chemolithotrophs

Chemolithotrophs are microorganisms that obtain energy by oxidizing inorganic molecules such as hydrogen gas (H₂), ammonia (NH₃), reduced sulfur compounds (H₂S, S²⁻), and ferrous iron (Fe²⁺). Unlike heterotrophic organisms that rely on organic carbon, chemolithotrophs transfer electrons from these inorganic donors to the electron transport chain (ETC), generating a proton motive force (PMF) that drives ATP synthesis through oxidative phosphorylation. However, because inorganic electron donors...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Minimizing decompression and warming during deep seawater collection increases abundance and activity of autochthonous bacteria and archaea.

The ISME journal·2026
Same author

Euxinic conditions and altered biogeochemical cycles in a Patagonian fjord influenced by volcanic activity.

Scientific reports·2026
Same author

Microbial fingerprinting of marine water masses in an Antarctic and hydrographically complex area.

BMC biology·2026
Same author

Agricultural intensification and pesticide pollution on water: cross-scale insights from a subtropical watershed.

The Science of the total environment·2026
Same author

Metabarcoding and metagenomic data across aquatic environmental gradients along the coasts of France and Chile.

Scientific data·2026
Same author

Evidence for priming-enhanced microbial degradation of polycyclic aromatic hydrocarbons in marine sediments.

Marine pollution bulletin·2025

Related Experiment Video

Updated: May 31, 2026

The Benthic Exchange of O2, N2 and Dissolved Nutrients Using Small Core Incubations
10:11

The Benthic Exchange of O2, N2 and Dissolved Nutrients Using Small Core Incubations

Published on: August 3, 2016

Nitrogen fixation in denitrified marine waters.

Camila Fernandez1, Laura Farías, Osvaldo Ulloa

  • 1Departamento de Oceanografía and Centro de Investigación Oceanográfica en el Pacífico Sur-Oriental (COPAS), Universidad de Concepción, Concepción, Chile. fernandez@obs-banyuls.fr

Plos One
|June 21, 2011
PubMed
Summary

Nitrogen fixation, the conversion of atmospheric nitrogen to ammonia, was found to occur significantly within oxygen-depleted zones in the eastern tropical South Pacific. This challenges previous assumptions about nitrogen cycling in marine environments.

More Related Videos

Measurement of the Potential Rates of Dissimilatory Nitrate Reduction to Ammonium Based on 14NH4+/15NH4+ Analyses via Sequential Conversion to N2O
08:05

Measurement of the Potential Rates of Dissimilatory Nitrate Reduction to Ammonium Based on 14NH4+/15NH4+ Analyses via Sequential Conversion to N2O

Published on: October 7, 2020

Estimating Sediment Denitrification Rates Using Cores and N2O Microsensors
07:59

Estimating Sediment Denitrification Rates Using Cores and N2O Microsensors

Published on: December 6, 2018

Related Experiment Videos

Last Updated: May 31, 2026

The Benthic Exchange of O2, N2 and Dissolved Nutrients Using Small Core Incubations
10:11

The Benthic Exchange of O2, N2 and Dissolved Nutrients Using Small Core Incubations

Published on: August 3, 2016

Measurement of the Potential Rates of Dissimilatory Nitrate Reduction to Ammonium Based on 14NH4+/15NH4+ Analyses via Sequential Conversion to N2O
08:05

Measurement of the Potential Rates of Dissimilatory Nitrate Reduction to Ammonium Based on 14NH4+/15NH4+ Analyses via Sequential Conversion to N2O

Published on: October 7, 2020

Estimating Sediment Denitrification Rates Using Cores and N2O Microsensors
07:59

Estimating Sediment Denitrification Rates Using Cores and N2O Microsensors

Published on: December 6, 2018

Area of Science:

  • Marine biology
  • Oceanography
  • Biogeochemistry

Background:

  • Nitrogen fixation is crucial for marine ecosystems, converting atmospheric dinitrogen gas to ammonia.
  • Traditionally, nitrogen fixation is believed to occur in open oceans, while nitrogen loss happens in oxygen-depleted zones.
  • The eastern tropical South Pacific (ETSP) features coastal upwelling and a permanent oxygen minimum zone (OMZ).

Purpose of the Study:

  • To investigate nitrogen fixation rates in the eastern tropical South Pacific (ETSP).
  • To determine if nitrogen fixation occurs within the oxygen minimum zone (OMZ) in this region.
  • To analyze the diazotrophic community composition associated with nitrogen fixation.

Main Methods:

  • Oceanographic cruises in 2005 and 2007 to measure nitrogen fixation rates.
  • Water column sampling from surface down to 400 m depth.
  • Molecular detection and phylogenetic analysis of the nifH gene.

Main Results:

  • Significant nitrogen fixation rates were observed in the water column, with substantial variability between cruises.
  • Nitrogen fixation rates in the subsurface oxygen-deficient layer were approximately five times higher than in the oxic euphotic layer.
  • The nifH gene was detected, and phylogenetic analysis revealed a diverse diazotrophic community, particularly during high fixation periods.

Conclusions:

  • Nitrogen fixation occurs in nutrient-rich coastal upwelling systems and within the OMZ of the ETSP.
  • This process can sporadically supplement fixed nitrogen in these regions.
  • The spatial separation of nitrogen fixation and loss processes may be less distinct than previously thought.