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

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...
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...
Microbial Growth Measurement: Indirect Methods01:27

Microbial Growth Measurement: Indirect Methods

Estimating microbial growth is essential for understanding population dynamics and environmental adaptations. Indirect methods provide valuable insights by measuring parameters such as turbidity, metabolic activity, and biomass, enabling efficient and reproducible assessments.During exponential growth, microbial cells scatter light proportionally to their biomass, a principle used in turbidity measurements. About one million cells per milliliter produce detectable scattering, which a...
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

Automated eDNA and eRNA profiling for biodiversity monitoring in marine and freshwater ecosystems.

Scientific reports·2026
Same author

Learning to See Peaks: Attention-Based Feature Extraction for Automated Chromatographic Peak Detection.

ACS omega·2026
Same author

Comparison of Spatio-Temporal Dynamics and Composition in Size-Fractionated and Unfractionated Northwestern Atlantic Microbial Communities.

Environmental microbiology reports·2026
Same author

National Near Real-Time Vaccine Effectiveness Against COVID-19 Severe Outcomes Using the Screening Method Among Older Adults Aged ≥50 Years in Canada.

Vaccines·2026
Same author

Prof Stephen P. Long, FRS (1950-2025).

Global change biology·2025
Same author

Diverse community of rhizobia-diatom symbioses fixes nitrogen in the South Pacific gyre.

ISME communications·2025

Related Experiment Video

Updated: Jun 8, 2026

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

Methodological underestimation of oceanic nitrogen fixation rates.

Wiebke Mohr1, Tobias Grosskopf, Douglas W R Wallace

  • 1Marine Biogeochemie, Leibniz-Institut für Meereswissenschaften, Kiel, Germany. wmohr@ifm-geomar.de

Plos One
|September 15, 2010
PubMed
Summary
This summary is machine-generated.

A new method using (15)N(2)-enriched seawater accurately measures dinitrogen (N(2)) fixation rates. This improves upon the traditional (15)N(2)-tracer addition method, which often underestimates fixation due to gas bubble issues.

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

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

Related Experiment Videos

Last Updated: Jun 8, 2026

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

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

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

Area of Science:

  • Marine biology
  • Biogeochemistry
  • Microbial ecology

Background:

  • Dinitrogen (N(2)) fixation is crucial for marine ecosystems.
  • Existing methods like (15)N(2)-tracer addition and acetylene reduction assay (ARA) have limitations.
  • Inconsistencies in N(2) fixation rates are often attributed to the excretion of newly fixed nitrogen.

Purpose of the Study:

  • To identify the cause of underestimation in the standard (15)N(2)-tracer addition method.
  • To develop and validate a more accurate method for measuring N(2) fixation rates.
  • To resolve discrepancies in oceanic fixed-nitrogen budget calculations.

Main Methods:

  • Demonstrated underestimation of N(2) fixation using gaseous (15)N(2) tracer bubbles.
  • Proposed and tested a modified method using (15)N(2)-enriched seawater.
  • Analyzed factors influencing underestimation, including incubation time and gas injection timing.

Main Results:

  • Gaseous (15)N(2) tracer bubbles fail to reach equilibrium, leading to assumed lower concentrations and underestimated fixation rates.
  • The magnitude of underestimation depends on incubation time, gas amount, and injection timing relative to fixation patterns.
  • The modified method using enriched seawater provides instantaneous and constant enrichment for accurate rate calculations.

Conclusions:

  • The traditional (15)N(2)-tracer addition method significantly underestimates N(2) fixation rates.
  • The proposed (15)N(2)-enriched seawater method offers a more accurate approach for laboratory and field studies.
  • This improved method is expected to reduce apparent imbalances in the oceanic fixed-nitrogen budget.