Video Experimental Relacionado
Updated: Jan 25, 2026
07:14
Automated, High-resolution Mobile Collection System for the Nitrogen Isotopic Analysis of NOx
Published on: December 20, 2016
12.1K
Pruebas de isótopos de nitrógeno para la suboxia oceánica expandida en el Cenozoico temprano
Emma R Kast1, Daniel A Stolper2,3, Alexandra Auderset4,5
1Department of Geosciences, Princeton University, Princeton, NJ 08540, USA. ekast@princeton.edu.
Science (New York, N.Y.)
|April 27, 2019
Resumen
La variabilidad del ciclo de nitrógeno marino durante millones de años no está clara. Las altas proporciones de isótopos de nitrógeno (δ15N) antes de hace 57 millones de años sugieren una suboxía generalizada, seguida de una disminución relacionada con la colisión Asia-India.
Área de la Ciencia:
- Paleoceanografía
- Geoquímica
- Ciclo del nitrógeno marino
Sus antecedentes:
- La variabilidad a largo plazo del ciclo del nitrógeno marino sigue siendo poco conocida.
- La proporción de isótopos de nitrógeno (δ15N) en los foraminíferos es un indicador clave para reconstruir las condiciones oceánicas pasadas.
Objetivo del estudio:
- Para investigar la variabilidad de millones de años del ciclo del nitrógeno marino.
- Comprender los impulsores de los cambios en la suboxia y la desnitrificación en escalas de tiempo geológicas.
Principales métodos:
- Análisis de la relación 15N/14N (δ15N) en la materia orgánica ligada al caparazón de los foraminíferos.
- Utilizamos tres núcleos de sedimentos para reconstruir las condiciones oceánicas pasadas.
Principales resultados:
- Los altos valores de δ15N antes de hace 57 millones de años indican suboxia y desnitrificación de la columna de agua expandida.
- Una disminución de δ15N entre 57 y 50 Ma, anterior al enfriamiento global, coincidió con la primera colisión Asia-India, posiblemente debido a las influencias del mar de Tetis.
- Los valores más bajos de δ15N de 50 a 35 Ma sugieren una desnitrificación generalizada de la plataforma continental.
- Un aumento en δ15N a 35 Ma se correlaciona con el crecimiento de las capas de hielo, la caída del nivel del mar y el estrechamiento de las plataformas continentales.
Conclusiones:
- El ciclo del nitrógeno marino ha sufrido cambios significativos durante millones de años, influenciados por eventos tectónicos y el cambio climático.
- Los factores oceanográficos y tectónicos, como la colisión Asia-India y la evolución del mar de Tetis, jugaron un papel crucial en la regulación del ciclo del nitrógeno y la anoxia oceánica.
Videos de Conceptos Relacionados
01:12Isotopes
63.5K
Elements have a set number of protons that determines their atomic number (Z). For example, all atoms with eight protons are oxygen; however, the number of neutrons can vary for atoms of the same element. The sum of the number of protons and the number of neutrons is the mass number (A). Atoms with the same atomic number but different mass numbers are called isotopes. Elements can have multiple isotopes, for example, carbon-12, carbon-13, and carbon-14.
An element's atomic mass, or weight,...
An element's atomic mass, or weight,...
63.5K
02:55The Evidence for Evolution
47.7K
Genetic variations accumulating within populations over generations give rise to biological evolution. Evolutionary changes can result in the formation of novel varieties and entire new species. These changes are responsible for the diverse forms of life inhabiting the planet. The evidence for evolution suggests that all living organisms descended from common ancestors.
47.7K
02:31Elements: Chemical Symbols and Isotopes
125.5K
A chemical symbol is an abbreviation used to indicate an element or an atom of an element. For example, the symbol for mercury is Hg. The same symbol is used to indicate one atom of mercury (microscopic domain) or to label a container of many atoms of the element mercury (macroscopic domain).
Some symbols are derived from the common English name of the element; others are abbreviations of the name in another language — Latin, Greek or German. For example, the symbol for aluminum (common name)...
Some symbols are derived from the common English name of the element; others are abbreviations of the name in another language — Latin, Greek or German. For example, the symbol for aluminum (common name)...
125.5K
01:49The Nitrogen Cycle
59.7K
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...
59.7K
01:20Overview of Nitrogen Metabolism
11.1K
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...
The largest pool of nitrogen available in the terrestrial ecosystem is gaseous nitrogen (N2) from the air, but this...
11.1K
01:22Inorganic Nitrogen Assimilation
504
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...
504