Video Experimental Relacionado
Updated: Jul 12, 2026
10:10
Assessment of the Acute Inhalation Toxicity of Airborne Particles by Exposing Cultivated Human Lung Cells at the Air-Liquid Interface
Published on: February 23, 2020
Efectos ambientales de una nube de polvo generada por el impacto: implicaciones para las extinciones del
Science (New York, N.Y.)
|January 21, 1983
Resumen
Un hipotético evento de impacto creó una nube de escombros, reduciendo significativamente la luz solar durante meses. Esto afectó la fotosíntesis y la visibilidad, causando un enfriamiento global y extinciones masivas en tierra y mar.
Área de la Ciencia:
- Paleoclimatología Paleoclimatología
- Estudios de cráteres de impacto Estudios de cráteres de impacto
- Eventos de extinción masiva Eventos de extinción masiva
Sus antecedentes:
- El límite entre el Cretácico y el Terciario (K-T) marca un evento significativo de extinción masiva.
- Los impactos de asteroides o cometas son hipotéticos desencadenantes para la extinción K-T.
Objetivo del estudio:
- Para modelar los efectos climáticos y radiativos de una nube de escombros de impacto K-T.
- Para evaluar el impacto potencial de tal nube en la disponibilidad de luz y la temperatura en la superficie de la Tierra.
Principales métodos:
- Desarrollo de un modelo numérico que simule la evolución de la nube de escombros y la transferencia radiativa.
- Análisis de las salidas del modelo para determinar la reducción de la luz y los cambios de temperatura.
Principales resultados:
- La nube de escombros podría haber bloqueado la luz solar por debajo de los niveles fotosintéticos durante meses.
- Las temperaturas superficiales pueden haber disminuido significativamente, especialmente en los continentes (hasta 40 Kelvin).
- La visibilidad para los animales podría haberse reducido por un período más corto.
Conclusiones:
- Las extinciones oceánicas pueden haber resultado del cese de la fotosíntesis.
- Las extinciones terrestres fueron probablemente impulsadas por una combinación de luz reducida y temperaturas más bajas.
- Las nubes de escombros inducidas por el impacto representan un mecanismo plausible para las extinciones masivas.
Más Videos Relacionados
Videos de Conceptos Relacionados
01:50Threats to Biodiversity
There have been five major extinction events throughout geological history, resulting in the elimination of biodiversity, followed by a rebound of species that adapted to the new conditions. In the current geological epoch, the Holocene, there is a sixth extinction event in progress. This mass extinction has been attributed to human activities and is thus provisionally called the Anthropocene. In 2019 the human population reached 7.7 billion people and is projected to comprise 10 billion by...
02:56The Fossil Record
The fossil record documents only a small fraction of all organisms that have ever inhabited Earth. Fossilization is a rare process, and most organisms never become fossils. Moreover, the fossil record only exhibits fossils that have been discovered. Nevertheless, sedimentary rock fossils of long-lived, abundant, hard-bodied organisms dominate the fossil record. These fossils offer valuable information, such as an organism's physical form, behavior, and age. Studying the fossil record helps...
02:35What is Evolutionary History?
Scientists record evolutionary history by analyzing fossil, morphological, and genetic data. The fossil record documents the history of life on Earth and provides evidence for evolution. However, both fossil and living organisms offer evidence that outlines Earth’s evolutionary history.Phylogenetic trees illustrate the evolutionary relationships among these organisms. Scientists infer organisms’ common ancestry by evaluating shared morphological and genetic characteristics. Together, the fossil...
02:26Ecological Disturbance
An ecological disturbance is a temporary disruption in the environment resulting from abiotic, biotic, or anthropogenic factors, causing a pronounced change in an ecosystem. The impact of an ecological disturbance, which can depend on its intensity, frequency, and spatial distribution, plays a significant role in shaping the species diversity within the ecosystem.Ecological disturbances can be caused by an event as small as the trampling of underbrush to an incident as wide-ranging as a forest...
01:50Global Climate Change
Throughout its ~4.5 billion year history, the Earth has experienced periods of warming and cooling. However, the current drastic increase in global temperatures is well outside of the Earth’s cyclic norms, and evidence for human-caused global climate change is compelling. Paleoclimatology, the study of ancient climate conditions, provides ample evidence for human-caused global climate change by comparing recent conditions with those in the past.
01:27Microbes and Climate Change
Microorganisms are pivotal agents in Earth's biogeochemical cycles, significantly influencing climate dynamics through their metabolic activities. These microbes modulate the levels of key greenhouse gases by both contributing to and helping mitigate climate change.Microbial Contributions to Greenhouse Gas EmissionsRising global temperatures accelerate microbial metabolism, which, in turn, speeds up the decomposition of organic matter. This process releases carbon dioxide (CO₂) through...