Dinámica de los aerosoles y del ozono posterior al impacto del asteroide de Chicxulub. Efectos sobre la fotosíntesis del fitoplancton
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Fecha
2014-06-26
Autores
Esmoris Espinosa, Ivan
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Universidad Central "Marta Abreu" de Las Villas
Resumen
El impacto de grandes asteroides tiene consecuencias devastadoras sobre los ecosistemas terrestres, causan desastres climáticos globales, provocan inmensos incendios forestales y colapsan la fotosíntesis. En este trabajo se modela el proceso de fotosíntesis del fitoplancton; en diferentes momentos, después del impacto del asteroide de Chicxulub. Se consideran organismos de eficiencia alta, media y baja, diferentes tipos de aguas costeras (tipo 1,5 y 9) y ángulos solares cenitales (00, 45o y 60o). Las estimaciones muestran que hubo gran afectación a este proceso básico, debido primeramente a los bajos niveles de luz producido por la gran cantidad de polvo (primeros meses) y aerosoles (fundamentalmente sulfatos) que ingresaron en la estratosfera. Una vez sedimentado el polvo y precipitado los aerosoles, la principal afectación se debió a la reducción de la capa de ozono (relacionado con la presencia de los aerosoles de sulfatos y halógenos), permitiendo la entrada de niveles altos de radiación ultravioleta que ejerce un efecto nocivo sobre la fotosíntesis. En la medida que se recuperaba el ozono se fueron estableciendo mejores condiciones para los organismos fotosintetizadores. Además se estimaron índices de productividad primaria (tasas de fotosíntesis integrada) y daño biológico (daño al ADN, índice ultravioleta, peso espectral del ultravioleta A y B), que brindan criterios para una mejor valoración de cómo transcurrió la recuperación de la fotosíntesis.
Impact of large asteroid has devastating consequence about terrestrial ecosystem, to cause global climatic disasters, provoke big forestall fires and collapse the photosynthesis. In this work, we model the phytoplankton photosynthesis process in different moments after the Chicxulub asteroid impact. We consider organism with different efficiency (high, medium and low), costal water (type 1, 5 and 9) and different solar zenith angle. The estimations show that had a large encumbrance to this basic process; firstly due to, the light low levels produced by great quantity of dust (first month) and aerosols (fundamentally sulfates aerosols) released into stratosphere. When the dust settled and aerosols precipitated, the most important affectation was because of ozone depletion (related with the presence of sulfate aerosols and halogens), which allowed high levels of ultraviolet input that exert a harmful effect on photosynthesis. Better conditions for photosynthetic organism was establishing as the ozone was recovering. Additionally, we was estimates primary productivity index (integrated photosynthesis rate) and biological damage indexes (DNA damage, ultraviolet index, weight spectrum of ultraviolet A and B) that give some criteria for a better valuation of how the photosynthesis recovery lapse.
Impact of large asteroid has devastating consequence about terrestrial ecosystem, to cause global climatic disasters, provoke big forestall fires and collapse the photosynthesis. In this work, we model the phytoplankton photosynthesis process in different moments after the Chicxulub asteroid impact. We consider organism with different efficiency (high, medium and low), costal water (type 1, 5 and 9) and different solar zenith angle. The estimations show that had a large encumbrance to this basic process; firstly due to, the light low levels produced by great quantity of dust (first month) and aerosols (fundamentally sulfates aerosols) released into stratosphere. When the dust settled and aerosols precipitated, the most important affectation was because of ozone depletion (related with the presence of sulfate aerosols and halogens), which allowed high levels of ultraviolet input that exert a harmful effect on photosynthesis. Better conditions for photosynthetic organism was establishing as the ozone was recovering. Additionally, we was estimates primary productivity index (integrated photosynthesis rate) and biological damage indexes (DNA damage, ultraviolet index, weight spectrum of ultraviolet A and B) that give some criteria for a better valuation of how the photosynthesis recovery lapse.
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Palabras clave
Dinámica, Aerosoles, Ozono, Asteroide de Chicxulub, Efectos Nocivos, Fotosíntesis del Fitoplancton, Modelos Atmosféricos