Güneş Kaynaklı Ultraviyole Radyasyonunun Karasal Ekosistemler Üzerine Etkileri

Yıl 2009, Cilt: 2 Sayı: 33, 67 - 77, 01.12.2009

Nihal Kenar Osman Ketenoğlu

Öz

Atmosferdeki ozon yoğunluğunun azalışı sebebiyle artan ultraviyole radyasyon miktarı, canlıları ve ekosistem yapısını etkilemektedir. Atmosfer bileşenleri, bulut örtüsü, yükseklik, albedo, güneş ışınlarının eğimi ve bitki kanopi şekli gibi parametreler, yeryüzüne ulaşan ultraviyole ışınlarının miktarında değişimlere yol açmaktadır. Ultraviyole ışınlarının yoğunluğundaki artış, canlılarda aktif oksijen türevlerinin üretimine, serbest radikallerin oluşmasına, DNA hasarına ve bitkiler için fotosentezin kısmi engellenmesine sebep olmaktadır. Bunun yanında ultraviyole radyasyonu, ekosistem seviyesinde türlerin rekabet dengesini, simbiyotik ilişkileri, biyojeokimyasal döngüleri ve fitoplankton verimliliğini etkilemektedir. Sonuç olarak güneş kaynaklı UV radyasyonunun artışı, doğal dengenin bozulmasına neden olmaktadır.

Anahtar Kelimeler

Ultraviyole radyasyon, karasal ekosistemler, ozon azalımı

Solar Ultraviolet Radiation Effects On Terrestrial Ecosystems

Öz

The amount of enhanced solar ultraviolet radiation because of ozone depletion in the atmosphere affects organisms and structure of ecosystems. Parameters as atmospheric components, cloud cover, altitude, albedo, solar gradient and plant canopies causes alteration in the amount of ultraviolet radiation arriving at the earth. Increased of ultraviolet radiation induces products of active oxygen species, formation of free radicals, DNA damages and detention of photosynthesis partly. Besides, ultraviolet radiation imprints competition balance of species, symbiotic relationships, biogeochemical cycles and phytoplankton productivity at the ecosystem level. As a result, increased of solar ultraviolet radiation provokes breakdown of natural balance.

Anahtar Kelimeler

Ultraviolet radiation, terrestrial ecosystems, ozone depletion

Kaynakça

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