Güneş Kaynaklı Ultraviyole Radyasyonunun Karasal Ekosistemler Üzerine Etkileri

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

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.

Keywords:

Ultraviolet radiation, terrestrial ecosystems, ozone depletion,

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1. Akman, Y., Ketenoğlu, O., Kurt. L., Evren, H. ve Düzenli, S., Çevre Kirliliği, Çevre Biyolojisi. Palme Yayınları, Ankara, (2000).
2. Cockell, C., Blaustein, A. R., Ecosystems, Evolution and Ultraviolet Radiation, Springer, (2001).
3. Acar, Y., Ekici, M., Kutuplardaki ozon incelmesi, (2009). http://www.meteor.gov.tr. Erişim Tarihi: 02.03.2009.
4. Ghetti, F., Checcucci, G. and Bornman, J. F., Environmental UV radiation : impacts on ecosystems and human healths and predictive models, Nato Science Series, IV. Earth and Environmental Science (vol. 57), Italy, (2001).
5. Zerefos, C. S., Bais, A. F., Solar ultraviolet radiation: modelling, measurements, and effects, NATO ASI Series I: Global Environmental Change 52; 332p., (1997).
6.Newman, P. A., Stratospheric Ozone, Elektronik Kitap, (2003). http://www.ccpo.odu.edu/SEES/ozone/class/Chap_1/index.htm. Erişim Tarihi: 02.03.2009
7. Rozema, J., Boelen, P., Blokker, P., Depletion of stratospheric ozone over the Antarctic and Arctic: Responses of plants of polar terrestrial ecosystems to enhanced UV-B, an overview, Environmental Pollution, 137, 428-442, (2005).
8. Solomon, S., Stratospheric ozone depletion: a review of concepts and history, Review of Geophysics, 37, 275-316, (1999).
9. Paul, N. D., Gwynn-Jones, D., Ecological roles of solar UV radiation : towards an integrated approach, Trends in Ecology and Evolution, 18 (1), 48-55, (2003).
10. Caldwell, M. M., Björn, L. O., Bornman, J. F., Flint, S. D., Kulandaivelu, G., Teramura, A. H. and Tevini, M. (1998). Effects of increased solar ultraviolet radiation on terrestrial ecosystems, Journal of Photochemistry and Photobiology B: Biology, 46, 40–52.
11. Caldwell, M. M., Flint, S.D., Stratospheric ozone reduction, solar UV-B radiation and terrestrial ecosystems, Climatic Change, 28, 375-394, Netherlands, (1994).
12. Tiitto, R. J., Hagmann, H., Aphalo, P. J., Lavola, A., Tgelberg, R. and Veteli, T., Growth and defense in deciduous trees and shrubs under UV-B, Environmental Pollution, 137, 404-414, (2005).
13. Callaghan, T. V., Björn, L. O., Chernov Y., Chapin T., Christensen T. R., Huntley B., Ims, R. A., Johansson, M., Jolly, D., Jonasson, S., Matveyeva N., Panikov, N., Oechel, W., Shaver, G., Elster J., Jónsdóttir, I. S., Laine, K., Taulavuori, K., Taulavuori, E. and Zöckler C., Responses to projected changes in climate and UV-B at the species level, Ambio, 33 (7), 418-435, (2004).
14. Rozema, J., Lenssen, G. M., Van de Staaij, J. W. M., Tosserams, M., Visser, A. J. and Broekman, R. A., Effects of UV-B radiation on terrestrial plants and ecosystems: interaction with CO enrichment, Plant Ecology, 128, 183-191, (1997).
15. Rozema, J., Van de Staaij, J., Björn, L. O., Caldwell, M., UV as an environmental factor in plant life: stres and regulation, Tree, 12 (1), 22-28, (1997).
16. Zepp, R.G., Callaghan, T.V. and Erickson, D. J., Effects of enhanced solar ultraviolet radiation on biogeochemical cycles, Journal of Photochemistry and Photobiology, 46; 69-82, (1998).
17. Björn, L. O., Callaghan T. V., Johnsen, I., Lee, J.A., Manetas, Y., Paul, N. D., Sonesson, M., Wellburn, A. R., Coop, D., Heide-Jørgensen, H. S., Gehrke, C., Gwynn-Jones, Johanson, D. U., Kyparissis, A., Levizou, E., Nikolopoulos, D., Petropoulou, Y. and Stephanou, M., The effects of UV-B radiation on European heathland species, Plant Ecology, 128, 253–264, (1997).
18. Solheim B., Zielke M., Bjerke J. W. and J., Effects of enhanced UV-B radiation on nitrogen fixation in arctic ecosystems, Plant Ecology, 182, 109-118, (2006).
19. Davidson, A.T., The impact of UV-B radiation on marine plankton, Mutation Research, 422, 119- 129, (1998).
20. Rousseaux, M. C., Ballare, C. L., Giordano, C. V., Scopel, A. L., Zima, A. M., Szwarcberg-Bracchitta, M., Searles, P. S., Caldwell, M. M. and Diaz, S. B., Ozone depletion and UVB radiation: Impact on plant DNA damage in southern South America, PNAS, 96 (26), 15310–15315, (1999).
21. Zepp, R. G., Callaghan, T. V. and Erickson D. J., Interactive effects of ozone depletion and climate change on biogeochemical cycles, Photochem. Photobiol. Sci., 2, 51–61, (2003).
22. Milchunas, D. G., King, J. Y., Mosier, A. R., Moore, J. C., Morgan, J. A., Quirk, M. H., Slusser, J. R., UV radiation effects on plant growth and forage quality in a shortgrass steppe ecosystem, Photochemistry and Photobiology, 79 (5), 404 – 410, (2004).
23. Akman, Y., İklim ve Biyoiklim, Kariyer Matbaacılık, 350 s., Ankara, (1999).
24. http://www.meteor.gov.tr. Erişim Tarihi: 02.03.2009.
25. Kadıoğlu, M., Küresel iklim değişimi ve Türkiye, İ.T.Ü. Tesisat Mühendisliği Dergisi, 82,5-11, (2004).
26. Öztürk, Münir A., Seçmen, Ö., Bitki Ekolojisi, Ege Üniversitesi Basımevi, İzmir, (2004).
27. Grant, R. H., Partitioning of biologically active radiation in plant canopies, International Journal of Meteorology, 40, 26-40, (1997).
28. Lud, D. Huiskes, A. H. L., Moerdijk, T. C. W. and Rozema J., The effects of altered levels of UV-B radiation on an Antarctic grass and lichen, Plant Ecology, 154, 89-99, (2001).