کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
9522669 1634961 2005 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Late Pleistocene record of elevated UV radiation in an Antarctic lake
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات علوم زمین و سیاره ای (عمومی)
پیش نمایش صفحه اول مقاله
Late Pleistocene record of elevated UV radiation in an Antarctic lake
چکیده انگلیسی
Elevated ultraviolet irradiance (UVR, 280-400 nm) damages DNA and induces reorganisation within biological communities at the Earth's surface. Southern high latitude aquatic ecosystems may be particularly susceptible because of low stratospheric ozone levels and extremely low contents of photoprotective dissolved organic matter (DOM). Surveys of shallow lakes and ponds in eastern Antarctica show that cyanobacteria survive elevated UVR exposure by increasing extra-cellular concentrations of photoprotective compounds, which are preserved in sediments together with photosynthetic pigments. Thus, reconstruction of long-term changes in biological UVR receipt, to provide a context for evaluating the long-term significance of recent changes in ozone column depth, is feasible in Antarctic settings. The sediment in Lake Reid (69° 23′ S, 76° 53′ E), Antarctica, spans the late-Pleistocene and contains UVR-absorbing pigments from benthic cyanobacteria. Here we show that mean exposure of these benthic cyanobacteria to UVR during the last glacial was more than three times higher than during the Holocene, likely due to short periods of photosynthetic activity coinciding with relatively high UVR fluxes, or due to increased UVR transmission to the Earth's surface resulting from changes in external factors such as stratospheric ozone levels, cloud cover and surface albedo.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Earth and Planetary Science Letters - Volume 236, Issues 3–4, 15 August 2005, Pages 765-772
نویسندگان
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