کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4467939 1622290 2009 16 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Lilliput effect in late Maastrichtian planktic foraminifera: Response to environmental stress
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات فرآیندهای سطح زمین
پیش نمایش صفحه اول مقاله
Lilliput effect in late Maastrichtian planktic foraminifera: Response to environmental stress
چکیده انگلیسی

The Lilliput effect marks morphologic and intraspecies size reductions in response to environmental stresses commonly associated with the aftermath of mass extinctions. This study shows that the Lilliput effect is a universal biotic response associated with greenhouse warming, mesotrophic or restricted basins, shallow marginal settings and volcanically active regions during the late Maastrichtian. Sedimentary sequences analyzed from Tunisia, Egypt, Texas, Argentina, the South Atlantic and Indian Ocean reveal that the biotic stress response appears uniform, regardless of the cause, varying only with the degree of biotic stress. Overall, late Maastrichtian environments span a continuum from optimum conditions to the catastrophic (mass extinctions) with a predictable set of biotic responses relative to the degree of stress induced by oxygen, salinity, temperature and nutrient variations as a result of climate and sea level changes and volcanism. Early stages of biotic stress result in diversity reduction and the elimination of large specialized species (k-strategists) leading to morphologic size reduction via selective extinction/disappearances and intraspecies dwarfing of survivors. Later stages of biotic stress result in the complete disappearance of k-strategists, intraspecies dwarfing of r-strategists and dominance by low oxygen tolerant small heterohelicids. At the extreme end of the biotic response are volcanically influenced environments, which cause the same detrimental biotic effects as observed in the aftermath of the K–T mass extinction, including the disappearance of most species and blooms of the disaster opportunist Guembelitria.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Palaeogeography, Palaeoclimatology, Palaeoecology - Volume 284, Issues 1–2, 20 December 2009, Pages 47–62
نویسندگان
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