کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
8916522 | 1642147 | 2018 | 39 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Changes in ultrastructural features of the foraminifera Ammonia spp. in response to anoxic conditions: Field and laboratory observations
ترجمه فارسی عنوان
تغییرات در ویژگی های فراساختاری فورامینفرا گونه های آمونیاک در پاسخ به شرایط بی هوازی: مشاهدات میدانی و آزمایشگاهی
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
فسیل شناسی
چکیده انگلیسی
The ultrastructure of the living foraminiferan, Ammonia sp. (phylotype unknown), collected from surficial and deeper, subsurface (anoxic) sediments from the Dutch Wadden Sea, was examined to provide information on the physiology of the foraminiferal cell and its adaptive strategies to lowâoxygen conditions. The observed changes in cell ultrastructure under anoxia were further compared with the cell ultrastructure of Ammonia sp. (phylotype T6), from oxic and anoxic incubation experiments. The ultrastructural evidence indicates that under lowâoxygen conditions Ammonia spp. may accumulate lipid droplets. In addition, the size of the lipid droplets may increase with the duration of anoxic conditions, becoming over 5 μm in size, while the remaining cytosol of the foraminiferan become less electron dense. In some specimens, lipid droplets were also found in the space between the plasma membrane and the organic lining. We expect that the apparent increase in the number and size of the lipid droplets is indicative of a stress response of the foraminifera to the adverse anoxic conditions. Other ultrastructural changes in response to anoxia include the presence of intact bacteria and electron dense opaque bodies within the foraminiferal cytosol, and a possible thickening of the organic lining. The role of the bacteria remains enigmatic but they may be linked to foraminiferal dormancy in anoxia.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Marine Micropaleontology - Volume 138, January 2018, Pages 72-82
Journal: Marine Micropaleontology - Volume 138, January 2018, Pages 72-82
نویسندگان
K.A. Koho, C. LeKieffre, H. Nomaki, I. Salonen, E. Geslin, G. Mabilleau, L.H. Søgaard Jensen, G.-J. Reichart,