کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9522385 | 1634971 | 2005 | 20 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Deep Pacific CaCO3 compensation and glacial-interglacial atmospheric CO2
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موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
علوم زمین و سیاره ای (عمومی)
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چکیده انگلیسی
Benthic foraminiferal δ13C suggests that there was a net shift of isotopically light metabolic CO2 from the upper ocean into the deep ocean during the last glacial period. According to the 'CaCO3 compensation' hypothesis, this should have caused a transient drop in deep ocean CO32â that was eventually reversed by seafloor dissolution of CaCO3. The resulting increase in whole-ocean pH may have had a significant impact on atmospheric CO2, compounding any decrease that was due to the initial vertical CO2 shift. The opposite hypothetically occurred during deglaciation, when CO2 was returned to the upper ocean (and atmosphere) and deep ocean CO32â temporarily increased, followed by excess burial of CaCO3 and a drop in whole-ocean pH. The deep sea record of CaCO3 preservation appears to reflect these processes, with the largest excursion during deglaciation (as expected), but various factors make quantification of deep sea paleo-CO32â difficult. Here we reconstruct deep equatorial Pacific CO32â over the last glacial-interglacial cycle using benthic foraminiferal Zn/Ca, which is strongly affected by saturation state during calcite precipitation. Our data are in agreement with the CaCO3 compensation theory, including glacial CO32â concentrations similar to (or slightly lower than) today, and a Termination I CO32â peak of â¼25-30 μmol kgâ1. The deglacial CO32â rise precedes ice sheet melting, consistent with the timing of the atmospheric CO2 rise. A later portion of the peak could reflect removal of CO2 from the atmosphere-ocean system due to boreal forest regrowth. CaCO3 compensation alone may explain more than one third of the atmospheric CO2 lowering during glacial times.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Earth and Planetary Science Letters - Volume 231, Issues 3â4, 15 March 2005, Pages 317-336
Journal: Earth and Planetary Science Letters - Volume 231, Issues 3â4, 15 March 2005, Pages 317-336
نویسندگان
Thomas M. Marchitto, Jean Lynch-Stieglitz, Sidney R. Hemming,