کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6384060 | 1326297 | 2015 | 55 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Impacts of low phytoplankton NO3â:PO43â utilization ratios over the Chukchi Shelf, Arctic Ocean
دانلود مقاله + سفارش ترجمه
دانلود مقاله ISI انگلیسی
رایگان برای ایرانیان
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
زمین شناسی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
The impact of Arctic denitrification is seen in the extremely low values for the geochemical tracer of microbial nitrogen (N) cycle source/sink processes Nââ (Mordy et al. 2010). The utility of Nââ as an oceanic tracer of microbial N cycle processes, however, relies on the assumption that phytoplankton utilize dissolved N and P in Redfield proportions, and thus changes in Nââ are due to either N2-fixation or denitrification. We present results from two cruises to the Chukchi Sea that quantify nutrient drawdown, nutrient deficits, and particulate nutrient concentrations to estimate production over the Chukchi Shelf and document lower than Redfield N:P utilization ratios by phytoplankton. These low ratios are used to calculate Nââ (assuming a Redfield NO3â:PO43â utilization ratio) and NNRââ (using the measured particulate N:P ratios) and, combined with current flow speed and direction measurements, to diagnose denitrification rates on the Chukchi Shelf. Our estimates of denitrification rates are up to 40% higher when Redfield proportions are used. However, the denitrification rates we calculate using NNRââ are still higher than previous estimates (up to 8 fold) of denitrification on the Chukchi shelf. These estimates suggest that Arctic shelves may be a greater sink of oceanic N than previously thought.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Deep Sea Research Part II: Topical Studies in Oceanography - Volume 118, Part A, August 2015, Pages 105-121
Journal: Deep Sea Research Part II: Topical Studies in Oceanography - Volume 118, Part A, August 2015, Pages 105-121
نویسندگان
Matthew M. Mills, Zachary W. Brown, Kate E. Lowry, Gert L. van Dijken, Susan Becker, Sharmila Pal, Claudia R. Benitez-Nelson, Meryssa M. Downer, Aaron L. Strong, James H. Swift, Robert S. Pickart, Kevin R. Arrigo,