کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
7699707 | 1496680 | 2013 | 11 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Euphotic zone nitrification in the NE subarctic Pacific: Implications for measurements of new production
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی (عمومی)
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چکیده انگلیسی
Ammonium (NH4+) oxidation rates, nitrate (NO3â) uptake rates and dissolved nutrient concentrations were measured throughout the euphotic zone along the Line P oceanographic transect in the NE subarctic Pacific, on three cruises (winter, spring and late-summer) in 2009. NH4+ oxidation was found to proceed throughout the euphotic zone and rates ranged from undetectable to 97 nmol Lâ 1 dâ 1. Evidence was found to suggest that both light and NH4+ concentrations played a role in regulating NH4+ oxidation rates, with rates increasing as light decreased and NH4+ concentrations increased. The observation that NH4+ oxidation was a ubiquitous process throughout the euphotic zone demonstrates that not all NO3â present in this region of the water column should be considered new nitrogen, and has important implications for estimates of new production in the NE subarctic Pacific. Depth-integrated NO3â uptake rates ranged from 0.65 to 6.0 mmol mâ 2 dâ 1, and we found that euphotic zone NH4+ oxidation could have supported between 3 and 100% of the phytoplankton NO3â demands along Line P. Taking potential euphotic zone NO3â regeneration into account resulted in new production estimates being reduced by an average of ~ 50%. During spring and late-summer, the degree by which new production was reduced, when euphotic zone NO3â regeneration was taken into consideration, was tightly anti-correlated to total NO3â uptake rates. This indicates that the implications of euphotic zone nitrification for estimates of new production are greatest in the less productive regions of the oceans.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Marine Chemistry - Volume 155, 20 September 2013, Pages 113-123
Journal: Marine Chemistry - Volume 155, 20 September 2013, Pages 113-123
نویسندگان
Damian S. Grundle, S. Kim Juniper, Karina E. Giesbrecht,