Variability in dissolved inorganic nitrogen in surface layer of the Arctic Ocean

2016 Fiscal Year Final Research Report

• Project/Area Number: 26281004
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Environmental dynamic analysis
• Research Institution: Tokyo University of Marine Science and Technology
• Principal Investigator: Kawai Michiyoi 東京海洋大学, その他部局等, 准教授 (50601382)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 北極海 / 栄養塩 / 窒素

Outline of Final Research Achievements

Nitrogen is the limiting nutrients to phytoplankton production in the surface We have investigated supply process of dissolved inorganic nitrogen (DIN) to the surface layer of the Arctic Ocean. A fixed point observation for two weeks revealed that DIN concentration is very low, even in nano-molar level. Temporal events such as a passing of an eddy could bring some trace of DIN to promote local primary production during summer/autumn.
Year-round observations in the central Canada Basin using moored water sampler and sensors showed that DIN is low throughout a year, even during the mid-winter, probably due to very strong stratification which limits entrainment of deeper nutrient rich water to surface layer. Nevertheless, fluorescence data showed a peak at the beginning of Spring. At the moment, it is not clear what is the source of nitrogen supporting this production.

Free Research Field

化学海洋学