Arctic Ocean circulation and eddies characterizing nutrient and phytoplankton distributions in the Canada Basin

RIGC FY2011成果報告会http://www.godac.jamstec.go.jp/darwin/cruise/mirai/mr02-05/ehttp://www.godac.jamstec.go.jp/darwin/cruise/mirai/mr04-05/ehttp://www.godac.jamstec.go.jp/darwin/cruise/mirai/mr08-04/ehttp://www.godac.jamstec.go.jp/darwin/cruise/mirai/mr09-03/ehttp://www.godac.jamstec.go.jp/darwin/cruise/mirai/mr10-05/

栄養塩・基礎生産の観測とモデルとの連携

北極海生態系モデル研究会（2012年5月24日, JAMSTEC横浜研究所）http://www.godac.jamstec.go.jp/darwin/cruise/mirai/mr04-05/ehttp://www.godac.jamstec.go.jp/darwin/cruise/mirai/mr08-04/

平成27年度「みらい」主要課題 : ｢北極海における海洋気候-生態系変動観測研究」

2013年度日本海洋学会春季大会（2013年3月21日～3月25日, 東京海洋大学） ; シンポジウム「急激な海氷減少と北極海海洋生態系の変化II」 / タイトルは学会プログラム掲載のものhttp://www.godac.jamstec.go.jp/darwin/cruise/mirai/mr04-05/ehttp://www.godac.jamstec.go.jp/darwin/cruise/mirai/mr08-04/ehttp://www.godac.jamstec.go.jp/darwin/cruise/mirai/mr12-e03/

Cold water upwelling and entrainment near the Anadyr Strait: Implications to the North Pacific-Arctic interaction

The Tenth Symposium on Polar Science/Ordinary sessions: [OM] Polar Meteorology and Glaciology, Wed. 4 Dec. / Entrance Hall (1st floor) , National Institute of Polar Researc

Preliminary results on R/V Mirai 2012 Arctic Ocean cruise and future observation plan of ECOARCS/GRENE project

第3回極域科学シンポジウム/特別セッション「これからの北極研究」11月28日（水） 国立極地研究所 2階大会議

Fixed-Point Observation of Mixed Layer Evolution in the Seasonally Ice-Free Chukchi Sea: Turbulent Mixing due to Gale Winds and Internal Gravity Waves

第6回極域科学シンポジウム[OM] 極域気水圏11月16日（月）　国立極地研究所１階交流アトリウ

Impact of an unusually large warm-core eddy on distributions of nutrients and phytoplankton in the southwestern Canada Basin during late summer/early fall 2010

http://www.godac.jamstec.go.jp/darwin/cruise/mirai/mr04-05/

Global nutrients data synthesis based on Reference Material of Nutrients of Seawater

Realistic distributions of nitrate, phosphate and silicate and inventories of them in the world’s ocean are basic issues of geochemical study of nitrogen, phosphorous and silicon cycles as well as tracer use of nutrients for deep ocean circulation. WOA09 and WGHC were global hydrographic datasets created by objective analysis and offset correction/objective analysis, respectively. However synthesis using mathematics methods and experience could get apparent global comparability but does not have a firm foundation, therefore accuracy is unknown for nutrients data inWOA05/09 and WGHC. Recently hydrographic dataset such as CARINA and PACIFICA were also created by synthesis. We did global synthesis work based on Reference Material of Nutrients in Seawater (RMNS) for WOCE/CLIVAR cruises datasets, WGHC datasets and some new hydrographic cruises which cover the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, the Southern Ocean and the Arctic Ocean. Among 69982 profiles in 5174 cruises, we could put correction factors of nutrients concentration for 14491 profiles in 268 cruises for nitrate, 18378 profiles in 412 cruises for phosphate and 15825 profiles in 268 cruises for silicate. Global Nutrients Dataset 2010, GND10, is newly created as 0.5 deg. [U+F0B4] 0.5 deg. and 50 m interval of 138 levels gridded dataset based on corrected nutrients profiles described above. One feature of GND10 is that nitrate vs. phosphate ratio in deep waters in WOA dataset showed a peak at 14.6 while nitrate vs. phosphate ratio in GND10 showed a peak at 14.3 and kurtosis of frequency distribution of nitrate vs. phosphate ratio is larger in GND10 dataset rather than that in WOA dataset. A reason of larger kurtosis of distribution of nitrate vs. phosphate ratio might be that comparability of nitrate and phosphate concentration data was improved. Newly created GND10 can provide more realistic distribution of nutrients in the world ocean because comparability of nutrients concentration in GND10 is improved based on RMNS. The GND10 would be useful to study changes in the distribution of concentrations of nutrients in the world ocean and also useful as new initial conditions for modelers who studies global changes. Carbonate system data and oxygen data will be merged with factor corrected nutrients data to study coupling of carbonate system and nutrients cycles, too.Poster abstract EGU2013-3742-1, European Geosciences Union (EGU) General Assembly 2013 (7?12 April, 2013, Vienna, Austria

Do Strong Winds Impact Water Mass, Nutrient, and Phytoplankton Distributions in the Ice‐Free Canada Basin in the Fall?

In general, strong wind events can enhance ocean turbulent mixing, followed by episodic nutrient supply to the euphotic zone and phytoplankton blooms. However, it is unclear whether such responses to strong winds occur in the ice‐free Canada Basin, where the seasonal pycnocline is strong and the nutricline is deep. In the present study, we monitored a fixed‐point observation (FPO) station in the Canada Basin for about 3 weeks in the fall of 2014 to examine the oceanic and biological responses to strong winds. At the FPO site, oceanic microstructure measurements, hydrographic surveys, and water sampling were performed with high temporal resolution, recording internal wave propagation, eddy passage, and water mass changes. Strong winds and internal wave propagation significantly enhanced the mixing above and at the seasonal pycnocline, but their effects were diminished at the nutricline, which was much deeper than the seasonal pycnocline. Therefore, wind‐induced mixing did not increase the upward nutrient supply from the nutricline and did not impact phytoplankton (chlorophyll a) distribution in the surface layer of the FPO site. The temporal evolution of the chlorophyll a concentration was most closely related to water mass changes. We also observed prominent subsurface chlorophyll a maxima with abundant large‐sized phytoplankton that were likely carried by warm‐core eddies to the FPO site. Phytoplankton biomass may have been sustained by the high concentration of ammonium within the eddy and ammonium regeneration at the seasonal pycnocline, where particulate organic matter likely accumulated

Enhancement/reduction of biological pump depends on ocean circulation in the sea-ice reduction regions of the Arctic Ocean

http://www.godac.jamstec.go.jp/darwin/cruise/mirai/mr08-04/