Effects of the Anticyclonic Eddies on Water Masses, Chemical Parameters and Chlorophyll Distributions in the Oyashio Current Region

Byline: Masashi Kusakabe (1), Andrey Andreev (1,2), Vyacheslav Lobanov (2), Igor Zhabin (2), Yuichiro Kumamoto (1), Akihiro Murata (1) Keywords: Eddy; Oyashio; Kuril Islands; North Pacific; chemical parameters Abstract: Data from the R/V Mirai cruise (May--June 2000) have been examined to discover how mesoscale processes associated with eddy dynamics direct affect the water masses, the distributions and the vertical fluxes of the dissolved oxygen, nutrients and dissolved inorganic carbon in the western subarctic Pacific. Using maps of the temperature, salinity, dissolved oxygen, nutrients, chlorophyll and sea-air pCO.sub.2 difference we show that the boundaries of the anticyclone eddies in the study region were composed of high productivity coastal Oyashio water. The coastal waters were wrapped around the anticyclone eddies (thus creating a high productivity belt) and intruded inside of them. Using SeaWifs data we demonstrate that temporal variations in the position and the strength of anticyclone eddies advected the Kuril island coastal high productivity waters to the pelagic part, resulting in temporal variations of the chlorophyll in the Oyashio region. Computed vertical fluxes of the dissolved oxygen (DO), inorganic carbon (DIC) and silicate show that the anticylonic eddies in the Kuroshio-Oyashio Zone are characterized by enhanced vertical fluxes of the DO and DIC between the upper ([sigma].sub.I, = 26.7--27.0) and lower ([sigma].sub.I, = 27.1--27.5) intermediate layer, probably due to the intrusions of the Oyashio waters into the eddies. Author Affiliation: (1) Japan Marine Science and Technology Center, Natsushima, Yokosuka, 237-0061, Japan (2) V.I. Il'ichev Pacific Oceanological Institute, 43 Baltiyskaya, Vladivostok, 690041, Russia Article History: Registration Date: 12/10/2004