Mechanism of Nutrient Supply to Warm-Core Ring off Sanriku, Japan

摘要: The mechanism by which nutrient is supplied to a warm-core ring (WCR) was investigated in order understand the greater productivity of WCR than that Kuroshio, where originattes. A single observed January and May, 1997. thermostad (a layer isothermal isohaline water) had different properties from differences: Δwater temperature: −0.698°C, Δsalinity: −0.048, Δsigma θ: +0.072, Δnitrite+nitrate-N: +1.83 μM, Δphosphate: +0.011 μM Δsilicate: +3.2 μM. We examined three possible mechanisms for supply winter, namely: 1) inflow Oyashio surface water into WCR; 2) isopycnal mixing with water; 3) entrainment below WCR. results were as follows: When decrease salinity due water, increase nutrients (nitrite+nitrate-N, phosphate-P silicate-Si) estimated be only 17–27% increase. mixing, 30–42% May winter convection, depth calculated 620 m according salt budget. this case 82–95% main concluded mixing.