When ocean dynamic drives the land to ocean input of iron

Nishioka and co-authors demonstrate the pivotal role of tidal mixing in the Kuril Islands chain (KIC) for determining iron (Fe) supply to the euphotic zone of the Western Subartic Pacific. Indeed, Fe derived from sediments in the Sea of Okhotsk is discharged through the KIC into the intermediate water masses (~ 800 m) of the western North Pacific. The redistribution of this Fe-rich intermediate water by intensive mixing as it crosses the KIC is the predominant process determining the ratio of micronutrient (Fe) to macronutrients (e.g., nitrate) in subsurface waters. This process explains the significant phytoplankton growth and great seasonal variability observed in the Western compared to the Eastern Subarctic Pacific.

13 2 Nishioka l

Figure: This image shows the role of tidal mixing in the oceanic dissolved Fe cycle in the subarctic North Pacific, with section profiles of dissolved Fe from this Nishioka’s work and from previous Nishioka’s works (Line P and 165°E line [Nishioka et al., 2001, 2007]).
A basin-scale vertical section profiles for disolved Fe is also shown on the bottom right corner of the figure.Please click here to see the figure larger.



Nishioka, J., T. Nakatsuka, Y.W. Watanabe, I. Yasuda, K. Kuma, H. Ogawa, et al. (2013) Intensive mixing along an island chain controls oceanic biogeochemical cycles Global Biogeochemical Cycles, Volume: 27, Issue: 3 DOI: http://dx.doi.org/10.1002/gbc.20088

Nishioka, J., S. Takeda, C. S. Wong, and W. K. Johnson (2001), Sizefractionated iron concentrations in the northeast Pacific Ocean: Distribution of soluble and small colloidal iron, Mar. Chem., 74, 157–179.

Nishioka, J., et al. (2007), Iron supply to the western subarctic Pacific: Importance of iron export from the Sea of Okhotsk, J. Geophys. Res.,112, C10012, DOI: htttp://dx.doi.org/10.1029/2006JC004055.

Latest highlights

Science Highlights

Thorium-Protactinium fate across the tropical Atlantic Ocean: what reveals the water column-sediment coupling

Twenty seawater profiles and twenty core-top 231-protactinium and 230-thorium analyses were realised by Ng and colleagues along five depth transects across the northern tropical Atlantic open ocean.


Science Highlights

Constraining Oceanic Copper Cycling through Artificial Intelligence and Ocean Circulation Inverse Model

Using available observations of dissolved copper, artificial neural networks, and an ocean circulation inverse model, authors calculated a global estimate of the 3-dimensional distribution and cycling of dissolved copper in the ocean


Science Highlights

Particulate rare earth elements distributions, processes and characterisation of nepheloids in the North Atlantic

Lagarde et al. realised the first basin scale section of particulate rare earth elements concentrations across the North Atlantic Ocean.


Science Highlights

Isopycnal mixing controls protactinium and thorium distributions in the Pacific Southern Ocean

Pavia and co-workers determined the physical and chemical speciation as well as the vertical distribution of Protactinium-231 and Thorium-230 at 12 stations across the Southern Pacific Antarctic Circumpolar Current…