HR: 1340h
AN: A33A-0828    [Abstracts]
TI: Behavior of Atmospheric Phosphorus in Aerosol over the Central North Pacific
AU: * Meguro, A
EM: meguro@ori.u-tokyo.ac.jp
AF: Ocean Research Institute, The University of Tokyo, 1-15-1 Minamidai, Nakano-ku, 164- 8639, Japan
AU: Narita, Y
EM: narita@ori.u-tokyo.ac.jp
AF: Ocean Research Institute, The University of Tokyo, 1-15-1 Minamidai, Nakano-ku, 164- 8639, Japan
AU: Iwamoto, Y
EM: yoko-iwamoto@ori.u-tokyo.ac.jp
AF: Ocean Research Institute, The University of Tokyo, 1-15-1 Minamidai, Nakano-ku, 164- 8639, Japan
AU: Iguchi, H
AF: Ocean Research Institute, The University of Tokyo, 1-15-1 Minamidai, Nakano-ku, 164- 8639, Japan
AU: Mano, Y
AF: Ocean Research Institute, The University of Tokyo, 1-15-1 Minamidai, Nakano-ku, 164- 8639, Japan
AU: Uematsu, M
EM: uematsu@ori.u-tokyo.ac.jp
AF: Ocean Research Institute, The University of Tokyo, 1-15-1 Minamidai, Nakano-ku, 164- 8639, Japan
AB: Phosphorus is an essential element of ocean primary production as well as nitrogen and iron. However, it usually depletes in the surface layer of the central area of an open ocean since most phosphorus in the ocean is supplied by a riverine input. Thus, the input of phosphorus from air to sea plays important role on the surface layer of the ocean remote from the land. To clarify a distribution and a behavior of phosphorus over the central North Pacific, the observation was carried out on the KH-05-2 cruise of the R/V Hakuho-maru (8 August to 21 September, 2005). The mean concentrations of atmospheric phosphorus over the central North Pacific in the fine mode (D<2.5 μm), the coarse mode (D>2.5 μm) and total mode were 1.3±1.1, 1.7±2.3 and 3.0±2.8 ng m^-3, respectively. It was estimated that phosphorus derived from sea salt, crustal substance and the other were 1%, 10% and 89%, respectively. The unknown phosphorus could be land-origin since it had similar trends of Al and NH₄⁺ and was transported from the Asian continent by a backward trajectory analysis. The central Pacific Ocean was classified into four areas (Southwest, central south, central north and Northwest) on the basis of airmass type. The mean phosphorus concentration in the coarse mode varied from 1.1 to 2.6 ng m^-3 in the four areas, while mean phosphorus concentration in fine mode was almost constant. And the influxes of phosphorus from air to the ocean were estimated to be 1.8-4.6 μg m^-2 d^-1 in the coarse mode and 0.11 μg m^-2 d^-1 in the fine mode.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0365 Troposphere: composition and chemistry
DE: 0470 Nutrients and nutrient cycling (4845, 4850)
DE: 1029 Composition of aerosols and dust particles
DE: 1065 Major and trace element geochemistry
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting