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Journal of Oceanography

, Volume 65, Issue 2, pp 235–244 | Cite as

Long-term bottom water warming in the north Ross Sea

  • Hirokazu OzakiEmail author
  • Hajime Obata
  • Mikio Naganobu
  • Toshitaka Gamo
Original Articles

Abstract

We measured potential temperature, salinity, and dissolved oxygen profiles from the surface to the bottom at two locations in the north Ross Sea (65.2°S, 174.2°E and 67.2°S, 172.7°W) in December 2004. Comparison of our data with previous results from the same region reveals an increase in potential temperature and decreases in salinity and dissolved oxygen concentration in the bottom layer (deeper than 3000 m) over the past four decades. The changes were significantly different from the analytical precisions. Detailed investigation of the temperature, salinity, dissolved oxygen and σ 3 value distributions and the bottom water flow in the north Ross Sea suggests a long-term change in water mass mixing balance. That is to say, it is speculated that the influence of cool, saline, high-oxygen bottom water (high-salinity Ross Sea Bottom Water) formed in the southwestern Ross Sea has possibly been decreased, while the influences of relatively warmer and fresher bottom water (low-salinity Ross Sea Bottom Water) and the Adélie Land Bottom Water coming from the Australia-Antarctic Basin have increased. The possible impact of global warming on ocean circulation needs much more investigation.

Keywords

Bottom water circulation dissolved oxygen long-term change potential temperature Ross Sea salinity 

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Copyright information

© Springer Science+Business Media B.V. 2009

Authors and Affiliations

  • Hirokazu Ozaki
    • 1
    Email author
  • Hajime Obata
    • 1
  • Mikio Naganobu
    • 2
  • Toshitaka Gamo
    • 1
  1. 1.Marine Inorganic Chemistry Group, Ocean Research InstituteThe University of TokyoMinamidai, Nakano-ku, TokyoJapan
  2. 2.Southern Ocean Living Resources Research Section, Oceanic Resources DivisionNational Research Institute of Far Seas FisheriesFukuura, Kanazawa-ku, Yokohama, KanagawaJapan

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