Abstract:

The China R/V Xuelong went on the first Arctic scientific cruise, and we obtained 271 hydro-chemical samples from 22 deep-sea stations in the Bering Basin in late July, 1999. Here we describe vertical properties of silicate [Si] , dissolved inorganic nitrogen [DIN] or [N] (nitrate plus ammonium plus nitrite) , phosphate [P] and oxygen [ O₂ ] in seawater under potential temperature-salinity structure. The seasonal stratification in the summer and the water exchanges of the North Pacific Ocean over the Bering Basin resulted in that the four layers of vertical structure with two thermoclines may be found. Vertical [Si] and [N] and [P] profiles show that the nutrients are consumed mainly in ≤50 m and the order of deficient nutrients is [Si] the first, [N] the second and [P] the third. The [N] and [P] increase with depth downward to about 500 m and then both decrease, but the [Si] increases from 150 m to 2000 m or the bottom. In ≥ 150 m the [ O₂ ] decreases, which is related with both [P] and [N] increasing closely. Seawater [N] : [P] ratios are 6 - 12 in ≤50 m, 10.5 - 14.3 in 100 - 150 m and 11.7 - 15.8 from 300 m to the bottom.

Key words: nutrients, oxygen, potential temperature, salinity, Bering Basin, Arctic