Calcium in the Sea of Okhotsk
Abstract
Calcium in the Sea of Okhotsk - Sakhalin and Kamchatka slopes, Derugin and Kuril basins and Sakhalinsky Bay - was determined in June-July 2002 during the KOMEX expedition with an error less than 0.1% by the method of Tsunogai. The main features of calcium distribution are following: 1. The average Ca/Cl ratios for the whole water column and for the deep waters of the Sea of Okhotsk are about 0.5% higher than Pacific ocean averages. 2. The average Ca/Cl ratio for the surface layer was also much higher. The highest values were observed in the Sakhalinsky Bay, at Sakhalin and South Kamchatka slopes. The calcium excess corresponds to the different contribution of river runoff to the processes of fresh and salt waters mixing and transport. 3. The Ca/Cl ratio within the subsurface layer are lower than at the surface due to biological uptake of dissolved CaCO3 from the seawater. Below 100 m Ca/Cl values increase steadily with depth as a result of biogenic carbonate dissolution. The variations in Ca/Cl ratio within the water column were about 0.4-0.7%. 4. The greatest value of Ca/Cl was found in 200 m layer above the seafloor for the deepest part of the Derugin basin (bottom depth 1760 m). The ratio of calcium to alkalinity in this layer is higher than it would be expected from dissolution of calcium carbonate. Probably observed calcium excess of 15 umol/kg could be derived from the proton flux associated with the intensive organic matter decomposition (dissolved oxygen content 13 umol/kg) and stagnant circulation conditions. 5. Ca/Cl ratio is also high within the bottom water in the Kuril basin. But for some locations the ratio decreases inside the thin near bottom layer up to the values typical for Pacific waters overflowed through the Bussol sill from the depth of about 2300 m. The bottom water renewal also confirmed by the similar distribution of the other water properties.
- Publication:
-
EGS - AGU - EUG Joint Assembly
- Pub Date:
- April 2003
- Bibcode:
- 2003EAEJA.....8063P