Carbonate compensation depth (English spelling)

Japanese: 炭酸塩補償深度 - たんさんえんほしょうしんど（英語表記）calcium-carbonate compensation depth

The depth in the ocean where the supply rate and dissolution rate of carbonate particles are equal. The point where the calcium carbonate layer in the sediments becomes zero was originally called the compensation line. _CaCO3 particles produced by organisms on the ocean surface sink to the seafloor. Surface water is supersaturated with calcium carbonate, but seawater deeper than a few hundred meters becomes undersaturated. At depths of 3,500 to 4,500 meters or deeper, the dissolution rate of _CaCO3 increases dramatically due to low temperatures and high water pressure. Because the settling rate of _CaCO3 particles is greater than the dissolution rate, _CaCO3 in sediments dissolves on the deep seafloor [Geological Society Research Association: 1996].

Source: Asakura Publishing Dictionary of Petrology Information

Japanese:

海洋で,炭酸塩粒子の供給速度と溶解速度が等しくなる深度．堆積物の中の炭酸カルシウム層がゼロとなるところを補償線と呼んだのが始まりである．海洋表面で生物が作ったCaCO₃の粒子は海底に沈降する．表面水は炭酸カルシウムで過飽和であるが，数100mより深い場所の海水は不飽和となる．3 500～4 500m以深では低温高水圧のためCaCO₃の溶解速度は飛躍的に増加する．CaCO₃粒子の沈降速度が溶解速度に比べて大きいため，深海底では堆積物中のCaCO₃は溶解する［地学団体研究会 : 1996］．

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