Comparing the vertical distribution of oxygen and AOU (Pacific and Atlantic)

　In marine chemistry, it is standard practice to consider the vertical distribution of each parameter, so let's compare the vertical distributions of dissolved oxygen (DO) and apparent oxygen consumption (AOU).

【High production area in the Atlantic subtropics：①Graph】

　The distribution (① in the figure below) in the subtropical North Atlantic near the African continent (12.5N, -22.5E) is shown. This area is known for its high biological productivity because the wind sometimes blows continuously from north to south and upwelling occurs due to Ekman pumping (Mauritanian upwelling area). As a result, a large amount of particulate organic matter settles from the surface layer and decomposes near the pycnocline, consuming oxygen. Because it is close to the starting point of the deep circulation, the oxygen concentration in deep water is high. As a result, a significant minimum in dissolved oxygen concentration and maximum in AOU can be seen near the pycnocline.

【North Pacific subarctic zone (end of deep circulation)：②graph】

　The distribution of the North Pacific subarctic zone (47.5N, -152.5E) near the end of the deep circulation (② in the figure below) is shown. The deep water of the North Pacific Ocean is characterized by a lower oxygen concentration than the deep water of the North Atlantic Ocean. Oxygen is gradually consumed during deep circulation over many years.

　Please understand the characteristics of oxygen and AOU distribution in the North Atlantic and North Pacific.