Dynamics of carbon dioxide uptake and nutrients in subtropical oceanic waters

比较了亚热带海洋表层水中痕量营养盐浓度和二氧化碳分压(PCO2)的空间变化。为此，设计了一套具有高分辨率时间变化的二氧化碳分压监测系统，并于2005-2006年对其进行了性能测试。开发的系统搭载在东京海洋科技大学的RAT Umitaka-Maru上，并于2006年11月29日至12月14日在从东京到悉尼的邮轮航段上进行了亚热带水域的表面监测。在监测二氧化碳分压的同时，用比色法连续观察pH值，并进行高灵敏的营养素连续流动分析。PCO2具有较小的空间尺度(~数十公里)的变化，这种变化可分为三种类型。第一种模式伴随着温度的降低、盐度的升高和营养盐浓度的增加，这可以归因于垂直混合和/或上升流的增强。第二种模式伴随着盐度的广泛下降，可能反映了降水对海水的稀释。第三种也是最常见的模式是PCO_2和微量磷的共同变化，这可能是由生物活动引起的

Spatial variations of trace concentrations of nutrients and partial pressure of carbon dioxide (pCO_2) were compared for surface waters of the subtropical ocean. For this purpose, a pCO_2 monitoring system with high resolution of temporal variation was designed, and its performance was tested from 2005 through 2006. The developed system was carried onboard RAT Umitaka-maru of the Tokyo University of Marine Science and Technology, and surface monitoring in the subtropical waters was conducted during the period from 29 Nov to 14 Dec. in 2006, on a cruise leg from Tokyo to Sydney. Along with pCO_2 monitoring, the continuous observation of pH by colorimetric determination and the high-sensitive continuous flow analysis of nutrients were also performed. The pCO_2 showed variations of smaller spatial scales (〜tens of km), and these variations were categorized into three patterns. The first pattern accompanies decrease of temperature, increase of salinity, and increase of nutrient concentrations, which can be ascribed to enhanced vertical mixing and/or upwelling. The second pattern accompanies an extensive decrease of salinity and may reflect dilution of seawater by precipitation. The third and most frequently observed pattern was co-variation of pCO_2 and trace phosphate, which was presumably caused by biological activity