Spatiotemporal and Long-term Variations of Partial Pressure of Carbon Dioxide in Lake Hamana

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K20436
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 63010:Environmental dynamic analysis-related
• Research Institution: Shizuoka University
• Principal Investigator: Kubo Atsushi 静岡大学, 理学部, 講師 (90803958)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 二酸化炭素 / 沿岸海域 / 海洋学 / 陸水学 / 有機物 / アルカリ度 / pH / 酸性化

Outline of Final Research Achievements

DIC and TA of surface waters were investigated monthly to identify the seasonal and spatial variations of pCO2 in Lake Hamana. The pCO2 in the lake water were ranged from 29 to 1476 micro-atm, and were undersaturated for atmospheric pCO2 at the most observations. Since there was a strong negative correlation between pCO2 and dissolved oxygen saturation, seasonal and spatial variations of pCO2 were derived from primary production and organic matter decomposition. Carbon dioxide consumption due to active biological activity is the most controlling factor of seasonal and spatial variations of pCO2 in Lake Hamana because pCO2 was undersaturated and dissolved oxygen saturation were oversaturated at the most observations.
At the most surface water of the lake, pCO2 was not change significantly during 1995 and 2019. In contrast, pCO2 at the bottom layer of central lake and river mouth had a decrease trend because of decreasing trend of terrestrial organic carbon input.

Free Research Field

沿岸海洋学

Academic Significance and Societal Importance of the Research Achievements

本研究課題では、都市沿岸海域における二酸化炭素収支推定を行った。また、その結果から得られた塩分とアルカリ度の直線回帰式より、過去のデータが多くある塩分とpHから過去の二酸化炭素収支推定を行った。この手法を公共用水域調査が行われている日本沿岸海域に拡張することで、国内の二酸化炭素収支の時系列変化を明らかにすることが可能となる。