[A-CG42] 沿岸海洋生態系─１．水循環と陸海相互作用

[ACG42-P03] 気仙沼湾奥部における地下水湧出に伴う炭素輸送

*杉本 亮¹、中島 壽視¹、Isaac Santos²、谷口 真人³ (1.福井県立大学海洋生物資源学部、2.サザンクロス大学、3.総合地球環境学研究所)

キーワード：海底湧水、二酸化炭素分圧、ラドン222

Submarine groundwater discharge (SGD) is an important source of nutrients, trace metals, and carbon to coastal ecosystem. To quantify this processes in Kesennuma Bay, 24-hours mooring surveys for SGD tracers (Rn and Ra isotopes) and biogeochemical properties (nutrients, dissolved carbon and iron) were conducted during neap and spring tides in summer 2017. In this presentation, we will show results of simultaneous measurements of ²²²Rn and pCO₂. Although pCO₂ showed clear diurnal variation according to the photosynthesis/respiration process in both periods, excess CO₂ was supplied through significant groundwater discharge during the lowest tide in spring. These data will be used to quantify carbon flux from SGD and emission rate of CO₂ to atmosphere.