日本地球惑星科学連合2023年大会

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セッション記号 A (大気水圏科学) » A-CG 大気海洋・環境科学複合領域・一般

[A-CG31] Nutrient footprint of primary production in the coastal and marginal seas of East and Southeast Asia

2023年5月21日(日) 15:30 〜 16:45 106 (幕張メッセ国際会議場)

コンビーナ:張 勁(富山大学 学術研究部理学系)、森本 昭彦(愛媛大学)、Qian Liu(Ocean University of China)、Takahiro Endoh(RIAM Research Institute for Applied Mechanics)、座長:森本 昭彦(愛媛大学)

15:30 〜 15:45

[ACG31-06] A significant contribution of open ocean to nutrient and phytoplankton inventory in the Seto Inland Sea

*LENG QIAN1郭 新宇1森本 昭彦1 (1.愛媛大学 沿岸環境科学研究センター)

キーワード:硝酸塩現存量、外洋起源硝酸塩、半閉鎖性海域

The semi-enclosed coastal seas serve as a transition region from land to the open ocean and are affected by both, but the role of the open ocean remains unclear. The Seto Inland Sea (SIS), which is connected to the Pacific Ocean, is a typical one of semi-enclosed seas. We developed a three-dimensional coupled physical-biogeochemical model, embedded with a nutrient source tracking technique, to quantitatively assess the material inventory of SIS originating from the open ocean. Our model shows that the open ocean contributes 73% and 60% of the annual mean dissolved inorganic nitrogen (DIN) and phytoplankton (PHY) inventories across the SIS, implying a large proportion of open ocean origin. The oceanic contribution to the total DIN and PHY inventory decreased from the south part of SIS to the interior, showing lower values in the nearshore areas. The open ocean imported 797 mol/s DIN to the SIS each year, among which 25% was consumed by biogeochemical processes in the SIS while the other returned to the open ocean again. Our results indicated the significant effect of the open ocean in typical semi-enclosed seas, suggesting the need to consider the impact of open ocean nutrient input associated with climate change when performing nutrient management.