日本地球惑星科学連合2018年大会

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[JJ] ポスター発表

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

[A-CG42] 沿岸海洋生態系─1.水循環と陸海相互作用

2018年5月24日(木) 15:30 〜 17:00 ポスター会場 (幕張メッセ国際展示場 7ホール)

コンビーナ:杉本 亮(福井県立大学海洋生物資源学部)、小路 淳(広島大学大学院生物圏科学研究科)、山田 誠(龍谷大学経済学部、共同)、藤井 賢彦(北海道大学大学院地球環境科学研究院)

[ACG42-P06] 海底湧水の流出場の条件が海底湧水由来の熱の空間的広がりに及ぼす影響

*山田 誠1杉本 亮2本田 尚美3 (1.龍谷大学経済学部、2.福井県立大学海洋生物資源学部、3.総合地球環境学研究所)

キーワード:海底湧水、海底湧水由来の熱、海底の状態

Submarine groundwater discharge (SGD) originating from terrestrial groundwater carries various substances with water as a carrier from the land to the sea. It is pointed out that the submarine groundwater discharge(SGD) originating from terrestrial groundwater supplies not only various substances with water as a carrier from the land to the sea but also supplies thermal energy from the land to the sea area. Generally, it is said that the form of outflow differs depending on the state of the seabed. For example, under sea bed conditions like rocky, SGD often spurt out. On the other hand, under sea bed conditions such as covered with sediments, SGD often seeps out. Finally, since the SGD flows into the sea, in the long term, regardless of the sea bed conditions, the substances contained in the SGD flow into the sea. However, depending on the flow rate, the thermal energy derived from the SGD may be lost before it flows into the sea. In other words, there is a possibility that the sea bed conditions which strongly influences the influx velocity of the SGD can strongly influence the spatial spread of the heat derived from the SGD at the coastal area. In this study, in order to examine how the spatial spread of the heat derived from the SGD differs depending on the sea bed conditions, the temperature distribution of the sea bed and surrounding seawater was investigated in three areas (Wakasa area, Obama city, Fukui Pref.; Hiji-machi, Oita Pref.; Yuza-machi, Yamagata Pref.) with different sea bed conditions. The state of the sea bed is covered with sediments in the Wakasa area, Yuza-machi is sedimented thinly on the rocky area, and Hiji-machi is a sediment-free rocky place.
The observation results are as follows. In the Wakasa area, the influence of heat from the SGD on the temperature of the sea bed and sea water was not observed at all. In Yuza-machi, although it is a narrow spatial range, the influence of heat from the SGD on the temperature of the sea bed and sea water around the SGD discharge point was observed. In Hiji-machi, the influence of temperature was strongly observed only at the SGD discharge point on the seabed, but there was no spatial spread of influence. On the other hand, as for the temperature of the sea water, there was a spatial spread of the influence of the heat derived from the SGD. In this way, it became clear that the spatial extent of the influence of the heat derived from the SGD greatly varies depending on the state of the sea bed. In the presentation, we will discuss in detail the reasons for these differences.