[A-CG40] 沿岸海洋⽣態系─１．⽔循環と陸海相互作⽤

[ACG40-P02] 火山性砂浜域における淡水性地下水湧出が植物プランクトンの一次生産速度に及ぼす影響

原田 佳奈¹、*杉本 亮¹、中島 壽視¹、富永 修¹ (1.福井県立大学海洋生物資源学部)

キーワード：地下水湧出、13C isotope tracer、野外実験

Research on how SGD nutrients impact marine biota has increased in recent years. The documented response of marine organisms to SGD is quite variable and site-specific, and can be positive or negative from a population or community perspective. Additionally, the response to SGD is sometimes unclear and could change depending on the specific location or time of the year. The most documented response to SGD-derived nitrogen and phosphorus loading is related to increasing the primary productivity of phytoplankton or microphytobenthos. However, in some cases, no response was found near sites receiving fresh groundwater springs, indicating SGD loading does not always induce an increase in primary productivity. Here, we present the phytoplankton primary productivity around fresh groundwater springs in the Chokai volcano coast assessed by the field experiments. Although fresh groundwater springs were significant nutrient sources, the primary productivity of phytoplankton decreased with increasing groundwater impact, possibly due to physical and physiological disturbances such as low salinity and temperature.