Garis besar topik

    • Agitation of sediments and improvement of seabed environment using steel girders (JF Osaka Fisheries Federation)



    • 海底耕耘: seabed tilling 植物プランクトン: phytoplankton 埋没: burial

      Nutrient regression effects (Ariake Sea, Sea of Harima) (Numano et al., 2004; Nakanishi et al., 2012)

      →pore water dissolution, organic matter decomposition, desorption

      Verification and quantification of regression amounts are required according to the target sea area.



    • On-site tilling experiment (otter trawl)



    • 採取項目: sampling item

      濁度: turbidity 密度: density 水温: water temperature 酸素濃度: oxygen concentration

      栄養塩試料: nutrient sample

      堆積物試料（耕耘点のみ）: sediment sample (tilling points only) 含水率: moisture content間隙水: pore water 堆積物直上酸素濃度: oxygen concentration directly above sediment



    • Seawater velocity at a depth of 36 m and passage


    • 底引き網オッタートロール漁法（沖合底引き網）: Otter trawl fishing method (offshore trawl)

      オッターボード（網を左右に広げる）: Otter board (spreading the net from side to side)

      The otter board spreads the net to a constant width, allowing the net to be pulled continuously for a long period of time.

       

      マリンネット北海道: Marine Net Hokkaido, Hokkaido Research Organization, Fisheries Research Department



    • The increase in DIN due to the tilling effect is equivalent to 22.4% of the total DIN in the water.