新川・春日川河口干潟(瀬戸内海備讃瀬戸)における 懸濁粒子中のリンの挙動  [in Japanese] Behavior of phosphorus in particles in Shinkawa and Kasugagawa estuarine tidal flat, Bisan-seto, Seto Inland Sea, Japan  [in Japanese]

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Abstract

<p>干潟域における懸濁物の挙動を知るために,瀬戸内海東部に位置する新川・春日川河口干潟域において,一潮汐間の連続的な観測を2010年5月から11月の間に計5回実施し,懸濁態リンを有機および無機態に分別定量した。栄養塩濃度は8月の溶存態無機窒素(DIN)を除いて塩分と負の相関関係にあり,河川から流入した栄養塩が海水に希釈されることで,干潟域の栄養塩濃度が決定されていると考えられた。一方,懸濁態有機リン(POP)および懸濁態無機リン(PIP)濃度は,塩分に対し有意な相関関係が認められる場合と,認められない場合があった。POPは概ねクロロフィルa(Chl a)濃度と有意な正の相関関係が認められ,同時に水中POP/Chl a比が植物プランクトンのそれと同程度であったことから,干潟域のPOP濃度には植物プランクトンの増減が河川由来の物質の多寡よりも大きく影響していたと考えられた。しかしながら,Chl a濃度が低い時にはPOP/Chl a比が高く,陸起源粒子あるいはデトリタスのような植物プランクトン以外の粒子の寄与が大きいと考えられた。また,PIPは7月を除いて塩分と負の相関関係にあり,干潟域のPIP濃度は主に河川由来の粒子の影響を受けており,干潟堆積物の再懸濁の影響は量的に小さいことが考えられた。一方,干潟の沖合では河川由来の粒子の影響は見られなかった。</p>

<p>In order to identify the behavior of particles in the tidal flat, one-tidal time-series surveys were carried out five times during May and November, 2010 in Shinkawa-Kasugagawa estuarine tidal flat where is located in the eastern Seto Inland Sea, Japan, and particulate phosphorus was measured dividing organic and inorganic forms. Nutrients were negatively correlated with salinity except dissolved inorganic nitrogen in August. It suggests that nutrient concentrations were regulated by both nutrient discharge from riverine water and the dilution by offshore seawater. However, particulate organic phosphorus (POP) and inorganic phosphorus (PIP) were not always correlated with salinity. POP, on the other hand, often correlated with Chl a, and moreover, POP/Chl a ratios in tidal flat water were similar with those of phytoplankton. These results suggested that standing stock of phytoplankton largely affected the composition of particulate organic matter in the tidal flat. When concentrations of Chl a in the tidal flat water were low, POP/Chl a ratios were high, suggesting that phytoplankton was scarcely contributed but other particles, such as the terrestrial and detrital particles, largely contributed to particles in the tidal flat. PIP had a good correlation with salinity except July, which suggests that riverine particles affected PIP in the tidal flat. Moreover, it was scarcely observed that resuspension of the sediment affected PIP in the tidal flat.</p>

Journal

  • Oceanography in Japan

    Oceanography in Japan 23(2), 29-44, 2014

    The Oceanographic Society of Japan

Codes

  • NII Article ID (NAID)
    110009816830
  • NII NACSIS-CAT ID (NCID)
    AN10382760
  • Text Lang
    JPN
  • Article Type
    Journal Article
  • ISSN
    0916-8362
  • NDL Article ID
    025356742
  • NDL Call No.
    Z15-778
  • Data Source
    NDL  NII-ELS  IR  J-STAGE 
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