造礁サンゴ3種 (パリカメノコキクメイシ、フカアナハマサンゴ、コノハシコロサンゴ) の赤土懸濁条件下における酸素消費量 Oxygen consumption rate of the corals <i>Goniastrea aspera</i>, <i>Porites lobata</i>, and <i>Pavona frondifera</i> under red soil stress in the Ryukyu Islands, Okinawa, Japan

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Author(s)

    • Ismail Mohamed
    • Laboratory of Ecology and Systematics, Faculty of Science, University of the Ryukyus|Laboratory of Geology, Biological and Geological Sciences Department, Suez Canal University
    • 土屋 誠 Tsuchiya Makoto
    • 琉球大学大学院理工学研究科海洋環境学専攻 Laboratory of Ecology and Systematics, Faculty of Science, University of the Ryukyus

Abstract

パリカメノコキクメイシ、フカアナハマサンゴ、トゲシコロサンゴについて赤土の懸濁条件下での酸素消費量を室内実験によって測定した。単位表面積あたりの酸素消費量は種毎に異なり、また赤土の懸濁量によっても影響を受ける。明暗いずれの条件下でもパリカメノコキクメイシの酸素消費量が他の2種よりも多く、褐虫藻の密度が他の2種よりも高いことと何らかの関係があることが示唆された。特に暗条件下では褐虫藻の密度が高い種ほど酸素消費量が多かった。赤土の懸濁量とサンゴ類の酸素消費量の関係から考えると, 塊状のサンゴ (パリカメノコキクメイシとフカアナハマサンゴ) がコノハシコロサンゴよりも赤土の懸濁に対しては抵抗力があり、実験開始後、酸素消費量に影響が出るのが遅かった。これらの種はそのような条件に適応しやすいのではないかとも推測される。これらの結果は、今後赤土が流入し続けるような状況において、サンゴ群集が受ける攪乱やその後の変化が予測しうるものであることを示唆する。

Effects of short-term sedimentation on common coastal coral species, <i>Goniastrea aspera</i>, <i>Porites lobata</i> and <i>Pavona frondifera</i>, from the reef flat southeast of the Ryukyu Islands, Okinawa, Japan were investigated in laboratory experiments using oxygen uptake respirometers. The O<sub>2</sub> consumption rate was significantly different among species and between sediment treatments (20 and 200mg l<sup>-1</sup> red soil suspension, <i>P</i><0.05). In dark experiments, <i>Goniastrea</i> showed higher respiration rates (0.020±0.002ml O<sub>2</sub> cm<sup>-2</sup>h<sup>-1</sup>) than did <i>Pavona</i> (0.017±0.003mL O<sub>2</sub> cm<sup>-2</sup>h<sup>-1</sup>) and <i>Porites</i> (0.010±0.001ml O<sub>2</sub> cm<sup>-2</sup>h<sup>-1</sup>). In light experiments, <i>Goniastrea</i> also showed higher O<sub>2</sub> consumption rates (0.021±0.003ml O<sub>2</sub> cm<sup>-2</sup>h<sup>-1</sup>) than did <i>Porites</i> (0.010±0.004ml O<sub>2</sub> cm<sup>-2</sup>h<sup>-1</sup>) and <i>Pavona</i> (0.007±0.001ml O<sub>2</sub> cm<sup>-2</sup>h<sup>-1</sup>). Zooxanthellae densities were 6.53±0.13, 3.12±0.05, and 4.37±0.07 (×10<sup>6</sup>cells cm<sup>-2</sup>; mean±SE, n=8) in <i>Goniastrea</i>, <i>Porites</i>, and <i>Pavona</i>, respectively. Coral respiration rate increased proportionally with zooxanthellae density in <i>Goniastrea</i> and <i>Pavona</i>. High zooxanthellae density may increase the O<sub>2</sub> production that contributes to colony respiration; however, in <i>Porites</i>, the relationship between zooxanthellae density and coral respiration rate was not clear. The massive corals, <i>Goniastrea</i> and <i>Porites</i>, are more resistant to sediment stress than is the plate-like coral, <i>Pavona</i>. <i>Goniastrea</i> showed high tolerance and adaptation to stress conditions in all experiments, at all times (12h), with similar trends in both dark and light conditions. <i>Porites</i> was affected only within the first 3h under light conditions, while <i>Pavona</i> was the most affected species. These results help us to understand coral damage caused by red soil sedimentation, as well as coral mortality and potential shifts in community structure related to prolonged or repeated elevated levels of sedimentation on coastal reefs.

Journal

  • Journal of the Japanese Coral Reef Society

    Journal of the Japanese Coral Reef Society 2005(7), 11-22, 2005

    The Japanese Coral Reef Society

Codes

  • NII Article ID (NAID)
    130003670757
  • Text Lang
    UNK
  • ISSN
    1345-1421
  • Data Source
    J-STAGE 
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