中部デボニアンサンゴ礁における珊瑚の光共生
Jonathan Jung1, Simon F Zoppe2, Till Söte3
1Climate Geochemistry Department, Max Planck Institute for Chemistry, Mainz, Germany. jonathan.jung@mpic.de.
Nature
|October 24, 2024
まとめ
中期デヴォニアンのサンゴには 窒素同位体比が示され 栄養素が少ない水域で 古代のサンゴ礁が繁栄していたことが示されています この古代のサンゴ fotosymbiosisは おそらく燃料として 最も生産的なサンゴ礁の生態系です
科学分野:
- 古生物学と海洋生物学
- バイオジオケミストリーと同位体ジオケミストリー
- 進化生物学 と 共生
背景:
- 栄養素が少ない熱帯の水域では 石珊瑚の生存は 光合成ダイノフラゲラットとの共生に依存しています
- 進化の歴史と地質学的な時間における 珊瑚藻共生の流行は 十分に理解されていない.
- 過去の共生を理解することで,その生態学的および進化的役割が明確になります.
研究 の 目的:
- 珊瑚と藻類の光交響の進化史を調査する
- 中部デボニアンサンゴの光交代の発生率を決定する.
- デボニアンのサンゴ礁の生地化学的条件を推測する
主な方法:
- サンゴに結合した有機物質 (CB-δ15N) の窒素同位体比 (15N/14N) の分析.
- 中デヴォニア (Givetian) のサンゴサンプルの同位体値と現代のサンゴの共生データとの比較
- CB-δ15N値に基づいて,活発な光共生体を持つとないサンゴを区別する.
主要な成果:
- 植民地のタブラとファシキュレットのルゴースサンゴは,低CB-δ15N値 (2.51 ± 0.97‰) を示し,光共生体を宿している.
- 単体および (擬似) 植民地のルゴースサンゴは,より高いCB-δ15値 (5.52 ± 1.63 ‰) を示し,光共生体がないことを示唆した.
- デボニアン期のサンゴの異質性は,現代の共生生体を持つサンゴと,共生生体を持たないサンゴを反映しています.
結論:
- デヴォン期中盤のタブラートと一部のファシキュラート・ルゴスサンゴは 活発な光共生体を宿していたが,他のサンゴはそうではなかった.
- 低CB-δ15N値は,現代の亜熱帯回転に類似した,オリゴトロフ的条件でデヴォン期のサンゴ礁が存在することを示唆しています.
- 広範囲に広がったデボニアン時代 オリゴトロフィーは 珊瑚の光共生を促し 古代のサンゴ礁の生態系の 高い生産性に寄与しました
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