大约在侧面的氧化还原变异性. 1.9 亿年前的海洋环境是由有机碳和同位素组成的海洋环境
Kento Motomura1,2, Andrey Bekker1,3, Minoru Ikehara4
1Department of Earth and Planetary Sciences, University of California, Riverside, California, USA.
Geobiology
|August 12, 2024
概括
早期的真核生物大概在19亿年前在富含营养的海洋中壮成长. 高的生物生产率和循环支持可居住的环境,即使是在岛屿弧线附近的开放海洋环境中.
科学领域:
- 地质化学 地质化学
- 古生物学的古生物学
- 海洋学 海洋学 海洋学
背景情况:
- 欧核生物的进化与地球的氧化有关,它出现在古原生态时代.
- 了解早期海洋营养循环对于解释真核生物的出现和扩张至关重要.
- 之前的研究缺乏限制在海洋和陆地营养循环在此期间.
研究的目的:
- 为了研究开放海洋的氧化还原条件和生物活动在1.9亿年前的Flin Flon海洋岛屿弧度周围.
- 分析营养循环及其在支持早期真核生物生命中的作用.
- 为了限制在古新生态时期的海洋营养循环.
主要方法:
- 来自加拿大Flin Flon带的黑色页岩中对氧化还原敏感元素含量的分析.
- 对有机碳和同位素组成 (δ13Corg和δ15Nbulk) 的检查.
- 地化学数据与现代氧气最小区环境的比较.
主要成果:
- 黑色页岩显示了可变的suboxic到eocinic氧化还原条件.
- 升高的 δ13Corg (大约. -23‰) 和 δ15N批量 (大约. +13.7‰) 表明高生物生产率和增强的脱化.
- 地质化学模式类似于现代气有限的氧气最小区域,这意味着气的生物可用性很大.
结论:
- 这个CA. 1.9亿年前,海洋可能有广泛的生物可利用,支持高生产率.
- 持续向上游区供应气,为早期的真核生物创造了适宜居住的环境.
- 这些条件促进了真核生物的生存,即使在岛屿弧周围的中海环境中.
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