海洋珊瑚中放射性核素239+240Pu的来源与时间序列

本文针对当前太平洋和大西洋海域珊瑚中239+240Pu的研究现状，首次对已研究的10个珊瑚中239+240Pu比活度和240Pu/239Pu原子比值的时间序列进行了综合比较和分析，并探讨了其来源和对环境的指示意义。研究结果表明，海洋珊瑚中的239+240Pu主要来源于大气核试验的全球性沉降和太平洋核试验的近地局部沉降。岸礁和环礁珊瑚生长环境的差异，是导致其骨骼中239+240Pu比活度也出现差异的主要原因。1952－1958年，太平洋大规模的核试验使得近地局部沉降的Pu核素成为海洋中珊瑚可富集Pu核素的主要来源。因此，珊瑚中239+240Pu比活度与全球大气Pu核素沉降有着不同的时间序列模式。太平洋珊瑚中239+240Pu比活度的时间序列（主峰时间为1954年）与大西洋珊瑚的时间序列（主峰时间为1964年）也不同。海洋珊瑚中的Pu核素可能对大尺度海水流动的方向、厄尔尼诺现象以及大洋中潟湖海水小尺度的波动周期等有指示作用。

Source and time series of 239+240Pu in marine corals

The 10 time series of 239+240Pu specific activity and 240Pu/239Pu atom ratio in reef and atoll corals in the Pacific Ocean and Atlantic Ocean were analyzed and compared, at the same time discussed its source and its significance to the environment. The results showed that 239+240Pu in corals mainly came from global fallout and Pacific Proving Grounds (PPG) close-in fallout. As the difference growth environments between shore reefs and atolls, the time series of 239+240Pu in corals also showed different characteristics. Large-scale atmospheric nuclear weapons test between 1952 and 1958 in the Pacific Proving Grounds made close-in fallout or local input of Pu become the main source of available Pu for corals in seawater. The time series of 239+240Pu in corals have different time series patterns from that of global fallout Pu. So the time series of 239+240Pu specific activity in Pacific corals (the main peak time position corresponds to 1954) and in Atlantic corals (the main peak time position corresponds to 1964) have different patterns. Pu in corals maybe indicate the direction of seawater current, El Nio phenomena on a large spatial scale and the fluctuation period of lagoon seawater on a small spatial scale in ocean.