PNAS：北太平洋的气候与急剧的生态系统转变

摘要 : 英国埃克塞特大学生命与环境科学学院一项研究提出，更长、频率更低的气候波动可能归结于北太平洋的急剧而尚未得到解释的生态系统转变。

英国埃克塞特大学生命与环境科学学院一项研究提出，更长、频率更低的气候波动可能归结于北太平洋的急剧而尚未得到解释的生态系统转变。在1977年和1989年记录下了北太平洋浮游生物和鱼类物种——包括该区域的具有经济重要性的鲑鱼物种——的丰富程度和分布的迅速而广泛的变化是人们称之为稳态转换的实例。Chris Boulton 和Tim Lenton注意到了海洋生态系统对于环境变化性的变化敏感，他们分析了自从1900年以来北太平洋的海洋表面温度涨落，识别出了朝着更长、频率更低的变化时期的一种趋势。此外，这组作者在太平洋年代际振荡指标中发现了一个类似的模式，太平洋年代际振荡指标是一个被广泛引用的太平洋气候变化性指标，人们已经把它与1977年和1989年的稳态变化联系在了一起。这组作者说，这些结果揭示出了过去一个世纪的太平洋的气候变化性已经转变成了一种振荡的模式，在这种模式中，该地区的生态系统更可能表现出大而急剧的气候触发的稳态转换。这些发现提示，变化的气候变化性可能造成了1977年和1989年的北太平洋稳态转换。

原文链接：

Slowing down of North Pacific climate variABIlity and its implications for abrupt ecosystem change

原文摘要：

Marine ecosystems are sensitive to stochastic environmental variability, with higher-amplitude, lower-frequency––i.e., “redder”––variability posing a greater threat of triggering large ecosystem changes. Here we show that fluctuations in the Pacific Decadal Oscillation (PDO) index have slowed down markedly over the observational record (1900–present), as indicated by a robust increase in autocorrelation. This “reddening” of the spectrum of climate variability is also found in regionally averaged North Pacific sea surface temperatures (SSTs), and can be at least partly explained by observed deepening of the ocean mixed layer. The progressive reddening of North Pacific climate variability has important implications for marine ecosystems. Ecosystem variables that respond linearly to climate forcing will have become prone to much larger variations over the observational record, whereas ecosystem variables that respond nonlinearly to climate forcing will have become prone to more frequent “regime shifts.” Thus, slowing down of North Pacific climate variability can help explain the large magnitude and potentially the quick succession of well-known abrupt changes in North Pacific ecosystems in 1977 and 1989. When looking ahead, despite model limitations in simulating mixed layer depth (MLD) in the North Pacific, global warming is robustly expected to decrease MLD. This could potentially reverse the observed trend of slowing down of North Pacific climate variability and its effects on marine ecosystems.

doi: 10.1073/PNAS.1501781112

作者：Chris A. Boulton 和T

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