Department of Chemical and Physical Sciences, University of Toronto, 3359 Mississauga Road North, Ontario, Canada L5L 1C6.
Department of Botany, Smithsonian National Museum of Natural History, 1000 Constitution Avenue, NW, Washington, District Of Columbia 20560, USA.
Nat Commun. 2017 Jun 1;8:15543. doi: 10.1038/ncomms15543.
Accelerated warming and melting of Arctic sea-ice has been associated with significant increases in phytoplankton productivity in recent years. Here, utilizing a multiproxy approach, we reconstruct an annually resolved record of Labrador Sea productivity related to sea-ice variability in Labrador, Canada that extends well into the Little Ice Age (LIA; 1646 AD). Barium-to-calcium ratios (Ba/Ca) and carbon isotopes (δC) measured in long-lived coralline algae demonstrate significant correlations to both observational and proxy records of sea-ice variability, and show persistent patterns of co-variability broadly consistent with the timing and phasing of the Atlantic Multidecadal Oscillation (AMO). Results indicate reduced productivity in the Subarctic Northwest Atlantic associated with AMO cool phases during the LIA, followed by a step-wise increase from 1910 to present levels-unprecedented in the last 363 years. Increasing phytoplankton productivity is expected to fundamentally alter marine ecosystems as warming and freshening is projected to intensify over the coming century.
北极海冰的加速融化与近年来浮游植物生产力的显著增加有关。在这里，我们利用多指标方法，重建了加拿大拉布拉多海与海冰变化相关的生产力的年度分辨率记录，该记录可以追溯到小冰期（1646 年）。在长寿珊瑚藻中测量的钡钙比（Ba/Ca）和碳同位素（δC）与海冰变化的观测和代理记录显著相关，并显示出与北大西洋多年代际振荡（AMO）的时间和相位基本一致的持久协同变化模式。结果表明，小冰期期间与 AMO 冷相位相关的亚北极西北大西洋生产力降低，随后从 1910 年到现在的水平逐步增加——在过去的 363 年中是前所未有的。预计随着未来一个世纪的变暖变咸，浮游植物生产力的增加将从根本上改变海洋生态系统。
