The response of the Subarctic North Pacific to abrupt climate change: Reconstructing dust flux and biological productivity during the last deglaciation

亚北极北太平洋对气候突变的响应：重建末次冰消期期间的尘埃通量和生物生产力

• 批准号: 1060907
• 负责人: Gisela Winckler
• 金额: $ 35.45万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2016-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1060907&HistoricalAwards=false
• 关键词: response; Subarctic; North; Pacific; abrupt

The focus of this study by researchers at the Lamont-Doherty Earth Observatory of Columbia University is to test how the Subarctic North Pacific responds to and potentially mitigates climate change. The Subarctic Pacific constitutes one of the high-nutrient-low chlorophyll regions where the biological pump is relatively inefficient at transferring carbon from the atmosphere to the deep sea. Iron, contained in mineral dust from Chinese deserts, is thought to stimulate biological production in this region. However, our understanding of the links between dust, biological production and climate is hampered by the lack of reliable dust flux records in the Subarctic North Pacific as well as longstanding discrepancies among specific techniques that have been used in previous research to reconstruct biological productivity. Cores collected during a recent German-led expedition (INOPEX) provide extensive coverage of this previously largely undersampled remote region and offer a unique opportunity for study. Using a suite of geochemical proxies (thorium and uranium isotopes, helium isotopes, and trace elements), the researchers will produce a map of the spatial pattern of dust supply and biological productivity and calibrate it by comparing to present day information from satellites and other observations. The researchers will then apply their calibration to down-core records, focusing on the abrupt climate changes of the last deglaciation. The sequence from the cold and dusty Heinrich Stadial 1, through the dust-poor Bølling-Allerød warm period and a return to the near-glacial conditions of the Younger Dryas stadial provides for an outstanding natural experiment to test how the Subarctic North Pacific?s ecosystem responds to and mediates climate change.Broader impacts include involvement of undergraduates and high school students in the research, training of local high school teachers, and enhancing international collaborations. In addition, the results of this international collaboration will inform decision makers in exploring large-scale artificial iron fertilization of the ocean as a geo-engineering option to mitigate global warming. Reliable estimates of the long-term carbon sequestration capacity and impact on the ecosystem remain controversial. This work will assess the past response to natural variability of iron input in one of the key regions of the global ocean and will, in turn, lay the foundation to develop quantitative predictions about the possible efficacy and consequences of artificial iron fertilization.

哥伦比亚大学拉蒙特-多尔蒂地球观测站的研究人员进行的这项研究的重点是测试亚北极北太平洋如何应对和潜在地缓解气候变化。亚北极太平洋是生物生长的高营养低叶绿素区域之一。泵在将碳从大气转移到深海方面效率相对较低，中国沙漠的矿物尘埃中含有的铁被认为可以刺激该地区的生物生产。然而，我们对灰尘、生物生产和海洋之间联系的了解还不够。由于亚北极北太平洋地区缺乏可靠的尘埃通量记录，以及先前研究中用于重建生物生产力的特定技术之间长期存在的差异，气候变化受到阻碍。在最近由德国领导的探险队（INOPEX）期间收集的岩心提供了广泛的数据。研究人员覆盖了这个以前采样不足的偏远地区，并使用一套地球化学替代物（钍和铀同位素、氦同位素和微量元素）提供了独特的研究机会。将绘制灰尘供应和生物生产力的空间模式图，并通过与来自卫星和其他观测的当前信息进行比较来校准它，然后研究人员将其校准应用于地下记录，重点关注气候的突变。最后一次冰消期，从寒冷多尘的 Heinrich Stadial 1 到灰尘贫乏的 Bølling-Allerød 温暖期，再到新仙女木体育场的近冰川条件的回归，提供了一次出色的自然实验。测试亚北极北太平洋生态系统如何响应和调节气候变化。更广泛的影响包括本科生和高中生参与研究、培训当地高中教师以及加强国际合作。国际合作将为决策者探索大规模的海洋人工铁施肥作为缓解全球变暖的地球工程选择提供依据。 这项工作将评估长期碳封存能力和对生态系统影响的可靠估计。这过去对全球海洋关键区域之一铁输入自然变化的反应，反过来将为对人工铁施肥的可能功效和后果进行定量预测奠定基础。