Land Cover and hydrology - assessing controls on Si cycling in a changing Arctic

土地覆盖和水文 - 评估不断变化的北极对硅循环的控制

• 批准号: 1451527
• 负责人: Joanna Carey
• 金额: $ 8.7万
• 依托单位: Carey Joanna C
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-01-01 至 2018-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1451527&HistoricalAwards=false
• 关键词: Land; Cover; hydrology; assessing; controls

Dr. Joanna C. Carey has been awarded an NSF EAR Postdoctoral fellowship to carry out a research and education plan at the Marine Biological Laboratory in Woods Hole, MA. Her research will examine how shifting land cover and permafrost thaw is altering silicon (Si) biogeochemistry in the Arctic. By examining ten large river systems in Alaska, this project will quantify how warming of the terrestrial landscape is altering Si availability in downstream receiving waters. Because Si availability in marine systems is critical for the survival of diatoms, the most abundant type of phytoplankton in marine waters, the results of this research will have direct implications for marine carbon dynamics. Land cover and hydrology are two important controls over Si export to marine systems, but to date these factors have yet to be examined in conjunction in Arctic ecosystems. In addition to a lack of baseline information on Arctic Si cycling, the rapid pace of warming in polar latitudes makes this work timely. The education arm of this fellowship will consist of engagement with local Alaskan communities through working with the Yukon River Inter-tribal Watershed Council and outreach with public high school Earth Science courses in Providence, RI to teach students about climate change and Arctic ecosystems. In addition, Dr. Carey will share the results of her research results with policy makers. Although geochemical factors exert large controls over riverine Si fluxes, watershed land cover (i.e. terrestrial vegetation) has also recently been identified as another important control over riverine Si fluxes in temperate and tropical systems. However, the role of terrestrial biological processes has yet to be examined in the Arctic. Hydrologic flowpaths, including water residence time, is another critical driver of riverine Si fluxes. Both of these factors are rapidly changing in Arctic ecosystems due to recent warming, potentially impacting the magnitudes and timing of Si exports to coastal receiving waters and shifting phytoplankton species compositions. The novel use of germanium (Ge)/Si tracers will allow Dr. Carey to decipher between geochemical vs. biological drivers of Si fluxes across a gradient of vegetation and permafrost cover. Using a space-for-time substitution, this work will create the first predictive framework of how future warming will alter Si availability in marine waters.

Joanna C.博士凯里已被授予美国国家科学基金会博士后奖学金，在马萨诸塞州伍兹霍尔的海洋生物实验室开展研究和教育计划。她的研究将探讨土地覆盖和永久冻土融化是如何改变北极的硅（Si）地球化学的。通过研究阿拉斯加的10个大型河流系统，该项目将量化陆地景观的变暖如何改变下游接收沃茨的硅可用性。由于硅在海洋系统中的可用性是至关重要的硅藻，在海洋沃茨中最丰富的浮游植物的生存，这项研究的结果将有海洋碳动力学的直接影响。土地覆被和水文是两个重要的控制硅出口到海洋系统，但迄今为止，这些因素还没有被检查在北极生态系统。除了缺乏关于北极硅循环的基线信息外，极地纬度变暖的快速步伐使得这项工作非常及时。该奖学金的教育部门将包括通过与育空地区河部落间流域理事会合作与当地阿拉斯加社区接触，并与国际扶轮普罗维登斯的公立高中地球科学课程合作，向学生讲授气候变化和北极生态系统。此外，凯里博士还将与政策制定者分享她的研究成果。虽然地球化学因素对河流硅通量有很大的控制作用，但流域土地覆盖（即陆地植被）最近也被认为是温带和热带系统中河流硅通量的另一个重要控制因素。然而，陆地生物过程在北极的作用还有待研究。水文流动路径（包括水停留时间）是河流硅通量的另一个关键驱动因素。由于最近的变暖，这两个因素在北极生态系统中迅速变化，可能会影响硅出口到沿海接收沃茨的幅度和时间，并改变浮游植物物种组成。锗（Ge）/Si示踪剂的新用途将使Carey博士能够在植被和永久冻土覆盖的梯度上破译Si通量的地球化学与生物驱动因素之间的关系。使用空间换时间的替代，这项工作将创建未来变暖将如何改变海洋沃茨中硅的可用性的第一个预测框架。