Collaborative Research: US GEOTRACES GP17-ANT: Nitrogen isotope dynamics on the Amundsen Sea continental margin

合作研究：美国GEOTRACES GP17-ANT：阿蒙森海大陆边缘的氮同位素动力学

基本信息

批准号：
2148921
负责人：
Daniel Sigman
金额：
$ 36.6万
依托单位：
Princeton University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2023
资助国家：
美国
起止时间：
2023-03-01 至 2026-02-28
项目状态：
未结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2148921&HistoricalAwards=false
关键词：
Collaborative Research US GEOTRACES GP17

项目摘要

The continental shelf of Antarctica is a dynamic and often biologically productive polar environment, with global importance for ocean circulation, nutrient and carbon cycling. Due to its high latitude location and the impacts of the proximal Antarctic ice sheet, the Antarctic continental shelf stands to change quickly under ongoing global warming. Yet the natural state of the Antarctic continental shelf is poorly known, and previous research suggests that this environment has changed through time, which would also signal how it may change in the future. This study will investigate the operation of the nitrogen cycle on the Antarctic continental shelf, using the natural isotopes of nitrogen. Nitrogen is a critical nutrient for life, limits biological productivity in many environments, and provides a holistic view of the balance between biological growth and decomposition in ocean waters. The nitrogen isotope measurements, combined with the other measurements of the U.S. GEOTRACES GP17-ANT expedition, will determine the major sources and sinks of biological productivity on a segment of the Antarctic continental shelf – the Amundsen Sea shelf – that may be particularly susceptible to change as Antarctic ice sheet melting accelerates. The measurements will also provide key baseline information to support the reconstruction of past changes using sediment cores and other archives. The project will train graduate and undergraduate students and support one early career postdoctoral researcher.The U.S. GEOTRACES GP17-ANT expedition will provide the opportunity to generate complementary data sets of trace elements and isotopes on the Amundsen Sea shelf, an Antarctic margin environment characterized by abundant sea ice, melting ice shelves, and highly productive polynyas. For all stations of GP17-ANT, full depth profiles of the nitrogen and oxygen isotope ratios of nitrate will be measured, along with nitrogen isotope ratios of total dissolved nitrogen at a few representative stations to provide insight into nitrogen sources and cycling in the water column. Moreover, suspended particle nitrogen isotope ratios will be measured from the GEOTRACES high-volume pump samples from deeper depths than standard methods allow, to investigate regeneration and ground-truth the application of deep-sea coral nitrogen isotope ratios as a paleo-proxy. Lastly, from surface sediment samples, bulk sediment and diatom-bound nitrogen isotope ratios will be measured, providing ground-truthing for ongoing paleo-oceanographic reconstructions using longer sediment cores.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

南极洲大陆架是一个动态且经常具有生物生产力的极地环境，对海洋环流、营养物和碳循环具有全球重要性。由于其高纬度位置和近端南极冰盖的影响，南极大陆架随时可能发生变化。然而，南极大陆架的自然状态却鲜为人知，之前的研究表明，这种环境随着时间的推移而发生了变化，这也预示着它在未来可能会发生怎样的变化。利用氮的天然同位素研究南极大陆架氮循环的运行情况氮是生命的关键营养物质，限制了许多环境中的生物生产力，并提供了海洋中生物生长和分解之间平衡的整体视图。氮同位素测量与美国 GEOTRACES GP17-ANT 探险队的其他测量相结合，将确定南极大陆架部分生物生产力的主要来源和汇 -阿蒙森海架——随着南极冰盖融化加速，该大陆架可能特别容易发生变化。这些测量还将提供关键的基线信息，以支持利用沉积岩芯和其他档案重建过去的变化。支持一名早期职业博士后研究员。美国 GEOTRACES GP17-ANT 探险将提供生成阿蒙森海陆架微量元素和同位素互补数据集的机会，阿蒙森海陆架是一个以丰富的海洋为特征的南极边缘环境对于 GP17-ANT 的所有站，将测量硝酸盐的氮和氧同位素比的全深度剖面，以及几个代表性站的总溶解氮的氮同位素比。此外，将从比标准方法允许的深度更深的 GEOTRACES 大容量泵样本中测量悬浮颗粒氮同位素比率，以研究再生和循环。最后，将从表面沉积物样本中测量大量沉积物和硅藻结合的氮同位素比率，为正在进行的古海洋重建提供地面真相。更长的沉积岩芯。这反映了 NSF 的法定使命，并且通过使用基金会的智力优点和更广泛的影响审查标准进行评估，被认为值得支持。