Gulf of Alaska Deep and Intermediate Watermass Changes and Paleoventilation

今天，北太平洋并不是全球海洋深层和中层水的重要来源。这是过去的事吗？在过去的气候制度中，这一系统的变化很少受到限制，也很有争议，但它是全球系统的重要组成部分，对全球热量输送和深海的碳预算具有深远影响。这项研究由俄勒冈州立大学的科学家领导，测试了北太平洋次表层环流在调节全球气候(即与太平洋温盐翻转相关的热量传输)和碳循环(即在冰川时期在北太平洋深处储存“古老的”富含二氧化碳的水团)中所起的作用的假设。这项研究将集中在阿拉斯加湾新遗址的深度横断面上，深度从~4200米到~700米不等。研究人员将在海底有孔虫中产生4万年来的稳定氧和碳同位素记录，以评估古水团结构，在有孔虫中产生放射性碳，以评估水团通风年龄，并在沉积氧化物中产生钕同位素，以追踪地下水团来源的变化。该项目的更广泛影响包括劳动力发展--培训本科生和研究生--以及教育和接触国家和国际政策制定者。这项工作将与一名澳大利亚科学家密切合作进行，由于重点放在最近收集的综合大洋钻探计划岩芯上，它将有助于来自13个国家的研究人员之间的合作。

The North Pacific today is not a significant source of deep and intermediate water to the global oceans. Was it in the past? Changes in this system during past climate regimes are poorly constrained and controversial, but are an important part of the global system with profound implications for global heat transports and carbon budgets of the deep sea. This research, led by scientists from Oregon State University, tests hypotheses about the role of North Pacific subsurface circulation in modulating global climate (i.e., heat transport associated with thermohaline overturn in the Pacific) and the carbon cycle (i.e., storage of an "old" CO2-rich watermass in the deep North Pacific during glacial time). The study will focus on a depth transect of new sites from the Gulf of Alaska ranging from ~4200 m to ~700 m depth. The researchers will generate 40,000 year records of stable oxygen and carbon isotopes in benthic foraminifera to assess paleo watermass structures, radiocarbon in foraminifera to assess watermass ventilation ages, and Neodymium isotopes in sedimentary oxides to trace changes in the sources of subsurface watermasses. The broader impacts of this project include workforce development-- training undergraduate and graduate students-- along with education and outreach to national and international policymakers. The work will be carried out in close collaboration with an Australian scientist, and because of the focus on recently collected Integrated Ocean Drilling Program cores it will contribute to collaborations among researchers from 13 countries.