Collaborative Research: Controls on Alkenone Temperature Estimates in Subtropical and Subpolar Waters

副热带锋(STF)是南大洋的北部边界，将STF以北的低营养、温暖的亚热带表层水域与南方较凉爽、营养丰富的亚极区水域隔开。在新西兰以东，STF在水深上停泊在查塔姆隆起，这是一个1000公里长的水下大陆高原。新西兰国家水与大气研究所(NIWA)在查塔姆隆起保持着两个相距仅200公里的沉积物捕集器阵列。这些陷阱虽然间隔很近，但正好位于STF的轴线之外，因此可以比较亚热带和亚极地水域在类似环境条件下的年度循环，例如天气和光照水平，而不会出现锋面迁移的复杂情况。在这个项目中，罗格斯大学和夏威夷大学的研究人员将在这些地点检查古海洋表面温度(SST)记录所基于的替代物的形成过程，并解决生物体之间的季节性差异问题，这两个生物体可以说是目前使用的两个最重要的古温度估计器(例如，U37K‘精度，有孔虫18O值)。要检验的基本假设是：1.表层混合层输出的烷烃和有孔虫的幕式输送是造成烷烃和有孔虫温度重建差异的根本原因。夏季亚热带水域营养物质的枯竭和亚极区冬季长时间黑暗期间的次表层生产力是控制U 37 K‘SST重建精度的重要环境影响因素。美国、新西兰和欧洲科学家之间的合作代表着美国派？S在与国际同行接触方面的重大投资。合并后的结果将通过广泛传播共享数据来加强所有成员的研究，并有助于促进未来的合作伙伴关系。此外，对将在本研究中发挥核心作用的学生的培训将促进培训和学习。更好地量化SST记录将有助于古气候重建，从而产生社会效益。

The subtropical front (STF) is the northern boundary of the Southern Ocean, separating oligotrophic, warm subtropical surface waters north of the STF from cooler, nutrient-rich, subpolar waters to the south. East of New Zealand, the STF is bathymetrically anchored to the Chatham Rise, a 1000 km long submerged continental plateau. The National Institute of Water and Atmospheric Research (NIWA), New Zealand, maintains two sediment trap arrays only 200 km apart on the Chatham Rise. The traps, although closely spaced, sit just out of the axis of the STF and thus allow comparison of subtropical and subpolar waters under similar environmental conditions such as weather and light levels over the annual cycle without the complication of frontal migrations. In this project, researchers at Rutgers University and the University of Hawaii will examine at these sites the processes involved in the formation of the proxies on which paleo-sea surface temperatures (SST) records are based and resolve the issue of differential seasonality between the organisms which are arguably two of the most important paleotemperature estimators now in use (e.g. U37 K ' accuracy, foraminiferal ä18O values). The principle hypotheses to be tested are:1. Episodic delivery of alkenones and foraminifera exported from the surface mixed layer are the underlying cause of differences between alkenone and foraminiferal temperature reconstructions.2. Nutrient depletion in subtropical waters during summer months and subsurface production during prolonged winter darkness in subpolar waters are important environmental influences controlling the accuracy of U 37 K ' SST reconstructions.Efforts in this work primarily and actively address the broader impact criteria of enhancing infrastructure for research. Collaborations among United States, New Zealand, and European scientists represent a significant investment in outreach with international colleagues by the US PI?s. The combined results will enhance the research of all members by disseminating shared data widely and serve to stimulate future partnerships. Additionally, training of students who will take central roles in this research addresses advancing training and learning. Better quantification of SST records will benefit paleoclimatic reconstructions and thus have societal benefits.