Collaborative research: Exploring the role of oceanic and atmospheric forcing on Arctic marine climate from newly developed annual shell based records in coastal Norway

海洋学家和古气候学家使用不同的指标来研究过去的海洋温度和盐度历史。其中许多记录在海洋沉积物中，但沉积速率如此之小，以至于从它们可以估计的时间序列只能解析发生在十年或更长时间尺度上的变化。当文蛤和其他双壳类贝类生长时，它们会在贝壳中加入它们生活的水中的地球化学特征。它们还会在壳里放上年轮，就像树轮一样。通过研究长寿命贝壳中相邻环的化学，该项目的主要调查者(PI)希望能够重建挪威北部近海区域近地表水域的年度温度和盐度变化。他们将集中精力研究中世纪暖期(公元1000年至公元1200年)、小冰期(公元1200年至公元1850年)和现代(公元1850年至今)。由此得到的温度和盐度变化历史将有助于理解在这些已知的气候变化期内海洋状况是如何变化的，并有助于验证或约束气候模型。近期目标是沿地处战略位置的北极岛屿因戈伊岛和罗尔夫索岛，重建过去千年内关键气候间隔期间的年度水文变化。它们将向后预报年度海表面温度(SST)和海表面盐度(SSS)的变化。他们还将确定海洋放射性碳库效应中的基线变异性。这些岛屿沿线的现代近地表海洋学受挪威海岸流的物理特性影响，而相对较深的水文条件主要取决于大西洋流入。研究现场的试点数据表明，基于壳牌的记录与区域SST/SSS条件之间有很强的联系。因此，Ingoy和Rolvsoy似乎是研究全新世晚期海洋气候变化的理想地点。已经开发了一些假设和目标来测试在过去千年中主要气候模式对挪威北部附近区域海洋学的相对影响。目标1：发展基于壳层的近地表年度记录(主贝壳年代学和同位素)，以重建中世纪气候异常、小冰期、目标2：建立近100年来相对深水(200米)的年度贝壳记录(主贝壳年代学和同位素)，以描述北大西洋流对该地点水文地理的作用。目标3：建立自公元1600年以来表层海洋放射性碳库效应的年代际记录，以估计INGO的水源贡献的变化。目标4：估计冬季北大西洋涛动、表层大西洋经向翻转环流、将与来自Akvaplan-Niva(挪威)、爱荷华州立大学(ISU)和贝茨学院(缅因州)的同事建立一个研究北极海洋气候变化的国际伙伴关系。将通过让两名K-12教师参与实地工作、通过与K-12学生的课堂互动、通过K-12教师讲习班、通过以公民为基础的科学(通过与Ingoy的挪威当地人互动)以及通过一名摄影记者参加一个实地赛季，来实现外联、公众参与和传播成果。至少一名女博士生和大约五名本科生将得到该项目的支持和参与。在执行支助大学和贝茨学院与气候变化、古气候和海洋学有关的几门课程中，公共政策研究所将使用在该项目中形成的数据和想法。Pi Wanamaker将在Ames公共图书馆主持一系列关于气候变化的公开讲座，并继续担任爱德华兹初级科学之夜的联合主席，自2012年以来，该活动已影响到1000名学生和社区成员。

Oceanographers and paleoclimatologists use various proxies to study the past history of ocean temperature and salinity. Many of these are recorded in the marine sediments, but sedimentation rates are so small that the time series that can be estimated from them only resolve changes that occur on decadal time scales or longer. When clams and other bivalves grow, they incorporate, in their shells, geochemical signatures from the water in which they live. They also lay down growth rings, like tree rings, in their shells. By studying the chemistry of adjacent rings in long-lived clam shells the principal investigators (PIs) of this project expect to be able to reconstruct the annual temperature and salinity variations of near surface waters in a region offshore of northern Norway. They will focus their efforts on the Medieval Warm Period (1000 AD to 1200 AD), the Little Ice Age (1200 AD to 1850 AD), and the modern era (1850 AD until the present). The resultant histories of temperature and salinity variation will be useful for understanding how the ocean conditions changed during these known periods of climate variation and for validating or constraining climate models.The PIs? immediate goal is to reconstruct annual hydrographic variability during key climate intervals within the last millennium along the strategically located Arctic islands of Ingoy and Rolvsoy. They will hindcast changes in annual sea surface temperature (SST) and sea surface salinity (SSS). They will also establish the baseline variability in the marine radiocarbon reservoir effect. The modern near-surface oceanography along the islands is influenced by the physical properties of the Norwegian Coastal Current, while the relatively deep hydrographic conditions predominately depend on Atlantic inflow. Pilot data from the study site demonstrate a strong link between shell-based records and regional SST/SSS conditions. Hence, Ingoy and Rolvsoy seem situated in an ideal location to study marine climate change during the late Holocene. Hypotheses and objectives have been developed to test the relative influence of dominant climate modes on the regional oceanography near northern Norway during the last millennium.Objective 1: Develop near-surface annual shell-based records (master shell chronology and isotopes) to reconstruct regional hydrographic variability (SST and SSS) along the northernmost coast of Norway during intervals of the Medieval Climate Anomaly, the Little Ice Age, and for Modern Climate.Objective 2: Develop relatively deep-water (200 m) annual shell-based records (master shell chronology and isotopes) for the last 100 years to characterize the role of the North Atlantic Current on hydrography at the site.Objective 3: Establish a decadal record of the surface marine radiocarbon reservoir effect since AD 1600 to estimate changes in source water contributions at Ingoy.Objective 4: Estimate the relative influence of the winter North Atlantic Oscillation, the surface Atlantic Meridional Overturning Circulation, and the Atlantic Multidecadal Oscillation on regional hydrography (at Ingoy) and shell-based records.An international partnership for studying Arctic marine climate change will be developed with colleagues from the Akvaplan-niva (Norway), Iowa State University (ISU) and Bates College (Maine). Outreach, public engagement, and dissemination of the results will be accomplished through engagement of two K-12 teachers in the field work, through classroom interactions with K-12 students, through a K-12 teacher workshop, through citizen-based science (via interactions with native Norwegians at Ingoy), and via a photo-journalist who will join the PIs for one field season. At least one female PhD student and approximately five undergraduate students will be supported by and involved with the project. The PIs will use data and ideas developed in this project for several courses at ISU and Bates College relating to climate change, paleoclimate and oceanography. PI Wanamaker will facilitate a public lecture series on climate change at the Ames Public library and continue to act as co-chair of Edwards Elementary Science Night, which has impacted 1,000 students and community members since 2012.