Radiocarbon in Dissolved Organic Matter in Ocean Water

深海溶解有机碳(DOC)的平均放射性碳(14C)年龄为4000-6500年。然而，用于估计这一范围的数据集仅基于世界海洋中的几个地点。为此，加州大学欧文分校的一名科学家将参加三次CLIVAR重复水文测量航次，从太平洋和大西洋的六个没有数据的详细剖面上采集水样(南太平洋沿32°S的P6、南大西洋沿30°S的A10和北大西洋沿50°W的A20)。海水样品将用加速器质谱仪进行分析，以确定DOC的14C特征。此外，来自DOC的黑碳将被分离并分析14C和13C特征。利用该数据集，这位科学家计划检验以下三个假设：(1)南太平洋散装DOC的14C介于南太平洋和北太平洋的值之间，这些14C年龄可用于确定太平洋深水DOC循环的时间尺度；(2)大西洋散装DOC的14C水平在北部(43°N)最高，赤道区(10°N)较低，南大西洋(30°S)最低，反映了西大西洋深水向南移动时DOC循环的时间尺度；(3)黑碳在公海水域中构成了相当大的DOC，其14C年龄大于2万14C年。倡导者将帮助高中教师为他们的课程准备科学课程，并在夏季教授一门名为《放射性碳在生态和地球系统科学中》的短期课程。她目前是佛罗里达海洋科学教育卓越中心的董事会成员，并协助开发大学水平的网络教育课程。作为该项目的一部分，一名研究生和两名本科生将得到支持和培训。

The average radiocarbon (14C) age of dissolved organic carbon (DOC) in the deep ocean ranges from 4000-6500 14C years. However, the data set used to estimate this range is based on only a few sites in the world ocean. For this reason, a scientist from the University of California, Irvine will participate in three CLIVAR Repeat Hydrography cruises to collect water samples from six detailed profiles in the Pacific and Atlantic Oceans for which there is no data (P6-along 32°S in the South Pacific, A10 along 30°S in the South Atlantic, and A20 along 50°W in the North Atlantic). Seawater samples will be analyzed by accelerator mass spectrometry to determine the 14C signatures of DOC. In addition, the black carbon from DOC will be isolated and analyzed for 14C and 13C signatures. With the data set, the scientist plans to test the following three hypotheses: (1) 14C of bulk DOC in the South Pacific Ocean is intermediate between values in the Southern Ocean and those in the North Pacific, and these 14C ages can be used to determine the timescale of DOC cycling in deep waters of the Pacific; (2) 14C levels in bulk DOC of the Atlantic Ocean are highest in the north (43°N), lower in the equatorial region (10°N) and lowest in the South Atlantic (30°S), and reflects the timescale of DOC cycling as deep water travels south in the western Atlantic; and (3) black carbon constitutes a significant amount of DOC in open ocean water, and its 14C age is greater than 20,000 14C years.The proponent will help high school teachers prepare science curricula for their classes and teaches a short course called "Radiocarbon in Ecology and Earth System Science" during the summer. She currently serves on the board for the Florida Center for Ocean Science Education Excellence and aids in the development of college level web-based educational classes. One graduate and two undergraduate students will be supported and trained as part of this project.