An Evaluation of Variability in the 14co2 Cycle in the UpperOcean

这项研究将检查大西洋和太平洋几个地点的带状珊瑚年度样本中的碳和氧同位素比率。目标是确定主温跃层的通风相对于二氧化碳的可变性，并确定过去500年来表层海洋14℃十年时间尺度变化的原因和空间范围。首先，将重建来自赤道和南大西洋的带状珊瑚的高精度(+2/)14C记录。将为这些地点以及北太平洋和南太平洋建立与以前使用的类似的上层海洋等周期混合模式。其次，将从世界海洋的四个地点--北大西洋(佛罗里达)、北中太平洋(夏威夷)、东赤道太平洋(加拉帕戈斯)和西南太平洋(大堡礁)重建小冰期(公元1400-1850年)的高精度14C记录。将确定西南太平洋(亚伯拉罕斯礁)蒙德极小期表层海洋14℃的十年时间尺度变化是否是一种全海洋现象，并将评估这些变化对表层环流和二氧化碳循环的潜在影响。第三，将测量北、中、西南太平洋带状珊瑚的Suess效应以及18O和13C的变化，以评估化石燃料CO2输入海洋的情况。第四，将对巴布亚新几内亚Huon半岛凸起珊瑚礁的化石珊瑚进行高精度的14C测量，这些化石珊瑚已经用230Th质谱仪进行了准确的测年。这里的目标是开发一种方法，将已知年轮(9700个历年BP)的放射性碳年代学延长到全新世早期和冰川消退期，当时大气中的二氧化碳含量大大低于19世纪的水平。

This research will examine carbon and oxygen isotope ratios in annual samples of banded corals from several sites in the Atlantic and Pacific Oceans. The goals are to establish the vriability of the ventilation of the main thermocline with respect to CO2 and to determine the cause and spatial extent of decade time scale changes in surface ocean 1 4 C during the past 500 years. First, high precision (+2 / ) 1 4 C records will be reconstructed for the post-bomb period (1953-present) for banded corals from the equatorial and South Atlantic. Isopycnal mixing models for the upper ocean, similar to that used previously, will be constructed for these locations and for the North and South Pacific. Second, high precision 1 4 C records will be reconstructed for the Little Ice Age (A.D. 1400-1850) from four sites in the world's ocean - North Atlantic (Florida), North Central Pacific (Hawaii), eastern equat Pacific (Galapagos) and Southwest Pacific (Great Barrier Reef). It will be determined whether the decade time scale changes noticed in surface ocean 1 4 C during the Maunder minimum in the Southwest Pacific (Abrahams Reef) were an ocean- wide phenomena, and the potential impact of these changes on surface circulation and on the cycling of CO2 will be assessed. Third, the Suess effect and the changes in 1 8 O and 1 3 C in banded corals from the North Central and Southwestern Pacific will be measured in order to assess the input of fossil fuel CO2 into the ocean. Fourth, high precision 1 4 C will be measured on fossil corals that have been accurately dating using 230 Th by mass spectrometry from the raised reefs of the Huon Peninsula, Papua New Guinea. The goal here is to develop a method to extend the radiocarbon chronology past that available from known-aged tree rings (9,700 calendar yrs BP), into the early Holocene and deglaciation periods when atmospheric pCO2 was substantially lower than nineteenth century levels.