Further Calibration of Long-Chain Alkenones for Paleoceanographic Study

目前，人们普遍认为长链烯酮在评估海洋表层水的古温度和某种程度上的古生产力方面很有希望。目前，由于对产生这些生物标志物的浮游植物物种的生态、产生这些生物标志物的浮游植物物种的生态以及在沉积记录中保存这些生物标志物的过程的无知，我们无法准确地解释海洋沉积物岩芯中烯烃地层记录的完整古海洋学意义。这项研究将提高我们从烷基化合物的沉积记录中提取真实古海洋信息的能力。该项目将综合实验室浮游植物培养和现场颗粒样本的分析结果。现场样本包括从海洋表面水域收集的精选悬浮颗粒物组，通过沉积物捕集器以时间序列收集的垂直运输颗粒物，以及通过在加利福尼亚州北部东西走向断面的三个地点进行取心收集的底层沉积物。拟议工作的两个主要目标是澄清1)产生烯酮的浮游植物随季节变化在真光带中的位置，这些生物在一年中何时具有生产力，以及地表水温是通过在下伏沉积物中测量的烯酮不饱和模式记录的，这是这些因素的结果，以及2)由于这些因素，岩心下部的烯酮浓度记录如何与上覆水域裸子植物生产力和可能的总初级生产力随时间的相对变化有关。

Long-chain alkenones are now widely recognized as promising for the assessment of paleotemperature and to some extent paleoproductivity in surface waters of the ocean. Ourability to interpret accurately the complete paleoceanographic implications of stratigraphic records for the alkenones inmarine sediment cores is currently limited by an ignorance of the ecology of the phytoplankton species that produce these biomarkers and of the ecology of the phytoplankton species that produce these biomarkers and of the processes responsible for their preservation in the sedimentary record. This research will advance our ability to extract realistice paleoceanographic information from the sedimentary record for the alkenonoes. The project willintegrate results from analyses of laboratory phytoplankton cultures and particulate samples from the field. The field samples include select sets of suspended particulate materials collected from ocean surface waters, vertically transported particulate materials collected in time series by sediment traps and underlying sediments collected by coring at three locations along an east-west transect off northern California. The two major goals of the proposed work are to clarify 1) where alkenone-producing phytoplankton reside withing the euphotic zone as a function of season, when these organisms are productive during the year and what surface water temperature is recorded by alkenone unsaturation patterns measured in underlying sediments as a consequence of these factors and 2) how the downcore record for alkenone concentration relates torelative changes in prymnesiophyte productivity and perhaps total primary productivity in overlying waters with time.