REU: Phytoplankton Flux and the Sediment Record of Paleoproductivity in the Northern California Current and Central Pacific

该项目涉及对横跨加利福尼亚州北部洋流和中太平洋环流的横断面的沉积物陷阱和岩芯中可保存的浮游植物的研究。硅藻、硅鞭毛藻、甲藻和钙质超微化石将在两年内在每月和半月诱捕样本中在物种或属一级进行量化。这项研究将考察从高生产力和季节性变化的海岸带到少营养环流的生产量和通量的时空变化，并将水柱的季节性输入与表层沉积物的多年积累进行比较。多变量统计将被用来描述最能反映沉积物组合的季节性圈闭样本的混合物；圈闭数据中的人为变化，如增加或移除某些分类群，可以模拟溶解、类似厄尔尼诺的条件和实际上没有记录在圈闭中的其他过程的影响。这种比较的结果将使人们能够更好地了解沉积物记录中的信息偏差程度。一旦这个问题得到解决，将在每个地点的岩芯中研究上一次冰川/间冰期循环的化石记录，从而将对产量的时间变化的分析扩展到地质尺度。将研究保存在沉积物圈闭样品和加利福尼亚洋流和中太平洋环流下岩心中的硅质微化石的保存情况。将利用圈闭样品中硅质组分通量的时空变异性来解释沉积记录，以便了解气候变化对该地区海洋条件的影响。这项研究将与其他研究人员一起研究圈闭和沉积物样本中的许多其他变量。这些结果将提供该地区已完成的用于重建古气候的地质材料保存控制的最详细情况。

This project involves a study of preservable phytoplankton in sediment traps and cores from a transect across the northern California Current and Central Pacific Gyre. Diatoms, silicoflagellates, dinoflagellates, and calcareous nannofossils will be quantified at the species or generic level in monthly and semi-monthly trap samples over a two year period. The study will examine the spatial and temporal variability of production and flux from the highly productive and seasonally variable coastal zone to the oligotrophic gyre, and compare the seasonal input from the water column with the multi-year accumulation in the surface sediments. Multivariate statistics will be used to describe the mixture of seasonal trap samples which best reflects the sediment assemblage; artificial changes in the trap data, such as increasing or removing certain taxa, can simulate the effects of dissolution, El Nino-like conditions, and other processes not actually recorded in the traps. The results of this comparison will permit a better understanding of the degree of information bias in the sediment record. Once this question is resolved, the fossil record for the last glacial/interglacial cycle will be studied in cores from each site, thus extending the analysis of temporal variation in production to the geologic scale. %%% The preservation of silicieous microfossils preserved in sediment trap samples and in cores underneath the California Current and Central Pacific Gyre will be examined. The temporal and spatial variability of flux of the siliceous components in the trap samples will be used to interpret the sedimentary record so that the effect of changes in climate on the oceanographic conditions in the region can be understood. This study will be done in conjunction with other researchers looking at many other variables in the trap and sediment samples. These results will provide the most detailed picture of the controls on preservation of geologic material used to reconstruct paleoclimate that has been done in this region.