Early Diagenesis of Pigments in Anoxic Marine Sediments

点击翻译按钮获取中文摘要

The highly productive Peru upwelling system is regularly perturbed by periodic El Nino-Southern Oscillation events that result in warmer-than-average sea surface temperatures and a sharp reduction in the reduction in the region's productivity. An historical record of El Nino in Peru Margin sediments has been derived from the distribution of alkenones and Uk37 as proxy for paleo-sea surface temperature. This research will enhance and expand on these results with a more detailed study of Peru sediments extending over 500 ybp. The initial focus of the study will be to deconvolute diagenetic and input driven changes in the sedimentary record of chlorins and carotenoids. By measuring the distribution of both pigments (carotenoids, chlorins) and their degradation products (loliolides, pyrroles), transient changes in depositional conditions will be able to be identified. This information will be combined with data from the total pigment in sediment expressed as the molar sum: (pigment + degradation product), to measure changes in original input. Changes in hydrography preserved in the alkenone record with expected changes in the nature and intensity of primary production preserved in the record of algal pigments in sediments will then be compared.