The significance of radiolarian isotopic signals for paleoceanographic reconstructions

放射虫同位素信号对古海洋重建的意义

• 批准号: 27111597
• 负责人: Dr. Andrea Abelmann
• 金额: --
• 依托单位: Alfred-Wegener-Institut (AWI) Helmholtz-Zentrum für Polar- und Meeresforschung
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2006
• 资助国家: 德国
• 起止时间: 2005-12-31 至 2008-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/27111597?language=en
• 关键词: significance; radiolarian; isotopic; signals; paleoceanographic

The proposed study aims to further develop the novel approach to reconstruct past nutrient utilization and productivity based on silicon isotopes (δ30Si) from radiolarian and diatom opal. Such reconstruction is crucial for the understanding of past nutrient and carbon cycling in areas characterized by strong deposition of biogenic opal, such as the Southern Ocean, and its effect on global biogeochemical cycles and climate development. Currently we have started the funded one-year study (November 2006), which will concentrate on the establishment of isotope records from sediment cores PS2498-1 and PS1778-5, located in the Subantarctic and the Polarfront Zone of the Atlantic Southern Ocean, respectively. This will provide first information on glacial-interglacial variability in different Southern Ocean zones and from heterotrophous and autotrophous siliceous microplankton. Following the reviewer’s suggestions, this pioneering study will be augmented during a second year (requested herein) by the systematic study of surface sediments from different physical and biological settings in the Atlantic, the Indian and the Pacific sectors of the Southern Ocean. This will include the investigation of the δ30Si signal from specific size class radiolarians and diatoms as well as a radiolarian census. The proposed project will provide the first information about latitudinal changes of isotopic signals in siliceous microorganisms in comparison to the different hydrographic and biological regimes of the Southern Ocean. Such results will provide the basic reference for further paleoceanographic interpretation of siliceous microplankton isotope records. This study is part of the International Polar Year 2007/08 BIPOMAC (“Bipolar Climate Machinery”) network aimed to document and decipher polar processes regulating climate development and variability.

本研究旨在进一步发展基于放射虫和硅藻蛋白石的硅同位素（δ30Si）重建过去养分利用和生产力的新方法。这种重建对于理解以生物成因蛋白石强烈沉积为特征的地区（如南大洋）过去的营养和碳循环及其对全球生物地球化学循环和气候发展的影响至关重要。目前，我们已经开始了为期一年的资助研究（2006年11月），该研究将集中于建立沉积物岩心PS2498-1和PS1778-5的同位素记录，分别位于亚南极和大西洋南大洋的极锋区。这将提供关于不同南大洋带的冰期-间冰期变异性以及异养和自养硅质微型浮游生物的第一手资料。根据审稿人的建议，这项开创性的研究将在第二年（本文所要求的）通过对大西洋、印度洋和南大洋太平洋部分不同物理和生物环境的表面沉积物进行系统研究而得到加强。这将包括对特定尺寸类放射虫和硅藻的δ30Si信号的调查以及放射虫普查。拟议的项目将提供有关硅质微生物同位素信号的纬度变化的第一手资料，并与南大洋不同的水文和生物状况进行比较。这些结果将为硅质浮游生物同位素记录的进一步古海洋学解释提供基础参考。这项研究是2007/08年国际极地年BIPOMAC（“两极气候机器”）网络的一部分，该网络旨在记录和破译调节气候发展和变率的极地过程。