Assessing the effects of calcite saturation on the benthic foraminiferal Mg/Ca-temperature relationship using a homothermal depth transect in the Norwegian Sea

使用挪威海恒温深度样线评估方解石饱和度对底栖有孔虫 Mg/Ca-温度关系的影响

• 批准号: 0341412
• 负责人: Yair Rosenthal
• 金额: $ 22.17万
• 依托单位: Rutgers University New Brunswick
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-05-01 至 2007-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0341412&HistoricalAwards=false
• 关键词: Assessing; effects; calcite; saturation; benthic

Under this award the PIs will be address the question: What is the effect of calcite saturation on the Mg/Ca - temperature relationship in benthic foraminifera?They propose an 11 day cruise in the Norwegian Sea to collect about 30 multi-cores and 15 giant gravity cores that cover a range of calcite saturation levels at constant temperature and salinity. Benthic foraminiferal Mg/Ca from lightly saturated waters display a steep decrease with increasing water depth. The current global Mg/Ca-temperature relationship can only explain a fraction of the decrease, leading to the hypothesis that the degree of calcite saturation also affects benthic foraminiferal Mg/Ca at the low temperatures typical of themajority of the deep ocean. The depth transect from the homothermal and homohaline Norwegian Sea, that was previously studied by Mackensen et al., (1985) provides an ideal opportunity not only to test the hypothesis, but also to quantify the Mg/Ca - calcite saturation relationship at low temperatures. The PI propose to reoccupy the sites that were used for the Mackensen et al. 1985 faunal study (). Based on that study, they expect a high abundance of live benthic foraminifera. To further test their hypothesis they propose studying two down-core records (one spanning the HL-LGM transition at 150 yr resolution and one record spanning 0 to 35 ka at 250 yr resolution). Because Norwegian Sea's bottom water temperature (BWT) is close to freezing, they expect little Glacial-Interglacial variation. Any significant down-core change would suggest additional control on Mg/Ca ratios in benthic foraminifera.

根据该奖项，PI将解决以下问题：方解石饱和度对底栖有孔虫中Mg/Ca -温度关系的影响是什么？他们建议在挪威海进行为期11天的巡航，以收集大约30个多岩心和15个巨型重力岩心，这些岩心在恒定的温度和盐度下覆盖一系列方解石饱和度。 轻度饱和沃茨的底栖有孔虫Mg/Ca随水深的增加而急剧下降。目前的全球Mg/Ca-温度关系只能解释一小部分的下降，从而导致假设方解石饱和度也影响底栖有孔虫Mg/Ca在低温下的典型themmajority的深海。Mackensen等人先前研究的同盐和同盐挪威海的深度断面，（1985）提供了一个理想的机会，不仅可以检验假设，而且可以量化低温下Mg/Ca -方解石饱和度关系。主要研究者建议重新使用Mackensen等人1985年动物群研究使用的场地（）。根据这项研究，他们预计活的底栖有孔虫丰度很高。 为了进一步验证他们的假设，他们建议研究两个下芯记录（一个跨越HL-LGM过渡在150年的分辨率和一个记录跨越0至35万年在250年的分辨率）。由于挪威海的底层水温（BWT）接近冰点，他们预计冰川间冰期的变化很小。任何显着的向下核心的变化将表明额外的控制镁/钙比底栖有孔虫。