Mechanisms and Rates of Preservation of Biogenic Remains in Continental Shelf and Slope Environments

大陆架和斜坡环境中生物遗迹的保存机制和速率

• 批准号: 0345618
• 负责人: Karla Parsons-Hubbard
• 金额: --
• 依托单位: Oberlin College
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-10-01 至 2009-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0345618&HistoricalAwards=false
• 关键词: Mechanisms; Rates; Preservation; Biogenic; Remains

Mechanisms and Rates of Preservation of Biogenic Remains in Continental Shelf and Slope EnvironmentsKarla M. Parsons-HubbardOberlin CollegeEAR-0345618ABSTRACTThe Shelf and Slope Experimental Taphonomy Initiative (SSETI) is a long-term experiment studying the fate of organism remains on the sea floor. The fossilization potential of organisms that die at the sediment-water interface is poorly understood, particularly in deep offshore shelf and slope environments. The modern shelf and slope setting is a reasonable proxy for ancient epicontinental sea deposits and has only rarely been studied with respect to its fossilization potential. The SSETI experiment began in 1993 when molluscan remains, crustaceans, echinoids, and woody plant debris were deployed in mesh bags in 21 different EODs at 10 major sites on the continental shelf and slope of the Gulf of Mexico and Caribbean. Each site has multiple replicates for repeated sampling over the ensuing years to decades. The project proposed here is to recover experimental arrays that have been on the sea floor for 12 years. Collections of samples have been taken at targeted intervals (1 year, 2 years, 8 years) to document taphonomic rates and processes, and to determine whether different types of shell, wood, test, or cuticle respond differently to processes in the taphonomically active zone (TAZ) in different environments and over time. To answer these questions, repeated sampling of the remains must be accompanied by a detailed characterization of the TAZ. This is accomplished through porewater geochemical analysis using in situ micro-electrode sampling and through measurements of sediment oxygen demand. The goal of this work is to link the instantaneous chemical conditions in the TAZ to the long-term effects on shells residing at, or just below, the sediment-water interface. Results through year eight show a very tight correlation between the porewater geochemistry and dissolution of molluscan material. These findings are greatly advancing knowledge about the cycling of carbonate on the sea floor and has important applications to paleontology, paleoecology, and has direct implications for carbon budgets and climate modeling. In particular, the results of this work are critical to planners seeking to use the sea floor as a carbon sink.

大陆架和陆坡环境中生物遗迹的保存机制和速率。陆架和斜坡实验埋藏学倡议（SSETI）是一项研究海底生物遗骸命运的长期实验。 人们对在沉积物-水界面死亡的生物体的生物化潜力知之甚少，特别是在深海陆架和斜坡环境中。 现代陆棚和陆坡环境是古代陆表海沉积的合理替代物，很少有人研究其石化潜力。SSETI实验开始于1993年，当时在墨西哥湾和加勒比海大陆架和斜坡的10个主要地点，将软体动物遗骸，甲壳类动物，海胆和木本植物残骸放置在21个不同EOD的网袋中。在随后的几年到几十年里，每个地点都有多次重复取样。这里提议的项目是恢复在海底放置了12年的实验阵列。 以目标间隔（1年、2年、8年）收集样本，以记录埋藏速率和过程，并确定不同类型的贝壳、木材、测试或角质层是否对埋藏过程有不同的反应。活跃区（TAZ）在不同的环境中并随着时间的推移。为了回答这些问题，对遗骸的重复取样必须伴随着对TAZ的详细描述。 这是通过使用原位微电极取样进行孔隙水地球化学分析和通过测量沉积物需氧量来实现的。这项工作的目标是将TAZ中的瞬时化学条件与对沉积物-水界面处或下方的贝壳的长期影响联系起来。通过第八年的结果表明，孔隙水地球化学和溶解的软体动物材料之间的关系非常紧密。这些发现极大地推进了关于海底碳酸盐循环的知识，并对古生物学，古生态学具有重要的应用，并对碳预算和气候建模具有直接影响。特别是，这项工作的结果对于设法利用海底作为碳汇的规划者至关重要。