Age-Dependent Bioturbation of Deep-Sea Sediments: Tests of Mechanisms at Three Bathyal Sites

深海沉积物的年龄依赖性生物扰动：三个深海地点的机制测试

• 批准号: 9521116
• 负责人: Craig Smith
• 金额: $ 28万
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-12-01 至 1998-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9521116&HistoricalAwards=false
• 关键词: Age; Dependent; Bioturbation; Deep; Sea

9521116 Smith The mechanisms and rates of sediment mixing by the feeding and movements of animals, termed bioturbation, may profoundly influence chemical recycling, microstratigraphy, and faunalcommunity structure at the deep-sea floor. Recent studies of ingestion by bottom-dwelling fauna suggest they consume newly sedimented, highly organic particles. If such selective feeding is widespread, biogeochemical models, based on single bioturbation tracers, would provide unreliable predictions about bioturbation, microbial metabolism, sediment diagenesis, and strata formation. This study will test three alternative, mechanistic hypotheses by: assaying ratiotracer activities in deposit-feeder guts and on sediment particles of various sizes. Specifically, tracer-dependent mixing may result from (1) sizedependent ingestion of Th- 234-rich particles by deposit feeders, (2) selective ingestion of young, food-rich particles by deposit feeders, independent of size, or (3) passive cascade and/or active sequestering of newly deposited particles in animal burrows. ***

9521116 Smith 动物的进食和运动引起的沉积物混合机制和速率（称为生物扰动）可能会深刻影响深海海底的化学循环、微观地层学和动物群落结构。 最近对海底动物摄入的研究表明，它们消耗新沉积的高度有机颗粒。 如果这种选择性进食广泛存在，基于单一生物扰动示踪剂的生物地球化学模型将提供有关生物扰动、微生物代谢、沉积物成岩作用和地层形成的不可靠预测。 这项研究将通过以下方式测试三种替代的机制假设：测定沉积物饲养肠道和不同尺寸的沉积物颗粒中的比率示踪剂活性。具体而言，示踪剂依赖性混合可能是由于（1）沉积物饲养者对富含 Th-234 的颗粒进行尺寸依赖性摄取，（2）沉积物饲养者选择性地摄取年轻的富含食物的颗粒，与尺寸无关，或（3）动物洞穴中新沉积颗粒的被动级联和/或主动隔离。 ***