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: 9527382
• 负责人: David DeMaster
• 金额: $ 26.51万
• 依托单位: North Carolina State University
• 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 1999-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9527382&HistoricalAwards=false
• 关键词: Age; dependent; Bioturbation; Deep; sea

9527382 DeMaster 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. ***

由动物的进食和运动引起的沉积物混合的机制和速率，称为生物扰动，可能深刻地影响深海海底的化学循环、微地层学和动物群落结构。最近对海底动物摄食的研究表明，它们会消耗新沉积的、高度有机的颗粒。如果这种选择性取食是普遍存在的，那么基于单一生物扰动示踪剂的生物地球化学模型对生物扰动、微生物代谢、沉积物成岩作用和地层形成的预测将不可靠。这项研究将通过分析比率示踪剂在沉积物饲养动物肠道和不同大小的沉积物颗粒中的活性来测试三种可供选择的机械假设。具体来说，示踪剂依赖的混合可能是由(1)沉积物喂食者对富含Th- 234的颗粒的大小依赖的摄入，(2)沉积物喂食者对年轻的、富含食物的颗粒的选择性摄入，与大小无关，或(3)动物洞穴中新沉积颗粒的被动级联和/或主动隔离造成的。＊＊＊