Collaborative Research: Interactions Among Deposit-Feeding, Organic Matter Diagenesis andAnimal Nutrition

存款喂养碳埋藏的全球影响是深远的。即使它们只消耗一小部分沉积有机质（OM），存款馈线影响OM成岩作用的速度和程度，通过增加氧气渗透到沉积物中，重新分配颗粒，并刺激整个混合层的成岩活动。沉积有机资源同时决定着底栖动物的活动，并受底栖动物活动的影响。了解存款喂养和OM成岩作用如何相互作用，是至关重要的发展现实耦合的生物/化学模式的碳循环在海洋沉积物。在这项研究中，斯基德韦海洋学研究所和得克萨斯大学奥斯汀分校的研究人员将研究OM成岩作用和沉积物-馈线生态之间的联系和反馈，通过研究实验微观世界中的走廊带喂养orbinid多毛类动物（Haploscoloplos robustus）的觅食行为。沉积OM浓度对个体摄食率，斑块密度和率x密度相互作用的影响将从最佳觅食的角度进行研究。记录个体功能反应、沉积物混合、微生物介导的有机转化和营养同化之间的动态平衡是拟议研究的主要重点。为研究生物-微生物-沉积物耦合系统，提出了一种基于同位素的13 C示踪实验方法。沉积碳和标记OM添加物的细菌共代谢将导致细菌合成的OM的形成，其具有不同于（12 C）沉积碳和添加的（13 C）OM的分子13 C同位素特征。测量加入的标记物掺入细菌氨基酸和脂肪酸库以及随后的存款饲养生物量将用于追踪碳作为H的函数的命运。捕食率和种群密度。OM成岩作用，微生物生产，蠕虫觅食行为和增长之间的反馈将被量化独立操纵有机供应，人口密度和沉积物混合率方面的更广泛的影响，这个研究项目将具有几个机构间的合作，并将涉及培训一名研究生（在UT）和两名本科生从SkIO/萨凡纳国家CIRE实习计划。

The global effects of deposit feeding on carbon burial are profound. Even though they consume only a small fraction of sedimentary organic matter (OM), deposit feeders influence the rate and extent of OM diagenesis by increasing oxygen penetration into sediments, redistributing particles, and stimulating diagenetic activity throughout the mixed layer. Sedimentary organic resources simultaneously determine, and are determined by, the activities of the benthic infauna. Understanding how deposit feeding and OM diagenesis interact is critical to developing realistically coupled biological/chemical models of carbon cycling in marine sediments. In this study, investigators at the Skidaway Institute of Oceanography and the University of Texas at Austin will study linkages and feedbacks between OM diagenesis and deposit-feeder ecology by examining the foraging behavior of a conveyor-belt feeding orbiniid polychaetes (Haploscoloplos robustus) in experimental microcosms. Effects of sedimentary OM concentrations on individual feeding rates, patch density, and rate x density interactions will be examined from an optimal foraging perspective. Documenting the dynamic balance among individual functional responses, sediment mixing, microbially-mediated organic transformations, and nutrient assimilation is a major focus of the proposed study. To study the coupled organism-microbe-sediment system, a novel isotopomer-based 13C tracer experiment is proposed. Bacterial co-metabolism of sedimentary carbon and labeled OM additions will lead to the formation of bacterially-synthesized OM having molecular 13C isotopic signatures that are distinct from both the (12C) sedimentary carbon and the added (13C) OM. Measurement of the incorporation of added label into a bacterial amino acid and fatty acid pools and subsequently deposit feeder biomass will be used to trace the fate of carbon as a function of H. robustus feeding rate and population density. Feedbacks among OM diagenesis, microbial production, and worm foraging behavior and growth will be quantified by independently manipulating organic supply, population density, and sediment mixing rate.In terms of broader impacts, this research project will feature several inter-institutional collaborations and will involve the training one graduate student (at UT) and two undergraduate students from the SkIO/Savannah State CIRE internship program.