Physical-Biological Interactions in the Fertilization Ecology of Broadcast Spawners: The Role of Gamete Traits and Turbulence Structure

广播产卵器受精生态中的物理生物相互作用：配子性状和湍流结构的作用

• 批准号: 0849695
• 负责人: John Crimaldi
• 金额: $ 45万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-01 至 2013-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0849695&HistoricalAwards=false
• 关键词: Physical; Biological; Interactions; Fertilization; Ecology

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The goal of this research is to determine the role of key biological and physical factors on fertilization rates in broadcast spawning, the reproductive strategy used by many benthic invertebrates. The objectives are to quantify the effect of gamete traits, instantaneous turbulence structure, and unsteady flow phenomena on subsequent gamete coalescence processes and fertilization rates. Fertilization is typically modeled as a bimolecular reaction, with the fertilization rate proportional to concentrations of gametes. Conventional thought has been that since turbulence produces efficient dilution of gamete concentrations, it hinders fertilization success. However, this conclusion is based on consideration of average turbulent dispersion. Recent work has provided evidence that instantaneous turbulence structure promotes local coalescence at shorter timescales, before dilution takes place, thus enhancing fertilization rates. This work will extend idealized numerical and laboratory studies to include ecologically relevant factors specific to the broadcast spawning process. It integrates numerical simulations and laboratory experiments to investigate process-level effects of individual biological and physical factors. The numerical simulations will consider the effects of gamete viscosity, rheology, and taxis, for 2D pseudo-turbulent flow, unsteady obstacle wakes, and 3D chaotic mixing scenarios. The laboratory experiments will model the effects of gamete viscosity, rheology, morphology, and buoyancy, using 3D boundary layer turbulence, obstacle wakes, and surface waves. A novel two-color planar laser-induced fluorescence system will be used to quantify concentrations of gamete surrogates, including those regions where they overlap. Surrogates made using dyed solutions of glycerol and a biopolymer will model the viscosity and rheology of sea urchin gametes, and fluorescent particles will be used to investigate size and inertial effects. Floating particles will be used to study the effect of convergence zones in free-surface turbulence on fertilization rates for species with buoyant gametes.The educational and outreach goals are to integrate research methods into the PI's teaching curriculum as an effective tool for learning fluid mechanics, and to use the topic of broadcast spawning to get K-16 students interested in engineering and science. A numerical simulation platform will be integrated into a course; students will use the simulation environment and their knowledge of the Navier-Stokes equation to model an unsteady cylinder wake. Likewise, a simplified version of the obstacle wake experiment will be developed as a teaching tool. The PI will also develop an interactive laboratory demonstration to use with visiting groups. The demonstration will include a removable benthic seascape for the bed of the teaching flume, complete with sea urchin mimics that spawn viscous gamete surrogates. Visitors will be able to experiment with hands-on props such as flow obstacles and a removable bed-roughness section. Several permanent posters and a short video about broadcast spawning in nature will enhance the demonstration. Finally, the PLIF system will be used to make educational movies for dissemination via a digital library of the American Physical Society.

该奖项是根据2009年《美国复苏和再投资法案》(公法111-5)资助的。这项研究的目标是确定关键的生物和物理因素在广播产卵中对受精率的作用，这是许多底栖无脊椎动物使用的繁殖策略。其目的是量化配子特征、瞬时湍流结构和非定常流动现象对后续配子合并过程和受精率的影响。受精通常被模拟为一个双分子反应，受精率与配子浓度成正比。传统的观点认为，由于湍流会有效稀释配子浓度，因此会阻碍受精成功。然而，这一结论是基于对平均湍流弥散的考虑。最近的工作提供了证据，表明瞬时湍流结构在稀释发生之前，在较短的时间尺度上促进了局部融合，从而提高了受精率。这项工作将扩展理想化的数值和实验室研究，以包括特定于广播产卵过程的生态相关因素。它将数值模拟和实验室实验相结合，以研究单个生物和物理因素对过程水平的影响。数值模拟将考虑二维拟湍流、非定常障碍物尾迹和三维混沌混合场景中配子粘度、流变性和趋势性的影响。实验室实验将使用3D边界层湍流、障碍物尾迹和表面波来模拟配子粘度、流变学、形态和浮力的影响。一种新的双色平面激光诱导荧光系统将被用来定量配子替代物的浓度，包括它们重叠的区域。用甘油和生物聚合物的染色溶液制成的替代品将模拟海胆配子的粘度和流变学，荧光颗粒将用于研究尺寸和惯性效应。漂浮粒子将被用来研究自由表面湍流中汇聚区对浮游物种受精率的影响。教育和推广目标是将研究方法整合到PI的教学课程中，作为学习流体力学的有效工具，并利用广播产卵的主题来激发K-16学生对工程和科学的兴趣。课程中将整合一个数值模拟平台；学生将使用模拟环境和他们对纳维-斯托克斯方程的知识来模拟非定常圆柱尾迹。同样，将开发简化版本的障碍尾迹实验作为教学工具。国际和平协会还将开发一个互动式实验室演示，供来访团体使用。演示将包括用于教学水槽床的可拆卸海底海景，以及模拟海胆产卵的粘性配子替代品。参观者将能够试验实际操作的道具，如水流障碍物和可拆卸的床面粗糙度部分。几张永久海报和一段关于自然界广播产卵的短视频将加强演示。最后，PLIF系统将被用于制作教育电影，通过美国物理学会的数字图书馆进行传播。