RUI: Scale-Dependence of Flow Effects on Coral Reef Community Primary Production

了解海洋环境中物质通量的控制是海洋学的一个主要目标。在沿海海洋环境中，人们越来越认识到水动力学在调节这些通量方面的作用。珊瑚礁是海洋中最具生产力的生态系统之一，水流对于维持珊瑚礁初级生产者的高光合作用速率至关重要。在许多珊瑚礁上，主要的主要生产成分是由自由生活的藻类组成的，它们在死珊瑚上形成一层薄薄的饰面。在几十厘米的空间尺度上，礁藻草皮的光合作用速率因水的运动而显著提高，并且在固氮速率方面也证明了类似的模式。在相似的空间尺度上，其他珊瑚礁生物的代谢和养分吸收过程也与流速呈正相关。该项目将通过以下方式更全面地了解水流在调节珊瑚礁初级生产中的作用：1)在更大的空间尺度上研究水流如何影响珊瑚礁群落初级生产的普遍性，以及表面粗糙度如何影响这种关系；2)更详细地研究藻皮物理结构、水流和边界层动力学之间的小规模相互作用，因为这将允许扰动的生态过程与水动力学和传质的物理过程之间的耦合。使用相关和实验方法，将在几个空间尺度上测试关于流动、剪切应力和粗糙度对净群落初级产量影响的明确假设。更广泛的影响包括通过培训本科生和研究生以及博士后研究人员，对海洋科学人力资源的开发做出重大贡献，以及更好地了解对关键海洋生态系统的流动影响。

Understanding the control of material fluxes in marine environments is a major goal of oceanography. In coastal marine environments, there is a growing appreciation for the role of hydrodynamics in modulating these fluxes. Coral reefs are among the most productive ecosystems in the ocean and water flow is central to maintaining high rates of photosynthesis in reef primary producers. On many reefs the major primary producing component is comprised of free-living algae that form a thin veneer over dead coral. Rates of photosynthesis by reef algal turfs on spatial scales of tens of centimeters are enhanced significantly by water motion, and similar patterns have been demonstrated for rates of nitrogen fixation. Metabolic and nutrient uptake processes of other reef organisms are also positively related to flow speed on similar spatial scales.This project will develop a more complete understanding of the role of water flow in modulating coral reef primary production by: 1) examining the generality of how flow effects reef community primary production at larger spatial scales and how surface roughness affects this relationship, and, 2) investigating in more detail the small-scale interactions between algal turf physical structure, flow, and boundary layer dynamics, as this will allow a coupling between the ecological process of disturbance and the physical processes of hydrodynamics and mass transfer. Using both correlational and experimental methods, explicit hypotheses about the effects of flow, shear stress, and roughness on net community primary production at several spatial scales will be tested.Broader impacts include a significant contribution to the development of human resources in marine science via training of both undergraduate and graduate students and a postdoctoral researcher, and better understanding of flow effects on a critical marine ecosystem.