Collaborative Research: Can Larvae Utilize Dissolved Settlement Cues in the Wave-Driven Flow on Coral Reefs?

这个项目的目的是确定水中的化学线索是否会影响底栖海洋无脊椎动物的幼虫在受波浪驱动的水流影响的栖息地的定居，这种水流是许多沿海栖息地的特征。这个问题将通过研究裸鳃Phestilla sibogae来解决，它的幼虫会对其猎物的一种特定的代谢物做出反应，Porites compressa是一种丰富的珊瑚，在夏威夷以波浪为主的浅生境中形成珊瑚礁。被充分研究的以珊瑚为食的裸鳃P. sibogae将成为生活在珊瑚礁上的底栖无脊椎动物的模型，这些无脊椎动物依靠从浮游生物中招募幼虫来发现和补充种群，并在大小距离上保持遗传连续性。哈德菲尔德在幼虫生物学方面的专业知识将与Koehl在生物力学方面的专业知识和Koseff在环境流体动力学方面的专业知识相结合，以解决以下问题：(1)环境水流如何分散自然界中溶解的线索？(2)在平流和溶解性线索混合较低的微生境中，sibogae幼虫是否在野外繁殖？(3)在波浪驱动的水流中，sibogae的幼虫是否会对水生线索做出反应，从而影响它们在礁石上的滞留和沉降？这项关于溶解线索在暴露于波浪驱动流的地点的幼虫定居中的作用的机制研究超越了早期对单向流动中这类过程的研究。这项关于刚性冠层形成生物对沿海栖息地小尺度流动和物质运输影响的研究，补充了对柔性大型植物冠层的类似研究，也补充了对珊瑚礁的更大规模流动研究。该项目对幼虫生态学（幼虫补充过程对种群的动态和遗传结构以及沿海底栖生物栖息地的群落结构产生深远影响）和珊瑚礁生态学（珊瑚礁结构可以改变水生营养物质、食物、废物和繁殖体对生活在这些重要热带生态系统中的生物群落的小规模流动和运输）具有潜在影响

Hadfield9907545The objective of this project is to determine whether water-borne chemical cues can affect the settlement of larvae of benthic marine invertebrates in habitats subjected to the wave-driven water flow that characterizes many coastal habitats. This question will be addressed by studying the nudibranch Phestilla sibogae, whose larvae metamorphose in response to a species-specific metabolite of its prey, Porites compressa, an abundant coral that forms reefs in shallow, wave--dominated habitats in Hawaii. The well-studied coral-eating nudibranch P. sibogae will serve as a model for benthic invertebrates that live on coral reefs and rely on recruitment of larvae from the plankton to found and replenish populations and maintain genetic continuity across small and large distances. The expertise of Hadfield in larval biology will be combined with that of Koehl in biomechanics and Koseff in environmental hydrodynamics to address the following questions: (1) How does ambient water flow disperse dissolved cues in nature? (2) Do P. sibogae larvae recruit in the field in microhabitats where advection and mixing of dissolved cues is low? (3) Do larvae of P. sibogae respond to water-borne cues in ways that affect their retention and settlement on a reef in wave-driven water flow? This mechanistic study of the role of dissolved cues in larval settlement at sites exposed to wave--driven flow goes beyond earlier studies of such processes in unidirectional flow. This investigation of the effects of rigid canopy-forming organisms on small-scale flow and mass transport in coastal habitats complements similar studies in flexible macrophyte canopies, and also complements larger--scale flow studies of coral reefs. The project has a potential impact on both larval ecology (larval recruitment processes can have profound effects on the dynamics and genetic structure of populations, and on community structure in coastal benthic habitats), and on coral reef ecology (reef structure can alter the small-scale flow and transport of water-born nutrients, food, wastes, and propagules to the community of organisms living in these important tropical ecosystems).***