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

这个项目的目标是确定水中的化学物质是否会影响底栖海洋无脊椎动物幼体在受波浪驱动水流的生境中的定居，而波浪驱动的水流是许多沿海生境的特征。这个问题将通过研究裸目Phestilla sibogae来解决，它的幼虫对其猎物Porites compresa的一种特定物种的代谢物做出变性反应，这种丰富的珊瑚在夏威夷以海浪为主的浅海生境中形成珊瑚礁。经过充分研究的食珊瑚裸枝P.sibogae将成为底栖无脊椎动物的模型，这些无脊椎动物生活在珊瑚礁上，依靠从浮游生物中招募幼虫来发现和补充种群，并在小距离和大距离上保持遗传连续性。Hadfield在幼虫生物学方面的专业知识将与Koehl在生物力学和Kosff在环境流体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)在溶解线索的平流和混合较低的微生境中，西伯氏原虫幼虫是否在野外进行招募？(3)在波浪驱动的水流中，锡伯氏原虫幼虫对水传播线索的反应方式是否会影响它们在礁石上的滞留和定居？这项关于溶解线索在暴露于波浪驱动的水流中的幼虫定居作用的机制研究，超越了早期对单向水流中此类过程的研究。这项关于刚性树冠形成生物对沿海生境中小尺度流动和质量传输的影响的研究是对柔性大型植物树冠的类似研究的补充，也是对更大规模的珊瑚礁流动研究的补充。该项目对幼虫生态(幼虫招募过程可能对种群动态和遗传结构以及沿海底栖生境的群落结构产生深远影响)和珊瑚礁生态(珊瑚礁结构可能改变水中营养物质、食物、废物和繁殖体向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)都有潜在影响。

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).***