Rhythms of a changing ocean: Chronobiology and control of reproduction in marine organisms

生命及其节律在海洋中进化，然而我们对生物节律的理解主要围绕着陆地模式的昼夜节律和季节周期。我对海洋生物的研究努力阐明循环生活史事件中的关键相互作用，遵循综合的观点，结合了时间生物学（生物活动与时间之间的关系）、物候学（周期性事件与气候条件之间的关系）和进化生物学（生物节律的适应性利益）的观点。我的长期目标是澄清底栖生物种群繁殖周期的介质和适应性意义。最近，我们发现24个北方物种属于6门，它们的繁殖经历了与珊瑚礁相似的季节性和月相的大规模产卵事件，尽管物种特定的diel成分保持了生殖隔离。我们还发现，深海物种可能很少受到环境变化的影响，仍然表现出季节性和月相的繁殖周期。目前提出的节律性生殖事件的机制和优势并不能完全解释为什么如此多的物种在春季释放后代，而不考虑繁殖模式（自由产卵、产卵）、幼虫类型（摄食、非摄食）、深度或区域。该计划的短期目标是：1)进一步研究深海物种的繁殖周期；2)比较不同生活史物种周期性繁殖的适应价值；3)梳理出深海和北方分类群繁殖节律的驱动因素；4)研究“哨兵”（更容易接受环境线索的生物）的概念；5)确定季节性繁殖物种的昼夜节律。通过整合生殖生物学，时间生物学和化学生态学的概念，我们希望解开生物钟，外部线索和社会互动各自所扮演的角色，并更好地了解底栖生态系统的功能。确定海洋分类群多层次生物节律的驱动因素不仅有助于了解我们的进化历史，而且有助于开发水产养殖技术和基于时间尺度的管理和保护策略。

Life and its rhythms evolved in the sea, yet our understanding of biological rhythms largely revolves around circadian and seasonal cycles in terrestrial models. My research on marine organisms strives to elucidate key interplays in cyclic life-history events, following an integrated view that combines the perspectives of chronobiology (relation between biological activity and time), phenology (relation between periodic events and climatic conditions) and evolutionary biology (adaptive benefits of biological rhythms). My long-term objective is to clarify the mediators and adaptive significance of reproductive periodicities in benthic populations. Recently we found that 24 boreal species belonging to 6 phyla undergo seasonal and lunar rhythms of reproduction with mass-spawning events similar to coral reefs, although species-specific diel components preserve reproductive isolation. We also found that deep-sea species, presumably exposed to little environmental variability, still exhibit seasonal and lunar breeding cycles. Currently proposed mechanisms and advantages of rhythmic reproductive events cannot fully explain why so many species release progeny in spring, irrespective of reproductive mode (free spawning, brooding), larval type (feeding, nonfeeding), depth or region. The short term objectives of the proposed program are to: 1) further investigate breeding periodicity in deep-sea species; 2) compare the adaptive value of periodic reproduction in species with different life histories; 3) tease out the drivers of breeding rhythms in deep-sea and boreal taxa; 4) investigate the concept of "sentinels" (organisms more receptive to environmental cues); and 5) identify circadian rhythms in species with seasonal breeding. By integrating concepts of reproductive biology, chronobiology and chemical ecology we hope to disentangle the respective roles played by biological clocks, external cues and social interactions and gain a finer understanding of benthic ecosystem functioning. Identifying the drivers of multileveled biological rhythms in marine taxa will not only provide insight into our evolutionary past but also help develop aquaculture techniques and time-scale-based management and conservation strategies.