Supporting data for<b> "</b><b>PHYLOGEOGRAPHY AND PLASTICITY OF MACROALGAE IN A CHANGING OCEAN"</b>
<p dir="ltr">Diverse marine environments shape the diversity of macroalgae, important primary producers in the ocean, influencing their distribution, phenotype, function, and evolution. This thesis examines the response of macroalgae to environmental changes, focusing on their phylogeographic distribution, phenotypic plasticity, and the molecular mechanisms driving these adaptive strategies. These studies emphasize the role of spatiotemporal variations in the natural environment in shaping species diversity and the evolutionary processes that influence the distribution and plasticity of macroalgae. The thesis begins with an exploration of the phylogeographic patterns of macroalgae in the Northwest Pacific, revealing the impact of historical processes, such as paleoclimate changes and post-glacial colonization, and how the region's unique geographical features affect the genetic structure of macroalgae. These findings highlight the importance of dispersal capacity, genetic differentiation, and environmental gradients in shaping species distributions. Specifically, the study of Ulva’s phylogeography in the Northwest Pacific illustrates the complexity of species classification, with molecular data revealing high species diversity and low intraspecific genetic diversity despite morphological similarities. This chapter underscores the significant influence of temperature on geographic distribution, with species exhibiting different thermal adaptations. Past environments play a crucial role in determining the distribution and function of contemporary macroalgae, and how they respond to current and future environmental changes will shape their future. To this end, the thesis investigates the effects of nitrogen sources and availability on the thermal plasticity of macroalgae, revealing how different nitrogen sources influence growth rates and gene expression, particularly in relation to nitrate metabolism. Additionally, the study of transgenerational thermal plasticity in <i>Ulva prolifera</i> highlights how past environmental stresses shape phenotypic traits across generations, promoting rapid growth and persistence under fluctuating environmental conditions. This research emphasizes the critical role of intergenerational memory in ecological resilience, offering insights into how marine macroalgae may respond to ongoing climate change. In summary, this thesis provides a comprehensive understanding of how environmental factors shape macroalgae, focusing on their adaptation strategies to historical and contemporary environmental changes. These findings contribute to our knowledge of marine biogeography, ecological resilience, and the mechanisms by which marine organisms adapt to climate change.</p>
