Patterns and mechanisms relating seagrass genotypic diversity and ecosystem response to biotic and abiotic stress

大量的研究和辩论集中在物种多样性与生态系统功能之间的关系。相反，很少有数据可用于评估物种内基因型多样性对个体相互作用，种群过程和生态功能的影响。许多海洋底栖和浮游生物群落由单一物种主导：巨藻林中的Macrocystis，温带海草床中的Zostera，以及贫营养开放海洋系统中的Prochlorococcus。这些物种内的遗传多样性可能发挥类似的作用，在其他系统中的物种多样性，但很少有数据可以链接功能分化的基因型，其对社区和生态系统水平的过程。PI的初步工作表明，克隆多样性的大叶藻（Zostera marina），增强阻力干扰放牧鹅，但这种影响的机制和影响的重要性下的干扰类型和强度的范围是未知的。大叶藻作为全球许多温带浅水群落中唯一的大型植物物种发挥着关键作用，在初级生产、营养循环、沉积物稳定和为相关动物物种提供栖息地方面发挥着关键的生态系统作用。该系统提供了一个机会，以评估基因型多样性的影响，不仅对个人和人口的过程，而且对社区和生态系统的过程，如初级生产力和丰富度和多样性的相关动物。研究人员将进行一系列的实验室、围隔生态系统和田间实验，以研究Z遗传变异的功能（生态）后果。以及这种变化如何有助于遗传多样性和生态系统过程之间的关系。具体而言，它们将：（1）量化关键生理参数如光合速率、养分吸收和短期生长的克隆变异，（2）调查在干扰和未干扰条件下克隆体和非克隆体之间的芽间相互作用及其对总体鳗鱼草产量的影响，（3）检查鳗鱼草基因型多样性与芽密度、幼苗补充、和相关的海草附着生物群落在析因田间实验，（4）量化的基因型多样性随时间的变化，在存在和不存在干扰的自然种群和这些变化的后果，其余的生态系统。鉴于在海洋系统中普遍减少的鳗草和其他关键的基础物种，这是至关重要的，以了解人口和社区过程的个体变异的后果。事实上，人类活动正在造成海草遗传多样性的下降，在生态系统过程的规模进行测量，这项研究将提供急需的信息，为联邦政府授权的恢复工作。最后，该项目将培养未来的科学家，包括博士后，研究生和本科生研究人员，包括来自代表性不足群体的成员。

Considerable research and debate has focused on the relationship between species diversity and ecosystem function. In contrast, few data are available to assess the impact of within species genotypic diversity on individual interactions, population processes, and ecological functions. Many marine benthic and planktonic communities are dominated by a single species: Macrocystis in kelp forests, Zostera in temperate seagrass beds, and Prochlorococcus in oligotrophic open ocean systems. Genetic diversity within these species may play an analogous role to species diversity in other systems, but few data are available that link functional differentiation of genotypes with their effect on community and ecosystem-level processes. The PIs' preliminary work suggests that clonal diversity in the eelgrass (Zostera marina), enhances resistance disturbance by grazing geese but the mechanisms underlying this effect and the importance of the effect under a range of disturbance types and intensities are unknown. Zostera plays a key role as the only macrophyte species in many temperate shallowwater communities worldwide, where it provides a critical ecosystem role, in terms of primary production, nutrient cycling, sediment stabilization, and provision of habitat for associated animal species. This system provides an opportunity to assess the effects of genotypic diversity on not only individual and population processes but also on community and ecosystem processes such as primary productivity and the abundance and diversity of associated animals. The PIs will conduct a series of laboratory, mesocosm, and field experiments to investigate the functional (ecological) consequences of genetic variation in Z. marina and how this variation contributes to the relationship between genetic diversity and ecosystem processes. Specifically, they will: (1) Quantify clonal variation in key physiological parameters such as photosynthetic rate, nutrient uptake and short term growth, (2) Investigate inter-shoot interactions between clonemates and non-clonemates and their impacts on overall eelgrass production under disturbed and undisturbed conditions, (3) Examine the inter-relationship between eelgrass genotypic diversity and disturbance on shoot density, seedling recruitment, and the associated community of seagrass epibionts in a factorial field experiment, and (4) Quantify changes in genotypic diversity over time in the presence and absence of disturbance in natural populations and the consequences of these changes for the rest of the ecosystem. Given the widespread decline of eelgrass and other key foundation species in marine systems, it is critical to understand the consequences of individual variation for population and community processes. Indeed, human activities are causing declines in genetic diversity in seagrasses at the scale at which ecosystem processes are measured and this research will provide much-needed information for federally mandated restoration efforts. Finally, this project will develop future scientists including a postdoctoral, and also graduate student and undergraduate researchers, including members from underrepresented groups.