Influences of Nonrandom Biodiversity Change on Marine Ecosystem Functioning

由于生态系统中物种的多样性受到各种因素的影响，因此了解这些因素如何改变多样性以及由此导致的多样性变化如何影响该系统中能量和物质的转化和流动是很重要的。将多样性和生态系统层面的过程联系起来的大多数研究都是陆地的(97%的研究)，并使用随机的物种组合来实验性地评估多样性对生态系统功能的影响。虽然这些研究表明，生物多样性影响生产力、养分循环和能量流动等过程，但它们未能评估与养分可获得性、消费者、生物入侵、非生物应激源、局部灭绝和栖息地丧失等因素相关的生物多样性非随机变化的后果。该项目将通过对潮间带海藻群落的观察和实验操作来评估非随机生物多样性变化的后果，以确定非生物胁迫、消费者和营养物质对多样性的影响。岩石潮间带海藻是评估这些生物多样性变化影响因素的最佳研究系统，因为先前的研究表明，干扰、草食和营养可获得性对海藻多样性有显著影响。这项研究将包括在博德加海洋保护区和加州北部海岸的博德加海洋实验室进行的补充野外和实验室实验，以评估这些非随机的生物多样性变化对生态系统层面过程的影响，包括初级生产力(生长和光合作用速率)和养分循环(氮素吸收速率)。该项目的具体目标是：(1)量化与草食、养分可获得性和非生物胁迫变化相关的海藻多样性的具体变化；(2)评估草食、营养和胁迫介导的多样性变化对海洋生态系统功能的影响；以及(3)将这些影响与从当地物种库中选择的随机海藻物种组合的影响进行比较。智力优势：这项研究综合了对单个海藻的生理速率和条件、群落结构和动态以及生态系统层面的过程(初级生产、氮素固定)的测量。消费者、营养素和压力的因素操纵将有助于量化这些因素如何结合在一起影响海藻多样性。最后，这项工作将有助于提供数量不多但不断增加的证据，表明海洋生态系统中的生物多样性影响这些系统中的生物地球化学过程。该项目将具体评估生物多样性-生态系统功能研究的一个新方面：非随机多样性变化对海洋生态系统中关键生物地球化学过程的影响。更广泛的影响：生物多样性正在从地方到全球范围内发生变化，必须了解这些变化的驱动因素和后果，以预测和改善其对生态系统进程的影响。该项目将为海洋生态系统的养护和管理提供重要信息。该研究还将为博士后研究人员、研究生和本科生提供培训和研究经验，包括为参加博德加海洋实验室(BML)夏季REU项目的少数族裔和代表性不足的学生提供机会。结果将通过BML的公共教育计划和外展进行传达。

Because the diversity of species in an ecosystem is influenced by a variety of factors, it is important to understand both how diversity is altered by these factors and how the resulting changes in diversity influence the transformation and flux of energy and matter in that system. Most research linking diversity and ecosystem-level processes has been terrestrial (97% of studies) and has used random assemblages of species to experimentally assess diversity's influences on ecosystem functioning. While these studies suggest that diversity influences processes such as productivity, nutrient cycling, and energy flow, they fail to evaluate the consequences of nonrandom changes in biodiversity associated with factors such as nutrient availability, consumers, biological invasions, abiotic stressors, local extinction, and habitat loss. This project will evaluate the consequences of nonrandom biodiversity changes by conducting observations and experimental manipulations of intertidal seaweed assemblages to determine the influences of abiotic stress, consumers, and nutrients on diversity. Rocky intertidal seaweeds are an optimal study system for evaluating these effectors of biodiversity change, as previous research has demonstrated dramatic impacts of disturbance, herbivory, and nutrient availability on seaweed diversity. The research will include complementary field and laboratory experiments in the Bodega Marine Reserve and at the Bodega Marine Laboratory on the northern California coast to assess the influences of these nonrandom biodiversity changes on ecosystem-level processes, including primary production (growth and photosynthetic rates) and nutrient cycling (nitrogen uptake rates). The specific objectives of the project are to: (1) Quantify specific changes in seaweed diversity associated with variation in herbivory, nutrient availability, and abiotic stress; (2) Evaluate the influences of herbivore-, nutrient-, and stress-mediated diversity changes on marine ecosystem functioning; and (3) Compare these impacts to the effects of random assemblages of seaweed species selected from the local species pool. Intellectual merit: This research integrates measurements of individual seaweeds' physiological rates and condition, community structure and dynamics, and ecosystem-level processes (primary production, nitrogen immobilization). The factorial manipulations of consumers, nutrients, and stress will help quantify how these factors combine to influence seaweed diversity. Finally, the work will contribute to the small, but growing, body of evidence suggesting that the diversity of organisms in marine ecosystems influences biogeochemical processes in those systems. This project will specifically evaluate a novel aspect of biodiversity-ecosystem function research: the influence of nonrandom diversity changes on key biogeochemical processes in a marine ecosystem. Broader impacts: Biodiversity is changing from local to global scales, and it is essential to understand both the drivers and consequences of these changes to predict and ameliorate their impacts on ecosystem processes. This project will provide crucial information for the conservation and management of marine ecosystems. The study will also provide training and research experience for postdoctoral researchers, graduate students, and undergraduates, including opportunities for minority and under-represented students participating in the summer REU program at Bodega Marine Laboratory (BML). Results will be communicated through the public education program at BML and through outreach.