LTER: NGA Phase II - Resilience and Connectivity Across Transitions in the Northern Gulf of Alaska Ecosystem

阿拉斯加北部湾 (NGA) 是一个高产的亚北极海洋生态系统，数百年来，各种沿海社区都依赖它。如今，NGA 生态系统继续在食品、文化和经济方面为国家渔业、当地沿海社区和部落政府提供支持。 NGA 长期生态研究 (LTER) 网站旨在了解这一动态生态系统。 NGA LTER 总体概念框架是，强烈的环境变化（无论是时间上还是空间上）通过物种适应和群落组织产生了高度弹性的生态系统。基于苏厄德线沿线 25 年的多学科观察和 NGA LTER 第一阶段的发现，第二阶段正在改善对该生物群落的关键生物体、生态过程和气候变化响应的机制理解。第二阶段继续教育各个级别的学生，并与当地社区互动，了解他们对这个生态系统的问题和担忧。多个机构和组织与 NGA LTER 合作并利用 NGA LTER，展示了该 LTER 站点以及为阿拉斯加湾地区收集的数据的重要性。在长期数据集和第一阶段研究结果的基础上，阿拉斯加北部湾 LTER 第二阶段研究有三个主要目标。首先，研究人员正在继续收集和分析长期生态系统数据，以了解物种丰富度和连通性，以及它们与事件规模和长期变化的关系。其次，该团队正在探索生物体的功能冗余作为生态系统恢复力的基础。尽管物种丰富度不高，NGA 仍拥有大量“冗余”类群，在整个食物网中具有类似的营养作用；研究人员提出，这些类群具有不同但互补的营养策略、生活史和生命周期时间，有助于功能冗余。冗余稳定了较高营养水平的变异性，从而赋予系统弹性（即，维持或恢复关键生态系统特性以应对干扰），而冗余稳定食物网的程度尚未在远洋海洋生态系统中得到很好的探索。第三，该团队正在研究 NGA 中物理锋面（即不同水团之间的转变）和相关生态交错带（即生物群落结构的转变）的生态作用。 NGA 正在利用新技术来克服在生物相关的时空尺度上研究锋面及其组成群落的历史局限性。研究人员假设锋面对关键生态系统特性（例如生产、出口、生物多样性）产生不成比例的影响，因此与整个生态系统的恢复力相关。此外，锋面可能会受到事件规模和长期环境变化的影响。这三个主题下的观察和实验与建模活动相结合，以了解额叶转变时发生的相关物理和生物关系。这些特定于生物群落的公式正在根据 NGA 预测的气候情景探索历史、当前和未来的生态状态。与其他 LTER 站点的合作进一步增强了对生态理论的理解。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

The Northern Gulf of Alaska (NGA) is a highly productive subarctic marine ecosystem, and diverse coastal communities have relied upon it for hundreds and thousands of years. Today, the NGA ecosystem continues to support national fisheries, local coastal communities, and Tribal governments in terms of food, culture, and economy. The NGA Long Term Ecological Research (LTER) site aims to understand this dynamic ecosystem. The NGA LTER overarching conceptual framework is that intense environmental variability – both temporally and spatially – has yielded a highly resilient ecosystem through species adaptation and community organization. Building off 25 years of multidisciplinary observations along the Seward Line and findings from Phase I of the NGA LTER, Phase II is improving mechanistic understanding of this biome’s key organisms, ecological processes, and responses to climate change. Phase II continues to educate students at all levels and to engage with local communities to understand the questions and concerns that they have regarding this ecosystem. Various agencies and organizations partner with and leverage the NGA LTER, demonstrating the importance of this LTER site and the data collected for the Gulf of Alaska region.Building on long-term data sets and findings from Phase-I, Northern Gulf of Alaska LTER Phase-II research has three primary goals. First, the investigators are continuing collection and analysis of long-term ecosystem data to understand species abundance and connectivity, as well as their relationships to event-scale and long-term change. Second, the team is exploring functional redundancy of organisms as an underpinning of ecosystem resilience. Despite modest species richness, the NGA hosts numerous instances of “redundant” taxa with comparable trophic roles throughout the food web; the investigators propose that these taxa, with differing but complimentary nutritional strategies, life histories, and life-cycle timing, contribute to functional redundancy. Redundancy stabilizes variability at higher trophic levels, thereby conferring resilience to the system (i.e., maintenance or recovery of key ecosystem properties in response to disturbance), and the degree to which redundancy stabilizes food webs has not been well explored in pelagic marine ecosystems. Third, the team is investigating the ecological role of physical fronts (i.e., transitions between different water masses) and associated ecotones (i.e., transitions in biological community structure) in the NGA. NGA is making use of new technologies that can overcome historical limitations to the study of fronts and their constituent communities at biologically relevant spatial and temporal scales. The investigators hypothesize that fronts exert a disproportionate influence on key ecosystem properties (e.g., production, export, biological diversity) and are thus related to whole-ecosystem resilience. In addition, fronts are likely to be influenced by both event-scale and long-term environmental change. The observations and experimentation under each of these three themes are coupled to modeling activities to understand relevant physical and biological relationships that occur at frontal transitions. These biome-specific formulations are exploring historical, current, and future ecological states based on climate scenarios predicted for the NGA. Collaboration with other LTER sites is further enhancing understanding of ecological theory.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.