LTER: Scales of Variability in Ecosystem Dynamics and Production on the Changing Northeast U.S. Shelf (NES II)

美国东北大陆架(NES)是西北大西洋从北卡罗来纳州到缅因州的大陆架上的区域。NES有着长期密集的人类利用历史，并提供包括航运、娱乐、保护和能源开发在内的一系列生态系统服务。NES还包括季节性动态和多产的生态系统，支持著名的渔业，其完整性对美国东北部经济的健康至关重要。NES生态系统的生产力是由浮游生物推动的，这些浮游生物在复杂的食物网中相互作用，其结构取决于环境条件(例如，温度、光照和营养水平)。由于与气候变化相关的气候变暖和人类利用，这些条件正在迅速变化。例如，NES正在见证美国迄今为止最大的沿海风力发电场的开发。美国东北大陆架长期生态研究计划(NES-LTER II)第二阶段提高了我们预测人为影响将如何影响大陆架浮游食物网动态的能力，以及它们支持从鱼类到鲸鱼和人类等较高营养水平的生产力的能力。由于NES面临将影响许多人的长期挑战，该项目强调积极的教育内容，以帮助培训下一代海洋科学家，并开展外联活动，以增加公众对海洋科学和技术的了解。该项目团队通过三个主要部分进行教育和推广：(1)对LTER研究中从本科生到博士后研究人员的早期职业研究人员的培训和指导；(2)LTER校园计划，吸引初中和高中教师和学生；(3)通过有针对性的活动、项目网站和社交媒体渠道进行公共推广。生态系统随季节到数十年的变化模式已被记录在NES中，但将物理环境变化、浮游生物食物网和较高营养水平联系起来的关键机制仍然知之甚少。因此，预测能力有限，管理策略在很大程度上是被动的。为了满足这些需求，NES II的目标是对食物网的结构和功能如何响应环境条件、自然变异性和人类诱导的变化进行机械性的理解。NES II结合了提供区域规模背景的观测、沿高梯度跨陆架横断面的过程巡航、内陆架位置的高频时间序列、生物-物理食物网耦合模型和目标种群模型。此外，研究小组正在调查群落结构和营养转移如何受到干扰的影响，这些干扰包括(I)热浪日益盛行，(Ii)与墨西哥湾流日益不稳定有关的近海水域入侵，以及(Iii)正在NES建设的离岸风力发电场。长期研究计划是以一个重要的科学问题为指导的：“气候变化如何影响远洋NES生态系统，特别是影响组成(例如，物种多样性和大小结构)和集合体(例如，初级生产力和向较高营养层的能量转移)变异性之间的关系？”研究人员正在评估NES生态系统拥有对环境剧烈变化具有弹性并将使生态系统保持整体生产力的生物多样性储藏库的程度。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The Northeast U.S. Shelf (NES) is the region of the Northwest Atlantic Ocean that overlies the continental shelf from North Carolina to Maine. The NES has a long history of intense human utilization and provides an array of ecosystem services including shipping, recreation, conservation, and energy development. The NES also comprises a seasonally dynamic and productive ecosystem, supporting renowned fisheries, whose integrity is critical to the health of the Northeast U.S. economy. The NES ecosystem’s productivity is fueled by planktonic organisms that interact with each other in complex food webs whose structure depends on environmental conditions (e.g., temperature, light, and nutrient levels). These conditions are rapidly changing because of climate-change-related warming and human utilization. For example, the NES is seeing the largest development of coastal wind farms in the U.S. to date. Phase II of the Northeast U.S. Shelf Long-Term Ecological Research program (NES-LTER II) advances our ability to predict how anthropogenic impacts will affect the dynamics of the shelf’s planktonic food webs and their ability to support the productivity of higher trophic levels, from fish to whales and humans. Because the NES is subject to long-term challenges that will impact many people, the project emphasizes an active education component for helping to train the next generation of marine scientists and outreach activities to increase public understanding of marine science and technology. The project team conducts education and outreach via three main components: (1) training and mentoring for early career researchers from undergraduates to postdoctoral researchers in LTER research; (2) an LTER Schoolyard program that engages middle and high school teachers and students; and (3) public outreach through targeted events, the project website, and social media channels.Patterns of ecosystem change over seasons to decades have been documented in the NES, but the key mechanisms linking changes in the physical environment, planktonic food webs, and higher trophic levels remain poorly understood. As a result, predictive capability is limited and management strategies are largely reactive. To address these needs, NES II is targeting a mechanistic understanding of how food web structure and function responds to environmental conditions, natural variability and human induced changes. NES II combines observations that provide regional-scale context, process cruises along a high gradient cross-shelf transect, high-frequency time series at an inner-shelf location, coupled biological-physical food web models, and targeted population models. In addition, the research team is investigating how community structure and trophic transfer are impacted by disturbances including (i) the increasing prevalence of heat waves, (ii) intrusions of offshore water associated with increasing instability in the Gulf Stream, and (iii) offshore wind farms now under construction on the NES. The long-term research plan is guided by the overarching science question: “How is climate change impacting the pelagic NES ecosystem and, in particular, affecting the relationship between compositional (e.g., species diversity and size structure) and aggregate (e.g., rates of primary production, and transfer of energy to higher trophic levels) variability?” The investigators are assessing the extent to which the NES ecosystem possesses a biodiversity reservoir that is resilient to dramatic changes in the environment and that will allow the ecosystem to maintain overall productivity.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.