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（英语：Northeast U.S. Shelf，缩写：内斯）是大西洋西北部的一个区域，覆盖在从北卡罗来纳州到缅因州的大陆架上。内斯有着悠久的人类利用历史，并提供了一系列生态系统服务，包括航运，娱乐，保护和能源开发。内斯还包括一个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。内斯生态系统的生产力是由在复杂的食物网中相互作用的浮游生物提供的，食物网的结构取决于环境条件（例如，温度、光照和营养水平）。由于与气候变化有关的变暖和人类利用，这些条件正在迅速变化。例如，内斯正在见证美国迄今为止最大规模的沿海风电场发展。美国东北部大陆架长期生态研究计划（NES-LTER II）的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的更高营养级生产力的能力。由于内斯面临着影响到许多人的长期挑战，该项目强调积极的教育部分，以帮助培训下一代海洋科学家，并强调开展外联活动，以提高公众对海洋科学和技术的了解。该项目团队通过三个主要组成部分开展教育和推广活动：（1）为LTER研究中的早期职业研究人员（从本科生到博士后研究人员）提供培训和指导;（2）参与初中和高中教师和学生的LTER校园计划;以及（3）通过有针对性的活动、项目网站内斯已经记录了生态系统在四季到几十年内的变化模式，但对物理环境变化、营养食物网和更高营养水平之间的关键机制仍然知之甚少。因此，预测能力有限，管理战略在很大程度上是被动的。为了满足这些需求，内斯II的目标是从机制上了解食物网结构和功能如何对环境条件、自然变异和人类引起的变化作出反应。内斯II结合提供区域尺度的背景下，过程巡航沿着高梯度跨大陆架样带，高频时间序列在大陆架内的位置，耦合生物物理食物网模型，和有针对性的人口模型的意见。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，包括（i）热浪的日益普遍，（ii）与墨西哥湾流不稳定性增加相关的近海水入侵，以及（iii）内斯正在建设的海上风电场。长期研究计划以首要科学问题为指导：“气候变化如何影响远洋内斯生态系统，特别是影响组成（例如，物种多样性和大小结构）和聚集体（例如，初级生产率，以及能量向更高营养级的转移）的变化？”调查人员正在评估内斯生态系统拥有生物多样性储备的程度，该储备对环境的巨大变化具有弹性，并使生态系统能够保持整体生产力。该奖项反映了NSF的法定使命，并通过使用基金会的知识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 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.