RAPID: Collaborative Research: Autumn transition in plankton ecology during an ocean heatwave on the Northeast U.S. Shelf

美国东北部的大陆架水域是全球产量最高的海域之一。它们变暖的速度也快于平均水平。虽然气候变化对海洋生物的各种影响已经被记录在案，但机械论的理解滞后。美国东北大陆架长期生态研究(NES-LTER)项目的目标是了解和预测浮游食物网的组成和结构如何随着环境的变化而在空间和时间上发生变化，以及群落的变化如何影响生态系统的生产力，特别是在较高的营养水平。这十年来，东北大陆架水域的热浪越来越普遍，2020年也不例外。该项目将夏季异常温暖的影响纳入NES-LTER概念框架，认识到海洋热浪叠加在长期变暖趋势上。东北大陆架提供一系列生态系统服务，包括食物、能源开采、航运、娱乐和保护；其完整性对美国东北经济的功能至关重要。面对气候变化和其他干扰模式，维持这些生态系统服务将需要有效和高效的管理。这项研究的一个更广泛的影响是，通过增进对生态系统动态和功能的了解，关键知识对该区域的有效管理作出了贡献。六名早期职业科学家的教育机会包括实地和实验室的研究培训。这些职业生涯早期的科学家在这一年参与关键数据的收集，而由于新冠肺炎大流行造成的干扰，新观测的机会极其有限。一个特殊的过程邮轮致力于在2020年夏季海洋热浪之后的秋季过渡期间表征整个东北大陆架的食物网和生产制度。实地观察记录了这种转变的性质，并验证了秋季条件沿着夏季和冬季群落结构、生产力和出口之间的线性连续体的假设。正在进行一套适用于过去夏季和冬季样带的NES-LTER测量，包括正在进行的微微浮游生物和基于气体示踪剂的生产力的连续采样、用于启动浮游生物生长和放牧率孵化实验的离散水样采样、以及用于对较大浮游生物进行遗传多样性采样和对食物网特征进行同位素分析的净拖网。最终，量化和了解季节、年际和十年时间尺度上的可变性是能够预测未来生产力和生态系统状态的。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 continental shelf waters off the Northeast U.S. are some of the most productive on the globe. They are also warming at a faster rate than average. While a variety of climate change impacts on ocean biology have been documented, mechanistic understanding lags behind. The goal of the Northeast U.S. Shelf Long-Term Ecological Research (NES-LTER) project is to understand and predict how the composition and structure of planktonic food webs change through space and time in response to the environment and how changes in the community impact ecosystem productivity, particularly at higher trophic levels. This decade has brought an increased prevalence of heat waves in the waters of the Northeast Shelf, and 2020 was no exception. This project incorporates the effect of an unusual warm temperature summer into the NES-LTER conceptual framework, recognizing that marine heat waves are superimposed on long-term warming trends. The Northeast Shelf provides an array of ecosystem services including food, energy extraction, shipping, recreation, and conservation; its integrity is critical to the function of the Northeast U.S. economy. In the face of climate change and other patterns of disturbance, sustaining these ecosystem services will require effective and efficient management. One broader impact of the study is the contribution of key knowledge for the effective management of the region through improved understanding of ecosystem dynamics and functioning. Educational opportunities for six early career scientists include research training in the field and the laboratory. These early career scientists are involved in critical data collection in a year when opportunities for new observations have been extremely limited due to disruptions caused by the COVID-19 pandemic. A special process cruise is dedicated to characterizing food webs and production regimes across the Northeast Shelf during the autumn transition following the summer 2020 ocean heat wave. Field observations are documenting the nature of the transition and testing the hypothesis that autumn conditions fall along a linear continuum between summer and winter community structure, productivity, and export. The suite of NES-LTER measurements applied to past summer and winter transects are being carried out, including underway continuous sampling for pico- to micro-plankton and gas tracer-based productivity, discrete water sampling to initiate incubation experiments for plankton growth and grazing rates at stations along a cross-shelf transect, and net tows to sample larger plankton for genetic diversity and isotopic analysis for food web characterization. Ultimately, quantifying and understanding variability on seasonal, interannual, and decadal time scales is enabling prediction of future productivity and ecosystem state.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.