Quantifying the drivers of midwater zooplankton community structure

在200米以下的水中部地区，也被称为黄昏地带，代表了海洋生物和化学的一个主要未知数。由于在深海取样的难度和相关的时间和成本，对海洋中漂流的动物（即浮游动物）的研究很少。自动化图像分析和遗传工具的出现使我们对浅水群落的多样性、丰度和大小分布的了解迅速增加。然而，我们对海洋深层的了解仍处于起步阶段，很少有研究将浮游动物生态学的这三个方面结合起来。这个项目的目的是利用现有的样本，这些样本是以前在北太平洋和北大西洋由美国国家科学基金会资助的研究中获得的，以研究水中浮游动物的丰度、多样性和大小分布如何随纬度和环境因素而变化。自动图像分析提供了丰度和大小的信息，基因分析提供了北大西洋和北太平洋从亚热带到亚北极环境中水群落多样性的前所未有的数据。该项目为至少两名本科研究人员提供了高质量的实践培训机会，并为本科和研究生课程提供了材料。两个讲习班培训教育工作者如何在课堂上使用美国国家科学基金会资助的生物和化学海洋学数据管理办公室（BCO-DMO）的开放获取海洋学数据。利用新的数据工具对浮游动物群落进行图像分析和元条形码的最新进展，为产生环境驱动因素与浮游动物多样性、丰度和大小分布之间的定量和预测关系提供了机会。虽然这些信息可用于上层海洋地区的浮游生物，但本研究的重点是中水群落，其特征仍然很差。获得这些数据是定量分析的第一步，以评估中水群落对生物地球化学循环的影响。该项目使用在北大西洋和北太平洋进行的两次巡航的存档样本来测试关于温度、水中缺氧、初级生产力和生物地理省如何影响浮游动物群落的大小、种类结构、生物多样性和行为（昼夜垂直迁移）的假设。这些新生成的0-1000 m浮游动物群落图像和元条形码数据集与其他海洋区域具有交叉可比性。这些数据描述了洄游和中水浮游动物群落是如何由环境变量构成的，并展示了环境变量如何影响它们的生物地球化学贡献（特别是活跃通量和中水通量衰减）。结合元条形码生成的图像分析数据工具在浮游生物生态学中具有广泛的应用，并允许对其他数据集进行元分析。该项目是对正在进行的旨在描述水中部功能和结构的国家和国际项目的补充。与现有的建模和处理项目相比，该项目覆盖了一个中等大的地理区域，从而为更广泛的社区范围内评估过渡带浮游动物的功能提供了强有力的比较基础。该奖项反映了美国国家科学基金会的法定使命，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。

Processes in the midwater region below 200 m depth, also known as the twilight zone, represent a major unknown for the biology and chemistry of the ocean. Studies of animals drifting in the oceans, known as zooplankton, are scarce due to the difficulty and associated time and costs of sampling deep waters. The advent of automated image analysis and genetic tools is leading to a rapid increase in our knowledge of the diversity, abundances and size distribution of communities in shallow waters. However, our understanding of the deeper layers of the ocean is still in its infancy, and there are few studies that combine these three facets of the ecology of the zooplankton. The objective of this project is to leverage existing samples, obtained from previously NSF-funded research in the North Pacific and North Atlantic, to study how the abundances, diversity, and size distribution of zooplankton in the midwater vary with latitude and environmental factors. Automated image analyses provide information on abundance and size, and genetic analyses give unprecedented data on the diversity of the midwater community for the North Atlantic and the North Pacific, from subtropical to subarctic environments. This project provides high quality hands-on training opportunities for at least two undergraduate researchers and generates material for undergraduate and graduate courses. Two workshops train educators on the classroom use of the NSF-funded Biological and Chemical Oceanography Data Management Office (BCO-DMO) open access oceanographic data.Recent advances in image analysis and metabarcoding of zooplankton communities via new data tools are an opportunity to generate quantitative and predictive relationships between environmental drivers and zooplankton diversity, abundances and size distribution. While this information is available for plankton in epipelagic regions, the focus of this study is on midwater communities, which remain poorly characterized. Obtaining these data is the first step towards a quantitative analysis that assesses the impact of the midwater community on biogeochemical cycles. The project uses archived samples from two cruises conducted in the N. Atlantic and N. Pacific to test hypotheses about how temperature, midwater hypoxia, primary productivity and biogeographic province shape the size class structure, biodiversity and behavior (diurnal vertical migration) of zooplankton communities. These newly-generated image and metabarcoding datasets of the mesozooplankton community from 0-1000 m are cross-comparable with other ocean regions. These data describe how migratory and midwater resident zooplankton communities are structured by environmental variables and demonstrate how this influences their biogeochemical contributions (specifically active flux and midwater attenuation of flux). Data tools generated for the image analysis in combination with metabarcoding has broad application in plankton ecology and allows metanalysis of other datasets. The project is complementary to ongoing national and international projects that seek to describe the function and structure of the midwater. In contrast to existing modeling and process projects, this project covers a moderately large geographic area and thus provides a strong comparative foundation for broader community-wide assessment of the function of zooplankton in the twilight zone.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.