Collaborative Research: Sources and transformations of export production: A novel 50-year record of pelagic-benthic coupling from coral and plankton bioarchives

海洋生物、环境和气候的变化会影响沉入海底的生物物质的时间和组成。随着这种物质下沉，它被深海珊瑚等海底生物消耗。与树木年轮类似，珊瑚保留了骨骼中嵌入的生长历史，可以使用一种名为微观地球化学的新技术进行分析。该项目正在汇编缅因湾50年来深海珊瑚的历史数据集，以了解沉入海底的生物物质如何随着时间的变化而变化。珊瑚分析的结果正在与小型浮游甲壳类和桡足类的档案样本进行比较，以更好地了解地表水生产力与珊瑚组织中的地球化学记录之间的联系。一种补充的建模方法是确定十年尺度海洋学变化的环境和气候驱动因素，以及连接表层和深海的有机物质的来源和转化。这一跨学科项目正在将变革性研究与更广泛的影响统一起来，重点放在科学教育和外联上，利用50年的历史背景扩大对气候、海洋学和海洋生态系统反应之间联系的理解。通过与一位科学纪录片制片人、来自国际扶轮和ME的K-12教师以及PBS学习媒体计划的伙伴关系，正在制定两个开放获取、媒体增强和与国家课程标准一致的教育课程计划。这些课程计划的主题是：1)深海探索：通往过去和未来的窗口，以及2)不断变化的星球上不断变化的食物网。该项目的教育目标包括培训三名研究生，五名早期职业研究人员的职业发展，以及为STEM中代表性不足群体的本科生提供研究经验。这项多方面的研究和教育工作正在解决一个被国家研究理事会描述为海洋科学最优先事项的问题：海洋生物地球化学和物理过程如何与当今的气候变异性及其变异性联系在一起？中上层-底栖生物耦合通过向海洋内陆输出表层产品来调节海洋生产和食物网动态、生物地球化学循环和气候反馈机制。然而，获得出口生产的长期数据集的机会很少，迫切需要检验以下假设：1)有机物质通过不同食物网络路径的来源和转化，以及2)这些过程随时间变化在气候、海洋和生态方面的可变性。拟议的工作是测试关于自下而上机制的关键假设，这些机制将水文地理学和生物地球化学循环中的十年尺度海洋学变化与浮游植物群落组成、浮游动物丰度和营养动态以及由此产生的出口产品构成联系起来。互补的方法正在产生浮游植物群落组成、浮游动物营养动态和出口组成的多个独立的50年以上、每年可分辨的时间序列。珊瑚组织和存档的浮游动物样本正在使用开创性的分子地球化学方法进行分析，以评估初级生产中与饮食相关的变化。深海珊瑚正在使用遥控潜水器(ROV)采集，浮游动物可以通过美国国家海洋和大气局管理的缅因湾长期监测项目的档案样本获得。稳定的同位素数据正在与现有长期海洋监测项目的其他数据相结合，并纳入统一的建模方法，以确定独特的生态系统状态及其环境驱动因素。该项目的重点是缅因湾的约旦盆地，那里有很长的海洋学研究历史，由于气候变暖正在经历重大变化，使其成为一个理想的自然实验室，用于测试关于出口有机物质组成变化的驱动因素的假设，以及初级(例如，植物碎屑)与次生生产(例如，桡足类粪便颗粒)以及大型与小型远洋浮游生物动力学的相对重要性。该奖项反映了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。

Changes in ocean life, the environment, and the climate can influence the timing and composition of biological material that sinks to the sea floor. As this material sinks it is consumed by bottom-dwelling organisms such as deep-sea corals. Similar to tree rings, corals preserve a history of growth embedded in their skeletons, which can be analyzed using a new technique called microgeochemistry. This project is compiling a historic dataset from deep-sea corals spanning 50 years in the Gulf of Maine to understand how biological material sinking to the bottom has changed with time. Results from the coral analysis are being compared with archival samples of small planktonic crustaceans, copepods, to better understand the connection between productivity in the surface waters and the geochemical record in the coral tissue. A complementary modeling approach is identifying environmental and climatic drivers of decadal-scale oceanographic change with the sources and transformations of organic matter that connect the surface and the deep ocean. This cross-disciplinary project is unifying transformational research with broader impacts focused on science education and outreach that broaden the understanding of the links between climate, oceanography, and marine ecosystem response using a 50-year historical context. Two open access, media-enhanced, and National curriculum standards-aligned educational lessons plans are being developed through partnerships with a science documentary filmmaker, K-12 teachers from RI and ME, and the PBS LearningMedia Program. The topics of these lesson plans are: 1) Deep-sea exploration: A window into the past and future, and 2) Changing food webs on a changing planet. The project’s educational goals include training of three graduate students, career development of five early career researchers, and research experiences for undergraduates from underrepresented groups in STEM. The multi-faceted research and education effort is addressing a question described as highest priority in the Ocean Sciences by the National Research Council: How are ocean biogeochemical and physical processes linked to today’s climate variability and its variability? Pelagic-benthic coupling regulates ocean production and food webs dynamics, biogeochemical cycling, and climate feedback mechanisms through the export of surface production to the ocean interior. Yet access to long-term data sets of export production are scarce and urgently needed to test assumptions about 1) the sources and transformations of organic matter through different food web pathways, and 2) the variability of these processes across climatic, oceanographic, and ecological changes through time. The proposed work is testing key hypotheses about bottom-up mechanisms that link decadal-scale oceanographic changes in hydrography and biogeochemical cycling with phytoplankton community composition, zooplankton abundance and trophic dynamics, and the resulting composition of export production. Complementary approaches are generating multiple and independent 50+ year, annually resolved time series of phytoplankton community composition, zooplankton trophic dynamics, and export composition. Coral tissue and archived zooplankton samples are being analyzed using pioneering molecular geochemistry approaches to assess changes in diet related variation in primary production. Deep-sea corals are being collected using a remotely operated vehicle (ROV), and zooplankton are available through archival samples from a Gulf of Maine long-term monitoring program managed by NOAA. The stable isotope data are being integrated with additional data from existing long-standing ocean monitoring programs and incorporated into a unifying modeling approach to identify unique ecosystem states and their environmental drivers. The project is focused on Jordan Basin in the Gulf of Maine, which has a long history of oceanographic study and is experiencing significant changes due to climate warming, making it an ideal natural laboratory for testing hypotheses on drivers of change in the composition of exported organic matter, and the relative importance of primary (e.g., phyto-detritus) vs. secondary production (e.g., copepod fecal pellets), and large vs. small pelagic plankton dynamics.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.