Doctoral Dissertation Research: Resolving Novel Arctic Late Season Phytoplankton Blooms

博士论文研究：解决北极晚季浮游植物大量繁殖的问题

• 批准号: 2210615
• 负责人: Karen Frey
• 金额: $ 6.01万
• 依托单位: Clark University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-07-01 至 2024-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2210615&HistoricalAwards=false
• 关键词: Doctoral; Dissertation; Research; Resolving; Novel

Warming temperatures and decreased sea ice cover in the Pacific and Central Arctic have led to changes in annual growth patterns of marine algae (phytoplankton), most notably permitting novel growth to occur during the fall season. Phytoplankton serve as the foundation of the Arctic marine food web, and disruptions in the timing of growth can be detrimental to current ecosystems. Limitations of satellite remote sensing such as the inability to detect phytoplankton bloom activity throughout the water column, under ice, and in cloudy conditions dictate the need for shipboard based measurements to provide more information on bloom dynamics. This project refines a novel methodology to estimate the growing stage of phytoplankton blooms throughout the water column using satellite imagery as a reference. Estimated summer bloom stages will be used along with atmospheric and oceanic conditions to identify the drivers of fall phytoplankton blooms to better estimate where they might occur. This information will be beneficial for predicting late season biological hotspots for conservation, scientific, and marine subsistence impacts.Repeat cruise measurements will be used to map modeled bloom stages throughout the water column in the summer and fall throughout the Pacific Arctic and northward to the ice edge. This research will also develop two models to (1) identify immediate drivers of observed late bloom growth and (2) identify midsummer preconditioning scenarios for fall blooms and validate model predictions with in situ observations. This research utilizes two NSF-funded cruises: the Distributed Biological Observatory in July 2013–2022 and the Synoptic Arctic Survey in fall 2022. Phytoplankton chlorophyll-a and pheophytin (degraded chlorophyll) concentrations will be collected on the 2022 cruises. NASA MODIS-Aqua satellite chlorophyll-a and in situ pheophytin proportions will be used to develop bloom stage models that distinguish growing versus senescent blooms. The bloom stage model will be applied to measurements collected throughout the water column to extract more information from cruise samples, broaden the context of observations, and understand bloom progression. The fall bloom driver and preconditioning models will be developed using a machine learning regression approach. Variables that will be examined include remotely sensed and modelled datasets of high wind speed events, wind direction, sea ice breakup and freeze-up dates, and in situ measurements of nutrients, temperature, salinity, and stratification.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.

太平洋和中部北极地区的温暖温度和海冰覆盖扩大导致了海洋藻类（Phytoplankton）年生长模式的变化，最值得注意的是，在秋季允许新的生长发生。浮游植物是北极海洋食品网的基础，而增长时间的破坏可能对当前的生态系统有害。卫星遥感的局限性，例如无法检测整个水柱，冰下的浮游植物盛开活动，在阴云状态下，需要基于船上的测量值来提供有关Bloom Dynamics的更多信息。该项目完善了一种新的方法，以使用卫星图像作为参考来估计整个水柱中浮游植物血液的增长阶段。估计的夏季盛开阶段将与大气和海洋条件一起使用，以识别秋天的浮游植物血液的驱动因素，以更好地估计可能发生的地方。信息将有益于预测季节后期的生物热点，以进行保护，科学和海洋生存影响。重建巡航测量结果将用于在夏季的整个水柱上绘制建模的盛开阶段，并落在整个太平洋北极地区，并在整个太平洋北极地区，向北到冰块。这项研究还将开发两个模型，以（1）确定观察到的晚鲜花生长的直接驱动因素，（2）确定仲夏预处理场景的秋季盛开，并通过原位观测来验证模型预测。 This research utilizes two NSF-funded cruises: the Distributed Biological Observatory in July 2013–2022 and the Synoptic Arctic Survey in fall 2022. Phytoplankton chlorophyll-a and pheophyll (degraded chlorophyll) concentrations will be collected on the 2022 cruises. NASA MODIS-AQUA卫星叶绿素-A和原位嗜植物比例将用于开发开花阶段模型，以区分增长与感觉盛开。 Bloom阶段模型将应用于在整个水柱中收集的测量，以从巡航样品中提取更多信息，扩大观测环境并了解Bloom的进展。将使用机器学习回归方法开发秋季绽放驱动程序和预处理模型。 Variables that will be examined include remotely sensed and modeled datasets of high wind speed events, Wind direction, sea ice breakup and freeze-up dates, and in situ measurements of nutrients, temperature, salinity, and stratification.This award reflects NSF's statutory mission and has been deemed precious of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.