Doctoral Dissertation Research: Temporal Variations in Pacific Ocean Dust Fluxes

这个博士论文研究项目调查了亚洲尘埃沉积在太平洋岛屿上的历史，以及气候变化如何影响过去43，000年来的尘埃沉积速率。来自亚洲沙漠的尘埃含有铁和磷，这两种营养物质可以极大地影响北太平洋的生态系统。 沙尘流入受到三个主要过程差异的影响，即空气中的沙尘量、长距离风输送以及通过降雨沉降到海洋或土壤中的沙尘。 尽管有这些重要的联系，亚洲尘埃通量在太平洋岛屿上的时间变化的长期记录还没有报道。 通过分析从夏威夷泥炭沼泽中提取的几个核心中的替代措施，博士生将生成太平洋岛屿上亚洲尘埃通量的原始长期记录。这一记录将有助于更好地探测亚洲尘埃通量-气候-生态系统的相互作用、变化和时间尺度，这些都超出了现代观测的范围。 这一新的记录将通过几个可广泛访问的数据库提供，其他研究人员可在正在进行的模拟尘埃在大气过程中的作用的努力中使用这些数据库。 研究结果还将用于为威斯康星州的少数民族和低收入高中生开展科学丰富活动。一些太平洋岛屿（如夏威夷）土壤中的石英含量丰富，这表明来自东亚沙漠的大陆尘埃不断进入北太平洋。该项目侧重于三个研究目标：1）重建夏威夷石英累积速率的历史; 2）区分古灰尘记录中气候和人类引起的石英通量; 3）将石英通量古记录与独立的气候历史记录进行比较，以推断气候变化对夏威夷灰尘沉积的影响。 代用指标包括亚洲粉尘通量的石英累积率，将亚洲粉尘输送到夏威夷的风的强度的平均石英粒度，有机碳累积，夏威夷古水文学的C/N比和Br含量，以及人为引起的当地粉尘排放强度的平均粒度分布。 通过重建和关联这些代理人，博士生将展示气候变化如何影响亚洲尘埃通量在夏威夷在过去的43,000年。研究结果将有助于正在进行的气候、大气尘埃和偏远生态系统之间联系的建模工作。

This doctoral dissertation research project investigates the history of Asian dust deposition on islands in the Pacific and how variability in climate has impacted rates of dust deposition over the past 43,000 years. Asian dust from deserts contains iron and phosphorous, two nutrients that can greatly influence ecosystems in the North Pacific. Dust influxes have been influenced by differentials in three major processes, the amount of dust in the air, long-distance wind transport, and dust settling via rainfall to the ocean or soils. Despite these important connections, long-term records of temporal variations in Asian dust flux onto islands in the Pacific have not been reported. By analyzing proxy measures available in several cores extracted from peat bogs on Hawai'i, the doctoral student will generate an original long-term record of Asian dust flux on islands in the Pacific. This record will help better detect Asian dust flux-climate-ecosystem interactions, variations, and timescales beyond those available in modern observations. This new record will be made available through several broadly accessible databases which can be used by other investigators in ongoing efforts to model the role of dust in atmospheric processes. The research results will also be used to develop a science enrichment activity for minority and low-income high school students in Wisconsin. The abundance of quartz in the soil of some Pacific islands such as Hawai'i demonstrates continuous addition of continental dust from East Asian deserts to the North Pacific. This project focuses on three research objectives: 1) reconstructing the history of quartz accumulation rates in Hawai'i; 2) distinguishing climate- from human-induced quartz flux in the paleodust records; and 3) comparing the quartz flux paleorecords with independent records of climate history to infer the influence of climate change on dust deposition in Hawai'i. Proxies include quartz accumulation rates for Asian dust flux, mean quartz grain size for the intensity of winds transporting Asian dust to Hawai'i, organic carbon accumulation, C/N ratio and Br content for Hawaiian paleohydrology, and mean grain size distribution for human-induced local dust emission intensity. By reconstructing and correlating these proxies, the doctoral student will demonstrate how climatologic variation has influenced Asian dust flux in Hawai'i over the last 43,000 years. The results will contribute to ongoing efforts to model the linkages among climate, atmospheric dust, and connections among remote ecosystems.