The fossil record of freshwater dinoflagellates and green algae in paleoenvironmental studies

古环境研究中淡水甲藻和绿藻的化石记录

• 批准号: RGPIN-2018-03924
• 负责人: McCarthy, Francine
• 金额: $ 1.82万
• 依托单位: Brock University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=711526
• 关键词: fossil; record; freshwater; dinoflagellates; green

Non-pollen palynomorphs (NPP) in a single “pollen slide” provide information about the entire lake ecosystem and surrounding watershed. Despite their common presence, even in sediments that lack mineralized microfossils, algal palynomorphs are typically ignored or mentioned in passing by pollen analysts. My students and I will combine phycological/ limnological and palynological/ paleolimnological approaches to promote their use as paleolimnological proxies by studying: 1) the taxonomy of algal palynomorphs, using germination studies and rDNA sequencing, in collaboration with H Gu (Xiamen). These findings will be applied to studies of the evolution of freshwater algae in collaboration with various colleagues aw well as to our paleolimnological studies. 2) the environmental control on algal palynomorphs, relating lakebed assemblages to measured environmental variables. A key aspect of the proposed research is to expand the calibration dataset beyond the 30 lakes in the Experimental Lakes Area of NW Ontario to other parts of eastern North America; this will investigate the significance of climate and geology on the palynological record, with the aim of developing regional transfer functions to allow quantitative reconstruction of water quality. Intrabasinal studies will also be conducted to assess variability across Lake George NY, in a multiproxy investigation with collaborators from Rensselaer Polytechnic (RPI). 3) the taphonomic factors that skew the palynological record relative to the phycological record, comparing lakebed samples with sediment trap and plankton tow assemblages at different times of year in lakes that vary in size, depth, geology, hydrology, human impact on the lake and watershed, etc. Continued seasonal sampling by PhD student A Krueger (including traps recently deployed at continuous-monitoring sites in the large, oligo-mesotrophic Lake George) will allow us to relate lakebed sediments to phytoplankton productivity over multiple years and to measured limnological parameters. Collaboration with researchers studying zooplankton and other phytoplankton groups will provide insights into the “top-down” effects of predation and competition on algal populations. These findings will then be applied to downcore and outcrop studies to reconstruct limnological changes associated with both warmer (last interglacial) and drier (8.2 k event) climates and with human impact. This will allow us to assess the impact of projected climate change and population growth on water quality and quantity in the Great Lakes region. Improved understanding of the spatial distribution of NPP and taphonomy will also be applied to studying unusual sedimentation events in organic-rich lakes, allowing us to assess the use of NPP as proxies of sudden-impact natural hazards. This will have potential applications for paleoseismological and paleotempestological studies.

在一个单一的“花粉幻灯片”的非花粉palynomorphs（NPP）提供有关整个湖泊生态系统和周围流域的信息。尽管它们普遍存在，即使在缺乏矿化微体化石的沉积物中，藻类孢粉通常被花粉分析师忽略或提及。我和我的学生将结合联合收割机藻类学/湖沼学和孢粉学/古湖沼学的方法，通过研究促进它们作为古湖沼学代理的使用： 1)利用萌发研究和rDNA序列分析对藻类孢粉形态进行分类。 这些发现将应用于淡水藻类演化的研究，与不同的同事aw合作，以及我们的古湖沼学研究。 2)环境对藻类孢粉的控制作用，将湖底组合与测量的环境变量联系起来。 拟议的研究的一个关键方面是扩大校准数据集以外的30个湖泊在西北安大略的实验湖区到北美东部的其他地区，这将调查气候和地质的意义上的孢粉记录，目的是开发区域转移功能，使水质的定量重建。还将与伦斯勒理工学院（RPI）的合作者进行流域内研究，以评估纽约州乔治湖的变异性。 3)使孢粉学记录相对于藻类学记录倾斜的埋藏学因素，在大小、深度、地质、水文、人类对湖泊和流域的影响等方面各不相同的湖泊中，比较一年中不同时间的湖底样品与沉积物陷阱和浮游生物拖曳组合。（包括陷阱最近部署在大型，寡-中营养乔治湖连续监测站点）将使我们能够与湖底沉积物浮游植物生产力多年来，并测量湖沼参数。与研究浮游动物和其他浮游植物群体的研究人员合作，将深入了解捕食和竞争对藻类种群的“自上而下”影响。 这些研究结果将被应用到地下岩芯和露头研究，以重建与温暖（末次间冰期）和干燥（8.2 K事件）气候和人类影响相关的湖沼变化。 这将使我们能够评估预计的气候变化和人口增长对五大湖地区水质和水量的影响。NPP和埋藏学的空间分布的更好的理解也将适用于研究异常沉积事件在有机丰富的湖泊，使我们能够评估使用NPP作为代理的突然影响的自然灾害。 这对古地震学和古地震学研究具有潜在的应用价值。