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

*单一“花粉玻片”中的非花粉孢粉形态(NPP)提供了关于整个湖泊生态系统和周围流域的信息。尽管藻类孢粉普遍存在，但即使在缺乏矿化微化石的沉积物中，藻类孢粉也通常被花粉分析员忽略或顺便提及。我和我的学生将结合植物学/湖沼学和孢粉学/古湖沼学的方法，通过研究：*1)利用发芽研究和rDNA测序，与厦门Hu合作，研究藻类孢粉的分类，以促进它们作为古湖泊学指标的使用。这些发现将被应用于与Aw的同事合作研究淡水藻类的进化，以及我们的古湖泊研究。2)对藻类孢粉的环境控制，将湖床组合与测量的环境变量联系起来。拟议研究的一个关键方面是将校准数据集从安大略省西北部实验湖地区的30个湖泊扩展到北美东部的其他地区；这将调查气候和地质对孢粉记录的意义，目的是开发区域转移函数，以便能够定量重建水质。在与伦斯勒理工学院(RPI)的合作者进行的一项多代理调查中，还将进行盆地内研究，以评估整个乔治湖的变异性。*3)扭曲孢粉记录相对于生理学记录的挖掘因素，将湖床样本与沉积物陷阱和浮游生物拖曳组合在一年中的不同时间进行比较，这些湖泊在大小、深度、地质、水文、人类对湖泊和分水岭的影响等方面存在差异。博士生A Krueger继续进行季节性采样(包括最近在大型、连续监测地点部署的陷阱)。少-中营养乔治湖)将使我们能够将湖床沉积物与多年浮游植物生产力和测量的湖湖学参数联系起来。与研究浮游动物和其他浮游植物群体的研究人员合作，将提供对捕食和竞争对藻类种群的“自上而下”影响的洞察。这些发现将被应用于岩心和露头研究，以重建与较暖(最后一次间冰期)和较干燥(8.2千克事件)气候以及人类影响有关的湖沼变化。这将使我们能够评估预计的气候变化和人口增长对大湖区水质和水量的影响。更好地理解NPP的空间分布和割草学也将被用于研究富含有机物质的湖泊中的异常沉积事件，使我们能够评估NPP作为突发性自然灾害的替代物的使用。这将对古地震学和古温学研究有潜在的应用。

***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.********