Dinoflagellate cysts and other NPP as paleolimnological proxies

甲藻包囊和其他 NPP 作为古湖泊学指标

• 批准号: DDG-2015-00037
• 负责人: McCarthy, Francine
• 金额: $ 0.73万
• 依托单位: Brock University
• 依托单位国家: 加拿大
• 项目类别: Discovery Development Grant
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=612440
• 关键词: Dinoflagellate; cysts; other; NPP; paleolimnological

Many microscopic fossils survive harsh acid treatments that dissolve mineral sediments; these acid-resistant microfossils (palynomorphs) include the well-known pollen record of sediments that reflects the vegetation in the surrounding region as well as a wide variety of non-pollen palynomorphs (NPP) that include algae, fungi, animal, plant, and even bacterial remains. Because these have a variety of habitats and lifestyles (terrestrial/ aquatic; photosynthesizers/consumers/decomposers, bottom-dwellers/ swimmers and floaters), NPPs in a single sample provide a wealth of information about the entire lake ecosystem and its surrounding watershed. Unfortunately, relatively little is known about these microfossils and how their assemblages relate to the biological communities that produce them. The cysts of dinoflagellates will receive particular attention because we (at Brock) have exceptional expertise in this field. The relationship between the lake plankton and the resistant fossil dinocyst record is especially complicated; they often bear little resemblance to the cellulosic motile thecae. Combining a biological approach involving germination studies and DNA analysis with a micropaleontological (palynological) approach, this study will aid our understanding of the dinoflagellate life cycle and cyst-theca relationships. The NPP record of several dozen lakes from mid-latitudes in eastern North America will be compared with a) the flora and fauna in each lake and its watershed; b) physico-chemical conditions (e.g., temperature, pH, dissolved oxygen, nutrient levels, heavy metal concentrations) in the water column and on the lakebed, and c) other (non-acid-resistant) microfossils in the lakebed sediments. The aim is to illustrate the potential of this taxonomically and ecologically varied group in studies of water quality, particularly in assessing human impact on lake ecosystems, and ultimately to generate equations to quantitatively reconstruct the various environmental parameters that influence palynomorph distribution. Statistical analysis will determine the preferences and tolerances of each species that can then be used to reconstruct long-term changes related to natural factors (e.g., drought) and human activity (e.g., agriculture). Sediment cores also will be collected from a variety of lakes (large/small, urban/ remote, well-mixed/ stratified, well-buffered/ sensitive to acidification) with relatively well-known histories (based on historic records and other paleolimnological indicators), and the modern calibration dataset from surface samples will allow long-term environmental change to be reconstructed. The increase in abundance of ragweed and other weeds allows the identification of human impact, providing added chronological control to identify human-induced changes in water quality, augmenting radiometric ages.

许多微观化石在溶解矿物沉积物的严酷酸处理中幸存下来;这些耐酸性微化石（孢粉形物）包括众所周知的沉积物花粉记录，反映了周围地区的植被以及各种非花粉孢粉形物（NPP），包括藻类、真菌、动物、植物甚至细菌遗骸。由于它们有各种各样的生境和生活方式（陆生/水生;光合作用者/消费者/分解者、底栖/游泳者和漂浮者），单一样本中的NPP提供了关于整个湖泊生态系统及其周围流域的丰富信息。不幸的是，人们对这些微化石以及它们的组合与产生它们的生物群落的关系知之甚少。甲藻的孢囊将受到特别关注，因为我们（在布洛克）在这一领域有特殊的专业知识。湖泊浮游生物与具抵抗力的恐龙化石之间的关系尤其复杂，它们通常与纤维素能动囊几乎没有相似之处。结合生物学方法，包括发芽研究和DNA分析与微体古生物学（孢粉学）的方法，这项研究将有助于我们了解甲藻的生活史和囊泡的关系。北美东部中纬度地区几十个湖泊的净初级生产力记录将与以下方面进行比较：a）每个湖泊及其流域的植物群和动物群; B）物理化学条件（例如，温度、pH值、溶解氧、营养水平、重金属浓度），以及c）湖底沉积物中的其他（非耐酸）微体化石。其目的是为了说明这种分类和生态变化的水质研究，特别是在评估人类对湖泊生态系统的影响，并最终生成方程，以定量重建的各种环境参数，影响palynomorph分布的潜力。统计分析将确定每个物种的偏好和容忍度，然后可以用来重建与自然因素有关的长期变化（例如，干旱）和人类活动（例如，农业）。还将从具有相对知名历史的各种湖泊（大/小、城市/偏远、混合/分层良好、缓冲良好/对酸化敏感）收集沉积物岩心（根据历史记录和其他古湖沼学指标），并利用地表样本的现代校准数据集重建长期环境变化。豚草和其他杂草数量的增加使得能够确定人类的影响，提供额外的时间控制，以确定人类引起的水质变化，增加放射性年龄。