Deciphering the ecology of key diatom taxa to understand climate-induced changes in West Greenland lakes

破译关键硅藻类群的生态，以了解气候引起的西格陵兰湖泊变化

• 批准号: 1203434
• 负责人: Jasmine Saros
• 金额: $ 35.4万
• 依托单位: University of Maine
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1203434&HistoricalAwards=false
• 关键词: Deciphering; ecology; key; diatom; taxa; Deciphering; ecology; key; diatom; taxa

Across the Arctic, paleolimnological records provide some of the few key archives documenting rates of ecological change in this region over the Holocene. In particular, striking changes in communities of diatoms (a type of algae that responds rapidly to environmental change and leaves a fossil in lake sediments) have occurred over the last 150 years, with species generally associated with warmer conditions increasing at unprecedented rates in the sediment record. However, changes in diatom assemblages in lake sediments from west Greenland are different from those in the rest of the Arctic in that they are rich in these 'warmer' water diatoms throughout the Holocene. This difference has raised questions about what we can use diatoms to infer in the Arctic, and suggests the need to clarify the ecological traits of key diatom taxa in order to advance our understanding of drivers of change. Recent research in alpine regions reveals that key diatom species that are used as indicators of 20th century warming in both arctic and alpine lakes respond specifically to both climate-induced changes in energy (mixing depths) and mass inputs (nutrients) to lake ecosystems. This suggests that spatially- and temporally-variable interactions between climate-induced changes in the physical and chemical structure of lakes may drive diatom community changes, but this is currently untested in arctic lakes.This research will couple comparative lake sampling with both small- and large-scale experiments to provide key ecological information that will enable interpretation of climate- induced ecological changes from several existing diatom records from southwest Greenland. The objective of this project is to determine the effects of climate-driven changes in nutrients and water column stability on the relative abundances of key diatom taxa, and to apply that information to existing diatom records to determine climate-induced changes in these lake ecosystems. A suite of lakes will be sampled to determine the factors controlling the distributions of key diatom species. A small-scale experiment will be conducted to assess the importance of nutrients and incubation depth on the abundances of these key diatom species. A large-scale experiment (whole lake manipulation) will be conducted to assess the importance of thermal stratification on these diatoms, which will be tested by deepening the mixed layer of a lake that typically stratifies thermallyduring the summer. This large-scale experiment will be the first whole-lake ecosystem test of the importance of changing energy influx on the community structure of these arctic lakes.This project will provide support for a postdoctoral research associate at the Climate Change Institute at the University of Maine. The postdoctoral associate will gain valuable experience conducting arctic ecosystems research, mentoring undergraduate students, and working in a multidisciplinary institute focused on multiple aspects of climate change. This research will also involve two undergraduates over the course of the project. A distributed graduate seminar focused on climate change and high latitude and altitude lake ecosystems will be developed and taught in conjunction with ecologists from four countries. Data from this project will be made available through the NOAA paleoclimate database and website, and the Diatom Paleolimnology Data Cooperative website.

在整个北极，古学记录提供了一些关键档案中的一些档案，记录了整个全新世的生态变化率。特别是，在过去的150年中，发生了硅藻群落的惊人变化（一种对环境变化迅速响应并在湖泊沉积物中留下的化石的藻类的变化），物种通常与较高的条件在沉积物记录中前所未有的速率上增加。然而，西绿地湖沉积物中的硅藻组合的变化与北极其他地区的硅藻含量不同，因为它们富含整个全新世的“温暖”水硅藻。这种差异提出了有关我们可以在北极推断的硅藻的问题，并提出需要阐明关键硅藻分类群的生态特征，以便促进我们对变革驱动因素的理解。高山区域的最新研究表明，在北极和高山湖泊中用作20世纪变暖指标的关键硅藻物种对气候引起的能量变化（混合深度）和质量输入（营养）（营养）和生态系统的质量变化有何反应。这表明，在气候引起的湖泊物理和化学结构变化之间存在空间和时间变化的相互作用可能会导致硅藻社区的变化，但目前在北极湖泊中未经测试。这项研究将对比较的湖泊采样来与小规模的实验相比，以提供对绿色的绿色植入式的重要信息，从而启用了几个现有的态度的生态学变化。该项目的目的是确定养分和水柱稳定性的气候变化对关键硅藻分类群相对丰度的影响，并将这些信息应用于现有的硅藻记录，以确定这些湖泊生态系统中气候诱导的变化。将采样一套湖泊，以确定控制关键硅藻分布的因素。将进行一个小规模的实验，以评估养分的重要性和对这些关键硅藻物种丰富性的孵化深度。将进行一个大规模的实验（全湖操纵），以评估热分层对这些硅藻的重要性，这将通过加深湖泊的混合层来测试，该湖泊通常会分层整个夏季的热塑化。这个大规模的实验将是第一个全湖生态系统测试，即能源涌入对这些北极湖的社区结构的重要性。该项目将为缅因州气候变化研究所的博士后研究助理提供支持。博士后助理将获得有价值的经验，从事北极生态系统研究，指导本科生，并在一家专注于气候变化的多个方面的多学科研究所工作。这项研究还将在整个项目过程中涉及两个大学生。将开发并与来自四个国家的生态学家共同开发和教授，该研讨会的分布式研究生研讨会将开发和教授高纬度和高度湖泊生态系统。该项目的数据将通过NOAA古气候数据库和网站以及Diotom古学数据合作网站提供。