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

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.

在整个北极地区，古湖沼学记录提供了几个关键的档案，记录了全新世以来该地区生态变化的速度。特别是，在过去150年里，硅藻（一种对环境变化迅速作出反应并在湖泊沉积物中留下化石的藻类）群落发生了惊人的变化，通常与温暖条件有关的物种在沉积物记录中以前所未有的速度增加。然而，硅藻组合的变化，从格陵兰岛西部湖泊沉积物中是不同的，在北极的其他地区，因为他们是丰富的这些“温暖”的水硅藻在整个全新世。这种差异提出了关于我们可以使用硅藻来推断北极的问题，并表明需要澄清关键硅藻类群的生态特征，以促进我们对变化驱动因素的理解。在高山地区的最新研究表明，关键硅藻物种，被用作北极和高山湖泊的世纪变暖的指标，特别是对气候引起的能量（混合深度）和质量输入（营养素）的变化湖泊生态系统。这表明，气候引起的湖泊物理和化学结构变化之间的空间和时间可变相互作用可能会驱动硅藻群落的变化，这项研究将把比较湖泊取样与小规模和大规模实验结合起来，以提供关键的生态信息，从而能够解释气候-格陵兰西南部现有的几种硅藻记录引发了生态变化。该项目的目标是确定气候驱动的营养物和水柱稳定性变化对关键硅藻分类群相对丰度的影响，并将该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引起的变化。将对一系列湖泊进行采样，以确定控制关键硅藻物种分布的因素。将进行一个小规模的实验，以评估营养物质和孵化深度对这些关键硅藻物种丰度的重要性。将进行一项大规模实验（全湖操作），以评估热分层对这些硅藻的重要性，这将通过加深夏季通常热分层的湖泊混合层来进行测试。这个大规模的实验将是第一个全湖生态系统测试的重要性，改变能源流入对这些北极湖泊的社区结构。这个项目将提供支持，在气候变化研究所在缅因州大学的博士后研究助理。博士后助理将获得进行北极生态系统研究，指导本科生，并在一个多学科的研究所工作，专注于气候变化的多个方面的宝贵经验。这项研究还将涉及两名本科生在项目的过程中。将与来自四个国家的生态学家一起开发和教授一个分布式研究生研讨会，重点是气候变化和高纬度和高海拔湖泊生态系统。该项目的数据将通过诺阿古气候数据库和网站以及硅藻古湖沼学数据合作网站提供。