Paleolimnology and Environmental Change

上个世纪气温变暖，以及预计未来20-50年气温将出现前所未有的上升，导致人们对气候变化对水生生态系统的潜在影响感到担忧。我实验室的研究重点是通过分析保存在湖泊沉积物岩芯中的物理、化学和生物信息，了解湖泊过去对气候和其他自然或人为因素的反应。古湖沼学研究可以为水生和陆地生态系统对气候变化的敏感性提供重要的见解。这项提议旨在提供研究和培训机会，以调查过去较温暖的时期如何影响安大略省北部北方湖泊的水平衡和水生生物产量，重点是全新世最高温度(HTM)，这是大约8,000到4,000年前的较温暖时期。在HTM期间，安大略省西北部的特点是公园类型的森林，有灌木丛和草，湖面低，火灾频繁。然而，关于湖泊如何对HTM做出反应的信息，从苏瞭望到蒂明斯(距离超过700公里)，横跨安大略省北部潮湿地区的信息基本上是未知的。很可能是HTM影响了整个地区，因为在安大略省北部最东端的蒂明斯附近，7000年前白松取代了云杉，大约4000年前又回到了云杉林。我们建议开发和应用从近岸和深水岩心使用物理、化学和生物指标的方法，以提供关于安大略省中部和东部北部地区湖泊水位和产量变化的信息，并提供关于全新世植被和火灾变化的信息。考虑到HTM期间的估计温度变化与预计的变暖相比很小，这项研究的信息将提供对与生活在更温暖的世界中相关的可能的干旱、藻类水华和火灾的脆弱性的评估。

Warmer temperatures over the last century and projections of unprecedented increases in temperature over the next 20-50 years, has led to concern on the potential impacts of climate change on aquatic ecosystems. Research in my lab focuses on understanding how lakes have responded to climate and other natural or human-induced factors in the past, by the analysis of the physical, chemical and biological information preserved in lake sediment cores. Paleolimnological studies can provide important insights on the sensitivity of aquatic and terrestrial ecosystems to climate change. This proposal seeks to provide research and training opportunities to investigate how warmer periods in the past influenced the water balance and aquatic production of boreal lakes from northern Ontario, with a focus on the Holocene Thermal Maximum (HTM), a warmer period circa 8,000 to 4,000 years ago. During the HTM, northwest Ontario was characterized by a parkland-type forest with scrubs and grasses, low lake-levels, and frequent fires. However, information on how lakes responded to the HTM, across the humid regions of northern Ontario from Sioux Lookout to Timmins (a distance of over 700 km) are largely unknown. It is likely that the HTM influenced this entire region, since the easternmost region of northern Ontario, near Timmins, saw white pine replacing spruce c. 7,000 years ago, before returning to a spruce forest circa 4,000 years ago. We propose to develop and apply approaches, using physical, chemical and biological proxies, from both near-shore and deep-water cores, to provide information on how lake levels and production changed across the central and eastern boreal regions of Ontario, as well as provide information on changes in vegetation and fire over the Holocene. Given that the estimated temperature changes during the HTM were small relative to the projected warming, information from this study will provide an assessment of vulnerability to possible droughts, algal blooms, and fires associated with living in a warmer world.