Paleolimnology and Environmental Change

上个世纪的气温升高以及对未来20-50年气温空前升高的预测，已引起人们对气候变化对水生生态系统潜在影响的关注。我实验室的研究重点是通过分析湖泊沉积物岩心中保存的物理、化学和生物信息，了解湖泊过去是如何对气候和其他自然或人为因素做出反应的。古湖泊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。该提案旨在提供研究和培训机会，以调查过去温暖时期如何影响安大略省北部北方湖泊的水平衡和水生生产，重点关注全新世热极大期（HTM），这是一个大约8000至4000年前的温暖时期。在HTM期间，安大略省西北部以灌木和草地为主的公园型森林为特征，湖泊水位低，火灾频发。然而，从苏望湖到蒂明斯（超过700公里的距离）横跨安大略省北部潮湿地区的湖泊如何应对HTM的信息在很大程度上是未知的。热媒很可能影响了整个地区，因为安大略省北部最东部的地区，Timmins附近，大约7000年前，白松取代了云杉，然后在大约4000年前又回到了云杉森林。我们建议开发和应用方法，使用来自近岸和深水岩心的物理、化学和生物代用物，提供安大略省中部和东部北方地区湖泊水位和产量变化的信息，以及提供全新世植被和火灾变化的信息。鉴于HTM期间估计的温度变化相对于预估的变暖较小，本研究的信息将提供与生活在更温暖的世界中有关的可能的干旱、藻华和火灾的脆弱性评估。

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.