Holocene evolution of lakes in the forest-tundra biome of northern Manitoba, Canada

摘要: Abstract The late-Quaternary paleoenvironmental history of the western Hudson Bay region Subarctic Canada is poorly constrained. Here, we present a regional overview post-glacial eight lakes which span forest-tundra biome in northern Manitoba. We show that during penultimate drainage phase Lake Agassiz lake water had an estimated pH ∼6.0, with abundant quillwort (Isoetes spp.) along lakeshore and littoral zone some floating green algae (Botryococcus spp. Pediastrum sp.). Based on multiple sediment proxies, modern ontogeny commenced at ∼7500 cal yrs BP. Pioneering diatom communities were shaped by turbid, higher alkalinity waters influenced base cation weathering surrounding till following drainage. By ∼7000 cal yrs BP, soil development Picea establish began slow trajectory acidification over remaining Holocene epoch. natural this slow, order several millennia for one unit. Each study exhibit relatively stable aquatic Thermal Maximum, suggesting period poor analogue climatic changes. During Neoglacial, beginning post-Little Ice Age represents most significant event to impact N. In context histories, rate floristic change last 200–300 years unprecedented, exception lakes. For nearly entire region, there strong linkage between landscape ecosystems; however relationship appears become decoupled or less post-LIA period. Significant 20th century changes ecosystem cannot be explained wholly terrestrial ecosystem, future Manitoba will strongly direct effects