A 1000‐year record of dry conditions in the eastern Canadian prairies reconstructed from oxygen and carbon isotope measurements on Lake Winnipeg sediment organics

Abstract

A short sediment core (162 cm), covering the period AD 920-1999, was sampled from the south basin of Lake Winnipeg for a suite of multi-proxy analyses leading towards a detailed characterisation of the recent millennial lake environment and hydroclimate of southern Manitoba, Canada. Information on the frequency and duration of major dry periods in southern Manitoba, in light of the changes that are likely to occur as a result of an increasingly warming atmosphere, is of specific interest in this study. Intervals of relatively enriched lake sediment cellulose oxygen isotope values (d 18 O cellulose ) were found to occur from AD 1180 to 1230 (error range: AD

An isotopic baseline (δ13C, δ15N) for fishes of Lake Winnipeg: Implications for investigating impacts of eutrophication and invasive species

“…Faster algal growth rates, in turn stimulated by increases in temperature or nutrient availability, typically result in increases in algal δ 13 C values (Calder and Parker, 1973;Schindler et al, 1997;Tamelander et al, 2009). It is worth noting that food web isotopic changes in response to eutrophication in Lake Winnipeg may have already occurred; hence, the results of paleolimnological sediment core isotopic analyses will be invaluable in this context (Buhay et al, 2009). Using our food web isotopic baseline, a possible means of detecting future departures due to eutrophication would be to routinely monitor the carbon and nitrogen isotopic composition of a common species like lake cisco from the same locations over time.…”

Placing the Common Era in a Holocene context: millennial to centennial patterns and trends in the hydroclimate of North America over the past 2000 years

“…Where spatial outliers existed separate from the main cluster of data within a region (e.g., data from Florida vs. the northeastern US; northern vs. southern Great Plains), we split our initial regions to ensure suitable representation of the data in our analysis. We used these designations to ask whether distinct trends were recognizable among commonly recognized regions and whether any trends have parallels to patterns of climate variation observed on finer timescales, such as north-south antiphased moisture variability along the western margin of North America (Cayan, 1996;Wise and Dannenberg, 2014). To facilitate comparison of centennial and longer trends, we calculated mean values for each record per century.…”

Expanded spatial extent of the Medieval Climate Anomaly revealed in lake‐sediment records across the boreal region in northwest Ontario

“…In Minnesota, sand deposits in Mina Lake indicate large declines in lake level during the 1300s (St. Jacques et al, 2008), high eolian deposition occurred from~1280 to 1410 CE in Elk Lake (Dean, 1997) and d 18 O from calcite indicated an arid period from~1100 to 1400 CE in Steel Lake (Tian et al, 2006). In Manitoba, the cellulose d 18 O record from the southern basin of Lake Winnipeg indicated severe dry conditions between 1180 and 1230 CE, and a less-severe dry period from 1320 to 1340 CE (Buhay et al, 2009). Relative warm conditions during the MCA in comparison to the Little Ice Age (LIA) have been inferred from pollen records in the central boreal region of Canada and in Wisconsin (Viau & Gajewski, 2009;Viau et al, 2012;Wahl et al, 2012).…”