Palynology of the Great Lakes: The Surface Sediments of Lake Ontario

Abstract

Pollen was analyzed in the surface 1 cm of sediment taken from 90 sample stations collected in 1968 from a 16 km grid on Lake Ontario. Sixty-nine taxa were identified and the more abundant taxa subjected to trend surface analysis. Pollen concentration in 60 samples ranged up to 240 000 grains per g dry sediment with tho higher concentration in the offshore silt and clay sediments of the basins. Pollen percentages of 80 stations were based on 100 a r more tree pollen with the average percentage values above 5% for tree pollen being Pinus 33.8, Querc~rs 23.6, Betrtla 8.3. Cupressineae 6.3, and Acer saccharum 5.5.The highest valtles of herb pollen were of weedy taxa, and these are Ambrosia 46.1, Gramineae 20.0, and Chenopodimeae 5.8. Throughout the greater part of the lake the percentages were generally uniform and reflect the vegetationof the drainage basin of the lake. Local variations are related to recycling of pollen from older sediments and to local river sources. Comparison of pollen percentages of Lake Ontario with percentages in the surface sediment of nearby small lakes shows that Lake Ontario has a generalized assemblage derived from a broad source region but that Tsuga, Ulmus, and Fagus are relatively underrepresented for poorly understood reasons. The general uniformity of percentages in Lake Ontario suggests that pollen diagrams can be widely correlated within the lake.Une analyse du contenu en pollen, d'un echantillon prkleve dans le centimetre superieur de sediment, a kt6 effectue en 1968 pour 90 stations differentes, reparties selon une grille de reference de 16 km, couvrant le Lac Ontario. Soixante eb neuf taxa furent identifies et les plus abondants soumis a une analyse des tendances (trend surface analysis). Le contenu en pollen de 60 Bchantillons dkpasse les 240 000 grains par g de sediment sec avec des concentrations superieures dans les sediments silteux et argileux des eaux plus profondes des bassins. Les pourcentages en pollen de 80 stations ont kt6 base sur 100 individus et plus de pollen d'arbre avec un pourcentage moyen superieur a 5% pour les especes suivantes: Pinus 33.8, Quercus 23.6, Betula 8.3, Cupressinea 6.3, et Acer Saccharum 5.5.Les pollens des plantes herbacees les plus frequemment rencontrks appartiement aux taxades mauvaises herbes, et donnent comme pourcentage: Ambrosia 46.1, Grarninea 20.0, et Chenopidiinea 4.8. Pour la majeur partie du lac, les pourcentages Btaient generalement uniformes et reretent ainsi la vegktation du bassin de drainage. Des variations locales sont dues au remaniement du pollen appartenant 2 des dtpBts preexistants e t a des sources locales. La comparaison des pourcentages de pollen du Lac Ontario avec les pourcentages des dep8ts de surface de petits lacs demontre que le Lac Ontario a dans l'ensemble un assemblage de pollen derive d'une region source de grande ttendue mais que les Tsuga, Ulmus, et Fagus sont relativement sous-represent& pour des raisons encore inconnues. L'uniformite relative des pourcentages du Lac Ontario suggere que les diagrammes de...

Pollen source areas of lakes with inflowing rivers: modern pollen influx data from Lake Baiyangdian, China

“…Most lakes have inflowing rivers, so waterborne pollen may also make a substantial contribution to the pollen influx to the lake (McAndrews and Power, 1973;Peck, 1973Peck, , 1974Bonny, 1978;Sun and Wu, 1987;Traverse, 1992;Huang et al, 2004;Xu et al, 2005;Brown et al, 2007). In order to attempt quantitative reconstructions of past vegetation and paleoclimate from the sedimentary record in such lakes, it is important to understand the relative importance of the different components of the pollen taphonomy and to characterize the spatial sensitivity of the record, the pollen source area.…”

Monitoring fluvial pollen transport, its relationship to catchment vegetation and implications for palaeoenvironmental studies

“…It is widely accepted that the majority of pollen and spores entering most medium-sized and larger lakes and near-shore marine sediments are fluvially transported from river catchments (Federova, 1952;Peck, 1973;McAndrews and Power, 1973;Crowder and Cuddy, 1973;Pennington, 1979;Bonny, 1980;Brown, 1985;David and Roberts, 1990;Traverse, 1992Traverse, , 1994 and that the ratio of fluvial to airborne (both wet and dry) input depends on the relationship between the size of the catchment, the lake surface area, the topography and the catchment vegetation. In classic studies, Peck (1973Peck ( , 1974 found 97% of the pollen and spore input to Oakdale reservoir was fluvial and Bonny (1978) found 87% of the input to Blelham Tarn was of fluvial origin.…”

Early Holocene drought in the Laurentian Great Lakes basin caused hydrologic closure of Georgian Bay

“…Small lake core sites in the Georgian Bay drainage basin are indicated by triangles and nearby climate stations by circles. The pollen diagram for Edward Lake is in McAndrews and Manville (1987) and that for Axe Lake is in McCarthy et al (2007). The subregions of the Great Lakes-St. Lawrence Forest bordering Georgian Bay and the North Channel are shown, following Rowe (1972): L.1-Huron-Ontario; L.4d-Georgian Bay, and L.10-Algoma.…”