Distributions of branched GDGTs in soils and lake sediments from western Uganda: Implications for a lacustrine paleothermometer

Publication year: 2011
Source: Organic Geochemistry, In Press, Accepted Manuscript, Available online 13 June 2011

Shannon E., Loomis , James M., Russell , Jaap S., Sinninghe Damsté

Bacterially produced branched glycerol dialkyl glycerol tetraethers (GDGTs) are ubiquitous in soils and lake sediments and can potentially be used to reconstruct past temperatures. In lakes, however, it is still unclear if these compounds are derived from eroded soils or if they are produced in situ. To better understand environmental controls on the distributions of these compounds and the sources of branched GDGTs to lake sediments, we compare branched GDGT distributions and concentrations in lake sediments and catchment soils within a 3600 meter altitudinal transect in western Uganda. Reconstructed mean annual air temperature (MAAT), determined from the degree of methylation…

 Highlights: ► We examine branched GDGTs in soils along an altitudinal transect in Uganda ► We compare GDGT concentrations/distributions in soils and adjacent lake sediments ► Branched GDGTs differ greatly between soils and lakes in dry environments ► Branched GDGTs in soils and lakes are similar when soils are water saturated ► Water saturation may help determine concentrations/distributions of branched GDGTs