Biogeochemical characteristics of settling particulate organic matter in Lake Superior: A seasonal comparison

摘要: To assess settling particulate organic matter (POM) seasonality and its availability to the benthic community, was studied in terms of mass fluxes main biogeochemical characteristics (including carbon (OC), nitrogen, stable nitrogen isotopic values) at two Lake Superior offshore sites over course a year. Fourier transform infrared spectroscopy (FTIR) hydrolysis, extraction, derivatization were used provide further compositional information. Carbon content, wet chemical data, FTIR spectra show that summer material is mainly autochthonous, with higher proportions amide carbohydrate. shows spring contains relatively high clay minerals, indicating major sources from sediment resuspension and/or runoff. Distinct amino acid distributions sites, revealed by principal component analysis (PCA) based on mol% composition, possibly result differences OM degree degradation occurring sites. Carbohydrate (PCHO), total hydrolyzable (THAA) data suggest nutritional value bulk POM heterotrophs should be lower than summer-fall, although both periods exhibited sinking OC. Due events an oxic water column, eventually buried Superior’s sediments has probably experienced extensive alteration due several cycles through column bacterially-active sediment-water interface.