Abstract:

An 85cm long sediment sequence from Mochou Lake on Mirror Peninsula in the Larsemann Hills, East Antarctica, was investigated for elemental geochemistry, biogeochemistry and strontium isotopic compositions in the acid-insoluble and acid-soluble fractions. The geochemical characters of the elements in the bulk sediments and the ~~ ~87 Sr /~~ ~86 Sr ratios in the acid-soluble fractions suggest that the lake is strongly affected by historical sea bird activities in the catchment area. The depth distributions of amino acids in the sediments show that the sedimentary organic matter is not influenced by post-depositional diagenetic processes, and their concentrations mainly reflect the historical variation in the primary biogenic production produced in the lake. The ~~ ~87 Sr /~~ ~86 Sr ratios in the acid-soluble fraction of the sediments are found to be negative correlation with the concentrations of total amino acid, indicating the enormous role of historical seabirds on nutrient supply into the Mochou Lake. The present results provide a foundation for further studies at a large temporal scale on the reconstruction of lacustrine palaeoecology and the records of palaeoclimate and historical sea bird occupation in the catchment area of the lake.